Articoli di riviste: "Motion correction"

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Hagedorn, John G., Steven G. Satterfield, John T. Kelso, Whitney Austin, Judith E. Terrill e Adele P. Peskin. "Correction of Location and Orientation Errors in Electromagnetic Motion Tracking". Presence: Teleoperators and Virtual Environments 16, n. 4 (1 agosto 2007): 352–66. http://dx.doi.org/10.1162/pres.16.4.352.

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We describe a method for calibrating an electromagnetic motion tracking device. Algorithms for correcting both location and orientation data are presented. In particular, we use a method for interpolating rotation corrections that has not previously been used in this context. This method, unlike previous methods, is rooted in the geometry of the space of rotations. This interpolation method is used in conjunction with Delaunay tetrahedralization to enable correction based on scattered data samples. We present measurements that support the assumption that neither location nor orientation errors are dependent on sensor orientation. We give results showing large improvements in both location and orientation errors. The methods are shown to impose a minimal computational burden.

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Zhu, Z. "The understanding of the FK5 and Hipparcos proper-motion systems". Proceedings of the International Astronomical Union 3, S248 (ottobre 2007): 18–19. http://dx.doi.org/10.1017/s1743921308018553.

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AbstractComparing proper motions of the FK5 and Hipparcos, several authors declared that the two proper-motion systems are inconsistent with the value of the precession correction obtained from VLBI and LLR observations. Based on the proper-motion data from the PPM and ACRS catalogues which are constructed on the FK5 system, the inconsistent values of the precessional correction and of the time-dependent term of equinox correction, derived from the different subsets of stellar samples, have been found. One of the reasons for those discrepancies should be mostly due to the internally biased proper-motion system of the FK5.

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Choi, Hoon Sik, Ki Mun Kang, In Bong Ha, Bae Kwon Jeong, Jin Ho Song, Chul Hang Kim e Hojin Jeong. "Comprehensive Analysis of Set-Up Gain of 6-Dimensional Cone-Beam CT Correction Method in Radiotherapy for Head and Neck and Brain Tumors". Computational and Mathematical Methods in Medicine 2022 (20 ottobre 2022): 1–9. http://dx.doi.org/10.1155/2022/2964023.

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This study quantitatively analyzed the gain of the six-dimensional (6D) cone-beam CT (CBCT) correction method compared with the conventional set-up method in 60 patients who underwent radiation treatment of head and neck and brain tumors. The correction gain of CBCT was calculated for the translational and rotational motion components separately and in combination to evaluate the individual and overall effects of these motion components. Using a statistical simulation mimicking the actual set-up correction process, the effective gain of periodic CBCT correction during the entire treatment fraction was analyzed by target size and CBCT correction period under two different correction scenarios: translation alone and full 6D corrections. From the analyses performed in this study, the gain of CBCT correction was quantitatively determined for each situation, and the appropriate CBCT correction strategy was suggested based on treatment purpose and target size.

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Odagiri, Hayato, Hiroshi Watabe, Kentaro Takanami, Kazuma Akimoto, Akihito Usui, Hirofumi Kawakami, Akie Katsuki et al. "Verification of the effect of data-driven brain motion correction on PET imaging". PLOS ONE 19, n. 7 (5 luglio 2024): e0301919. http://dx.doi.org/10.1371/journal.pone.0301919.

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Introduction Brain positron emission tomography/computed tomography (PET/CT) scans are useful for identifying the cause of dementia by evaluating glucose metabolism in the brain with F-18-fluorodeoxyglucose or Aβ deposition with F-18-florbetaben. However, since imaging time ranges from 10 to 30 minutes, movements during the examination might result in image artifacts, which interfere with diagnosis. To solve this problem, data-driven brain motion correction (DDBMC) techniques are capable of performing motion corrected reconstruction using highly accurate motion estimates with high temporal resolution. In this study, we investigated the effectiveness of DDBMC techniques on PET/CT images using a Hoffman phantom, involving continuous rotational and tilting motion, each expanded up to approximately 20 degrees. Materials and methods Listmode imaging was performed using a Hoffman phantom that reproduced rotational and tilting motions of the head. Brain motion correction processing was performed on the obtained data. Reconstructed images with and without brain motion correction processing were compared. Visual evaluations by a nuclear medicine specialist and quantitative parameters of images with correction and reference still images were compared. Results Normalized Mean Squared Error (NMSE) results demonstrated the effectiveness of DDBMC in compensating for rotational and tilting motions during PET imaging. In Cases 1 and 2 involving rotational motion, NMSE decreased from 0.15–0.2 to approximately 0.01 with DDBMC, indicating a substantial reduction in differences from the reference image across various brain regions. In the Structural Similarity Index (SSIM), DDBMC improved it to above 0.96 Contrast assessment revealed notable improvements with DDBMC. In continuous rotational motion, % contrast increased from 42.4% to 73.5%, In tilting motion, % contrast increased from 52.3% to 64.5%, eliminating significant differences from the static reference image. These findings underscore the efficacy of DDBMC in enhancing image contrast and minimizing motion induced variations across different motion scenarios. Conclusions DDBMC processing can effectively compensate for continuous rotational and tilting motion of the head during PET, with motion angles of approximately 20 degrees. However, a significant limitation of this study is the exclusive validation of the proposed method using a Hoffman phantom; its applicability to the human brain has not been investigated. Further research involving human subjects is necessary to assess the generalizability and reliability of the presented motion correction technique in real clinical scenarios.

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Zahneisen, Benjamin, Brian Keating, Aditya Singh, Michael Herbst e Thomas Ernst. "Reverse retrospective motion correction". Magnetic Resonance in Medicine 75, n. 6 (3 luglio 2015): 2341–49. http://dx.doi.org/10.1002/mrm.25830.

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Miyamoto, Masanori. "Is the Vorticity Vector of the Galaxy Perpendicular to the Galactic Plane?" Symposium - International Astronomical Union 156 (1993): 219–30. http://dx.doi.org/10.1017/s0074180900173255.

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The modern astrometric catalogue ACRS invites attempts to re-examine the systematic stellar motions, together with the luni-solar precessional correction and the fictitious equinoctial motion correction to the FK5 system, and gives encouraging results.On the basis of the three-dimensional Ogorodnikov-Milne model for the overall pattern analysis of the proper motions, the systematic stellar velocity field of about 30000 K-M giants chosen from the ACRS is first examined in the heliocentric distance interval 0.5 to 1.0 kpc. We have found in an iterative fashion a solution for the K-M giants that yields neither deformation-nor vorticity-field other than the classical ones (the Oort constants A and B). The important point to note here is that the generally accepted idea such that the K-M giants are a steady-state constituent of the galaxy is compatible with the luni-solar precessional correction proposed by the VLBI and LLR observations. The K-M giants give the rational set of corrections to the FK5 system: the luni-solar precessional correction Δp = −0″.27 ± 0″.03 / cent and the equinoctial motion correction including the planetary precessional correction Δe + Δλ = −0″.12 ± 0″.03 / cent. Thus, the precessional correction previously proposed with the modern techniques has been confirmed by the pattern analysis of the proper motions.Next, applying the corrections obtained above, we have performed the overall pattern analysis of the proper motions of about 3000 O-B5 stars, supergiants, and bright giants, which are chosen again from the ACRS, and considered as an entity of the galactic warp. It is found that the kinematics of these stars is quite different from that of K-M giants. These stars show additional shears and rotations around two mutually orthogonal axes lying in the galactic plane, besides the classical ones. The present finding implies that the young stars are streaming around the galactic center in a tilted sheet (the warp) with the velocity of 225 km/s, and the sheet itself is simultaneously rotating around the nodal line of the warp (galactic center — sun — anticenter line) with the angular velocity of 4 km/s/kpc in increasing sense of the present inclination of the warp.

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Polycarpou, Irene, Georgios Soultanidis e Charalampos Tsoumpas. "Synergistic motion compensation strategies for positron emission tomography when acquired simultaneously with magnetic resonance imaging". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379, n. 2204 (5 luglio 2021): 20200207. http://dx.doi.org/10.1098/rsta.2020.0207.

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Subject motion in positron emission tomography (PET) is a key factor that degrades image resolution and quality, limiting its potential capabilities. Correcting for it is complicated due to the lack of sufficient measured PET data from each position. This poses a significant barrier in calculating the amount of motion occurring during a scan. Motion correction can be implemented at different stages of data processing either during or after image reconstruction, and once applied accurately can substantially improve image quality and information accuracy. With the development of integrated PET-MRI (magnetic resonance imaging) scanners, internal organ motion can be measured concurrently with both PET and MRI. In this review paper, we explore the synergistic use of PET and MRI data to correct for any motion that affects the PET images. Different types of motion that can occur during PET-MRI acquisitions are presented and the associated motion detection, estimation and correction methods are reviewed. Finally, some highlights from recent literature in selected human and animal imaging applications are presented and the importance of motion correction for accurate kinetic modelling in dynamic PET-MRI is emphasized. This article is part of the theme issue ‘Synergistic tomographic image reconstruction: part 2’.

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Yang, Yongzhong, e Lingfeng Meng. "Physical Education Motion Correction System Based on Virtual Reality Technology". International Journal of Emerging Technologies in Learning (iJET) 14, n. 13 (15 luglio 2019): 105. http://dx.doi.org/10.3991/ijet.v14i13.10710.

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Compared with traditional physical education (PE), the computer virtual digital-based education system is convenient and efficient, which can effectively solve the shortcomings of traditional teaching mode, and correct the PE motions in real time. Thus, the athletes can master the motion technical skills as soon as possible and the training effect can be improved. For this, based on computer virtual reality technology, this paper constructs a PE motion correction system. Then, through the analysis for real-time motion data and human movement posture, it achieves the training objective of real-time PE teaching motion correction under the three-dimensional visualization. This shall provide a scientific basis for the evaluation of PE teaching and training methods.

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Mouchantaf, Mark, Marco Parisi, Gregorio Secci, Manon Biegun, Mikael Chelli, Philipp Schippers e Pascal Boileau. "Optimizing range of motion in reverse shoulder arthroplasty". Bone & Joint Open 5, n. 10 (10 ottobre 2024): 851–57. http://dx.doi.org/10.1302/2633-1462.510.bjo-2024-0097.r1.

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AimsOptimal glenoid positioning in reverse shoulder arthroplasty (RSA) is crucial to provide impingement-free range of motion (ROM). Lateralization and inclination correction are not yet systematically used. Using planning software, we simulated the most used glenoid implant positions. The primary goal was to determine the configuration that delivers the best theoretical impingement-free ROM.MethodsWith the use of a 3D planning software (Blueprint) for RSA, 41 shoulders in 41 consecutive patients (17 males and 24 females; means age 73 years (SD 7)) undergoing RSA were planned. For the same anteroposterior positioning and retroversion of the glenoid implant, four different glenoid baseplate configurations were used on each shoulder to compare ROM: 1) no correction of the RSA angle and no lateralization (C-L-); 2) correction of the RSA angle with medialization by inferior reaming (C+M+); 3) correction of the RSA angle without lateralization by superior compensation (C+L-); and 4) correction of the RSA angle and additional lateralization (C+L+). The same humeral inlay implant and positioning were used on the humeral side for the four different glenoid configurations with a 3 mm symmetric 135° inclined polyethylene liner.ResultsThe configuration with lateralization and correction of the RSA angle (C+L+) led to better ROM in flexion, extension, adduction, and external rotation (p ≤ 0.001). Only internal rotation was not significantly different between groups (p = 0.388). The configuration where correction of the inclination was done by medialization (C+M+) led to the worst ROM in adduction, extension, abduction, flexion, and external rotation of the shoulder.ConclusionOur software study shows that, when using a 135° inlay reversed humeral implant, correcting glenoid inclination (RSA angle 0°) and lateralizing the glenoid component by using an angled bony or metallic augment of 8 to 10 mm provides optimal impingement-free ROM.Cite this article: Bone Jt Open 2024;5(10):851–857.

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Wang, Tao, Hongbo Zhang e Guojian Tang. "Predictor-corrector guidance for entry vehicle based on fuzzy logic". Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, n. 2 (3 novembre 2017): 472–82. http://dx.doi.org/10.1177/0954410017737574.

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With the development of aerospace industry, the guidance system of an entry vehicle will be more robust, reliable and autonomous in the future. Based on fuzzy logic, the paper designs a predictor-corrector guidance law. The trajectory prediction is realized by numerical integration. The correction system is based on two fuzzy controllers, which correct the longitudinal motion and lateral motion synergistically. The error of flight range is eliminated by correcting the magnitude of bank angle. The altitude error is eliminated by correcting the attack angle. The lateral error is eliminated by regulating the reversal time of bank angle. Comparing with the traditional corrector based on Newton-Raphson iteration, the method in this paper only needs a single trajectory prediction in one correction cycle, which is favorable for on-board calculation. Moreover, the longitudinal motion and lateral motion are synergistically corrected in the predictor-corrector, which makes the method more robust and flexible.

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Cabas, Ashly, e Adrian Rodriguez-Marek. "VS-κ0 Correction Factors for Input Ground Motions Used in Seismic Site Response Analyses". Earthquake Spectra 33, n. 3 (agosto 2017): 917–41. http://dx.doi.org/10.1193/22315eqs188m.

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Input motions used in seismic site response analyses are commonly selected based on similarities between the shear wave velocity ( V S) at the recording station, and the reference depth at the site of interest (among other aspects such as the intensity of the expected ground motion). This traditional approach disregards the influence of the attenuation in the shallow crust on site response. Given that this attenuation (damping) can be characterized by the distance-independent high-frequency attenuation parameter κ0, a V S -κ0 correction framework for input motions is proposed to render them compatible with the assumed properties of the reference depth at the site. The proposed correction factors were applied to a subset of recordings from the KiK-net database, and compared to traditional deconvolution. Results indicate that V S -κ0 corrected motions outperform deconvolved motions in the characterization of the spectral energy in the high-frequency range. However, motions recorded at sites with soft deposits are not good candidates for the V S -κ0 correction approach. V S -κ0 corrections also affect amplification functions which are important in the assessment of site-specific seismic hazards.

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Wang, Haiying. "Three-Dimensional Image Recognition of Athletes' Wrong Motions Based on Edge Detection". Journal Européen des Systèmes Automatisés 53, n. 5 (15 novembre 2020): 733–38. http://dx.doi.org/10.18280/jesa.530516.

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The traditional 3D visual motion amplitude tracking algorithms cannot acquire the complete contour features, not to mention the correction of wrong motions in sports training. To solve the problem, this paper designs a 3D visual image recognition method based on contourlet domain edge detection, and applies it to the recognition of athlete’s wrong motions in sports training. Firstly, the visual reconstruction and feature analysis of human motions were carried out, and the edge detection features were extracted by edge detection algorithm. Then, a 3D visual motion amplitude tracking method was proposed based on improved inverse kinematics. The simulation results show that the proposed algorithm can effectively realize the recognition of 3D visual images of athlete motions, and improve the correction and judgment ability of athlete motions.

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Cha, Sungho, Jaehyuk Hur, Sung-Su Kim, Taehyung Kim e Joonseo Yim. "Quantification Method for Video Motion Correction Performance in Mobile Image Sensor". Electronic Imaging 2020, n. 9 (26 gennaio 2020): 320–1. http://dx.doi.org/10.2352/issn.2470-1173.2020.9.iqsp-320.

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The state-of-the art smartphones have a motion correction function such as an electric image stabilizer and record the video without shaking. As the motion is corrected in various ways according to the set maker, there is a difference in performance and it is difficult to distinguish clearly its performance. This paper defines the Effective angle of View and Motion, for video motion correction performance evaluation. In the case of motion, we classified the motion volume, motion standard deviation, and motion frequency parameters. The performance of motion correction on the electronic device can be scored for each of parameters. In this way, the motion correction performance can be objectively modelled and evaluated.

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Gräfe, Moritz, Vasilis Pettas, Julia Gottschall e Po Wen Cheng. "Quantification and correction of motion influence for nacelle-based lidar systems on floating wind turbines". Wind Energy Science 8, n. 6 (6 giugno 2023): 925–46. http://dx.doi.org/10.5194/wes-8-925-2023.

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Abstract. Inflow wind field measurements from nacelle-based lidar systems offer great potential for different applications including turbine control, load validation, and power performance measurements. On floating wind turbines nacelle-based lidar measurements are affected by the dynamic behavior of the floating foundations. Therefore, the effects on lidar wind speed measurements induced by floater dynamics must be understood. In this work, we investigate the influence of floater motions on wind speed measurements from forward-looking nacelle-based lidar systems mounted on floating offshore wind turbines (FOWTs) and suggest approaches for correcting motion-induced effects. We use an analytical model, employing the guide for the expression of uncertainty in measurements (GUM) methodology and a numerical lidar simulation for the quantification of uncertainties. It is found that the uncertainty of lidar wind speed estimates is mainly caused by the fore–aft motion of the lidar, resulting from the pitch displacement of the floater. Therefore, the uncertainty is heavily dependent on the amplitude and the frequency of the pitch motion. The bias of 10 min mean wind speed estimates is mainly influenced by the mean pitch angle of the floater and the pitch amplitude. We correct motion-induced biases in time-averaged lidar wind speed measurements with a model-based approach, employing the developed analytical model for uncertainty and bias quantification. Testing of the approach with simulated dynamics from two different FOWT concepts shows good results with remaining mean errors below 0.1 m s−1. For the correction of motion-induced fluctuation in instantaneous measurements, we use a frequency filter to correct fluctuations caused by floater pitch motions for instantaneous measurements. The correction approach's performance depends on the pitch period and amplitude of the FOWT design.

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Han, Zhengyang, Chuang Jiang, Xiaozhong Deng, Congcong Zhang, Longlong Geng e Yong Feng. "The Grinding and Correction of Face Gears Based on an Internal Gear Grinding Machine". Machines 12, n. 8 (23 luglio 2024): 496. http://dx.doi.org/10.3390/machines12080496.

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This paper presents a method of calculating and correcting grinding face gears on an internal gear grinding machine. The generating principle of face gears is studied, and the feasibility of grinding motion on an internal gear grinding machine is analyzed. Then, the motions that need to be followed for grinding are analyzed based on the gear machine tool structure. Four main error sources causing tooth surface deviation in the grinding movements are proposed. The mathematical modeling of the grinding of face gears containing proposed error sources on an internal gear grinding machine is accurately established. The influence of the error sources on the topological deviations of the tooth surface is explored. A sensitivity matrix is established for the influence of various error factors on the tooth surface deviations. The correction values of each error factor are obtained in the case of existing tooth surface deviations. Finally, a virtual machining experiment is conducted, which proves the accuracy of the proposed method for characterizing grinding and realizing corrections.

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Bourgeois, Marc E., Frank T. A. W. Wajer, Muriel Roth, André Briguet, Michel Décorps, Dirk van Ormondt, Christoph Segebarth e Danielle Graveron-Demilly. "Retrospective intra-scan motion correction". Journal of Magnetic Resonance 163, n. 2 (agosto 2003): 277–87. http://dx.doi.org/10.1016/s1090-7807(03)00154-x.

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Dawood, M., N. Lang, F. Büther, M. Schäfers, O. Schober e K. P. Schäfers. "Motion correction in PET/CT". Nuklearmedizin 44, S 01 (2005): S46—S50. http://dx.doi.org/10.1055/s-0038-1625215.

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Summary:Motion in PET/CT leads to artifacts in the reconstructed PET images due to the different acquisition times of positron emission tomography and computed tomography. The effect of motion on cardiac PET/CT images is evaluated in this study and a novel approach for motion correction based on optical flow methods is outlined. The Lukas-Kanade optical flow algorithm is used to calculate the motion vector field on both simulated phantom data as well as measured human PET data. The motion of the myocardium is corrected by non-linear registration techniques and results are compared to uncorrected images.

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Zahneisen, Benjamin, e Thomas Ernst. "Homogeneous coordinates in motion correction". Magnetic Resonance in Medicine 75, n. 1 (3 febbraio 2015): 274–79. http://dx.doi.org/10.1002/mrm.25552.

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Juan, Wang. "Convolutional Neural Network and Computer Vision-Based Action Correction Method for Long-Distance Running Technology". Security and Communication Networks 2022 (11 marzo 2022): 1–10. http://dx.doi.org/10.1155/2022/1467451.

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For long-distance running tactics, a computer vision-based motion correction solution is presented. The depth information is merged into the KCF algorithm to enhance it, which overcomes the classic KCF method’s incapacity to tackle the tracking drift issue caused by occlusion and extracts the technical features of long-distance running motions. Based on computer vision, the posture area of long-distance runners is detected, and the technical movements of long-distance runners are recognized. Calculate the centroid coordinates of the wrong technical movement correction area in long-distance running, and generate a tracking image of the wrong technical movement in long-distance running. The foreground and background information of the image is separated by the optical flow feature of machine vision, and the motion trajectory of the long-distance running error technique is extracted, and the motion correction of the long-distance running technique based on computer vision is realized. The experimental results show that the method in this paper has better accuracy in extracting long-distance running motion features and can accurately identify and correct the technical movements of the long-distance running, the technical movements of the head, and the technical movements of the body balance, and the correction efficiency is high.

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Zhang, Hong-Bo, Feng Guo, Miaohui Zhang, Ying Lin e Tsung-Chih Hsiao. "Human motion correction and representation method from motion camera". Journal of Engineering 2017, n. 7 (1 luglio 2017): 370–75. http://dx.doi.org/10.1049/joe.2017.0159.

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Wang, Huiliang, Jubo Li, Yang Gao e Jianjun Yang. "Closed-Loop Feedback Flank Errors Correction of Topographic Modification of Helical Gears Based on Form Grinding". Mathematical Problems in Engineering 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/635156.

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To increase quality, reduce heavy-duty gear noise, and avoid edge contact in manufacturing helical gears, a closed-loop feedback correction method in topographic modification tooth flank is proposed based on the gear form grinding. Equations of grinding wheel profile and grinding wheel additional radial motion are derived according to tooth segmented profile modification and longitudinal modification. Combined with gear form grinding kinematics principles, the equations of motion for each axis of five-axis computer numerical control forming grinding machine are established. Such topographical modification is achieved in gear form grinding with on-machine measurement. Based on a sensitivity analysis of polynomial coefficients of axis motion and the topographic flank errors by on-machine measuring, the corrections are determined through an optimization process that targets minimization of the tooth flank errors. A numerical example of gear grinding, including on-machine measurement and closed-loop feedback correction completing process, is presented. The validity of this flank correction method is demonstrated for tooth flank errors that are reduced. The approach is useful to precision manufacturing of spiral bevel and hypoid gears, too.

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Lamare, F., A. Bousse, K. Thielemans, C. Liu, T. Merlin, H. Fayad e D. Visvikis. "PET respiratory motion correction: quo vadis?" Physics in Medicine & Biology 67, n. 3 (1 febbraio 2022): 03TR02. http://dx.doi.org/10.1088/1361-6560/ac43fc.

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Abstract Positron emission tomography (PET) respiratory motion correction has been a subject of great interest for the last twenty years, prompted mainly by the development of multimodality imaging devices such as PET/computed tomography (CT) and PET/magnetic resonance imaging (MRI). PET respiratory motion correction involves a number of steps including acquisition synchronization, motion estimation and finally motion correction. The synchronization steps include the use of different external device systems or data driven approaches which have been gaining ground over the last few years. Patient specific or generic motion models using the respiratory synchronized datasets can be subsequently derived and used for correction either in the image space or within the image reconstruction process. Similar overall approaches can be considered and have been proposed for both PET/CT and PET/MRI devices. Certain variations in the case of PET/MRI include the use of MRI specific sequences for the registration of respiratory motion information. The proposed review includes a comprehensive coverage of all these areas of development in field of PET respiratory motion for different multimodality imaging devices and approaches in terms of synchronization, estimation and subsequent motion correction. Finally, a section on perspectives including the potential clinical usage of these approaches is included.

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Labeni, Merouane, Chaouki Boufenar e Mokhtar Taffar. "Visual Tracking With Object Center Displacement and CenterNet". International Journal of Computer Vision and Image Processing 12, n. 1 (gennaio 2022): 1–17. http://dx.doi.org/10.4018/ijcvip.290397.

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Modern artificial intelligence systems have revolutionized approaches to scientific and technological challenges in a variety of fields, thus remarkable improvements in the quality of state-of-the-art computer vision and other techniques are observed; object tracking in video frames is a vital field of research that provides information about objects and their trajectories. This paper presents an object tracking method basing on optical flow generated between frames and a ConvNet method. Initially, optical center displacement is employed to detect possible the bounding box center of the tracked object. Then, CenterNet is used for object position correction. Given the initial set of points (i.e., bounding box) in first frame, the tracker tries to follow the motion of center of these points by looking at its direction of change in calculated optical flow with next frame, a correction mechanism takes place and waits for motions that surpass a correction threshold to launch position corrections.

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Oostwoud Wijdenes, Leonie, Robert J. van Beers e W. Pieter Medendorp. "Vestibular modulation of visuomotor feedback gains in reaching". Journal of Neurophysiology 122, n. 3 (1 settembre 2019): 947–57. http://dx.doi.org/10.1152/jn.00616.2018.

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Humans quickly and sophisticatedly correct their movements in response to changes in the world, such as when reaching to a target that abruptly changes its location. The vigor of these movement corrections is time-dependent, increasing if the time left to make the correction decreases, which can be explained by optimal feedback control (OFC) theory as an increase of optimal feedback gains. It is unknown whether corrections for changes in the world are as sophisticated under full-body motion. For successful visually probed motor corrections during full-body motion, not only the motion of the hand relative to the body needs to be taken into account, but also the motion of the hand in the world should be considered, because their relative positions are changing. Here, in two experiments, we show that visuomotor feedback corrections in response to target jumps are more vigorous for faster passive full-body translational acceleration than for slower acceleration, suggesting that vestibular information modulates visuomotor feedback gains. Interestingly, these corrections do not demonstrate the time-dependent characteristics that body-stationary visuomotor feedback gains typically show, such that an optimal feedback control model fell short to explain them. We further show that the vigor of corrections generally decreased over the course of trials within the experiment, suggesting that the sensorimotor system adjusted its gains when learning to integrate the vestibular input into hand motor control. NEW & NOTEWORTHY Vestibular information is used in the control of reaching movements to world-stationary visual targets, while the body moves. Here, we show that vestibular information also modulates the corrective reach responses when the target changes position during the body motion: visuomotor feedback gains increase for faster body acceleration. Our results suggest that vestibular information is integrated into fast visuomotor control of reaching movements.

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Schulz, E. W., B. G. Sanderson e E. F. Bradley. "Motion Correction for Shipborne Turbulence Sensors". Journal of Atmospheric and Oceanic Technology 22, n. 1 (1 gennaio 2005): 55–69. http://dx.doi.org/10.1175/jtech-1685.1.

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Abstract A method for removing ship motion from wind measurements using a simple and inexpensive strap-down system of accelerometers is described and analyzed. In slight seas, error analysis indicates that mean root-mean-square uncertainties associated with the motion correction are 0.03 and 0.006 m s−1 for the horizontal and vertical wind, respectively, for all runs analyzed. The mean uncertainty in the wind stress due to motion correction is 8 × 10−4 N m−2. In a shallow coastal sea setting, ship motion appears to almost always be successfully detected and removed from the vertical component of the observed wind. The horizontal wind components appear to be successfully corrected in 86% of the runs analyzed. Motion correction is shown to have a significant influence on the covariance-calculated wind stress. In approximately half of the runs analyzed the wind stress changes by more than 15%. Motion correction has a smaller effect on the heat fluxes.

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Schweitzer, Richard, e Martin Rolfs. "Intrasaccadic motion streaks jump-start gaze correction". Science Advances 7, n. 30 (luglio 2021): eabf2218. http://dx.doi.org/10.1126/sciadv.abf2218.

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Rapid eye movements (saccades) incessantly shift objects across the retina. To establish object correspondence, the visual system is thought to match surface features of objects across saccades. Here, we show that an object’s intrasaccadic retinal trace—a signal previously considered unavailable to visual processing—facilitates this match making. Human observers made saccades to a cued target in a circular stimulus array. Using high-speed visual projection, we swiftly rotated this array during the eyes’ flight, displaying continuous intrasaccadic target motion. Observers’ saccades landed between the target and a distractor, prompting secondary saccades. Independently of the availability of object features, which we controlled tightly, target motion increased the rate and reduced the latency of gaze-correcting saccades to the initial presaccadic target, in particular when the target’s stimulus features incidentally gave rise to efficient motion streaks. These results suggest that intrasaccadic visual information informs the establishment of object correspondence and jump-starts gaze correction.

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Wittmann, Frieder, Olivier Lambercy e Roger Gassert. "Magnetometer-Based Drift Correction During Rest in IMU Arm Motion Tracking". Sensors 19, n. 6 (15 marzo 2019): 1312. http://dx.doi.org/10.3390/s19061312.

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Real-time motion capture of the human arm in the home environment has many usecases, such as video game and therapy applications. The required tracking can be based onoff-the-shelf Inertial Measurement Units (IMUs) with integrated three-axis accelerometers, gyroscopes,and magnetometers. However, this usually requires a homogeneous magnetic field to correctfor orientation drift, which is often not available inside buildings. In this paper, RPMC (RestPose Magnetometer-based drift Correction), a novel method that is robust to long term drift inenvironments with inhomogeneous magnetic fields, is presented. The sensor orientation is estimatedby integrating the angular velocity measured by the gyroscope and correcting drift around the pitchand roll axes with the acceleration information. This commonly leads to short term drift aroundthe gravitational axis. Here, during the calibration phase, the local magnetic field direction for eachsensor, and its orientation relative to the inertial frame, are recorded in a rest pose. It is assumed thatarm movements in free space are exhausting and require regular rest. A set of rules is used to detectwhen the user has returned to the rest pose, to then correct for the drift that has occurred with themagnetometer. Optical validations demonstrated accurate (root mean square error RMS = 6.1), lowlatency (61 ms) tracking of the user’s wrist orientation, in real time, for a full hour of arm movements.The reduction in error relative to three alternative methods implemented for comparison was between82.5% and 90.7% for the same movement and environment. Therefore, the proposed arm trackingmethod allows for the correction of orientation drift in an inhomogeneous magnetic field by exploitingthe user’s need for frequent rest.

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Boegle, Rainer, Julian Maclaren e Maxim Zaitsev. "Combining prospective motion correction and distortion correction for EPI: towards a comprehensive correction of motion and susceptibility-induced artifacts". Magnetic Resonance Materials in Physics, Biology and Medicine 23, n. 4 (6 agosto 2010): 263–73. http://dx.doi.org/10.1007/s10334-010-0225-8.

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29

Liu, Yang Ke, Chun Zhao Lv e Chang Li. "Motion Correction With Adaptive Karlman Filter". Advanced Materials Research 268-270 (luglio 2011): 1768–72. http://dx.doi.org/10.4028/www.scientific.net/amr.268-270.1768.

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Abstract (sommario):

In the digital image stabilization system, Kalman filter is the most commonly used filter for motion correction. When the wanted movements have large assumptions deviation with the movement model, the result of motion correction will cause divergence and even error. For this problem, a novel motion correction method with adaptive Karlman filter is proposed. The back and forth characteristic of the unwanted motion and the smoothness characteristic of the wanted motion is used to adjust the system noise and the observation error adaptively. Experiment results show that the proposed method can effectively distinguish the wanted and the unwanted movement. Compared with the method with fixed parameters, the proposed method takes into account the smoothness and delay of wanted motion at the same time and it is more adaptively.

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Salcedo-Bosch, Andreu, Francesc Rocadenbosch e Joaquim Sospedra. "A Robust Adaptive Unscented Kalman Filter for Floating Doppler Wind-LiDAR Motion Correction". Remote Sensing 13, n. 20 (18 ottobre 2021): 4167. http://dx.doi.org/10.3390/rs13204167.

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This study presents a new method for correcting the six degrees of freedom motion-induced error in ZephIR 300 floating Doppler Wind-LiDAR-derived data, based on a Robust Adaptive Unscented Kalman Filter. The filter takes advantage of the known floating Doppler Wind-LiDAR (FDWL) dynamics, a velocity–azimuth display algorithm, and a wind model describing the LiDAR-retrieved wind vector without motion influence. The filter estimates the corrected wind vector by adapting itself to different atmospheric and motion scenarios, and by estimating the covariance matrices of related noise processes. The measured turbulence intensity by the FDWL (with and without correction) was compared against a reference fixed LiDAR over a 25-day period at “El Pont del Petroli”, Barcelona. After correction, the apparent motion-induced turbulence was greatly reduced, and the statistical indicators showed overall improvement. Thus, the Mean Difference improved from −1.70% (uncorrected) to 0.36% (corrected), the Root Mean Square Error (RMSE) improved from 2.01% to 0.86%, and coefficient of determination improved from 0.85 to 0.93.

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31

Ratnatunga, Kavan U. "Correction to Absolute Proper Motion Using the IAS-Galaxy Model". Symposium - International Astronomical Union 141 (1990): 427–29. http://dx.doi.org/10.1017/s0074180900087192.

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Abstract (sommario):

The IAS-Galaxy model (Ratnatunga, Bahcall and Casertano 1989) is a software interface between theoretical models of the Galaxy and observed kinematic distributions. It has been developed for analysis of many kinematic catalogs to study global galactic structure. In addition, the IASG model can be used to estimate corrections needed to derive absolute parallax and absolute proper motion by evaluating, on a star-by-star basis, the expected mean motion of the reference stars.A theoretical Galaxy model is defined on an inertial coordinate frame. Proper motions are measured in a reference frame defined by a fundamental catalog. The observed distribution of proper motions in star catalogs can be directly compared with the expected distributions evaluated using IASG to check the accuracy of the adopted reference frame in realizing the inertial coordinate frame in the sky.

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Kumar, Ankur N., Kurt W. Short e David W. Piston. "A Motion Correction Framework for Time Series Sequences in Microscopy Images". Microscopy and Microanalysis 19, n. 2 (15 febbraio 2013): 433–50. http://dx.doi.org/10.1017/s1431927612014250.

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AbstractWith the advent of in vivo laser scanning fluorescence microscopy techniques, time-series and three-dimensional volumes of living tissue and vessels at micron scales can be acquired to firmly analyze vessel architecture and blood flow. Analysis of a large number of image stacks to extract architecture and track blood flow manually is cumbersome and prone to observer bias. Thus, an automated framework to accomplish these analytical tasks is imperative. The first initiative toward such a framework is to compensate for motion artifacts manifest in these microscopy images. Motion artifacts in in vivo microscopy images are caused by respiratory motion, heart beats, and other motions from the specimen. Consequently, the amount of motion present in these images can be large and hinders further analysis of these images. In this article, an algorithmic framework for the correction of time-series images is presented. The automated algorithm is comprised of a rigid and a nonrigid registration step based on shape contexts. The framework performs considerably well on time-series image sequences of the islets of Langerhans and provides for the pivotal step of motion correction in the further automatic analysis of microscopy images.

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Chen, Xingfan, Qican Zhang e Yajun Wang. "Dynamic 3D Measurement Based on Camera-Pixel Mismatch Correction and Hilbert Transform". Sensors 25, n. 3 (3 febbraio 2025): 924. https://doi.org/10.3390/s25030924.

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In three-dimensional (3D) measurement, the motion of objects inevitably introduces errors, posing significant challenges to high-precision 3D reconstruction. Most existing algorithms for compensating motion-induced phase errors are tailored for object motion along the camera’s principal axis (Z direction), limiting their applicability in real-world scenarios where objects often experience complex combined motions in the X/Y and Z directions. To address these challenges, we propose a universal motion error compensation algorithm that effectively corrects both pixel mismatch and phase-shift errors, ensuring accurate 3D measurements under dynamic conditions. The method involves two key steps: first, pixel mismatch errors in the camera subsystem are corrected using adjacent coarse 3D point cloud data, aligning the captured data with the actual spatial geometry. Subsequently, motion-induced phase errors, observed as sinusoidal waveforms with a frequency twice that of the projection fringe pattern, are eliminated by applying the Hilbert transform to shift the fringes by π/2. Unlike conventional approaches that address these errors separately, our method provides a systematic solution by simultaneously compensating for camera-pixel mismatch and phase-shift errors within the 3D coordinate space. This integrated approach enhances the reliability and precision of 3D reconstruction, particularly in scenarios with dynamic and multidirectional object motions. The algorithm has been experimentally validated, demonstrating its robustness and broad applicability in fields such as industrial inspection, biomedical imaging, and real-time robotics. By addressing longstanding challenges in dynamic 3D measurement, our method represents a significant advancement in achieving high-accuracy reconstructions under complex motion environments.

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Carlin, J. L., S. R. Majewski, D. I. Casetti-Dinescu e T. M. Girard. "Preliminary proper motion analysis of the Carina dwarf spheroidal". Proceedings of the International Astronomical Union 3, S248 (ottobre 2007): 492–93. http://dx.doi.org/10.1017/s174392130801990x.

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AbstractWe present preliminary results from a proper motion study of the Carina dwarf spheroidal galaxy. Our proper motions show a scatter of ~1.1 mas yr−1 per Carina member star, and we determinate the mean ensemble motion to an accuracy of ~7 mas century−1. While this is a precise measurement of the relative proper motions of Carina members, our correction to an absolute frame is limited by the small number of measured QSOs in the field.

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Navard, Pouyan, e Alper Yilmaz. "A Probabilistic-based Drift Correction Module for Visual Inertial SLAMs". International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVIII-2-2024 (11 giugno 2024): 297–300. http://dx.doi.org/10.5194/isprs-archives-xlviii-2-2024-297-2024.

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Abstract. Positioning is a prominent field of study, notably focusing on Visual Inertial Odometry (VIO) and Simultaneous Localization and Mapping (SLAM) methods. Despite their advancements, these methods often encounter dead-reckoning errors that leads to considerable drift in estimated platform motion especially during long traverses. In such cases, the drift error is not negligible and should be rectified. Our proposed approach minimizes the drift error by correcting the estimated motion generated by any SLAM method at each epoch. Our methodology treats positioning measurements rendered by the SLAM solution as random variables formulated jointly in a multivariate distribution. In this setting, The correction of the drift becomes equivalent to finding the mode of this multivariate distribution which jointly maximizes the likelihood of a set of relevant geo-spatial priors about the platform motion and environment. Our method is integrable into any SLAM/VIO method as an correction module. Our experimental results shows the effectiveness of our approach in minimizing the drift error by 10× in long treverses.

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Hees, A., e S. Pireaux. "A relativistic motion integrator: numerical accuracy and illustration with BepiColombo and Mars-NEXT". Proceedings of the International Astronomical Union 5, S261 (aprile 2009): 144–46. http://dx.doi.org/10.1017/s1743921309990299.

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AbstractToday, the motion of spacecraft is still described by the classical Newtonian equations of motion plus some relativistic corrections. This approach might become cumbersome due to the increasing precision required. We use the Relativistic Motion Integrator (RMI) approach to numerically integrate the native relativistic equations of motion for a spacecraft. The principle of RMI is presented. We compare the results obtained with the RMI method with those from the usual Newton plus correction approach for the orbit of the BepiColombo (around Mercury) and Mars-NEXT (around Mars) orbiters. Finally, we present a numerical study of RMI and we show that the RMI approach is relevant to study the orbit of spacecraft.

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Cifuentes-Lorenzen, Alejandro, James B. Edson, Christopher J. Zappa e Ludovic Bariteau. "A Multisensor Comparison of Ocean Wave Frequency Spectra from a Research Vessel during the Southern Ocean Gas Exchange Experiment". Journal of Atmospheric and Oceanic Technology 30, n. 12 (1 dicembre 2013): 2907–25. http://dx.doi.org/10.1175/jtech-d-12-00181.1.

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Abstract Obtaining accurate measurements of wave statistics from research vessels remains a challenge due to the platform motion. One principal correction is the removal of ship heave and Doppler effects from point measurements. Here, open-ocean wave measurements were collected using a laser altimeter, a Doppler radar microwave sensor, a radar-based system, and inertial measurement units. Multiple instruments were deployed to capture the low- and high-frequency sea surface displacements. Doppler and motion correction algorithms were applied to obtain a full 1D (0.035–1.3 ± 0.2 Hz) wave spectrum. The radar-based system combined with the laser altimeter provided the optimal low- and high-frequency combination, producing a frequency spectrum in the range from 0.035 to 1.2 Hz for cruising speeds ≤3 m s−1 with a spectral rolloff of f−4 Hz and noise floor of −20/−30 dB. While on station, the significant wave height estimates were comparable within 10%–15% among instrumentation. Discrepancies in the total energy and in the spectral shape between instruments arise when the ship is in motion. These differences can be quantified using the spectral behavior of the measurements, accounting for aliasing and Doppler corrections. The inertial sensors provided information on the amplitude of the ship’s modulation transfer function, which was estimated to be ~1.3 ± 0.2 while on station and increased while underway [2.1 at ship-over-ground (SOG) speed; 4.3 m s−1]. The correction scheme presented here is adequate for measurements collected at cruising speeds of 3 m s−1 or less. At speeds greater than 5 m s−1, the motion and Doppler corrections are not sufficient to correct the observed spectral degradation.

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Salcedo-Bosch, Andreu, Francesc Rocadenbosch e Joaquim Sospedra. "Enhanced Dual Filter for Floating Wind Lidar Motion Correction: The Impact of Wind and Initial Scan Phase Models". Remote Sensing 14, n. 19 (21 settembre 2022): 4704. http://dx.doi.org/10.3390/rs14194704.

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An enhanced filter for floating Doppler wind lidar motion correction is presented. The filter relies on an unscented Kalman filter prototype for floating-lidar motion correction without access to the internal line-of-sight measurements of the lidar. In the present work, we implement a new architecture based on two cooperative estimation filters and study the impact of different wind and initial scan phase models on the filter performance in the coastal environment of Barcelona. Two model combinations are considered: (i) a basic random walk model for both the wind turbulence and the initial scan phase and (ii) an auto-regressive model for wind turbulence along with a uniform circular motion model for the scan phase. The filter motion-correction performance using each of the above models was evaluated with reference to a fixed lidar in different wind and motion scenarios (low- and high-frequency turbulence cases) recorded during a 25-day campaign at “Pont del Petroli”, Barcelona, by clustered statistical analysis. The auto-regressive wind model and the uniform circular motion phase model permitted the filter to overcome divergence in all wind and motion scenarios. The statistical indicators comparing both instruments showed overall improvement. The mean deviation increased from 1.62% (without motion correction) to −0.07% (with motion correction), while the root-mean-square error decreased from 1.87% to 0.58%, and the determination coefficient (R2) improved from 0.90 to 0.96.

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박상일. "Motion correction captured by Kinect based on synchronized motion database". Journal of the Korea Computer Graphics Society 23, n. 2 (giugno 2017): 41–48. http://dx.doi.org/10.15701/kcgs.2017.23.2.41.

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40

Aun, J., J. Schuzer, S. Rollision, K. Bronson, Q. Tang, C. Liu, J. Zhou et al. "Next Generation Adaptive Coronary Motion Correction Reduces Coronary Motion Artifact". Journal of Cardiovascular Computed Tomography 17, n. 4 (luglio 2023): S79. http://dx.doi.org/10.1016/j.jcct.2023.05.195.

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41

McVeigh, E., G. Wesbey e A. Kahn. "Improvement In RV Motion Tracking With Intra-cycle Motion Correction". Journal of Cardiovascular Computed Tomography 19, n. 1 (gennaio 2025): S13. https://doi.org/10.1016/j.jcct.2024.12.034.

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42

Hossain, Md Biddut, Rupali Kiran Shinde, Shariar Md Imtiaz, F. M. Fahmid Hossain, Seok-Hee Jeon, Ki-Chul Kwon e Nam Kim. "Swin Transformer and the Unet Architecture to Correct Motion Artifacts in Magnetic Resonance Image Reconstruction". International Journal of Biomedical Imaging 2024 (2 maggio 2024): 1–12. http://dx.doi.org/10.1155/2024/8972980.

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We present a deep learning-based method that corrects motion artifacts and thus accelerates data acquisition and reconstruction of magnetic resonance images. The novel model, the Motion Artifact Correction by Swin Network (MACS-Net), uses a Swin transformer layer as the fundamental block and the Unet architecture as the neural network backbone. We employ a hierarchical transformer with shifted windows to extract multiscale contextual features during encoding. A new dual upsampling technique is employed to enhance the spatial resolutions of feature maps in the Swin transformer-based decoder layer. A raw magnetic resonance imaging dataset is used for network training and testing; the data contain various motion artifacts with ground truth images of the same subjects. The results were compared to six state-of-the-art MRI image motion correction methods using two types of motions. When motions were brief (within 5 s), the method reduced the average normalized root mean square error (NRMSE) from 45.25% to 17.51%, increased the mean structural similarity index measure (SSIM) from 79.43% to 91.72%, and increased the peak signal-to-noise ratio (PSNR) from 18.24 to 26.57 dB. Similarly, when motions were extended from 5 to 10 s, our approach decreased the average NRMSE from 60.30% to 21.04%, improved the mean SSIM from 33.86% to 90.33%, and increased the PSNR from 15.64 to 24.99 dB. The anatomical structures of the corrected images and the motion-free brain data were similar.

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Lee, Sukwon, e Sung-Hee Lee. "Projective Motion Correction with Contact Optimization". IEEE Transactions on Visualization and Computer Graphics 25, n. 4 (1 aprile 2019): 1746–59. http://dx.doi.org/10.1109/tvcg.2018.2818721.

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Chen, Fang, Jan Muller, Jens Muller, Juliane Muller, Matthias Kirsch e Ronald Tetzlaff. "Motion Correction in Multimodal Intraoperative Imaging". IEEE Transactions on Biomedical Circuits and Systems 14, n. 4 (agosto 2020): 671–80. http://dx.doi.org/10.1109/tbcas.2020.3005891.

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Catana, Ciprian. "Motion Correction Options in PET/MRI". Seminars in Nuclear Medicine 45, n. 3 (maggio 2015): 212–23. http://dx.doi.org/10.1053/j.semnuclmed.2015.01.001.

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46

Anan’ev, B. I. "Correction of motion under communication constraints". Automation and Remote Control 71, n. 3 (marzo 2010): 367–78. http://dx.doi.org/10.1134/s000511791003001x.

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Dance, Amber. "Publisher Correction: Molecular motion on ice". Nature Methods 17, n. 10 (3 settembre 2020): 1061. http://dx.doi.org/10.1038/s41592-020-0970-1.

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48

Dikaios, Nikolaos, e Tim D. Fryer. "Registration-weighted motion correction for PET". Medical Physics 39, n. 3 (15 febbraio 2012): 1253–64. http://dx.doi.org/10.1118/1.3675922.

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49

SKALSKI, J. "RELATIVE MOTION CORRECTION TO FISSION BARRIERS". International Journal of Modern Physics E 17, n. 01 (gennaio 2008): 151–59. http://dx.doi.org/10.1142/s0218301308009641.

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Abstract (sommario):

We discuss the effect of kinetic energy of the relative motion becoming spurious for separate fragments on the selfconsistent mean-field fission barriers. The treatment of the relative motion in the cluster model is contrasted with the necessity of a simpler and approximate approach in the mean-field theory. A scheme of the energy correction to the Hartree-Fock is proposed. The results obtained with the effective Skyrme interaction SLy 6 show that the correction, previously estimated as ~ 8 MeV in A = 70 - 100 nuclei, amounts to 4 MeV in the medium heavy nucleus 198 Hg and to null in 238 U . However, the corrected barrier implies a shorter fission half-life of the latter nucleus. The same effect is expected to lower barriers for multipartition (i.e. ternary fission, etc) and make hyperdeformed minima less stable.

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Zaitsev, Maxim, Burak Akin, Pierre LeVan e Benjamin R. Knowles. "Prospective motion correction in functional MRI". NeuroImage 154 (luglio 2017): 33–42. http://dx.doi.org/10.1016/j.neuroimage.2016.11.014.

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