scholarly journals Object representation and distance encoding in three-dimensional environments by a neural circuit in the visual system of the blowfly

2012 ◽  
Vol 107 (12) ◽  
pp. 3446-3457 ◽  
Author(s):  
Pei Liang ◽  
Jochen Heitwerth ◽  
Roland Kern ◽  
Rafael Kurtz ◽  
Martin Egelhaaf
Keyword(s):  
Visual System ◽  
Optic Flow ◽  
Moving Objects ◽  
Neural Circuit ◽  
Strong Dependence ◽  
Three Dimensional ◽  
Object Motion ◽  
Induced Response ◽  
Wide Field ◽  
Distance Information

Three motion-sensitive key elements of a neural circuit, presumably involved in processing object and distance information, were analyzed with optic flow sequences as experienced by blowflies in a three-dimensional environment. This optic flow is largely shaped by the blowfly's saccadic flight and gaze strategy, which separates translational flight segments from fast saccadic rotations. By modifying this naturalistic optic flow, all three analyzed neurons could be shown to respond during the intersaccadic intervals not only to nearby objects but also to changes in the distance to background structures. In the presence of strong background motion, the three types of neuron differ in their sensitivity for object motion. Object-induced response increments are largest in FD1, a neuron long known to respond better to moving objects than to spatially extended motion patterns, but weakest in VCH, a neuron that integrates wide-field motion from both eyes and, by inhibiting the FD1 cell, is responsible for its object preference. Small but significant object-induced response increments are present in HS cells, which serve both as a major input neuron of VCH and as output neurons of the visual system. In both HS and FD1, intersaccadic background responses decrease with increasing distance to the animal, although much more prominently in FD1. This strong dependence of FD1 on background distance is concluded to be the consequence of the activity of VCH that dramatically increases its activity and, thus, its inhibitory strength with increasing distance.

scholarly journals Three-dimensional structure from motion recovery of a moving object with noisy measurement

2020 ◽  
Vol 10 (1) ◽  
pp. 117
Author(s):  
Zoubaida Mejri ◽  
Lilia Sidhom ◽  
Afef Abdelkrim
Keyword(s):  
Structure From Motion ◽  
Moving Objects ◽  
Vision System ◽  
Three Dimensional ◽  
Object Motion ◽  
Dimensional Structure ◽  
Unknown Input ◽  
Dynamic Scenes ◽  
Motion Recovery ◽  
Noisy Measurement

In this paper, a Nonlinear Unknown Input Observer (NLUIO) based approach is proposed for three-dimensional (3-D) structure from motion identification. Unlike the previous studies that require prior knowledge of either the motion parameters or scene geometry, the proposed approach assumes that the object motion is imperfectly known and considered as an unknown input to the perspective dynamical system. The reconstruction of the 3-D structure of the moving objects can be achieved using just two-dimensional (2-D) images of a monocular vision system. The proposed scheme is illustrated with a numerical example in the presence of measurement noise for both static and dynamic scenes. Those results are used to clearly demonstrate the advantages of the proposed NLUIO.

scholarly journals Acoustic facilitation of object movement detection during self-motion

2011 ◽  
Vol 278 (1719) ◽  
pp. 2840-2847 ◽  
Author(s):  
F. J. Calabro ◽  
S. Soto-Faraco ◽  
L. M. Vaina
Keyword(s):  
Optic Flow ◽  
Animal Species ◽  
Moving Objects ◽  
Object Motion ◽  
Auditory Stimuli ◽  
Object Representations ◽  
Detection Rates ◽  
Object Movement ◽  
Psychophysical Studies ◽  
Self Motion

In humans, as well as most animal species, perception of object motion is critical to successful interaction with the surrounding environment. Yet, as the observer also moves, the retinal projections of the various motion components add to each other and extracting accurate object motion becomes computationally challenging. Recent psychophysical studies have demonstrated that observers use a flow-parsing mechanism to estimate and subtract self-motion from the optic flow field. We investigated whether concurrent acoustic cues for motion can facilitate visual flow parsing, thereby enhancing the detection of moving objects during simulated self-motion. Participants identified an object (the target) that moved either forward or backward within a visual scene containing nine identical textured objects simulating forward observer translation. We found that spatially co-localized, directionally congruent, moving auditory stimuli enhanced object motion detection. Interestingly, subjects who performed poorly on the visual-only task benefited more from the addition of moving auditory stimuli. When auditory stimuli were not co-localized to the visual target, improvements in detection rates were weak. Taken together, these results suggest that parsing object motion from self-motion-induced optic flow can operate on multisensory object representations.

scholarly journals A neural mechanism for detecting object motion during self-motion

2021 ◽  
Author(s):  
HyungGoo Kim ◽  
Dora Angelaki ◽  
Gregory DeAngelis
Keyword(s):  
Visual System ◽  
Moving Objects ◽  
Binocular Disparity ◽  
Motion Parallax ◽  
Neural Mechanism ◽  
Object Motion ◽  
Depth Cues ◽  
Behavioral Studies ◽  
Observer Motion ◽  
Self Motion

Detecting objects that move in a scene is a fundamental computation performed by the visual system. This computation is greatly complicated by observer motion, which causes most objects to move across the retinal image. How the visual system detects scene-relative object motion during self-motion is poorly understood. Human behavioral studies suggest that the visual system may identify local conflicts between motion parallax and binocular disparity cues to depth, and may use these signals to detect moving objects. We describe a novel mechanism for performing this computation based on neurons in macaque area MT with incongruent depth tuning for binocular disparity and motion parallax cues. Neurons with incongruent tuning respond selectively to scene-relative object motion and their responses are predictive of perceptual decisions when animals are trained to detect a moving object during selfmotion. This finding establishes a novel functional role for neurons with incongruent tuning for multiple depth cues.

Some Notes for Anaglyph Stereo Method in the Presentation of Moving Objects

1997 ◽  
Vol 9 (2) ◽  
pp. 132-134
Author(s):  
Hitomi Koike ◽  
◽  
Masanori Idesawa ◽  
Keyword(s):  
Computer Graphics ◽  
Visual System ◽  
Human Visual System ◽  
Moving Objects ◽  
Motion Parallax ◽  
Present Report ◽  
Three Dimensional ◽  
Texture Gradient ◽  
Binocular Stereo ◽  
Three Dimensional Presentation

The human visual system perceives three-dimensional structures by using all kinds of means, such as perspective, binocular parallax, motion parallax, texture gradient, etc[2]. Among these, binocular stereo viewing based on binocular parallax is one of the most important means in perceiving the three-dimensional structures of objects. In recent years, in the field of computer graphics, the three-dimensional presentation method based on binocular stereo viewing is widely used. In research on the elucidation of the human visual mechanism, studies with the use of three--dimensional presentation methods based on binocular stereo viewing as applied to computer graphics are being , carried out actively. These studies have led to new discoveries which were never anticipated in the past, and to new knowledge concerning the human visual system. For three-dimensional presentation based on binocular viewing, various methods are used; the anaglyph method is one of them (Fig.1). According to the anaglyph method, the images of the left eye and the right eye are depicted in different colors and are observed after they are separated by means of filters corresponding to these colors. For this reason, the anaglyph method is an extremely effective one for conducting a simple experiment on binocular stereo viewing[1]. However, in the observation of moving objects which the present authors have recently conducted, a strange phenomenon was observed that a triangle rotating on a plane with a uniform depth is perceived as if it were moving in a slanted way. When this phenomenon was examined, it was confirmed that it was due to the Pulfrich effect based on the difference in brightness between red and blue colors[4]. This fact indicates that it is necessary to pay sufficient attention to the existence of this phenomenon as long as the anaglyph method is used for the presentation and observation of moving objects. The present report is intended to introduce several of phenomena observed in the course of the study on the cause of this phenomenon.

Cyclopean Vision, Size Estimation, and Presence in Orthostereoscopic Images

2001 ◽  
Vol 10 (3) ◽  
pp. 312-330 ◽  
Author(s):  
Bernard Harper ◽  
Richard Latto
Keyword(s):  
Visual System ◽  
Three Dimensional ◽  
Point Of View ◽  
Psychophysical Experiment ◽  
Size Estimation ◽  
Human Form ◽  
Image Capture ◽  
Series Of Experiments ◽  
Abstract Shapes ◽  
And Control

Stereo scene capture and generation is an important facet of presence research in that stereoscopic images have been linked to naturalness as a component of reported presence. Three-dimensional images can be captured and presented in many ways, but it is rare that the most simple and “natural” method is used: full orthostereoscopic image capture and projection. This technique mimics as closely as possible the geometry of the human visual system and uses convergent axis stereography with the cameras separated by the human interocular distance. It simulates human viewing angles, magnification, and convergences so that the point of zero disparity in the captured scene is reproduced without disparity in the display. In a series of experiments, we have used this technique to investigate body image distortion in photographic images. Three psychophysical experiments compared size, weight, or shape estimations (perceived waist-hip ratio) in 2-D and 3-D images for the human form and real or virtual abstract shapes. In all cases, there was a relative slimming effect of binocular disparity. A well-known photographic distortion is the perspective flattening effect of telephoto lenses. A fourth psychophysical experiment using photographic portraits taken at different distances found a fattening effect with telephoto lenses and a slimming effect with wide-angle lenses. We conclude that, where possible, photographic inputs to the visual system should allow it to generate the cyclopean point of view by which we normally see the world. This is best achieved by viewing images made with full orthostereoscopic capture and display geometry. The technique can result in more-accurate estimations of object shape or size and control of ocular suppression. These are assets that have particular utility in the generation of realistic virtual environments.

scholarly journals Detecting moving objects in an optic flow field using direction- and speed-tuned operators

2014 ◽  
Vol 98 ◽  
pp. 14-25 ◽  
Author(s):  
Constance S. Royden ◽  
Michael A. Holloway
Keyword(s):  
Flow Field ◽  
Optic Flow ◽  
Moving Objects

Moving Objects Detection Algorithm Based on Three-Dimensional Gaussian Mixture Codebook Model Using XYZ Color Model

2013 ◽  
Vol 347-350 ◽  
pp. 3505-3509 ◽  
Author(s):  
Jin Huang ◽  
Wei Dong Jin ◽  
Na Qin
Keyword(s):  
Gaussian Mixture Model ◽  
Mixture Model ◽  
Moving Objects ◽  
Three Dimensional ◽  
Gaussian Mixture ◽  
Detection Algorithm ◽  
Color Model ◽  
Moving Objects Detection ◽  
Objects Detection ◽  
Model Algorithm

In order to reduce the difficulty of adjusting parameters for the codebook model and the computational complexity of probability distribution for the Gaussian mixture model in intelligent visual surveillance, a moving objects detection algorithm based on three-dimensional Gaussian mixture codebook model using XYZ color model is proposed. In this algorithm, a codebook model based on XYZ color model is built, and then the Gaussian model based on X, Y and Z components in codewords is established respectively. In this way, the characteristic of the three-dimensional Gaussian mixture model for the codebook model is obtained. The experimental results show that the proposed algorithm can attain higher real-time capability and its average frame rate is about 16.7 frames per second, while it is about 8.3 frames per second for the iGMM (improved Gaussian mixture model) algorithm, about 6.1 frames per second for the BM (Bayes model) algorithm, about 12.5 frames per second for the GCBM (Gaussian-based codebook model) algorithm, and about 8.5 frames per second for the CBM (codebook model) algorithm in the comparative experiments. Furthermore the proposed algorithm can obtain better detection quantity.

scholarly journals Binocular Contributions to Optic Flow Processing in the Fly Visual System

2001 ◽  
Vol 85 (2) ◽  
pp. 724-734 ◽  
Author(s):  
Holger G. Krapp ◽  
Roland Hengstenberg ◽  
Martin Egelhaaf
Keyword(s):  
Optic Flow ◽  
Functional Role ◽  
Optic Lobe ◽  
Receptive Fields ◽  
Flow Fields ◽  
Wide Field ◽  
Motion Information ◽  
Local Motion ◽  
Response Field

Integrating binocular motion information tunes wide-field direction-selective neurons in the fly optic lobe to respond preferentially to specific optic flow fields. This is shown by measuring the local preferred directions (LPDs) and local motion sensitivities (LMSs) at many positions within the receptive fields of three types of anatomically identifiable lobula plate tangential neurons: the three horizontal system (HS) neurons, the two centrifugal horizontal (CH) neurons, and three heterolateral connecting elements. The latter impart to two of the HS and to both CH neurons a sensitivity to motion from the contralateral visual field. Thus in two HS neurons and both CH neurons, the response field comprises part of the ipsi- and contralateral visual hemispheres. The distributions of LPDs within the binocular response fields of each neuron show marked similarities to the optic flow fields created by particular types of self-movements of the fly. Based on the characteristic distributions of local preferred directions and motion sensitivities within the response fields, the functional role of the respective neurons in the context of behaviorally relevant processing of visual wide-field motion is discussed.

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