Journal articles: 'System calibration and tracking'

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Xu, Xiaofei, Hongjun Hu, Shuhong Fu, and Yalong Yan. "Research on Beam Waveguide Focus Phase Calibration Method of Deep-space TT&C System." Journal of Physics: Conference Series 2410, no. 1 (December 1, 2022): 012010. http://dx.doi.org/10.1088/1742-6596/2410/1/012010.

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Abstract The angle auto-tracking capability is needed in the deep space system, but in the sum-differential dual channels tracking model, the deep-space TT&C system must calibrate its phase before tracking a satellite. Because of the big aperture and high frequency of the deep-space TT&C system antenna, it is impossible to build a calibrating tower which satisfy the far-field condition, and the traditional phase calibration method relies on the tower is not suitable. The radio star calibration method selects a appropriate satellite as the calibrating signal source, but the signal of which is very weak and is affected easily. In this paper, the principle of phase calibration is analyzed, and the beam waveguide focus calibration method is studied, the processes of antenna tracking and angle error signal demodulation are given. The beam waveguide focus calibration method simulates the far field signal through controlling the position of horn antenna which is at the focus of the beam waveguide. The method can be realized easily in engineering, and the limit of the traditional calibration tower and the affections of the weather in using radio star calibration method are avoided.

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Jayaram, Uma, and Roglenda Repp. "Integrated Real-Time Calibration of Electromagnetic Tracking of User Motions for Engineering Applications in Virtual Environments." Journal of Mechanical Design 124, no. 4 (November 26, 2002): 623–32. http://dx.doi.org/10.1115/1.1517562.

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A real-time integrated calibration system for virtual reality environments has been developed that enables accurate electromagnetic tracking of user motions. Electromagnetic tracking systems suffer degradation in accuracy due to the presence of metals and other electromagnetic distortions in the environment. Calibration of the virtual environment to account for these distortions is essential for VR applications in engineering where correlation between the virtual environment and the physical world is important. The major contribution of the paper is the presentation of a comprehensive methodology for calibrating the VR space, the numerical/mathematical techniques proposed for the calibration, and case studies for calibration accuracy and execution time to enable using these techniques in real time in an integrated setup.

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Liu, Yang Chuan, Xin Gao, Wei Wei Fu, Chuan Xu, and Yun Teng. "A Twice Calibrating Method for Binocular Stereovision System." Applied Mechanics and Materials 333-335 (July 2013): 161–66. http://dx.doi.org/10.4028/www.scientific.net/amm.333-335.161.

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Binocular stereovision system is regularly only calibrated once, that is each camera is calibrated using a picture of the calibration pattern laid in the cross field. This methods calibration accuracy is expected to be improved. A twice calibrating method is proposed here. Each cameras extrinsic and intrinsic parameters are calibrated in different fields. The extrinsic parameters are firstly calibrated in the cross field, then the intrinsic parameters are calibrated in the close-range field. By applying the method to one binocular stereovision system built in our lab, it is demonstrated that the proposed method can improve the calibration accuracy more than 3.4dB than the once calibrating method. Its accuracy makes this novel method more suitable for high accurate target tracking application.

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Kitbutrawat, Nathavuth, Hirozumi Yamaguchi, and Teruo Higashino. "EasyTrack: Zero-Calibration Smart-Home Tracking System." Journal of Information Processing 27 (2019): 445–55. http://dx.doi.org/10.2197/ipsjjip.27.445.

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Ko, Eun-Ji, and Myoung-Jun Kim. "User-Calibration Free Gaze Tracking System Model." Journal of the Korea Institute of Information and Communication Engineering 18, no. 5 (May 31, 2014): 1096–102. http://dx.doi.org/10.6109/jkiice.2014.18.5.1096.

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Ratnayake, R. M. T. S., S. J. Sooriyaarachchi, and C. D. Gamage. "Head Movement Invariant Eye Tracking System." Engineer: Journal of the Institution of Engineers, Sri Lanka 57, no. 1 (February 26, 2024): 45–55. http://dx.doi.org/10.4038/engineer.v57i1.7587.

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The human visual framework, consisting of the eyes, optic nerve, and brain, gives us the sense of sight to capture and interact with our surroundings. The eye, which provides stimulus to generate sight, is a complex organ that collects light and effectively converts it to an electro-chemical impulse inside neurons.Eye trackers are an important input modality for human-computer interfaces with vision-based applications. Eye-tracking systems have been proven to be valuable assistive devices for people with motor disabilities. Despite significant improvements in eye-tracking technology over time, current eye trackers in the market are complex and require intricate calibration procedures. Hence, there is still room for further research to develop an eye-tracking system with simpler calibration procedures.This paper presents the development of a head movement invariant real-time eye-tracking system with simpler calibration procedures that can operate non-intrusively. The complexity of setting up the system is also significantly reduced. Experiments conducted with a sample set of users showed an eye gaze accuracy improvement of over 11% compared to the existing setups commonly available in the market.

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Gieseler, Oliver, Hubert Roth, and Jürgen Wahrburg. "A novel 4 camera multi-stereo tracking system for application in surgical navigation systems." tm - Technisches Messen 87, no. 7-8 (July 26, 2020): 451–58. http://dx.doi.org/10.1515/teme-2019-0144.

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AbstractIn this paper, we present a novel 4 camera stereo system for application as optical tracking component in navigation systems in computer-assisted surgery. This shall replace a common stereo camera system in several applications. The objective is to provide a tracking component consisting of four single industrial cameras. The system can be built up flexibly in the operating room e. g. at the operating room lamp. The concept is characterized by independent, arbitrary camera mounting poses and demands easy on-site calibration procedures of the camera setup. Following a short introduction describing the environment, motivation and advantages of the new camera system, a simulation of the camera setup and arrangement is depicted in Section 2. From this, we gather important information and parameters for the hardware setup, which is described in Section 3. Section 4 includes the calibration of the cameras. Here, we illustrate the background of camera model and applied calibration procedures, a comparison of calibration results obtained with different calibration programs and a new concept for fast and easy extrinsic calibration.

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White, K. P., T. E. Hutchinson, and J. M. Carley. "Spatially dynamic calibration of an eye-tracking system." IEEE Transactions on Systems, Man, and Cybernetics 23, no. 4 (1993): 1162–68. http://dx.doi.org/10.1109/21.247897.

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Kaltiokallio, Ossi, Roland Hostettler, Hüseyin Yiğitler, and Mikko Valkama. "Unsupervised Learning in RSS-Based DFLT Using an EM Algorithm." Sensors 21, no. 16 (August 18, 2021): 5549. http://dx.doi.org/10.3390/s21165549.

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Received signal strength (RSS) changes of static wireless nodes can be used for device-free localization and tracking (DFLT). Most RSS-based DFLT systems require access to calibration data, either RSS measurements from a time period when the area was not occupied by people, or measurements while a person stands in known locations. Such calibration periods can be very expensive in terms of time and effort, making system deployment and maintenance challenging. This paper develops an Expectation-Maximization (EM) algorithm based on Gaussian smoothing for estimating the unknown RSS model parameters, liberating the system from supervised training and calibration periods. To fully use the EM algorithm’s potential, a novel localization-and-tracking system is presented to estimate a target’s arbitrary trajectory. To demonstrate the effectiveness of the proposed approach, it is shown that: (i) the system requires no calibration period; (ii) the EM algorithm improves the accuracy of existing DFLT methods; (iii) it is computationally very efficient; and (iv) the system outperforms a state-of-the-art adaptive DFLT system in terms of tracking accuracy.

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Capparini, Chiara, Michelle P. S. To, Clément Dardenne, and Vincent M. Reid. "Offline Calibration for Infant Gaze and Head Tracking across a Wide Horizontal Visual Field." Sensors 23, no. 2 (January 14, 2023): 972. http://dx.doi.org/10.3390/s23020972.

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Most well-established eye-tracking research paradigms adopt remote systems, which typically feature regular flat screens of limited width. Limitations of current eye-tracking methods over a wide area include calibration, the significant loss of data due to head movements, and the reduction of data quality over the course of an experimental session. Here, we introduced a novel method of tracking gaze and head movements that combines the possibility of investigating a wide field of view and an offline calibration procedure to enhance the accuracy of measurements. A 4-camera Smart Eye Pro system was adapted for infant research to detect gaze movements across 126° of the horizontal meridian. To accurately track this visual area, an online system calibration was combined with a new offline gaze calibration procedure. Results revealed that the proposed system successfully tracked infants’ head and gaze beyond the average screen size. The implementation of an offline calibration procedure improved the validity and spatial accuracy of measures by correcting a systematic top-right error (1.38° mean horizontal error and 1.46° mean vertical error). This approach could be critical for deriving accurate physiological measures from the eye and represents a substantial methodological advance for tracking looking behaviour across both central and peripheral regions. The offline calibration is particularly useful for work with developing populations, such as infants, and for people who may have difficulties in following instructions.

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VILLANUEVA, ARANTXA, RAFAEL CABEZA, and SONIA PORTA. "GAZE TRACKING SYSTEM MODEL BASED ON PHYSICAL PARAMETERS." International Journal of Pattern Recognition and Artificial Intelligence 21, no. 05 (August 2007): 855–77. http://dx.doi.org/10.1142/s0218001407005697.

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In the past years, research in eye tracking development and applications has attracted much attention and the possibility of interacting with a computer employing just gaze information is becoming more and more feasible. Efforts in eye tracking cover a broad spectrum of fields, system mathematical modeling being an important aspect in this research. Expressions relating to several elements and variables of the gaze tracker would lead to establish geometric relations and to find out symmetrical behaviors of the human eye when looking at a screen. To this end a deep knowledge of projective geometry as well as eye physiology and kinematics are basic. This paper presents a model for a bright-pupil technique tracker fully based on realistic parameters describing the system elements. The system so modeled is superior to that obtained with generic expressions based on linear or quadratic expressions. Moreover, model symmetry knowledge leads to more effective and simpler calibration strategies, resulting in just two calibration points needed to fit the optical axis and only three points to adjust the visual axis. Reducing considerably the time spent by other systems employing more calibration points renders a more attractive model.

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XU Tao, 徐涛, 李博 LI Bo, 刘廷霞 LIU Ting-xia, 薛乐堂 XUE Le-tang, and 陈涛 Chen Tao. "Initial calibration of tracking turntable for vehicle-borne opto-electronic tracking system." Optics and Precision Engineering 21, no. 3 (2013): 782–89. http://dx.doi.org/10.3788/ope.20132103.0782.

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Garde, Gonzalo, Andoni Larumbe-Bergera, Benoît Bossavit, Sonia Porta, Rafael Cabeza, and Arantxa Villanueva. "Low-Cost Eye Tracking Calibration: A Knowledge-Based Study." Sensors 21, no. 15 (July 28, 2021): 5109. http://dx.doi.org/10.3390/s21155109.

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Subject calibration has been demonstrated to improve the accuracy in high-performance eye trackers. However, the true weight of calibration in off-the-shelf eye tracking solutions is still not addressed. In this work, a theoretical framework to measure the effects of calibration in deep learning-based gaze estimation is proposed for low-resolution systems. To this end, features extracted from the synthetic U2Eyes dataset are used in a fully connected network in order to isolate the effect of specific user’s features, such as kappa angles. Then, the impact of system calibration in a real setup employing I2Head dataset images is studied. The obtained results show accuracy improvements over 50%, probing that calibration is a key process also in low-resolution gaze estimation scenarios. Furthermore, we show that after calibration accuracy values close to those obtained by high-resolution systems, in the range of 0.7°, could be theoretically obtained if a careful selection of image features was performed, demonstrating significant room for improvement for off-the-shelf eye tracking systems.

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Sun, Wenyuan, Jihao Liu, Yuyun Zhao, and Guoyan Zheng. "A Novel Point Set Registration-Based Hand–Eye Calibration Method for Robot-Assisted Surgery." Sensors 22, no. 21 (November 3, 2022): 8446. http://dx.doi.org/10.3390/s22218446.

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Pedicle screw insertion with robot assistance dramatically improves surgical accuracy and safety when compared with manual implantation. In developing such a system, hand–eye calibration is an essential component that aims to determine the transformation between a position tracking and robot-arm systems. In this paper, we propose an effective hand–eye calibration method, namely registration-based hand–eye calibration (RHC), which estimates the calibration transformation via point set registration without the need to solve the AX=XB equation. Our hand–eye calibration method consists of tool-tip pivot calibrations in two-coordinate systems, in addition to paired-point matching, where the point pairs are generated via the steady movement of the robot arm in space. After calibration, our system allows for robot-assisted, image-guided pedicle screw insertion. Comprehensive experiments are conducted to verify the efficacy of the proposed hand–eye calibration method. A mean distance deviation of 0.70 mm and a mean angular deviation of 0.68° are achieved by our system when the proposed hand–eye calibration method is used. Further experiments on drilling trajectories are conducted on plastic vertebrae as well as pig vertebrae. A mean distance deviation of 1.01 mm and a mean angular deviation of 1.11° are observed when the drilled trajectories are compared with the planned trajectories on the pig vertebrae.

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Coughlin, M. J., T. R. H. Cutmore, and T. J. Hine. "Automated eye tracking system calibration using artificial neural networks." Computer Methods and Programs in Biomedicine 76, no. 3 (December 2004): 207–20. http://dx.doi.org/10.1016/j.cmpb.2004.06.001.

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Mao, Shuai, Jin Shen, Yajing Wang, Wei Liu, and Jinfeng Pan. "A Three-Dimensional Tracking Method with the Self-Calibration Functions of Coaxiality and Magnification for Single Fluorescent Nanoparticles." Applied Sciences 10, no. 1 (December 23, 2019): 131. http://dx.doi.org/10.3390/app10010131.

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A self-calibrating variable magnification three-dimensional (3D) tracking system for single fluorescent nanoparticles is proposed. The system was based on astigmatic micro-imaging and has a simple configuration incorporating a dual-spot position detection unit ray transfer matrix. By analyzing this matrix and utilizing the beam vector measurement of a dual-spot position detection unit, it was demonstrated that the proposed tracking system had the self-calibration functions of coaxiality and magnification; thus, it could accurately track the adopted fluorescent nanoparticles through zoom microscopical measurements in 3D. The available measurements of the proposed system and accuracy were experimentally validated.

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Mokatren, Moayad, Tsvi Kuflik, and Ilan Shimshoni. "Calibration-Free Mobile Eye-Tracking Using Corneal Imaging." Sensors 24, no. 4 (February 15, 2024): 1237. http://dx.doi.org/10.3390/s24041237.

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In this paper, we present and evaluate a calibration-free mobile eye-traking system. The system’s mobile device consists of three cameras: an IR eye camera, an RGB eye camera, and a front-scene RGB camera. The three cameras build a reliable corneal imaging system that is used to estimate the user’s point of gaze continuously and reliably. The system auto-calibrates the device unobtrusively. Since the user is not required to follow any special instructions to calibrate the system, they can simply put on the eye tracker and start moving around using it. Deep learning algorithms together with 3D geometric computations were used to auto-calibrate the system per user. Once the model is built, a point-to-point transformation from the eye camera to the front camera is computed automatically by matching corneal and scene images, which allows the gaze point in the scene image to be estimated. The system was evaluated by users in real-life scenarios, indoors and outdoors. The average gaze error was 1.6∘ indoors and 1.69∘ outdoors, which is considered very good compared to state-of-the-art approaches.

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Li, Ruijin, Liming Zhang, Xianhua Wang, Weiwei Xu, Xin Li, Jiawei Li, and Chunhui Hu. "High-Precision Automatic Calibration Modeling of Point Light Source Tracking Systems." Sensors 21, no. 7 (March 24, 2021): 2270. http://dx.doi.org/10.3390/s21072270.

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To realize high-precision and high-frequency unattended site calibration and detection of satellites, automatic direction adjustment must be implemented in mirror arrays. This paper proposes a high-precision automatic calibration model based on a novel point light source tracking system for mirror arrays. A camera automatically observes the solar vector, and an observation equation coupling the image space and local coordinate systems is established. High-precision calibration of the system is realized through geometric error calculation of multipoint observation data. Moreover, model error analysis and solar tracking verification experiments are conducted. The standard deviations of the pitch angle and azimuth angle errors are 0.0176° and 0.0305°, respectively. The root mean square errors of the image centroid contrast are 2.0995 and 0.8689 pixels along the x- and y-axes, respectively. The corresponding pixel angular resolution errors are 0.0377° and 0.0144°, and the comprehensive angle resolution error is 0.0403°. The calculated model values are consistent with the measured data, validating the model. The proposed point light source tracking system can satisfy the requirements of high-resolution, high-precision, high-frequency on-orbit satellite radiometric calibration and modulation transfer function detection.

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Martínez del Horno, Miguel, Ismael García-Varea, and Luis Orozco Barbosa. "Calibration of Wi-Fi-Based Indoor Tracking Systems for Android-Based Smartphones." Remote Sensing 11, no. 9 (May 6, 2019): 1072. http://dx.doi.org/10.3390/rs11091072.

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With the growing development of smartphones equipped with Wi-Fi technology and the need of inexpensive indoor location systems, many researchers are focusing their efforts on the development of Wi-Fi-based indoor localization methods. However, due to the difficulties in characterizing the Wi-Fi radio signal propagation in such environments, the development of universal indoor localization mechanisms is still an open issue. In this paper, we focus on the calibration of Wi-Fi-based indoor tracking systems to be used by smartphones. The primary goal is to build an accurate and robust Wi-Fi signal propagation representation in indoor scenarios.We analyze the suitability of our approach in a smartphone-based indoor tracking system by introducing a novel in-motion calibration methodology using three different signal propagation characterizations supplemented with a particle filter. We compare the results obtained with each one of the three characterization in-motion calibration methodologies and those obtained using a static calibration approach, in a real-world scenario. Based on our experimental results, we show that the use of an in-motion calibration mechanism considerably improves the tracking accuracy.

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Odenbach, Robert, Niklas Thoma, Hendrik Mattern, and Michael Friebe. "Remotely controllable phantom rotation system for ultra-high field MRI to improve Cross Calibration." Current Directions in Biomedical Engineering 5, no. 1 (September 1, 2019): 429–31. http://dx.doi.org/10.1515/cdbme-2019-1570538325.

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AbstractOptical tracking systems, such as the Moiré Phase Tracking system (MPT), can be used to correct motion prospectively especially during magnetic resonance imaging (MRI, MR) in neurologic application. For that an MRI safe camera is mounted in the MRI bore to detect motion by tracking a specific MPT marker, which is rigidly attached on the subject’s head. To enable prospective updates of the imaging volume´s position and orientation, and therefore to correct motion from the subject, the motion information captured from the camera need to be transformed from the camera into the MR coordinate system. The process of finding the transformation between both coordinate systems is called cross calibration and is essential for the overall motion correction performance. For the procedure of the cross calibration, an MR visible phantom with an attached MPT-marker is measured simultaneously with MRI and the MPT camera in multiple specific alignment positions. To reduce cross calibration errors, it is essential to move the phantom precisely into specified alignment positions. Due to the long and narrow bore design of ultra-high field systems (tunnel length > 3 m), the phantom can not be moved simply from a person leaning inside the scanner bore. Thus, to rotate it after each measurement step, either a technician must work inside the tunnel during the complete period of the cross calibration or the table must be moved in and out of the bore multiple times. To improve this currently established cross calibration procedure, we have developed an MRI safe phantom rotation system, which can be controlled remotely and precisely from outside the MRI bore. Even for ultra-high field imaging, the rotation system is fully MRI compatible. Initial tests were performed at a 7T whole-body MRI system and have proven the benefit of our rotation system.

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Nguyen, Quoc Khanh, Seungman Kim, Seong-Heum Han, Seung-Kook Ro, Seung-Woo Kim, Young-Jin Kim, Wooram Kim, and Jeong Seok Oh. "Improved Self-Calibration of a Multilateration System Based on Absolute Distance Measurement." Sensors 20, no. 24 (December 18, 2020): 7288. http://dx.doi.org/10.3390/s20247288.

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Multilateration tracking systems (MLTSs) are used in industrial three-dimensional (3D) coordinate measuring applications. For high-precision measurement, system parameters must be calibrated properly in advance. For an MLTS using absolute distance measurement (ADM), the conventional self-calibration method significantly reduces estimation efficiency because all system parameters are estimated simultaneously using a complicated residual function. This paper presents a novel self-calibration method that optimizes ADM to reduce the number of system parameters via highly precise and separate estimations of dead paths. Therefore, the residual function to estimate the tracking station locations can be simplified. By applying a suitable mathematical procedure and solving the initial guess problem without the aid of an external device, estimation accuracy of the system parameters is significantly improved. In three self-calibration experiments, with ADM repeatability of approximately 3.4 µm, the maximum deviation of the system parameters estimated by the proposed self-calibration method was 68.6 µm, while the maximum deviation estimated by the conventional self-calibration method was 711.9 µm. Validation of 3D coordinate measurements in a 1000 mm × 1000 mm × 1000 mm volume showed good agreement between the proposed ADM-based MLTS and a commercial laser tracker, where the maximum difference based on the standard deviation was 17.7 µm. Conversely, the maximum difference was 98.8 µm using the conventional self-calibration method. These results confirmed the efficiency and feasibility of the proposed self-calibration method.

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Goswami, Mrinal, Somnath Mahato, Rowdra Ghatak, and Anindya Bose. "Potential of Multi constellation Global Navigation Satellite System in Indian Missile Test Range Applications." Defence Science Journal 70, no. 6 (October 12, 2020): 682–91. http://dx.doi.org/10.14429/dsj.70.15570.

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In this paper, the potentials of using Global Navigation Satellite System (GNSS) techniques in the complex calibration procedure of the tracking sensors for missile test range applications have been presented. The frequently used tracking sensors in test range applications are- electro-optical tracking stations (EOTS) and tracking radars. Over the years, the EOTS are used as the reference for bias estimation of the radars. With the introduction of GPS in test range applications, especially the DGPS, the reference for bias estimation got shifted to DGPS from the EOTS. However, the achievable position solution accuracy is limited to the order of a few meters for DGPS, EOTS, and Radars. With the evolution of Multi-constellation GNSS and carrier-phase based measurement techniques in satellite navigation, achievable position solution accuracies may be improved to sub-meter level. New navigation techniques like real time kinematic (RTK) and precise point positioning have the potentials for use in the calibration procedures of the missile test ranges to the accuracies of centimeter-level. Moreover, because of the availability of a large number of navigation signals over the Indian region, multi-constellation GNSS receivers can enhance signal availability, reliability, and accuracies during the calibration of missile test ranges. Currently available compact, low-cost GNSS modules also offer the possibilities of using these for cost-effective, networked RTK for dynamic calibration of test ranges reducing cost and resource requirements.

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Reimer, Dennis, Iana Podkosova, Daniel Scherzer, and Hannes Kaufmann. "Colocation for SLAM-Tracked VR Headsets with Hand Tracking." Computers 10, no. 5 (April 27, 2021): 58. http://dx.doi.org/10.3390/computers10050058.

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In colocated multi-user Virtual Reality applications, relative user positions in the virtual environment need to match their relative positions in the physical tracking space. A mismatch between virtual and real relative user positions might lead to harmful events such as physical user collisions. This paper examines three calibration methods that enable colocated Virtual Reality scenarios for SLAM-tracked head-mounted displays without the need for an external tracking system. Two of these methods—fixed-point calibration and marked-based calibration—have been described in previous research; the third method that uses hand tracking capabilities of head-mounted displays is novel. We evaluated the accuracy of these three methods in an experimental procedure with two colocated Oculus Quest devices. The results of the evaluation show that our novel hand tracking-based calibration method provides better accuracy and consistency while at the same time being easy to execute. The paper further discusses the potential of all evaluated calibration methods.

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Liu, Jihao, Wenyuan Sun, Yuyun Zhao, and Guoyan Zheng. "Ultrasound Probe and Hand-Eye Calibrations for Robot-Assisted Needle Biopsy." Sensors 22, no. 23 (December 3, 2022): 9465. http://dx.doi.org/10.3390/s22239465.

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In robot-assisted ultrasound-guided needle biopsy, it is essential to conduct calibration of the ultrasound probe and to perform hand-eye calibration of the robot in order to establish a link between intra-operatively acquired ultrasound images and robot-assisted needle insertion. Based on a high-precision optical tracking system, novel methods for ultrasound probe and robot hand-eye calibration are proposed. Specifically, we first fix optically trackable markers to the ultrasound probe and to the robot, respectively. We then design a five-wire phantom to calibrate the ultrasound probe. Finally, an effective method taking advantage of steady movement of the robot but without an additional calibration frame or the need to solve the AX=XB equation is proposed for hand-eye calibration. After calibrations, our system allows for in situ definition of target lesions and aiming trajectories from intra-operatively acquired ultrasound images in order to align the robot for precise needle biopsy. Comprehensive experiments were conducted to evaluate accuracy of different components of our system as well as the overall system accuracy. Experiment results demonstrated the efficacy of the proposed methods.

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Liu, Jiahui, Jiannan Chi, and Hang Sun. "An Automatic Calibration Method for Kappa Angle Based on a Binocular Gaze Constraint." Sensors 23, no. 8 (April 12, 2023): 3929. http://dx.doi.org/10.3390/s23083929.

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Kappa-angle calibration shows its importance in gaze tracking due to the special structure of the eyeball. In a 3D gaze-tracking system, after the optical axis of the eyeball is reconstructed, the kappa angle is needed to convert the optical axis of the eyeball to the real gaze direction. At present, most of the kappa-angle-calibration methods use explicit user calibration. Before eye-gaze tracking, the user needs to look at some pre-defined calibration points on the screen, thereby providing some corresponding optical and visual axes of the eyeball with which to calculate the kappa angle. Especially when multi-point user calibration is required, the calibration process is relatively complicated. In this paper, a method that can automatically calibrate the kappa angle during screen browsing is proposed. Based on the 3D corneal centers and optical axes of both eyes, the optimal objective function of the kappa angle is established according to the coplanar constraint of the visual axes of the left and right eyes, and the differential evolution algorithm is used to iterate through kappa angles according to the theoretical angular constraint of the kappa angle. The experiments show that the proposed method can make the gaze accuracy reach 1.3° in the horizontal plane and 1.34° in the vertical plane, both of which are within the acceptable margins of gaze-estimation error. The demonstration of explicit kappa-angle calibration is of great significance to the realization of the instant use of gaze-tracking systems.

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Wen Qingchuan, 温晴川, 达飞鹏 Da Feipeng, and 方旭 Fang Xu. "Calibration for Gaze Tracking System Based on Binocular Stereo Vision." Acta Optica Sinica 32, no. 10 (2012): 1015002. http://dx.doi.org/10.3788/aos201232.1015002.

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Ebisawa, Yoshinobu, Kazuki Abo, and Kiyotaka Fukumoto. "Remote Eye-gaze Tracking System by One-point Gaze Calibration." Journal of The Institute of Image Information and Television Engineers 65, no. 12 (2011): 1768–75. http://dx.doi.org/10.3169/itej.65.1768.

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Jiang, Tao, Haihua Cui, and Xiaosheng Cheng. "Accurate Calibration for Large-Scale Tracking-Based Visual Measurement System." IEEE Transactions on Instrumentation and Measurement 70 (2021): 1–11. http://dx.doi.org/10.1109/tim.2020.3016412.

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Yoon, Hyo Sik, Hyung Gil Hong, Dong Eun Lee, and Kang Ryoung Park. "Driver’s eye-based gaze tracking system by one-point calibration." Multimedia Tools and Applications 78, no. 6 (August 7, 2018): 7155–79. http://dx.doi.org/10.1007/s11042-018-6490-7.

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Takegami, Takeshi, Toshiyuki Gotoh, and Ghen Ohyama. "An algorithm for an eye tracking system with self-calibration." Systems and Computers in Japan 33, no. 10 (July 2, 2002): 10–20. http://dx.doi.org/10.1002/scj.10125.

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Bi, Songlin, Yonggang Gu, Jiaqi Zou, Lianpo Wang, Chao Zhai, and Ming Gong. "High Precision Optical Tracking System Based on near Infrared Trinocular Stereo Vision." Sensors 21, no. 7 (April 4, 2021): 2528. http://dx.doi.org/10.3390/s21072528.

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A high precision optical tracking system (OTS) based on near infrared (NIR) trinocular stereo vision (TSV) is presented in this paper. Compared with the traditional OTS on the basis of binocular stereo vision (BSV), hardware and software are improved. In the hardware aspect, a NIR TSV platform is built, and a new active tool is designed. Imaging markers of the tool are uniform and complete with large measurement angle (>60°). In the software aspect, the deployment of extra camera brings high computational complexity. To reduce the computational burden, a fast nearest neighbor feature point extraction algorithm (FNNF) is proposed. The proposed method increases the speed of feature points extraction by hundreds of times over the traditional pixel-by-pixel searching method. The modified NIR multi-camera calibration method and 3D reconstruction algorithm further improve the tracking accuracy. Experimental results show that the calibration accuracy of the NIR camera can reach 0.02%, positioning accuracy of markers can reach 0.0240 mm, and dynamic tracking accuracy can reach 0.0938 mm. OTS can be adopted in high-precision dynamic tracking.

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Cheng, Jun Ting, C. Zhao, and W. T. He. "Research and Realization of Auto-Calibration Technique Based on Structured Grating 3D Measuring System." Applied Mechanics and Materials 10-12 (December 2007): 594–98. http://dx.doi.org/10.4028/www.scientific.net/amm.10-12.594.

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This paper introduced present application in the world and some problems in the calibration technique of 3D measuring system. Auto-calibration technique of multiple targets tracking for detecting outline based on random placement and regular number is put forward. At the same time, the concrete algorithm is given. Then, according to the algorithm, the corresponding experimental result is obtained. Furthermore, the calibration accuracy is compared and analyzed. Finally, it comes to a conclusion that this algorithm can make the operation more simple and convenient. And the calibration accuracy is kept within 0.03mm.

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Zhang, Xi, Yuanzhi Xu, Haichao Li, Lijing Zhu, Xin Wang, and Wei Li. "Flexible method for accurate calibration of large-scale vision metrology system based on virtual 3-D targets and laser tracker." International Journal of Advanced Robotic Systems 16, no. 6 (November 1, 2019): 172988141989351. http://dx.doi.org/10.1177/1729881419893516.

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For the purpose of obtaining high-precision in stereo vision calibration, a large-size precise calibration target, which can cover more than half of the field of view is vital. However, large-scale calibration targets are very difficult to fabricate. Based on the idea of error tracing, a high-precision calibration method for vision system with large field of view by constructing a virtual 3-D calibration target with a laser tracker was proposed in this article. A virtual 3-D calibration target that covers the whole measurement space can be established flexibly and the measurement precision of the vision system can be traceable to the laser tracker. First, virtual 3-D targets by calculating rigid body transformation with unit quaternion method were constructed. Then, the high-order distortion camera model was taken into consideration. Besides, the calibration parameters were solved with Levenberg–Marquardt optimization algorithm. In the experiment, a binocular stereo vision system with the field of view of 4 × 3 × 2 m3 was built for verifying the validity and precision of the proposed calibration method. It is measured that the accuracy with the proposed method can be greatly improved comparing with traditional plane calibration method. The method can be widely used in industrial applications, such as in the field of calibrating large-scale vision-based coordinate metrology, and six-degrees of freedom pose tracking system for dimensional measurement of workpiece, as well as robotics geometrical accuracy detection and compensation.

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Shi, Lin, Baofeng Guo, Juntao Ma, Chaoxuan Shang, and Huiyan Zeng. "A Novel Channel Calibration Method for Bistatic ISAR Imaging System." Applied Sciences 8, no. 11 (November 5, 2018): 2160. http://dx.doi.org/10.3390/app8112160.

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In practical bistatic inverse synthetic aperture radar (ISAR) imaging systems, the echo signals are modulated by non-ideal amplitude and phase characteristics of the transmitting and receiving channels, which seriously distorts image quality. However, the conventional channel calibration method based on a transponder is not applicable to bistatic ISAR imaging systems, since the baseline of the system is up to hundreds of kilometers. A channel calibration method only using calibration satellite echo information is proposed for the system, with a linear frequency modulation (LFM) waveform. Firstly, echoes of the calibration satellite are collected by tracking the satellite and multi-period echoes are aligned in the time domain, according to the pulse compression result. Then, the signal to noise ratio (SNR) is improved by accumulating multi-period echoes coherently in the time domain and the calibration coefficient is constructed based on the accumulated signal. Finally, spectrum of the echo signal is multiplied with the calibration coefficient to compensate the influence of channel characteristics. The effectiveness of the proposed method is verified by the simulation experiment with real satellite echoes.

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Cheng, Ran, Zhihua Liu, Guodong Zhai, Qi Lv, Ming Yang, and Chenguang Cai. "High-Acceleration Vibration Calibration System Based on Phase-Locked Resonance Control." Sensors 22, no. 19 (September 23, 2022): 7208. http://dx.doi.org/10.3390/s22197208.

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In order to ensure the measurement accuracy of high-acceleration vibration sensors used in engineering applications, it is necessary to calibrate their key performance parameters at high acceleration. The high-acceleration vibration calibration system produces high-acceleration vibration by utilizing the resonance amplification principle; however, the resonance frequency of the resonant beam changes with increasing amplitude, affected by the influences of nonlinear and other factors. In this study, a phase-locked resonance tracking control method based on the phase resonance principle is proposed to accurately and quickly track the resonance frequency of the resonant beam, which can improve the accuracy and stability of resonance control. The resonant beam is able to produce stable vibration with an amplitude exceeding 7500 m/s2 by phase-locking and tracking the resonant frequency. A calibration system built with this method can provide stable vibration with an amplitude of 500–10,000 m/s2 in the range of 80–4000 Hz. Comparison experiments with the commonly used amplitude iteration amplification method demonstrate that the proposed method can give an acceleration stability control index of less than 0.5% and a resonance tracking time of less than 0.1 s.

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Chi, J. N., Y. Y. Xing, L. N. Liu, W. W. Gou, and G. S. Zhang. "Calibration method for 3D gaze tracking systems." Applied Optics 56, no. 5 (February 10, 2017): 1536. http://dx.doi.org/10.1364/ao.56.001536.

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Zhuang, Hanqi, Shui H. Motaghedi, Zvi S. Roth, and Ying Bai. "Calibration of multi-beam laser tracking systems." Robotics and Computer-Integrated Manufacturing 19, no. 4 (August 2003): 301–14. http://dx.doi.org/10.1016/s0736-5845(02)00076-5.

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Küderle, Arne, Sebastian Becker, and Catherine Disselhorst-Klug. "Increasing the Robustness of the automatic IMU calibration for lower Extremity Motion Analysis." Current Directions in Biomedical Engineering 4, no. 1 (September 1, 2018): 439–42. http://dx.doi.org/10.1515/cdbme-2018-0104.

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AbstractWith the advances of IMU-based human motion tracking, joint angle tracking in an home environment has become a realistic goal. Achieving it, could enable novel applications in rehabilitation and sports medicine. However, in existing systems the process of aligning the mounted sensors with the body coordinate system is either not robust enough or to complicated for fully unsupervised usage. In this publication the performance of a promising existing algorithm is evaluated with a range of different calibration motions. Further, an extension to this implementation is proposed, aiming to improve its stability when only non-ideal calibration data is available. It could be validated that the modification of the algorithm can increase the stability and reduce the dependency of the calibration on specific calibration motions. Based on these results, we recommend the proposed extension of the algorithm as a drop-in replacement for the existing implementation.

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Kim, Hyuno, Yuji Yamakawa, and Masatoshi Ishikawa. "Seamless Multiple-Target Tracking Method Across Overlapped Multiple Camera Views Using High-Speed Image Capture." Journal of Robotics and Mechatronics 34, no. 5 (October 20, 2022): 1043–52. http://dx.doi.org/10.20965/jrm.2022.p1043.

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Multiple-target tracking across multiple camera views is required for various practical tracking and surveillance applications. This study proposes a seamless tracking method based on label transfer using high-speed image capture. The proposed method does not require camera calibration to estimate the extrinsic parameters, and can be applied with simple line calibration. Therefore, it is effective for large-scale camera networks. In addition, owing to the features of the high-speed image capture and self-window, our method ensures seamless tracking of objects across multiple camera views. The feasibility of the method is proven through an experiment using a high-speed camera network system.

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Chen, Le Yang, and Fan Zhang. "Research on Information Engineering with Infrared Camera Measurement in Eye Tracking Technology." Advanced Materials Research 952 (May 2014): 257–60. http://dx.doi.org/10.4028/www.scientific.net/amr.952.257.

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The thesis provides detail research on eye movement device theory and realization with infrared camera. It discusses pupil coordinate system and field of view coordinate system, calibration and displaying of real-time eye movement measure for eye tracking device, calibration algorithm for actual focus point calculation by pupil center position, and analysis of Eye movement device.

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Alghamdi, Ahmed A., Thaar M. Aljuwaya, Abdullah S. Alomari, and Muthanna H. Al-Dahhan. "GEANT4 Simulation for Radioactive Particle Tracking (RPT) Technique." Sensors 22, no. 3 (February 5, 2022): 1223. http://dx.doi.org/10.3390/s22031223.

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In the past two decades, the radioactive particle tracking (RPT) measurement technique has been proven to visualize flow fields of most multiphase flow systems of industrial interest. The accuracy of RPT, and hence the data obtained, depend largely on the calibration process, which stands here as a basis for two subsequent processes: tracking and reconstruction. However, limitations in the RPT calibration process can be found in different experimental constrains and in assumptions made in the classical Monte Carlo approach used to simulate number of counts received by the detectors. Therefore, in this work, we applied a GEANT4-based Monte Carlo code to simulate the RPT calibration process for an investigated multiphase flow system (i.e., gas–liquid bubble column). The GEANT4 code was performed to simulate the number of counts received by 28 scintillation detectors for 931 known tracer positions while capturing all the types of photon interaction and overcoming solids’ angle limitations in classical approaches. The results of the simulation were validated against experimental data obtained using an automated RPT calibration device. The results showed a good agreement between the simulated and experimental counts, where the maximum absolute average relative deviation detected was about 5%. The GEANT4 model typically predicted the number of counts received by all the detectors; however, it over-estimated the counts when the number of primary events applied in the model was not the optimal.

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Wu, Chunyan, Li Yang, Zai Luo, and Wensong Jiang. "Linear Laser Scanning Measurement Method Tracking by a Binocular Vision." Sensors 22, no. 9 (May 7, 2022): 3572. http://dx.doi.org/10.3390/s22093572.

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The 3D scanning of a freeform structure relies on the laser probe and the localization system. The localization system, determining the effect of the point cloud reconstruction, will generate positioning errors when the laser probe works in complex paths with a fast speed. To reduce the errors, in this paper, a linear laser scanning measurement method is proposed based on binocular vision calibration. A simple and effective eight-point positioning marker attached to the scanner is proposed to complete the positioning and tracking procedure. Based on this, the method of marked point detection based on image moment and the principle of global coordinate system calibration are introduced in detail. According to the invariance principle of space distance, the corresponding points matching method between different coordinate systems is designed. The experimental results show that the binocular vision system can complete localization under different light intensities and complex environments, and that the repeated translation error of the binocular vision system is less than 0.22 mm, while the rotation error is less than 0.15°. The repeated error of the measurement system is less than 0.36 mm, which can meet the requirements of the 3D shape measurement of the complex workpiece.

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Han, Zhonghao, Lei Hu, Na Guo, Biao Yang, Hongsheng Liu, and Yuhan Wang. "A flexible motion tracking system based on inertial sensors." MATEC Web of Conferences 198 (2018): 04010. http://dx.doi.org/10.1051/matecconf/201819804010.

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As a newly emerging human-computer interaction, motion tracking technology offers a way to extract human motion data. This paper presents a series of techniques to improve the flexibility of the motion tracking system based on the inertial measurement units (IMUs). First, we built a most miniatured wireless tracking node by integrating an IMU, a Wi-Fi module and a power supply. Then, the data transfer rate was optimized using an asynchronous query method. Finally, to simplify the setup and make the interchangeability of all nodes possible, we designed a calibration procedure and trained a support vector machine (SVM) model to determine the binding relation between the body segments and the tracking nodes after setup. The evaluations of the whole system justify the effectiveness of proposed methods and demonstrate its advantages compared to other commercial motion tracking system.

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Adduci, M., K. Amplianitis, and R. Reulke. "A Quality Evaluation of Single and Multiple Camera Calibration Approaches for an Indoor Multi Camera Tracking System." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-5 (June 5, 2014): 9–15. http://dx.doi.org/10.5194/isprsarchives-xl-5-9-2014.

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Human detection and tracking has been a prominent research area for several scientists around the globe. State of the art algorithms have been implemented, refined and accelerated to significantly improve the detection rate and eliminate false positives. While 2D approaches are well investigated, 3D human detection and tracking is still an unexplored research field. In both 2D/3D cases, introducing a multi camera system could vastly expand the accuracy and confidence of the tracking process. Within this work, a quality evaluation is performed on a multi RGB-D camera indoor tracking system for examining how camera calibration and pose can affect the quality of human tracks in the scene, independently from the detection and tracking approach used. After performing a calibration step on every Kinect sensor, state of the art single camera pose estimators were evaluated for checking how good the quality of the poses is estimated using planar objects such as an ordinate chessboard. With this information, a bundle block adjustment and ICP were performed for verifying the accuracy of the single pose estimators in a multi camera configuration system. Results have shown that single camera estimators provide high accuracy results of less than half a pixel forcing the bundle to converge after very few iterations. In relation to ICP, relative information between cloud pairs is more or less preserved giving a low score of fitting between concatenated pairs. Finally, sensor calibration proved to be an essential step for achieving maximum accuracy in the generated point clouds, and therefore in the accuracy of the produced 3D trajectories, from each sensor.

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Yuan, S., J. Alme, M. Keil, I. Ravasenga, M. Richter, and D. Röhrich. "The charge sensitivity calibration of the upgraded ALICE Inner Tracking System." Journal of Instrumentation 17, no. 04 (April 1, 2022): C04036. http://dx.doi.org/10.1088/1748-0221/17/04/c04036.

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Abstract The ALICE detector is undergoing an upgrade for run 3 at the LHC. A new Inner Tracking System (ITS) is part of this upgrade. The upgraded ALICE ITS features the ALPIDE, a monolithic active pixel sensor. Due to IC fabrication variations and radiation damage, the threshold values for the ALPIDE chips in the ITS need to be measured and adjusted periodically to ensure the quality of data. The calibration is implemented within the ALICE Online-Offline (O2) computing system, thus it runs in the same framework as the normal operations. This paper describes the concept and first implementation of the charge sensitivity scanning procedures for the upgraded ALICE ITS in the ALICE O2 system, and demonstrates the first results of the scanning of the data taken from the installed ITS.

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Read, R. "Remote Monitoring of the Calibration of a System of Tracking Arrays." IEEE Journal of Oceanic Engineering 12, no. 1 (January 1987): 198–206. http://dx.doi.org/10.1109/joe.1987.1145244.

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Jiang, Hong, Toshiyuki Takatsuji, and Sonko Osawa. "1124 A Compact Laser Tracking System for the Calibration of CMM." Proceedings of the JSME annual meeting 2000.2 (2000): 183–84. http://dx.doi.org/10.1299/jsmemecjo.2000.2.0_183.

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Shao, Mingwei, Zhenzhong Wei, Mengjie Hu, and Guangjun Zhang. "Calibration method for a vision guiding-based laser-tracking measurement system." Measurement Science and Technology 26, no. 8 (July 14, 2015): 085009. http://dx.doi.org/10.1088/0957-0233/26/8/085009.

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Ge, Tiezhi, Mingshan Wei, Qiang Su, Longcheng Huang, and Gang Quan. "Method of Tower-less Calibration for Phase Parameter of Tracking System." MATEC Web of Conferences 22 (2015): 01016. http://dx.doi.org/10.1051/matecconf/20152201016.

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Chi, Jiannan, Zuoyun Yang, Guosheng Zhang, Tongbo Liu, and Zhiliang Wang. "A Novel Multi-Camera Global Calibration Method for Gaze Tracking System." IEEE Transactions on Instrumentation and Measurement 69, no. 5 (May 2020): 2093–104. http://dx.doi.org/10.1109/tim.2019.2922754.

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Journal articles on the topic 'System calibration and tracking'

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