scholarly journals Systematic misperceptions of 3D motion explained by Bayesian inference

2017 ◽  
Author(s):  
Bas Rokers ◽  
Jacqueline M. Fulvio ◽  
Jonathan Pillow ◽  
Emily A. Cooper

AbstractPeople make surprising but reliable perceptual errors. Here, we provide a unified explanation for errors in the perception of three-dimensional (3D) motion. To do so, we characterized the retinal motion signals produced by objects moving with arbitrary trajectories through arbitrary locations in 3D. Next, we developed a Bayesian model, treating 3D motion perception as optimal inference given sensory noise and the geometry of 3D viewing. The model predicts a wide array of systematic perceptual errors, that depend on stimulus distance, contrast, and eccentricity. We then used a virtual reality (VR) headset as well as a standard 3D display to test these predictions in both traditional psychophysical and more naturalistic settings. We found evidence that people make many of the predicted errors, including a lateral bias in the perception of motion trajectories, a dependency of this bias on stimulus contrast, viewing distance, and eccentricity, and a surprising tendency to misreport approaching motion as receding and vice versa. In sum, we developed a quantitative model that provides a parsimonious account for a range of systematic misperceptions of motion in naturalistic environments.


2010 ◽  
Vol 104 (5) ◽  
pp. 2886-2899 ◽  
Author(s):  
Thaddeus B. Czuba ◽  
Bas Rokers ◽  
Alexander C. Huk ◽  
Lawrence K. Cormack

Two binocular cues are thought to underlie the visual perception of three-dimensional (3D) motion: a disparity-based cue, which relies on changes in disparity over time, and a velocity-based cue, which relies on interocular velocity differences. The respective building blocks of these cues, instantaneous disparity and retinal motion, exhibit very distinct spatial and temporal signatures. Although these two cues are synchronous in naturally moving objects, disparity-based and velocity-based mechanisms can be dissociated experimentally. We therefore investigated how the relative contributions of these two cues change across a range of viewing conditions. We measured direction-discrimination sensitivity for motion though depth across a wide range of eccentricities and speeds for disparity-based stimuli, velocity-based stimuli, and “full cue” stimuli containing both changing disparities and interocular velocity differences. Surprisingly, the pattern of sensitivity for velocity-based stimuli was nearly identical to that for full cue stimuli across the entire extent of the measured spatiotemporal surface and both were clearly distinct from those for the disparity-based stimuli. These results suggest that for direction discrimination outside the fovea, 3D motion perception primarily relies on the velocity-based cue with little, if any, contribution from the disparity-based cue.



Author(s):  
Seok Lee ◽  
Juyong Park ◽  
Dongkyung Nam

In this article, the authors present an image processing method to reduce three-dimensional (3D) crosstalk for eye-tracking-based 3D display. Specifically, they considered 3D pixel crosstalk and offset crosstalk and applied different approaches based on its characteristics. For 3D pixel crosstalk which depends on the viewer’s relative location, they proposed output pixel value weighting scheme based on viewer’s eye position, and for offset crosstalk they subtracted luminance of crosstalk components according to the measured display crosstalk level in advance. By simulations and experiments using the 3D display prototypes, the authors evaluated the effectiveness of proposed method.



Author(s):  
Ying Yuan ◽  
Xiaorui Wang ◽  
Yang Yang ◽  
Hang Yuan ◽  
Chao Zhang ◽  
...  

Abstract The full-chain system performance characterization is very important for the optimization design of an integral imaging three-dimensional (3D) display system. In this paper, the acquisition and display processes of 3D scene will be treated as a complete light field information transmission process. The full-chain performance characterization model of an integral imaging 3D display system is established, which uses the 3D voxel, the image depth, and the field of view of the reconstructed images as the 3D display quality evaluation indicators. Unlike most of the previous research results using the ideal integral imaging model, the proposed full-chain performance characterization model considering the diffraction effect and optical aberration of the microlens array, the sampling effect of the detector, 3D image data scaling, and the human visual system, can accurately describe the actual 3D light field transmission and convergence characteristics. The relationships between key parameters of an integral imaging 3D display system and the 3D display quality evaluation indicators are analyzed and discussed by the simulation experiment. The results will be helpful for the optimization design of a high-quality integral imaging 3D display system.



Author(s):  
Takehito Teraguchi ◽  
Hiromasa Yamashita ◽  
Ken Masamune ◽  
Takeyoshi Dohi ◽  
Hongen Liao


Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 578 ◽  
Author(s):  
Bingrui Lv ◽  
Guilian Wang ◽  
Bin Li ◽  
Haibo Zhou ◽  
Yahui Hu

This paper describes the innovative design of a three-dimensional (3D) motion device based on a flexible mechanism, which is used primarily to produce accurate and fast micro-displacement. For example, the rapid contact and separation of the tool and the workpiece are realized by the operation of the 3D motion device in the machining process. This paper mainly concerns the device performance. A theoretical model for the static performance of the device was established using the matrix-based compliance modeling (MCM) method, and the static characteristics of the device were numerically simulated by finite element analysis (FEA). The Lagrangian principle and the finite element analysis method for device dynamics are used for prediction to obtain the natural frequency of the device. Under no-load conditions, the dynamic response performance and linear motion performance of the three directions were tested and analyzed with different input signals, and three sets of vibration trajectories were obtained. Finally, the scratching experiment was carried out. The detection of the workpiece reveals a pronounced periodic texture on the surface, which verifies that the vibration device can generate an ideal 3D vibration trajectory.



2002 ◽  
Vol 4 (4) ◽  
pp. 251-270 ◽  
Author(s):  
M. J. Plank ◽  
B. D. Sleeman ◽  
P. F. Jones

Angiogenesis, the growth of new blood vessels from existing ones, is an important, yet not fully understood, process and is involved in diseases such as rheumatoid arthritis, diabetic retinopathy and solid tumour growth. Central to the process of angiogenesis are endothelial cells (EC), which line all blood vessels, and are capable of forming new capillaries by migration, proliferation and lumen formation. We construct a cell-based mathematical model of an experiment (Vernon, R.B. and Sage, E.H. (1999) “A novel, quantitative model for study of endothelial cell migration and sprout formation within three-dimensional collagen matrices”,Microvasc. Res.57, 118–133) carried out to assess the response of EC to various diffusible angiogenic factors, which is a crucial part of angiogenesis. The model for cell movement is based on the theory of reinforced random walks and includes both chemotaxis and chemokinesis. Three-dimensional simulations are run and the results correlate well with the experimental data. The experiment cannot easily distinguish between chemotactic and chemokinetic effects of the angiogenic factors. We, therefore, also run two-dimensional simulations of a hypothetical experiment, with a point source of angiogenic factor. This enables directed (gradient-driven) EC migration to be investigated independently of undirected (diffusion-driven) migration.



This paper presents the 3D motion trajectories (lower case 3D alphabetic characters) recognition using optimal set of geometric primitives, angular and statistical features. It has been observed that the different combinations of these features have not been used in the literature for recognition of 3D characters. The standard dataset named “CHAR3D” has been used for analysis purpose. The dataset consists of 2858 character samples and each character sample is 3 dimensional pen tip velocity trajectory. In this dataset only single pen down segmented characters have been considered. The recognition has been performed using Random Forest (RF) and multiclass support vector machine (SVM) classifier on the optimal subset of extracted features. The best obtained recognition accuracy of 83.4% has been recorded using 3D points, angular and statistical features at 10 fold cross validation using SVM classifier. Moreover, the highest recognition accuracy of 96.88% has been recorded using an optimal subset of 32 dimensional features namely, geometric primitives, angular and statistical features at 10 fold cross validation by RF classifier.



2014 ◽  
Vol 602-605 ◽  
pp. 1838-1841 ◽  
Author(s):  
Kun Jiang ◽  
Fu Yan Zheng ◽  
Hai Kun Teng

Based on the Unity3D platform, using 3D MAX as the modeling tool, and the combined with the JSP and the C# to realize the interactive design, through the integration and XML integration, Completed the 3D engine room monitoring system design and implementation, practice shows that, Unity3D has a good network of 3D display and interactive function, it will have broader prospects of development in the virtual platform development, virtual reality technology has important strategic significance in the development of enterprise information management.



2003 ◽  
Vol 18 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Gongbing Shan ◽  
Peter Visentin

Overuse syndrome (OS) resulting from repetitive motion affects a significant percentage of performing musicians. Particularly susceptible to OS, violinists use different kinds of muscle control patterns in the right and left limbs and must assume a complex asymmetrical posture to hold and play the instrument. There is a clear need for developing efficient and effective strategies to prevent OS in violinists, keeping biological loads under physiological limits and focusing on physical economy during training. The first step in developing such strategies requires quantitative kinematic description of the motions involved in violin performance. This study supplies such information for the arms and violin bow. The motions of eight professional violinists and three advanced university music students were captured using a nine-camera VICON V8i motion capture system. Each performed a fundamental control skill employing all four strings of the violin. The data were analyzed using quantitative model comparison and statistical analysis. The results of this study show parameters such as elbow height normalized by body height and shoulder and elbow joint motion to have highly consistent patterns between the subjects. Wrist control patterns varied widely. Playing on different strings influences right arm patterns significantly, but not left. This is the first study providing quantitative 3-D kinematic data on shoulders, elbows, wrists, and bow. It provides a foundation for further exploration of the kinematic characteristics of violin performance, for the examination of the potential causes of OS, and for an evaluation of practices that might minimize injuries.



2020 ◽  
Vol 33 (5) ◽  
pp. 761-767
Author(s):  
Yongwook Kim ◽  
Seungmook Kang

BACKGROUND: Few studies have explored the relationship between muscle strength, range of motion (ROM), and balance in the horizontal plane of the hip joint using three-dimensional (3D) motion analysis. OBJECTIVE: We investigate the relationships of hip internal rotation (IR) and external rotation (ER) ROM, measured using a 3D motion capture system, with hip internal and external rotator strength and single-leg standing balance. METHODS: The participants were 40 healthy adults. Kinematic data on hip ROM were collected using an eight-camera motion analysis system. Hip rotational strength measurements were obtained using hand-held isometric dynamometry. A Single-leg standing test and a pendular test were conducted to evaluate static and dynamic balance ability using BioRescue. RESULTS: Significant correlations were found between hip strength and each variable measured during hip ROM assessments (p< 0.05). Significant positive correlations were found between the hip IR/ER strength ratio and the IR/ER ROM ratio (r= 0.72, p< 0.01). The subgroup with a normal IR/ER ratio of hip rotator strength and ROM showed significantly better dynamic balance ability than the subgroup with a hip rotator muscle imbalance (p< 0.05). CONCLUSIONS: There is a significant relationship between hip IR/ER strength and IR/ER ROM with a normal hip IR/ER strength and ROM ratio positively affecting dynamic balance ability.



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