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Mousavi, V., M. Khosravi, M. Ahmadi, N. Noori, A. Hosseini Naveh, and M. Varshosaz. "THE PERFORMANCE EVALUATION OF MULTI-IMAGE 3D RECONSTRUCTION SOFTWARE WITH DIFFERENT SENSORS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-1-W5 (December 11, 2015): 515–19. http://dx.doi.org/10.5194/isprsarchives-xl-1-w5-515-2015.
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Today, multi-image 3D reconstruction is an active research field and generating three dimensional model of the objects is one the most discussed issues in Photogrammetry and Computer Vision that can be accomplished using range-based or image-based methods. Very accurate and dense point clouds generated by range-based methods such as structured light systems and laser scanners has introduced them as reliable tools in the industry. Image-based 3D digitization methodologies offer the option of reconstructing an object by a set of unordered images that depict it from different viewpoints. As their hardware requirements are narrowed down to a digital camera and a computer system, they compose an attractive 3D digitization approach, consequently, although range-based methods are generally very accurate, image-based methods are low-cost and can be easily used by non-professional users. One of the factors affecting the accuracy of the obtained model in image-based methods is the software and algorithm used to generate three dimensional model. These algorithms are provided in the form of commercial software, open source and web-based services. Another important factor in the accuracy of the obtained model is the type of sensor used. Due to availability of mobile sensors to the public, popularity of professional sensors and the advent of stereo sensors, a comparison of these three sensors plays an effective role in evaluating and finding the optimized method to generate three-dimensional models. Lots of research has been accomplished to identify a suitable software and algorithm to achieve an accurate and complete model, however little attention is paid to the type of sensors used and its effects on the quality of the final model. The purpose of this paper is deliberation and the introduction of an appropriate combination of a sensor and software to provide a complete model with the highest accuracy. To do this, different software, used in previous studies, were compared and the most popular ones in each category were selected (Arc 3D, Visual SfM, Sure, Agisoft). Also four small objects with distinct geometric properties and especial complexities were chosen and their accurate models as reliable true data was created using ATOS Compact Scan 2M 3D scanner. Images were taken using Fujifilm Real 3D stereo camera, Apple iPhone 5 and Nikon D3200 professional camera and three dimensional models of the objects were obtained using each of the software. Finally, a comprehensive comparison between the detailed reviews of the results on the data set showed that the best combination of software and sensors for generating three-dimensional models is directly related to the object shape as well as the expected accuracy of the final model. Generally better quantitative and qualitative results were obtained by using the Nikon D3200 professional camera, while Fujifilm Real 3D stereo camera and Apple iPhone 5 were the second and third respectively in this comparison. On the other hand, three software of Visual SfM, Sure and Agisoft had a hard competition to achieve the most accurate and complete model of the objects and the best software was different according to the geometric properties of the object.
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Mizginov, V. A., and V. V. Kniaz. "EVALUATING THE ACCURACY OF 3D OBJECT RECONSTRUCTION FROM THERMAL IMAGES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W18 (November 29, 2019): 129–34. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w18-129-2019.
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Abstract. Thermal cameras are increasingly used in many photogrammetric and computer vision tasks. Nowadays it is possible to detect and recognize objects in infrared images, to solve such tasks as pedestrian detection (Huckridge et al., 2016), security applications, and autonomous driving (Wenbin, Li et al., 2017). Nevertheless, some tasks that are easily solved in the visible range data are still challenging to achieve in the infrared range. Reconstruction of a 3D object model from infrared images is challenging due to the low contrast of the original infrared image, noise of the sensor, and the absence of feature points on the image. Nevertheless, thermal cameras have their advantages, which make them popular for solving practical problems. Firstly, thermal cameras can be used in degraded environments (smoke, fog, precipitation, low light conditions). Secondly, infrared images can be fused with color images (Gao et al., 2013) to increases the system’s performance.This paper is focused on the evaluation of accuracy of 3D object reconstruction from thermal images. The evaluation of the accuracy is threefold. Firstly, we train four stereo matching methods (CAE, LF-Net, SURF, and SIFT) on the MVSIR dataset (Knyaz et al., 2017) and our new ThermalPatches dataset. We used two RTX 2080 Ti GPUs and the PyTorch library for the training. Secondly, we evaluate the matching score for the selected methods. Finally, we perform 3D object reconstruction using the SfM (Remondino et al., 2014) approach and matches for each method. We compare the object space accuracy of the resulting surfaces to the ground-truth 3D models generated with a structured light 3D scanner.
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Okawa, Marina, Takafumi Taketomi, Goshiro Yamamoto, Makoto Fujisawa, Toshiyuki Amano, Jun Miyazaki, and Hirokazu Kato. "A model-based tracking framework for textureless 3D rigid curved objects." Journal on Interactive Systems 3, no. 2 (January 23, 2013): 1. http://dx.doi.org/10.5753/jis.2012.611.
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This paper addresses the problem of tracking texturelessrigid curved objects. A common approach uses polygonalmeshes to represent curved objects inside an edge-based trackingsystem. However, in order to accurately recover their shape,high quality meshes are required, creating a trade-off betweencomputational efficiency and tracking accuracy. To solve thisissue, we suggest the use of quadrics calculated for each patchin the mesh to give local approximations of the object contour.This representation reduces considerably the level of detail of thepolygonal mesh while maintaining tracking accuracy. The noveltyof our research lies in using curves to represent the quadrics’projection in the current viewpoint for distance evaluation insteadof comparing directly the edges from the mesh and detectededges in the video image. In our tracking framework, we alsoinclude a method to calculate the measurable Degrees of Freedom(DoF) of the target object. This is used to recover the poseparameters when the object has less than 6DoF. Experimentalresults compare our approach to the traditional method ofusing sparse and dense meshes. Finally, we present a potentialAugmented Reality application of the proposed method.
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Gong, Yiping, Fan Zhang, Xiangyang Jia, Xianfeng Huang, Deren Li, and Zhu Mao. "Deep Neural Networks for Quantitative Damage Evaluation of Building Losses Using Aerial Oblique Images: Case Study on the Great Wall (China)." Remote Sensing 13, no. 7 (March 30, 2021): 1321. http://dx.doi.org/10.3390/rs13071321.
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Automated damage evaluation is of great importance in the maintenance and preservation of heritage structures. Damage investigation of large cultural buildings is time-consuming and labor-intensive, meaning that many buildings are not repaired in a timely manner. Additionally, some buildings in harsh environments are impossible to reach, increasing the difficulty of damage investigation. Oblique images facilitate damage detection in large buildings, yet quantitative damage information, such as area or volume, is difficult to generate. In this paper, we propose a method for quantitative damage evaluation of large heritage buildings in wild areas with repetitive structures based on drone images. Unlike existing methods that focus on building surfaces, we study the damage of building components and extract hidden linear symmetry information, which is useful for localizing missing parts in architectural restoration. First, we reconstruct a 3D mesh model based on the photogrammetric method using high-resolution oblique images captured by drone. Second, we extract 3D objects by applying advanced deep learning methods to the images and projecting the 2D object segmentation results to 3D mesh models. For accurate 2D object extraction, we propose an edge-enhanced method to improve the segmentation accuracy of object edges. 3D object fragments from multiple views are integrated to build complete individual objects according to the geometric features. Third, the damage condition of objects is estimated in 3D space by calculating the volume reduction. To obtain the damage condition of an entire building, we define the damage degree in three levels: no or slight damage, moderate damage and severe damage, and then collect statistics on the number of damaged objects at each level. Finally, through an analysis of the building structure, we extract the linear symmetry surface from the remaining damaged objects and use the symmetry surface to localize the positions of missing objects. This procedure was tested and validated in a case study (the Jiankou Great Wall in China). The experimental results show that in terms of segmentation accuracy, our method obtains results of 93.23% mAP and 84.21% mIoU on oblique images and 72.45% mIoU on the 3D mesh model. Moreover, the proposed method shows effectiveness in performing damage assessment of objects and missing part localization.
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Yilmazturk, Ferruh, and Ali Ersin Gurbak. "Geometric Evaluation of Mobile-Phone Camera Images for 3D Information." International Journal of Optics 2019 (September 30, 2019): 1–10. http://dx.doi.org/10.1155/2019/8561380.
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This study aimed to investigate the usability of smartphone camera images in 3D positioning applications with photogrammetric techniques. These investigations were performed in two stages. In the first stage, the cameras of five smartphones and a digital compact camera were calibrated using a calibration reference object, with signalized points having known three-dimensional (3D) coordinates. In the calibration process, the self-calibration bundle adjustment method was used. To evaluate the metric performances, the geometric accuracy tests in the image and object spaces were performed and the test results were compared. In the second stage, a 3D mesh model of a historical cylindrical structure (height = 8 m and diameter = 5 m) was generated using Structure-from-Motion and Multi-View-Stereo (SfM-MVS) approach. The images were captured using the Galaxy S4 smartphone camera, which produced the best result in the geometric accuracy tests for smartphone cameras. The accuracy tests on the generated 3D model were also applied in order to examine 3D object reconstruction capabilities of imaging with this device. The results demonstrated that smartphone cameras can be easily used as image acquisition tools for multiple photogrammetric applications.
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Grinyak, V. M. "Configuration of 3D Indoor Positioning System Based on Bluetooth Beacons." INFORMACIONNYE TEHNOLOGII 27, no. 1 (January 20, 2021): 32–40. http://dx.doi.org/10.17587/it.27.32-40.
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This paper devoted to research of indoors navigation problems under poor or insufficient quality of satellite navigational data environment. The problem of object positioning in 3D space by Bluetooth devices located indoors forming a multi-position tracking system is considered in this research. Emphasized that in order to succeed for such system it is required to pre-estimate distinctive accuracy. The proposed model interpretation of the positioning problem as the system of linear equations. The classic model interpretation for method of least squares is used for resolution. General problem of linearization around reference resolution is the locality of its features. There are three concepts of problems solvability, such as fundamental solvability (observability), solvability in conditions of instrumental measurement errors and solvability under conditions of finite accuracy of computation on a computer. The first aspect of solvability is interpreted by the completeness of the rank of the corresponding system of linear algebraic equations, the second and third ones represents by the conditionality of the problem and the convergence of the iterative estimation procedure. The conducted experiments show that for the positioning problem the attributes of the linearized model are accurate enough to represent the original nonlinear problem. Such interpretation allows to build theoretical accuracy estimation priors for object coordinates evaluations and to identify the areas with insufficient positioning accuracy. In this paper there are results of expected accuracy evaluation for various system patterns with full-scale experiments proving the theoretical calculations. Experiments for problems with using SKYLAB Beacon VG01 Bluetooth transmitters and smartphone HUAWEI WAS-LX1 are presented and confirmed that math model with linear approximation defined by authors is usable for solving indoors navigation problems using Bluetooth signal. So, for good enough quantity and appropriate location of the tracks the achievable positioning accuracy could be as good as 0.2—0.3 meters for all three coordinates. Such accuracy allows to navigate small hovering objects such as drones. In general, it looks promising to use Bluetooth trackers for solving positioning problems for indoors environments.
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Vetter, Sebastian, and Gunnar Siedler. "Automated 3D-Objectdocumentation on the Base of an Image Set." Geoinformatics FCE CTU 6 (December 21, 2011): 370–75. http://dx.doi.org/10.14311/gi.6.46.
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Digital stereo-photogrammetry allows users an automatic evaluation of the spatial dimension and the surface texture of objects. The integration of image analysis techniques simplifies the automation of evaluation of large image sets and offers a high accuracy [1]. Due to the substantial similarities of stereoscopic image pairs, correlation techniques provide measurements of subpixel precision for corresponding image points. With the help of an automated point search algorithm in image sets identical points are used to associate pairs of images to stereo models and group them. The found identical points in all images are basis for calculation of the relative orientation of each stereo model as well as defining the relation of neighboured stereo models. By using proper filter strategies incorrect points are removed and the relative orientation of the stereo model can be made automatically. With the help of 3D-reference points or distances at the object or a defined distance of camera basis the stereo model is orientated absolute. An adapted expansion- and matching algorithm offers the possibility to scan the object surface automatically. The result is a three dimensional point cloud; the scan resolution depends on image quality. With the integration of the iterative closest point- algorithm (ICP) these partial point clouds are fitted to a total point cloud. In this way, 3D-reference points are not necessary. With the help of the implemented triangulation algorithm a digital surface models (DSM) can be created. The texturing can be made automatically by the usage of the images that were used for scanning the object surface. It is possible to texture the surface model directly or to generate orthophotos automatically. By using of calibrated digital SLR cameras with full frame sensor a high accuracy can be reached. A big advantage is the possibility to control the accuracy and quality of the 3d-objectdocumentation with the resolution of the images. The procedure described here is implemented in software Metigo 3D.
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FIKUS, Bartosz, Robert PASZKOWSKI, and Paweł PŁATEK. "Application of 3D Scanning Technology for Evaluation of Virtual Model of Gun Geometry." Problems of Mechatronics Armament Aviation Safety Engineering 9, no. 1 (March 31, 2018): 105–14. http://dx.doi.org/10.5604/01.3001.0011.7183.
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The paper presents the results of reconstruction of selected gun elements with application of 3D scanning technology. Algorithm of under investigation process, the way of preparing object for scanning and measuring process were also presented. This article discusses also data acquisition of clouds of points and methods of some activities with measured geometry data (i.e. solving some imperfections caused by the preparation or by the measurement process). Geometry was remeshed by the creating a new mesh of polygons to unify shapes defined after previous steps. On the basis of cloud of points measurements, the solid geometry of the whole object was prepared. The effect proved satisfactory accuracy of the estimated parts’ characteristics and allowed for recommendation of the mentioned approach in the described process.
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Kniaz, V. V., V. A. Mizginov, L. V. Grodzitkiy, N. A. Fomin, and V. A. Knyaz. "DENSE 3D OBJECT RECONSTRUCTION USING STRUCTURED-LIGHT SCANNER AND DEEP LEARNING." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2020 (August 12, 2020): 777–83. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2020-777-2020.
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Abstract. Structured light scanners are intensively exploited in various applications such as non-destructive quality control at an assembly line, optical metrology, and cultural heritage documentation. While more than 20 companies develop commercially available structured light scanners, structured light technology accuracy has limitations for fast systems. Model surface discrepancies often present if the texture of the object has severe changes in brightness or reflective properties of its texture. The primary source of such discrepancies is errors in the stereo matching caused by complex surface texture. These errors result in ridge-like structures on the surface of the reconstructed 3D model. This paper is focused on the development of a deep neural network LineMatchGAN for error reduction in 3D models produced by a structured light scanner. We use the pix2pix model as a starting point for our research. The aim of our LineMatchGAN is a refinement of the rough optical flow A and generation of an error-free optical flow B̂. We collected a dataset (which we term ZebraScan) consisting of 500 samples to train our LineMatchGAN model. Each sample includes image sequences (Sl, Sr), ground-truth optical flow B and a ground-truth 3D model. We evaluate our LineMatchGAN on a test split of our ZebraScan dataset that includes 50 samples. The evaluation proves that our LineMatchGAN improves the stereo matching accuracy (optical flow end point error, EPE) from 0.05 pixels to 0.01 pixels.
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Li, Wei, Hongtai Cheng, and Xiaohua Zhang. "Efficient 3D Object Recognition from Cluttered Point Cloud." Sensors 21, no. 17 (August 30, 2021): 5850. http://dx.doi.org/10.3390/s21175850.
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Recognizing 3D objects and estimating their postures in a complex scene is a challenging task. Sample Consensus Initial Alignment (SAC-IA) is a commonly used point cloud-based method to achieve such a goal. However, its efficiency is low, and it cannot be applied in real-time applications. This paper analyzes the most time-consuming part of the SAC-IA algorithm: sample generation and evaluation. We propose two improvements to increase efficiency. In the initial aligning stage, instead of sampling the key points, the correspondence pairs between model and scene key points are generated in advance and chosen in each iteration, which reduces the redundant correspondence search operations; a geometric filter is proposed to prevent the invalid samples to the evaluation process, which is the most time-consuming operation because it requires transforming and calculating the distance between two point clouds. The introduction of the geometric filter can significantly increase the sample quality and reduce the required sample numbers. Experiments are performed on our own datasets captured by Kinect v2 Camera and on Bologna 1 dataset. The results show that the proposed method can significantly increase (10–30×) the efficiency of the original SAC-IA method without sacrificing accuracy.
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Corbett, Richard, Kees van den Doel, John E. Lloyd, and Wolfgang Heidrich. "TimbreFields: 3D Interactive Sound Models for Real-Time Audio." Presence: Teleoperators and Virtual Environments 16, no. 6 (December 1, 2007): 643–54. http://dx.doi.org/10.1162/pres.16.6.643.
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We describe a methodology for virtual reality designers to capture and resynthesize the variations in sound made by objects when we interact with them through contact such as touch. The timbre of contact sounds can vary greatly, depending on both the listener’s location relative to the object, and the interaction point on the object itself. We believe that an accurate rendering of this variation greatly enhances the feeling of immersion in a simulation. To do this, we model the variation with an efficient algorithm based on modal synthesis. This model contains a vector field that is defined on the product space of contact locations and listening positions around the object. The modal data are sampled on this high dimensional space using an automated measuring platform. A parameter-fitting algorithm is presented that recovers the parameters from a large set of sound recordings around objects and creates a continuous timbre field by interpolation. The model is subsequently rendered in a real-time simulation with integrated haptic, graphic, and audio display. We describe our experience with an implementation of this system and an informal evaluation of the results.
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Cai, Hong Xin, Qi Jia, HaoYu Shi, Yujie Jiang, Jingnan Xue, ChunXu Chen, Haotian Gong, Jie Liu, Eui-Seok Lee, and Heng Bo Jiang. "Accuracy and Precision Evaluation of International Standard Spherical Model by Digital Dental Scanners." Scanning 2020 (December 8, 2020): 1–6. http://dx.doi.org/10.1155/2020/1714642.
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With the popularization of digital technology and the exposure of traditional technology’s defects, computer-aided design and computer-aided manufacturing (CAD/CAM) has been widely used in the field of dentistry. And the accuracy of the scanning system determines the ultimate accuracy of the prosthesis, which is a very important part of CAD/CAM, so we decided to evaluate the accuracy of the intraoral and extraoral scanners. In this study, we selected the sphere model as the scanning object and obtained the final result through data analysis and 3D fitting. In terms of trueness and precision, the scanner of SHINING was significantly different from that of others; however, there was no significant difference between TRIOS and CEREC. SHINING showed the lowest level of accuracy, with CEREC slightly lower than TRIOS. The sphere model has also been proven to be scanned successfully.
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D’Amelio, S., V. Maggio, and B. Villa. "3D MODELING FOR UNDERWATER ARCHAEOLOGICAL DOCUMENTATION: METRIC VERIFICATIONS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-5/W5 (April 9, 2015): 73–77. http://dx.doi.org/10.5194/isprsarchives-xl-5-w5-73-2015.
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The survey in underwater environment has always presented considerable difficulties both operative and technical and this has sometimes made it difficult to use the techniques of survey commonly used for the documentation of Cultural Heritage in dry environment. The work of study concerns the evaluation in terms of capability and accuracy of the Autodesk123DCatch software for the reconstruction of a three-dimensional model of an object in underwater context. The subjects of the study are models generated from sets of photographs and sets of frames extracted from video sequence. The study is based on comparative method, using a reference model, obtained with laser scanner technique.
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Re, C., S. Robson, R. Roncella, and M. Hess. "Metric Accuracy Evaluation of Dense Matching Algorithms in Archeological Applications." Geoinformatics FCE CTU 6 (December 21, 2011): 275–82. http://dx.doi.org/10.14311/gi.6.34.
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In the cultural heritage field the recording and documentation of small and medium size objects with very detailed Digital Surface Models (DSM) is readily possible by through the use of high resolution and high precision triangulation laser scanners. 3D surface recording of archaeological objects can be easily achieved in museums; however, this type of record can be quite expensive. In many cases photogrammetry can provide a viable alternative for the generation of DSMs. The photogrammetric procedure has some benefits with respect to laser survey. The research described in this paper sets out to verify the reconstruction accuracy of DSMs of some archaeological artifacts obtained by photogrammetric survey. The experimentation has been carried out on some objects preserved in the Petrie Museum of Egyptian Archaeology at University College London (UCL). DSMs produced by two photogrammetric software packages are compared with the digital 3D model obtained by a state of the art triangulation color laser scanner. Intercomparison between the generated DSM has allowed an evaluation of metric accuracy of the photogrammetric approach applied to archaeological documentation and of precision performances of the two software packages.
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Kašparová, Magdaléna, Simona Halamová, Taťjana Dostálová, and Aleš Procházka. "Intra-Oral 3D Scanning for the Digital Evaluation of Dental Arch Parameters." Applied Sciences 8, no. 10 (October 7, 2018): 1838. http://dx.doi.org/10.3390/app8101838.
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Intra-oral scanning technology has brought a completely new approach to examination methods in dentistry. In comparison to traditional plaster casts, it allows more precise digital analysis of dental arch components during the treatment of dental disorders. Data acquired can also be used for the creation of three-dimensional (3D) models using 3D printers. This paper describes a data acquisition system, the mathematical processing of resulting three-dimensional model, and the statistical analysis of selected parameters of the dental arch. The study aims at comparing the results achieved from 20 models of the same individual acquired by different specialists. The proposed methodology includes mathematical rotation of objects into the optimal plane defined by the teeth tops’ location to increase the accuracy of the resulting parameters. The mean evaluated distances between canines (3-3) and premolars (5-5) are 24.29 mm and 37.98 mm, respectively, for the lower dental arch. The proposed object rotation increased these distance by 0.9% and 1.4%, respectively, reducing the rotation error. Moreover, the variability of results decreased and the mean value of the coefficient of variation was lowered by 12%. Image registration was then used to evaluate changes of dental arch parameters. This paper presents the advantages of digital models for visualisation of the dental arch allowing its flexible rotation and evaluation of its parameters.
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Bolognesi, M., A. Furini, V. Russo, A. Pellegrinelli, and P. Russo. "Accuracy of cultural heritage 3D models by RPAS and terrestrial photogrammetry." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-5 (June 5, 2014): 113–19. http://dx.doi.org/10.5194/isprsarchives-xl-5-113-2014.
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The combined use of high-resolution digital images taken from ground as well as from RPAS (Remotely Piloted Aircraft Systems) have significantly increased the potential of close range digital photogrammetry applications in Cultural Heritage surveying and modeling. It is in fact possible, thanks to SfM (Structure from Motion), to simultaneously process great numbers of aerial and terrestrial images for the production of a dense point cloud of an object. In order to analyze the accuracy of results, we started numerous tests based on the comparison between 3D digital models of a monumental complex realized by the integration of aerial and terrestrial photogrammetry and an accurate TLS (Terrestrial Laser Scanner) reference model of the same object.<br><br> A lot of digital images of a renaissance castle, assumed as test site, have been taken both by ground level and by RPAS at different distances and flight altitudes and with different flight patterns. As first step of the experimentation, the images were previously processed with Agisoft PhotoScan, one of the most popular photogrammetric software. The comparison between the photogrammetric DSM of the monument and a TLS reference one was carried out by evaluating the average deviation between the points belonging to the two entities, both globally and locally, on individual façades and architectural elements (sections and particular). In this paper the results of the first test are presented. A good agreement between photogrammetric and TLS digital models of the castle is pointed out.
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Cui, Meng-Yao, Shao-Ping Lu, Miao Wang, Yong-Liang Yang, Yu-Kun Lai, and Paul L. Rosin. "3D computational modeling and perceptual analysis of kinetic depth effects." Computational Visual Media 6, no. 3 (August 13, 2020): 265–77. http://dx.doi.org/10.1007/s41095-020-0180-x.
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Abstract Humans have the ability to perceive kinetic depth effects, i.e., to perceived 3D shapes from 2D projections of rotating 3D objects. This process is based on a variety of visual cues such as lighting and shading effects. However, when such cues are weak or missing, perception can become faulty, as demonstrated by the famous silhouette illusion example of the spinning dancer. Inspired by this, we establish objective and subjective evaluation models of rotated 3D objects by taking their projected 2D images as input. We investigate five different cues: ambient luminance, shading, rotation speed, perspective, and color difference between the objects and background. In the objective evaluation model, we first apply 3D reconstruction algorithms to obtain an objective reconstruction quality metric, and then use quadratic stepwise regression analysis to determine weights of depth cues to represent the reconstruction quality. In the subjective evaluation model, we use a comprehensive user study to reveal correlations with reaction time and accuracy, rotation speed, and perspective. The two evaluation models are generally consistent, and potentially of benefit to inter-disciplinary research into visual perception and 3D reconstruction.
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Song, Limei, Siyuan Sun, Yangang Yang, Xinjun Zhu, Qinghua Guo, and Huaidong Yang. "A Multi-View Stereo Measurement System Based on a Laser Scanner for Fine Workpieces." Sensors 19, no. 2 (January 18, 2019): 381. http://dx.doi.org/10.3390/s19020381.
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A new solution to the high-quality 3D reverse modeling problem of complex surfaces for fine workpieces is presented using a laser line-scanning sensor. Due to registration errors, measurement errors, deformations, etc., a fast and accurate method is important in machine vision measurement. This paper builds a convenient and economic multi-view stereo (MVS) measurement system based on a linear stage and a rotary stage to reconstruct the measured object surface completely and accurately. In the proposed technique, the linear stage is used to generate the trigger signal and synchronize the laser sensor scanning; the rotary stage is used to rotate the object and obtain multi-view point cloud data, and then the multi-view point cloud data are registered and integrated into a 3D model. The measurement results show a measurement accuracy of 0.075 mm for a 360° reconstruction in 34 s, and some evaluation experiments were carried out to demonstrate the validity and practicability of the proposed technique.
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Ravanelli, R., L. Lastilla, and M. Crespi. "3D MODELLING BY LOW-COST RANGE CAMERA: SOFTWARE EVALUATION AND COMPARISON." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W8 (November 14, 2017): 209–12. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w8-209-2017.
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The aim of this work is to present a comparison among three software applications currently available for the Occipital Structure Sensor<sup>TM</sup>; all these software were developed for collecting 3D models of objects easily and in real-time with this structured light range camera. The SKANECT, itSeez3D and Scanner applications were thus tested: a DUPLO<sup>TM</sup> bricks construction was scanned with the three applications and the obtained models were compared to the model virtually generated with a standard CAD software, which served as reference.<br><br> The results demonstrate that all the software applications are generally characterized by the same level of geometric accuracy, which amounts to very few millimetres. However, the itSeez3D software, which requires a payment of $7 to export each model, represents surely the best solution, both from the point of view of the geometric accuracy and, mostly, at the level of the color restitution. On the other hand, Scanner, which is a free software, presents an accuracy comparable to that of itSeez3D. At the same time, though, the colors are often smoothed and not perfectly overlapped to the corresponding part of the model. Lastly, SKANECT is the software that generates the highest number of points, but it has also some issues with the rendering of the colors.
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Barba, Salvatore, Maurizio Barbarella, Alessandro Di Benedetto, Margherita Fiani, Lucas Gujski, and Marco Limongiello. "Accuracy Assessment of 3D Photogrammetric Models from an Unmanned Aerial Vehicle." Drones 3, no. 4 (October 15, 2019): 79. http://dx.doi.org/10.3390/drones3040079.
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The unmanned aerial vehicle (UAV) photogrammetric survey of an archaeological site has proved itself to be particularly efficient. In order to obtain highly accurate and reliable results, it is necessary to design carefully the flight plan and the geo-referencing, while also evaluating the indicators of the accuracy rate. Using as a test case a UAV photogrammetric survey conducted on the archaeological site of the Roman Amphitheatre of Avella (Italy), in this paper, we propose a pipeline to assess the accuracy of the results according to some quality indicators. The flight configuration and the georeferencing chosen is then be checked via the residuals on the ground control points (GCPs), evenly distributed on the edges and over the entire area. With the aim of appraising the accuracy of the final model, we will suggest a method for the outlier detection, taking into account the statistical distribution (both global and of portion of the study object) of the reprojection errors. A filter to reduce the noise within the model will then be implemented through the detection of the angle formed by homologous rays, in order to reach a compromise between the number of the usable points and the reduction of the noise linked to the definition of the 3D model.
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Zhang, Yifan, Qing Wang, Anan Zhao, and Yinglin Ke. "A multi-object posture coordination method with tolerance constraints for aircraft components assembly." Assembly Automation 40, no. 2 (October 11, 2019): 345–59. http://dx.doi.org/10.1108/aa-02-2019-0030.
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Purpose This paper aims to improve the alignment accuracy of large components in aircraft assembly and an evaluation algorithm, which is based on manufacture accuracy and coordination accuracy, is proposed. Design/methodology/approach With relative deviations of manufacturing feature points and coordinate feature points, an evaluation function of assembly error is constructed. Then the optimization model of large aircraft digital alignment is established to minimize the synthesis assembly error with tolerance requirements, which consist of three-dimensional (3D) tolerance of manufacturing feature points and relative tolerance between coordination feature points. The non-linear constrained optimization problem is solved by Lagrange multiplier method and quasi-Newton method with its initial value provided by the singular value decomposition method. Findings The optimized postures of large components are obtained, which makes the tolerance of both manufacturing and coordination requirements be met. Concurrently, the synthesis assembly error is minimized. Compared to the result of the singular value decomposition method, the algorithm is validated in three typical cases with practical data. Practical implications The proposed method has been used in several aircraft assembly projects and gained a good effect. Originality/value This paper proposes a method to optimize the manufacturing and coordination accuracy with tolerance constraints when the postures of several components are adjusted at the same time. The results of this paper will help to improve the quality of component assemblies.
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Knyaz, V. A., D. G. Stepaniants, E. V. Ippolitov, and M. M. Novikov. "OPTICAL 3D MEASUREMENTS IN HYDRODYNAMIC TUNNEL FOR AIRCRAFT ICING STUDY." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2020 (August 12, 2020): 963–68. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2020-963-2020.
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Abstract. The study of how aircraft icing influences on aircraft aerodynamic performance is very important for developing measures and recommendation to improve aircraft flight safety. The effective method of aerodynamic processes modeling is experiment in wind (aerodynamic) tunnel or water (hydrodynamic) tunnel. They allow to perform experiments with a scaled model of an aircraft affected by icing and to visualize the wing flow process and changes caused by icing. While visualization of the wing flow yields useful qualitative information about flow, it is more important to retrieve quantitative 3D data of flow, which allows to forecast icing process and to develop anti-icing techniques and recommendations.The presented study addresses to creating an photogrammetric system and 3D measurement techniques for quantitate evaluation of 3D flow parameters in a hydrodynamic tunnel for aircraft icing influence exploration. Being an initial part of a long-term research project, this study is aimed at developing of an accurate calibration technique of the photogrammetric system for 3D measurement in condition of two optical media interfaces. The developed algorithms for imaging process through two optical media interfaces are used in calibration procedure and object 3D coordinates measuring. The results of the photogrammetric system calibration are given in comparison with standard (single media) case. Experimental 3D reconstruction of a typical object demonstrated high accuracy of the developed algorithms.
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Gabara, G., and P. Sawicki. "KORTOWO TEST FIELD FOR TESTING PHOTOGRAMMETRIC PRODUCTS ACCURACY – DESIGN AND FIRST EVALUATION." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-1/W2 (September 12, 2019): 23–29. http://dx.doi.org/10.5194/isprs-archives-xlii-1-w2-23-2019.
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<p><strong>Abstract.</strong> The continuous development of sensors, methods and technologies in the modern digital photogrammetry requires testing the quality and accuracy of software, processing workflow and products. The paper presents a new test field for performance analysis of software processing and accuracy assessment of photogrammetric 2D and 3D data collection, mapping, 3D object reconstruction and modeling based on low-altitude imagery with particular regard to unmanned aerial vehicles imagery. The first experiment was carried out using images captured by Phase One iXU-RS 1000 medium format aerial digital camera and Light Detection and Ranging (LiDAR) point cloud acquired by RIEGL LMS-Q680i airborne laser scanner. The process of complex digital processing was performed in Agisoft Metashape packages. The subblock of 169 images and 16 signalized ground points measured by Global Navigation Satellite Systems in the WGS 84 coordinate system using the Real-Time Network method were adopted in the preliminary investigations. The root mean square error RMSEXYZ on check points in the bundle block adjustment was equal to 0.032&thinsp;m. Vertical deviations between digital elevation model and LiDAR point clouds belong to the range from &minus;0.020&thinsp;m to 0.020&thinsp;m which is related to RIEGL LMS-Q680i accuracy and precision. Georeferenced orthomosaic was generated with ground sampling distance (GSD) equal to 0.020&thinsp;m, which was the same as the GSD of input images. The high accuracy of obtained processing results is related to accuracy of initial data, and it proves the usefulness of Kortowo test field.</p>
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Sun, Zheng, and Yingying Zhang. "Accuracy Evaluation of Videogrammetry Using A Low-Cost Spherical Camera for Narrow Architectural Heritage: An Observational Study with Variable Baselines and Blur Filters." Sensors 19, no. 3 (January 25, 2019): 496. http://dx.doi.org/10.3390/s19030496.
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Three-dimensional (3D) reconstruction using video frames extracted from spherical cameras introduces an innovative measurement method in narrow scenes of architectural heritage, but the accuracy of 3D models and their correlations with frame extraction ratios and blur filters are yet to be evaluated. This article addresses these issues for two narrow scenes of architectural heritage that are distinctive in layout, surface material, and lighting conditions. The videos captured with a hand-held spherical camera (30 frames per second) are extracted to frames with various ratios starting from 10 and increasing every 10 frames (10, 20, …, n). Two different blur assessment methods are employed for comparative analyses. Ground truth models obtained from terrestrial laser scanning and photogrammetry are employed for assessing the accuracy of 3D models from different groups. The results show that the relative accuracy (median absolute errors/object dimensions) of spherical-camera videogrammetry range from 1/500 to 1/2000, catering to the surveying and mapping of architectural heritage with medium accuracy and resolution. Sparser baselines (the length between neighboring image pairs) do not necessarily generate higher accuracy than those from denser baselines, and an optimal frame network should consider the essential completeness of complex components and potential degeneracy cases. Substituting blur frames with adjacent sharp frames could reduce global errors by 5–15%.
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Bori, Marwa Mohammed, and Zahraa Ezzulddin Hussein. "Integration the Low Cost Camera Images with the Google Earth Dataset to Create a 3D Model." Civil Engineering Journal 6, no. 3 (March 1, 2020): 446–58. http://dx.doi.org/10.28991/cej-2020-03091482.
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As known Close range photogrammetry represents one of the most techniques to create precise 3D model. Metric camera, digital camera, and Laser scanning can be exploited for the photogrammetry with variety level of cost that may be high. In this study, the cost level is taken in to consideration to achieve balance between the cost and the obtained accuracy. This study aims to detect potential of low cost tools for creating 3D model in terms of obtained accuracy and details and comparing it with corresponding studies. Smart phone camera is the most available for everyone; this gave the motivation for use in this study. In addition, Google Earth was used to integrate the 3D model produced from all sides including the roof. Then, two different types of the mobile camera were used in addition to the DSLR camera (Digital Single Lens Reflex) for comparison and analysis purposes. Thus, this research gave flexibility in work and low cost resulting from replacement the metric camera with the smart camera and the unmanned aerial vehicle (UAV) with Google Earth data. Mechanism of the work can be summarized in four steps. Firstly, photogrammetry planning to determine suitable baselines from object and location of targets that measured using GPS and Total station devices. Secondly, collect images using close range photogrammetry technique. Thirdly, processing step to create the 3D model and integrated with Google Earth images using the Agi Photoscan software. Finally, Comparative and evaluation stage to derive the accuracy and quality of the model obtained from this study using statistical analysis method. Regarding this Study, University of Baghdad, central library was selected as the case study. The results of this paper show that the low cost 3D model resulted from integrating phone and Google Earth images gave suitable result with mean accuracy level reached to about less than 5 meters compared with DSLR camera result, this may be used for several applications such as culture heritage and architecture documentation.
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Minami, Mamoru, and Wei Song. "Hand-Eye Motion-Invariant Pose Estimation with Online 1-Step GA -3D Pose Tracking Accuracy Evaluation in Dynamic Hand-Eye Oscillation-." Journal of Robotics and Mechatronics 21, no. 6 (December 20, 2009): 709–19. http://dx.doi.org/10.20965/jrm.2009.p0709.
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This paper presents online pose measurement for a 3-dimensional (3-D) object detected by stereo hand-eye cameras. Our proposal improves 3-D pose tracking accuracy by compensating for the fictional motion of the target in camera images stemming from the ego motion of the hand-eye camera caused by dynamic manipulator oscillation. This motion feed-forward (MFF) is combined into the evolutionary search of a genetic algorithm (GA) and fitness evaluation based on stereo model matching whose pose is expressed using a unit quaternion. The proposal’s effectiveness was confirmed in simulation tracking an object’s 3-D pose adversely affected by hand-eye camera oscillations induced by dynamic effects of robot motion.
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Mazlan, Siti Nur Humaira, Aini Zuhra Abdul Kadir, N. H. A. Ngadiman, and M. R. Alkahari. "Evaluation of geometrical benchmark artifacts containing multiple overhang lengths fabricated using material extrusion technique." Journal of Mechanical Engineering and Sciences 14, no. 3 (September 30, 2020): 7296–308. http://dx.doi.org/10.15282/jmes.14.3.2020.28.0573.
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Fused deposition modelling (FDM) is a process of joining materials based on material entrusion technique to produce objects from 3D model using layer-by-layer technique as opposed to subtractive manufacturing. However, many challenges arise in the FDM-printed part such as warping, first layer problem and elephant food that was led to an error in dimensional accuracy of the printed parts especially for the overhanging parts. Hence, in order to investigate the manufacturability of the FDM printed part, various geometrical and manufacturing features were developed using the benchmarking artifacts. Therefore, in this study, new benchmarking artifacts containing multiple overhang lengths were proposed. After the benchmarking artifacts were developed, each of the features were inspected using 3D laser scanner to measure the dimensional accuracy and tolerances. Based on 3D scanned parts, 80% of the fabricated parts were fabricated within ±0.5 mm of dimensional accuracy as compared with the CAD data. In addition, the multiple overhang lengths were also successfully fabricated with a very significant of filament sagging observed.
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Cao, Yuchen, Lan Hu, and Laurent Kneip. "Representations and Benchmarking of Modern Visual SLAM Systems." Sensors 20, no. 9 (April 30, 2020): 2572. http://dx.doi.org/10.3390/s20092572.
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Simultaneous Localisation And Mapping (SLAM) has long been recognised as a core problem to be solved within countless emerging mobile applications that require intelligent interaction or navigation in an environment. Classical solutions to the problem primarily aim at localisation and reconstruction of a geometric 3D model of the scene. More recently, the community increasingly investigates the development of Spatial Artificial Intelligence (Spatial AI), an evolutionary paradigm pursuing a simultaneous recovery of object-level composition and semantic annotations of the recovered 3D model. Several interesting approaches have already been presented, producing object-level maps with both geometric and semantic properties rather than just accurate and robust localisation performance. As such, they require much broader ground truth information for validation purposes. We discuss the structure of the representations and optimisation problems involved in Spatial AI, and propose new synthetic datasets that, for the first time, include accurate ground truth information about the scene composition as well as individual object shapes and poses. We furthermore propose evaluation metrics for all aspects of such joint geometric-semantic representations and apply them to a new semantic SLAM framework. It is our hope that the introduction of these datasets and proper evaluation metrics will be instrumental in the evaluation of current and future Spatial AI systems and as such contribute substantially to the overall research progress on this important topic.
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di Luggo, A., M. Campi, L. Repola, V. Cera, S. Scandurra, M. Pulcrano, and M. Falcone. "EVALUATION OF HISTORICAL HERITAGE DOCUMENTATION: REALITY BASED SURVEY AND DERIVATIVE MODELS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W17 (November 29, 2019): 115–22. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w17-115-2019.
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Abstract. Three-dimensional acquisition systems for architecture have significantly evolved over just a few decades, with them allowing point clouds to be generated through active and passive optical sensor equipment.Accuracy levels vary considerably in relation to both the equipment and techniques used, with the data obtained acting as a scaffolding for the creation of derived models that allow specific analyses to be carried out.Ongoing research on Palazzo Donn’Anna, a Neapolitan sixteenth-century building of particular historical and artistic value, is being carried out in this context and the first results are presented in this paper.The entire building has been the subject of an instrumental survey. The north-east façade was proposed as a case-study for the experimentation of diversified reality-based sensors so as to compare the accuracy and precision of the data. The comparison was also aimed at evaluating the performance of some processing softwares. Finally, in order to obtain an estimate of the data in the transcription from the point cloud to a derived 3D model, the reproduction of the same portion of the prospectus in a derivative model of both object-oriented and NURBS types was experimented.
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Rajendra, Y. D., S. C. Mehrotra, K. V. Kale, R. R. Manza, R. K. Dhumal, A. D. Nagne, and A. D. Vibhute. "Evaluation of Partially Overlapping 3D Point Cloud's Registration by using ICP variant and CloudCompare." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-8 (November 28, 2014): 891–97. http://dx.doi.org/10.5194/isprsarchives-xl-8-891-2014.
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Terrestrial Laser Scanners (TLS) are used to get dense point samples of large object’s surface. TLS is new and efficient method to digitize large object or scene. The collected point samples come into different formats and coordinates. Different scans are required to scan large object such as heritage site. Point cloud registration is considered as important task to bring different scans into whole 3D model in one coordinate system. Point clouds can be registered by using one of the three ways or combination of them, Target based, feature extraction, point cloud based. For the present study we have gone through Point Cloud Based registration approach. We have collected partially overlapped 3D Point Cloud data of Department of Computer Science & IT (DCSIT) building located in Dr. Babasaheb Ambedkar Marathwada University, Aurangabad. To get the complete point cloud information of the building we have taken 12 scans, 4 scans for exterior and 8 scans for interior façade data collection. There are various algorithms available in literature, but Iterative Closest Point (ICP) is most dominant algorithms. The various researchers have developed variants of ICP for better registration process. The ICP point cloud registration algorithm is based on the search of pairs of nearest points in a two adjacent scans and calculates the transformation parameters between them, it provides advantage that no artificial target is required for registration process. We studied and implemented three variants Brute Force, KDTree, Partial Matching of ICP algorithm in MATLAB. The result shows that the implemented version of ICP algorithm with its variants gives better result with speed and accuracy of registration as compared with CloudCompare Open Source software.
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Danilov, S., M. Kozyrev, M. Grechanichenko, L. Grodzitskiy, V. Mizginov, and V. V. Kniaz. "SYNTHETIC VISION SYSTEM CALIBRATION FOR CONFORM PROJECTION ON THE PILOT’S HEAD-UP DISPLAY." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2020 (August 12, 2020): 575–81. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2020-575-2020.
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Abstract. Situational awareness of the crew is critical for the safety of the air flight. Head-up display allows providing all required flight information in front of the pilot over the cockpit view visible through the cockpit’s front window. This device has been created for solving the problem of informational overload during piloting of an aircraft. While computer graphics such as scales and digital terrain model can be easily presented on the such display, errors in the Head-up display alignment for correct presenting of sensor data pose challenges. The main problem arises from the parallax between the pilot’s eyes and the position of the camera. This paper is focused on the development of an online calibration algorithm for conform projection of the 3D terrain and runway models on the pilot’s head-up display. The aim of our algorithm is to align the objects visible through the cockpit glass with their projections on the Head-up display. To improve the projection accuracy, we use an additional optical sensor installed on the aircraft. We combine classical photogrammetric techniques with modern deep learning approaches. Specifically, we use an object detection neural network model to find the runway area and align runway projection with its actual location. Secondly, we re-project the sensor’s image onto the 3D model of the terrain to eliminate errors caused by the parallax. We developed an environment simulator to evaluate our algorithm. Using the simulator we prepared a large training dataset. The dataset includes 2000 images of video sequences representing aircraft’s motion during takeoff, landing and taxi. The results of the evaluation are encouraging and demonstrate both qualitatively and quantitatively that the proposed algorithm is capable of precise alignment of the 3D models projected on a Head-up display.
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Amini, H., P. Pahlavani, and R. Karimi. "3D RECONSTRUCTION OF BUILDINGS WITH GABLED AND HIPPED STRUCTURES USING LIDAR DATA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-2/W3 (October 22, 2014): 47–52. http://dx.doi.org/10.5194/isprsarchives-xl-2-w3-47-2014.
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Buildings are the most important objects in urban areas. Thus, building detection using photogrammetry and remote sensing data as well as 3D model of buildings are very useful for many applications such as mobile navigation, tourism, and disaster management. In this paper, an approach has been proposed for detecting buildings by LiDAR data and aerial images, as well as reconstructing 3D model of buildings. In this regard, firstly, building detection carried out by utilizing a Supper Vector Machine (SVM) as a supervise method. The supervise methods need training data that could be collected from some features. Hence, LiDAR data and aerial images were utilized to produce some features. The features were selected by considering their abilities for separating buildings from other objects. The evaluation results of building detection showed high accuracy and precision of the utilized approach. The detected buildings were labeled in order to reconstruct buildings, individually. Then the planes of each building were separated and adjacent planes were recognized to reduce the calculation volume and to increase the accuracy. Subsequently, the bottom planes of each building were detected in order to compute the corners of hipped roofs using intersection of three adjacent planes. Also, the corners of gabled roofs were computed by both calculating the intersection line of the adjacent planes and finding the intersection between the planes intersection line and their detected parcel. Finally, the coordinates of some nodes in building floor were computed and 3D model reconstruction was carried out. In order to evaluate the proposed method, 3D model of some buildings with different complexity level were generated. The evaluation results showed that the proposed method has reached credible performance.
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Hastedt, H., T. Luhmann, H. J. Przybilla, and R. Rofallski. "EVALUATION OF INTERIOR ORIENTATION MODELLING FOR CAMERAS WITH ASPHERIC LENSES AND IMAGE PRE-PROCESSING WITH SPECIAL EMPHASIS TO SFM RECONSTRUCTION." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2021 (June 28, 2021): 17–24. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2021-17-2021.
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Abstract. For optical 3D measurements in close-range and UAV applications, the modelling of interior orientation is of superior importance in order to subsequently allow for high precision and accuracy in geometric 3D reconstruction. Nowadays, modern camera systems are often used for optical 3D measurements due to UAV payloads and economic purposes. They are constructed of aspheric and spherical lens combinations and include image pre-processing like low-pass filtering or internal distortion corrections that may lead to effects in image space not being considered with the standard interior orientation models. With a variety of structure-from-motion (SfM) data sets, four typical systematic patterns of residuals could be observed. These investigations focus on the evaluation of interior orientation modelling with respect to minimising systematics given in image space after bundle adjustment. The influences are evaluated with respect to interior and exterior orientation parameter changes and their correlations as well as the impact in object space. With the variety of data sets, camera/lens/platform configurations and pre-processing influences, these investigations indicate a number of different behaviours. Some specific advices in the usage of extended interior orientation models, like Fourier series, could be derived for a selection of the data sets. Significant reductions of image space systematics are achieved. Even though increasing standard deviations and correlations for the interior orientation parameters are a consequence, improvements in object space precision and image space reliability could be reached.
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Baumgart, M., N. Druml, and M. Consani. "PROCEDURE ENABLING SIMULATION AND IN-DEPTH ANALYSIS OF OPTICAL EFFECTS IN CAMERA-BASED TIME-OF-FLIGHT SENSORS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2 (May 30, 2018): 83–89. http://dx.doi.org/10.5194/isprs-archives-xlii-2-83-2018.
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This paper presents a simulation approach for Time-of-Flight cameras to estimate sensor performance and accuracy, as well as to help understanding experimentally discovered effects. The main scope is the detailed simulation of the optical signals. We use a raytracing-based approach and use the optical path length as the master parameter for depth calculations. The procedure is described in detail with references to our implementation in Zemax OpticStudio and Python. Our simulation approach supports multiple and extended light sources and allows accounting for all effects within the geometrical optics model. Especially multi-object reflection/scattering ray-paths, translucent objects, and aberration effects (e.g. distortion caused by the ToF lens) are supported. The optical path length approach also enables the implementation of different ToF senor types and transient imaging evaluations. The main features are demonstrated on a simple 3D test scene.
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Valença, J. "Systems based on photogrammetry to evaluation of built heritage: tentative guidelines and control parameters." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-5 (June 6, 2014): 607–13. http://dx.doi.org/10.5194/isprsarchives-xl-5-607-2014.
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Technological innovations based on close-range imaging have arisen. The developments are related with both the advances in mathematical algorithms and acquisition equipment. This evolution allows to acquire data with large and powerful sensors and the fast and efficient processing of data. In general, the preservation of built heritage have applied these technological innovations very successfully in their different areas of intervention, namely, photogrammetry, digital image processing and multispectral image analysis. Furthermore, commercial packages of software and hardware have emerged. Thus, guidelines to best-practice procedures and to validate the results usually obtained should be established. Therefore, simple and easy to understand concepts, even for nonexperts in the field, should relate the characteristics of: (i) objects under study; (ii) acquisition conditions; (iii) methods applied; and (iv) equipment applied. In this scope, the limits of validity of the methods and a comprehensive protocol to achieve the required precision and accuracy for structural analysis is a mandatory task. Application of close-range photogrammetry to build 3D geometric models and for evaluation of displacements are herein presented. Parameters such as distance-to-object, sensor size and focal length, are correlated to the precision and accuracy achieved for displacement in both experimental and on site environment. This paper shows an early stage study. The aim consist in defining simple expressions to estimate the characteristics of the equipment and/or the conditions for image acquisition, depending on the required precision and accuracy. The results will be used to define tentative guidelines considered the all procedure, from image acquisition to final results of coordinates and displacements.
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Liu, Guihua, Weilin Zeng, Bo Feng, and Feng Xu. "DMS-SLAM: A General Visual SLAM System for Dynamic Scenes with Multiple Sensors." Sensors 19, no. 17 (August 27, 2019): 3714. http://dx.doi.org/10.3390/s19173714.
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Presently, although many impressed SLAM systems have achieved exceptional accuracy in a real environment, most of them are verified in the static environment. However, for mobile robots and autonomous driving, the dynamic objects in the scene can result in tracking failure or large deviation during pose estimation. In this paper, a general visual SLAM system for dynamic scenes with multiple sensors called DMS-SLAM is proposed. First, the combination of GMS and sliding window is used to achieve the initialization of the system, which can eliminate the influence of dynamic objects and construct a static initialization 3D map. Then, the corresponding 3D points of the current frame in the local map are obtained by reprojection. These points are combined with the constant speed model or reference frame model to achieve the position estimation of the current frame and the update of the 3D map points in the local map. Finally, the keyframes selected by the tracking module are combined with the GMS feature matching algorithm to add static 3D map points to the local map. DMS-SLAM implements pose tracking, closed-loop detection and relocalization based on static 3D map points of the local map and supports monocular, stereo and RGB-D visual sensors in dynamic scenes. Exhaustive evaluation in public TUM and KITTI datasets demonstrates that DMS-SLAM outperforms state-of-the-art visual SLAM systems in accuracy and speed in dynamic scenes.
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Neuville, Romain, Jacynthe Pouliot, and Roland Billen. "Identification of the Best 3D Viewpoint within the BIM Model: Application to Visual Tasks Related to Facility Management." Buildings 9, no. 7 (July 10, 2019): 167. http://dx.doi.org/10.3390/buildings9070167.
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Visualizing building assets within building information modeling (BIM) offers significant opportunities in facility management as it can assist the maintenance and the safety of buildings. Nevertheless, taking decisions based on 3D visualization remains a challenge since the high density of spatial information inside the 3D model requires suitable visualization techniques to achieve the visual task. The occlusion is ubiquitous and, whilst solutions already exist such as transparency, none currently solve this issue with an automatic and suitable management of the camera. In this paper, we propose the first RESTful web application implementing a 3D viewpoint management algorithm and we demonstrate its usability in the visualization of assets based on a BIM model for visual counting in facility management. Via an online questionnaire, empirical tests are conducted with architects, the construction industry, engineers, and surveyors. The results show that a 3D viewpoint that maximizes the visibility of 3D geometric objects inside the viewport significantly improves the success rate, the accuracy, and the certainty of a visual counting task compared to the traditional four side points of view (i.e., from the front, back, left, and right viewpoints). Finally, this first validation lays the foundation of future investigations in the 3D viewpoint usability evaluation, both in terms of visual tasks and application domains.
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Koehl, Mathieu, Anthony Viale, and Sophie Reeb. "A Historical Timber Frame Model for Diagnosis and Documentation before Building Restoration." International Journal of 3-D Information Modeling 4, no. 4 (October 2015): 34–63. http://dx.doi.org/10.4018/ij3dim.2015100103.
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The aim of the project that is described in this paper was to define a four-level timber frame survey mode of a historical building: the so-called “Andlau's Seigniory”, Alsace, France. This historical building was built in the late XVIth century and was in a stage of renovation in order to become a heritage interpretation centre. The used measurement methods combine Total Station measurements, Photogrammetry and 3D Terrestrial Laser scanner. Different modelling workflows were tested and compared according to the data acquisition method, but also according to the characteristics of the reconstructed model in terms of accuracy and level of detail. 3D geometric modelling of the entire structure was performed including modelling the degree of detail adapted to the needs. The described 3D timber framework exists now in different versions, from a theoretical and geometrical one up to a very detailed one, in which measurements and evaluation of deformation by time are potentially allowed. The virtually generated models involving archaeologists, architects, historians and specialists in historical crafts, are intended to be used during the four stages of the project: (i) knowledge of the current state of needs for diagnosis and understanding of former construction techniques; (ii) preparation and evaluation of restoration steps; (iii) knowledge and documentation concerning the archaeological object; (iv) transmission and dissemination of knowledge through the implementation of museum animations. Among the generated models one can also find a documentation of the site in the form of virtual tours created from panoramic photographs before and during the restoration works. Finally, the timber framework model was structured and integrated into a 3D GIS, where the association of descriptive and complementary digital documents was possible. Both offer tools leading to the diagnosis, the understanding of the structure, knowledge dissemination, documentation and the creation of educational activities. The integration of these measurements in a historical information system will lead to the creation of an interactive model and the creation of a digital visual display unit for consultation. It will be offered to any public to understand interactively the art of constructing a Renaissance structure, with detailed photos, descriptive texts and graphics. The 3D digital model of the framework will be used directly in the interpretation path, within the space dedicated to “Seigniory” of Andlau. An interactive touch-screen will be installed. It will incorporate several levels of playgrounds (playful, evocative and teaching). In a virtual way, it will deal with the different stages of building a wooden framework and clarify the art of construction.
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Sun, Guoxiang, Xiaochan Wang, Haihui Yang, and Xianjie Zhang. "A Canopy Information Measurement Method for Modern Standardized Apple Orchards Based on UAV Multimodal Information." Sensors 20, no. 10 (May 25, 2020): 2985. http://dx.doi.org/10.3390/s20102985.
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To make canopy information measurements in modern standardized apple orchards, a method for canopy information measurements based on unmanned aerial vehicle (UAV) multimodal information is proposed. Using a modern standardized apple orchard as the study object, a visual imaging system on a quadrotor UAV was used to collect canopy images in the apple orchard, and three-dimensional (3D) point-cloud models and vegetation index images of the orchard were generated with Pix4Dmapper software. A row and column detection method based on grayscale projection in orchard index images (RCGP) is proposed. Morphological information measurements of fruit tree canopies based on 3D point-cloud models are established, and a yield prediction model for fruit trees based on the UAV multimodal information is derived. The results are as follows: (1) When the ground sampling distance (GSD) was 2.13–6.69 cm/px, the accuracy of row detection in the orchard using the RCGP method was 100.00%. (2) With RCGP, the average accuracy of column detection based on grayscale images of the normalized green (NG) index was 98.71–100.00%. The hand-measured values of H, SXOY, and V of the fruit tree canopy were compared with those obtained with the UAV. The results showed that the coefficient of determination R2 was the most significant, which was 0.94, 0.94, and 0.91, respectively, and the relative average deviation (RADavg) was minimal, which was 1.72%, 4.33%, and 7.90%, respectively, when the GSD was 2.13 cm/px. Yield prediction was modeled by the back-propagation artificial neural network prediction model using the color and textural characteristic values of fruit tree vegetation indices and the morphological characteristic values of point-cloud models. The R2 value between the predicted yield values and the measured values was 0.83–0.88, and the RAD value was 8.05–9.76%. These results show that the UAV-based canopy information measurement method in apple orchards proposed in this study can be applied to the remote evaluation of canopy 3D morphological information and can yield information about modern standardized orchards, thereby improving the level of orchard informatization. This method is thus valuable for the production management of modern standardized orchards.
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Rossi, Eduardo, and Costanza Bonadonna. "SCARLET-1.0: SpheriCal Approximation for viRtuaL aggrEgaTes." Geoscientific Model Development 14, no. 7 (July 15, 2021): 4379–400. http://dx.doi.org/10.5194/gmd-14-4379-2021.
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Abstract. Aggregation of particles occurs in a large variety of settings and is therefore the focus of many disciplines, e.g., Earth and environmental sciences, astronomy, meteorology, pharmacy, and the food industry. In particular, in volcanology, ash aggregation deeply influences the sedimentation of volcanic particles in the atmosphere during and after a volcanic eruption, affecting the accuracy of model predictions and the evaluation of hazard and risk assessments. It is thus very important to provide an exhaustive description of the outcome of an aggregation process, starting from its basic geometrical features such as the position in space of its components and the overall porosity of the final object. Here we present SCARLET-1.0, a MATLAB package specifically created to provide a 3D virtual reconstruction for volcanic ash aggregates generated in central collision processes. In centrally oriented collisions, aggregates build up their own structure around the first particle (the core), acting as a seed. This is appropriate for aggregates generated in turbulent flows in which particles show different degrees of coupling with respect to the turbulent eddies. SCARLET-1.0 belongs to the class of sphere-composite algorithms, a family of algorithms that approximate 3D complex shapes in terms of a set of sphere-composite nonoverlapping spheres. The conversion of a 3D surface to its equivalent sphere-composite structure then allows for an analytical detection of the intersections between different objects that aggregate together. Thus, provided a list of colliding sizes and shapes, SCARLET-1.0 places each element in the vector around the core, minimizing the distances between their centers of mass. The user can play with different parameters that control the minimization process. Among them the most important ones are the cone of investigation (Ω), the number of rays per cone (Nr), and the number of orientations of the object (No). All the 3D shapes are described using the Standard Triangulation Language (STL) format, which is the current standard for 3D printing. This is one of the key features of SCARLET-1.0, which results in an unlimited range of applications of the package. The main outcome of the code is the virtual representation of the object, its size, porosity, density, and the associated STL file. In addition, the object can be potentially 3D printed. As an example, SCARLET-1.0 has been applied here to the investigation of ellipsoid–ellipsoid collisions and to a more specific analysis of volcanic ash aggregation. In the first application we show that the final porosity of two colliding ellipsoids is less than 20 % if flatness and elongation are greater than or equal to 0.5. Higher values of porosities (up to 40 %–50 %) can instead be found for ellipsoids with needle-like or extremely flat shapes. In the second application, we reconstruct the evolution in time of the porosity of two different aggregates characterized by different inner structures. We find that aggregates whose population of particles is characterized by a narrow distribution of sizes tend to rapidly reach a plateau in the porosity. In addition, to reproduce the observed densities, almost no compaction is necessary in SCARLET-1.0, which is a result that suggests how ash aggregates are not well described in terms of the maximum packing condition.
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Soleman, Jehuda, Florian Thieringer, Joerg Beinemann, Christoph Kunz, and Raphael Guzman. "Computer-assisted virtual planning and surgical template fabrication for frontoorbital advancement." Neurosurgical Focus 38, no. 5 (May 2015): E5. http://dx.doi.org/10.3171/2015.3.focus14852.
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OBJECT The authors describe a novel technique using computer-assisted design (CAD) and computed-assisted manufacturing (CAM) for the fabrication of individualized 3D printed surgical templates for frontoorbital advancement surgery. METHODS Two patients underwent frontoorbital advancement surgery for unilateral coronal synostosis. Virtual surgical planning (SurgiCase-CMF, version 5.0, Materialise) was done by virtual mirroring techniques and superposition of an age-matched normative 3D pediatric skull model. Based on these measurements, surgical templates were fabricated using a 3D printer. Bifrontal craniotomy and the osteotomies for the orbital bandeau were performed based on the sterilized 3D templates. The remodeling was then done placing the bone plates within the negative 3D templates and fixing them using absorbable poly-dl-lactic acid plates and screws. RESULTS Both patients exhibited a satisfying head shape postoperatively and at follow-up. No surgery-related complications occurred. The cutting and positioning of the 3D surgical templates proved to be very accurate and easy to use as well as reproducible and efficient. CONCLUSIONS Computer-assisted virtual planning and 3D template fabrication for frontoorbital advancement surgery leads to reconstructions based on standardizedmeasurements, precludes subjective remodeling, and seems to be overall safe and feasible. A larger series of patients with long-term follow-up is needed for further evaluation of this novel technique.
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Myint, Myo, Kenta Yonemori, Akira Yanou, Khin Nwe Lwin, Mamoru Minami, and Shintaro Ishiyama. "Visual Servoing for Underwater Vehicle Using Dual-Eyes Evolutionary Real-Time Pose Tracking." Journal of Robotics and Mechatronics 28, no. 4 (August 19, 2016): 543–58. http://dx.doi.org/10.20965/jrm.2016.p0543.
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[abstFig src='/00280004/12.jpg' width='300' text='ROV with dual-eyes cameras and 3D marker' ] Recently, a number of researches related to underwater vehicle has been conducted worldwide with the huge demand in different applications. In this paper, we propose visual servoing for underwater vehicle using dual-eyes cameras. A new method of pose estimation scheme that is based on 3D model-based recognition is proposed for real-time pose tracking to be applied in Autonomous Underwater Vehicle (AUV). In this method, we use 3D marker as a passive target that is simple but enough rich of information. 1-step Genetic Algorithm (GA) is utilized in searching process of pose in term of optimization, because of its effectiveness, simplicity and promising performance of recursive evaluation, for real-time pose tracking performance. The proposed system is implemented as software implementation and Remotely Operated Vehicle (ROV) is used as a test-bed. In simulated experiment, the ROV recognizes the target, estimates the relative pose of vehicle with respect to the target and controls the vehicle to be regulated in desired pose. PID control concept is adapted for proper regulation function. Finally, the robustness of the proposed system is verified in the case when there is physical disturbance and in the case when the target object is partially occluded. Experiments are conducted in indoor pool. Experimental results show recognition accuracy and regulating performance with errors kept in centimeter level.
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Künne, Marco, Sebastian Hagemeier, Eireen Käkel, Hartmut Hillmer, and Peter Lehmann. "Investigation of measurement data of low-coherence interferometry at tilted surfaces in the 3D spatial frequency domain." tm - Technisches Messen 88, s1 (August 24, 2021): s65—s70. http://dx.doi.org/10.1515/teme-2021-0051.
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Abstract The 3D transfer characteristics of interference microscopes and their effect on the interference signals occurring at surface slopes are studied. The interference image stacks acquired during a depth scan are 3D Fourier transformed. This allows a comprehensive frequency domain analysis of the interferograms. The double foil model introduced in a previous publication enables the interpretation of the signal spectra and the underlying transfer behavior of the interferometer using the concept of the Ewald sphere, which is limited by the numerical aperture (NA) of the imaging system. Analysis in the 3D spatial frequency domain directly discloses that the lateral dimensions of the transfer function depend on the axial spatial frequency. In this contribution we investigate measuring objects produced by Nanoimprint-Lithography. The corresponding signal spectra bear information that can be utilized to optimize the subsequent signal processing algorithms. These include envelope and phase evaluation procedures of the interference signals. A narrow bandpass filter is used to actively select certain frequency components in order to improve the robustness of the estimation of the envelope position. Although the shape and width of the envelope are affected, this procedure increases the reliability of the evaluation process and improves the accuracy of the measured topography especially at steeper surface slopes.
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Fujimori, Takahito, Motoki Iwasaki, Yukitaka Nagamoto, Takahiro Ishii, Hironobu Sakaura, Masafumi Kashii, Hideki Yoshikawa, and Kazuomi Sugamoto. "Three-dimensional measurement of growth of ossification of the posterior longitudinal ligament." Journal of Neurosurgery: Spine 16, no. 3 (March 2012): 289–95. http://dx.doi.org/10.3171/2011.11.spine11502.
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Object Ossification of the posterior longitudinal ligament (OPLL) is a progressive disease that causes cervical myelopathy. Because 2D evaluation of ossification growth with plain lateral radiographs has limitations, the authors developed a unique technique to measure ossification progression and volume increase by using multidetector CT scanning. Methods The authors used serial thin-slice volume data obtained by multidetector CT scanning in 5 patients. The mean patient age was 63 years, and the mean follow-up duration was 3.1 years. First, a 3D model of OPLL was semiautomatically segmented at a specific threshold. Then, a preoperative model of OPLL was superimposed on a postoperative model using voxel-based registration of the vertebral bodies. Progression and volume increase were measured using a digital viewer that was developed by the authors. Progression was visualized using a color-coded contour on the surface of the OPLL model. Results All patients had progression of 0.5 mm or greater. The mean values concerning OPLL growth were as follows: maximum progression length, 4.7 mm; progression rate, 1.5 mm/year; volume increase, 1622 mm3; volume expansion rate, 37%; and volume increase rate, 484 mm3/year. The accuracy of superimposition by voxel-based registration, defined as closeness to the true value, was less than 0.31 mm. For intraobserver reproducibility of the volume measurement, the mean intraclass correlation coefficient, root mean square error, and coefficient of variation were 0.987, 16.0 mm3, and 1.7%, respectively. Conclusions Ossification of the posterior longitudinal ligament progresses even after surgery. Three-dimensional evaluation with the aid of CT scans is a useful and reliable method for assessing that growth.
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Prahara, Adhi, Ahmad Azhari, and Murinto Murinto. "Vehicle pose estimation for vehicle detection and tracking based on road direction." International Journal of Advances in Intelligent Informatics 3, no. 1 (March 31, 2017): 35. http://dx.doi.org/10.26555/ijain.v3i1.88.
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Vehicle has several types and each of them has different color, size, and shape. The appearance of vehicle also changes if viewed from different viewpoint of traffic surveillance camera. This situation can create many possibilities of vehicle poses. However, the one in common, vehicle pose usually follows road direction. Therefore, this research proposes a method to estimate the pose of vehicle for vehicle detection and tracking based on road direction. Vehicle training data are generated from 3D vehicle models in four-pair orientation categories. Histogram of Oriented Gradients (HOG) and Linear-Support Vector Machine (Linear-SVM) are used to build vehicle detectors from the data. Road area is extracted from traffic surveillance image to localize the detection area. The pose of vehicle which estimated based on road direction will be used to select a suitable vehicle detector for vehicle detection process. To obtain the final vehicle object, vehicle line checking method is applied to the vehicle detection result. Finally, vehicle tracking is performed to give label on each vehicle. The test conducted on various viewpoints of traffic surveillance camera shows that the method effectively detects and tracks vehicle by estimating the pose of vehicle. Performance evaluation of the proposed method shows 0.9170 of accuracy and 0.9161 of balance accuracy (BAC).
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AL-Baghdadi, Jasim Ahmed Ali, Hassan Ali Alizze, and Kasim Abed AL-Hussein. "Accuracy Assessment of Various Resolutions Digital Cameras For Close Range Photogrammetry Applications." Journal of Engineering 24, no. 9 (August 30, 2018): 78. http://dx.doi.org/10.31026/j.eng.2018.09.06.
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Due to the great evolution in digital commercial cameras, several studies have addressed the using of such cameras in different civil and close-range applications such as 3D models generation. However, previous studies have not discussed a precise relationship between a camera resolution and the accuracy of the models generated based on images of this camera. Therefore the current study aims to evaluate the accuracy of the derived 3D buildings models captured by different resolution cameras. The digital photogrammetric methods were devoted to derive 3D models using the data of various resolution cameras and analyze their accuracies. This investigation involves selecting three different resolution cameras (low, medium and high) and evaluating their calibration accuracies. Assessing the accuracy of the three selected cameras in capturing indoor and outdoor objects; and analyzing the accuracy and the quality of the produced models. The study revealed that:1) It is recommended to use the photos of a high-resolution camera for producing precise 3D models of objects in the outdoor environment especially when the camera/object distance is more than 40 m because the accuracy of the produced models can be precise (RMSE ±10.36mm) with excellent quality; 2) The Low-resolution camera can be utilised to produce adequate 3D models of object in the indoor environment (RMSE ±6.32mm) especially when the camera/object distance is less than 40 m.
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Bronzino, G. P. C., N. Grasso, F. Matrone, A. Osello, and M. Piras. "LASER-VISUAL-INERTIAL ODOMETRY BASED SOLUTION FOR 3D HERITAGE MODELING: THE SANCTUARY OF THE BLESSED VIRGIN OF TROMPONE." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W15 (August 20, 2019): 215–22. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w15-215-2019.
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<p><strong>Abstract.</strong> The advent of new mobile mapping systems that integrate different sensors has made it easier to acquire multiple 3D information with high speed. Today, technological development has allowed the creation of portable systems particularly suitable for indoor surveys, which mainly integrating LiDAR devices, chambers and inertial platforms, make it possible to create in a fast and easy way, full 3D model of the environment. However, the performance of these instruments differs depending on the acquisition context (indoor and outdoor), the characteristics of the scene (for example lighting, the presence of objects and people, reflecting surfaces, textures) and, above all, the mapping and localization algorithms implemented in devices. The purpose of this study is to analyse the results, and their accuracy, deriving from a survey conducted with the KAARTA Stencil 2 handheld system. This instrument, composed of a 3D LiDAR Velodyne VLP-16, a MEMS inertial platform and a feature tracker camera, it is able to realize the temporal 3D map of the environment. Specifically, the acquisition tests were carried out in a context of metrical documentation of an architectural heritage, in order extract architectural detail for the future reconstruction of virtual and augmented reality environments and for Historical Building Information Modeling purposes. The achieved results were analysed and the discrepancies from some reference LiDAR data are computed for a final evaluation. The system was tested in the church and cloister of the Sanctuary of the Beata Vergine del Trompone in Moncrivello (VC) (Italy).</p>
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Miguel-Díez, Felipe de, Eduardo Tolosana-Esteban, and Tobias Cremer. "3D-Simulation of Wood Stacks to Analyze the Influence of Log Properties on Stack Volume." Environmental Sciences Proceedings 3, no. 1 (November 13, 2020): 76. http://dx.doi.org/10.3390/iecf2020-08063.
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The quantification of the solid wood content in a wood stack has been an object of investigation since the 18th century. Particularly, the log parameters exert a considerable influence on the volume of the stack, such as (1) the log midpoint diameter, (2) average bark thickness, (3) crookedness, and (4) log taper. Although many of these parameters have already been studied and some are already considered in many countries when measuring wood stacks, their influence has not been analyzed individually so far since a broad statistical database is needed and the data collection is very costly. Consequently, a 3D-simulation model was developed based on a cross-platform game engine. This model generates virtual wood stacks based on a data set of logs which are defined by the user. The simulation of a stack can be done in a few seconds only and each stack generated can be visualized once all iterations are done. The simulation results are the stacked cubic volume, solid wood cubic volume, and the respective conversion factors. The model, fed with both real data and user-defined data, allows for a detailed analysis of the effect of each parameter on the results, as the user can vary their values discretionary. To obtain the first results from real data, 1000 logs of Scots pine (Pinus sylvestris L.) were measured. The first simulations based on these data show reliable results and it is possible to quantify the influence of the proportion of crooked wood in a pile on the stack volume and the conversion factor. In addition, the results are highly in line with the real trials that have already been performed in parallel. A further scientific evaluation and statistical analysis will be done in a second study phase. However, the model already provides a reasonable tool that is easy to apply for the forest and wood industry in order to make the most accurate estimate possible of the solid wood content in a wood pile.
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Trysnyuk, Taras V. "Mobile environmental monitoring system of the Dniester: modeling of technical system of hydro resources and extreme floods." Environmental safety and natural resources 38, no. 2 (June 30, 2021): 121–28. http://dx.doi.org/10.32347/2411-4049.2021.2.121-128.
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The mobile environmental monitoring system is aimed at increasing the processing speed of measurement analyzes and increasing the scale of the study. The algorithm of analysis and modeling of extreme floods includes: construction of a series of hydrographic maps of the largest floods and graphs of characteristic water levels, assessment of the peculiarities of floods, formation of a database on channel morphometry and the state of flood objects. An important role is given to the assessment and forecast of the state of the Dniester and anthropogenic impacts on it in connection with such indicators as morbidity and control of pollution caused by flooding. Man-caused ecological safety of use of hydro resources and hydroecosystems in general should be based on the hydroecosystem concept of balanced nature use. GIS technologies (ArcView GIS 3.2a) were used to directly implement the tasks of estimating the time of penetration of pollutants into groundwater. The evaluation of the protective properties of the rocks of the aeration zone was performed by creating a spatial model to determine the relationship between objects using the module Georgesessig ArcGIS. Survey materials allow you to create 3D terrain models with an accuracy of 15–20 cm and aerial mosaics at a scale of 1: 1,000 – 1: 5,000.
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Abe, Yuichiro, Shigenobu Sato, Koji Kato, Takahiko Hyakumachi, Yasushi Yanagibashi, Manabu Ito, and Kuniyoshi Abumi. "A novel 3D guidance system using augmented reality for percutaneous vertebroplasty." Journal of Neurosurgery: Spine 19, no. 4 (October 2013): 492–501. http://dx.doi.org/10.3171/2013.7.spine12917.
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Augmented reality (AR) is an imaging technology by which virtual objects are overlaid onto images of real objects captured in real time by a tracking camera. This study aimed to introduce a novel AR guidance system called virtual protractor with augmented reality (VIPAR) to visualize a needle trajectory in 3D space during percutaneous vertebroplasty (PVP). The AR system used for this study comprised a head-mount display (HMD) with a tracking camera and a marker sheet. An augmented scene was created by overlaying the preoperatively generated needle trajectory path onto a marker detected on the patient using AR software, thereby providing the surgeon with augmented views in real time through the HMD. The accuracy of the system was evaluated by using a computer-generated simulation model in a spine phantom and also evaluated clinically in 5 patients. In the 40 spine phantom trials, the error of the insertion angle (EIA), defined as the difference between the attempted angle and the insertion angle, was evaluated using 3D CT scanning. Computed tomography analysis of the 40 spine phantom trials showed that the EIA in the axial plane significantly improved when VIPAR was used compared with when it was not used (0.96° ± 0.61° vs 4.34° ± 2.36°, respectively). The same held true for EIA in the sagittal plane (0.61° ± 0.70° vs 2.55° ± 1.93°, respectively). In the clinical evaluation of the AR system, 5 patients with osteoporotic vertebral fractures underwent VIPAR-guided PVP from October 2011 to May 2012. The postoperative EIA was evaluated using CT. The clinical results of the 5 patients showed that the EIA in all 10 needle insertions was 2.09° ± 1.3° in the axial plane and 1.98° ± 1.8° in the sagittal plane. There was no pedicle breach or leakage of polymethylmethacrylate. VIPAR was successfully used to assist in needle insertion during PVP by providing the surgeon with an ideal insertion point and needle trajectory through the HMD. The findings indicate that AR guidance technology can become a useful assistive device during spine surgeries requiring percutaneous procedures.