scholarly journals Color from Motion: Dichoptic Activation and a Possible Role in Breaking Camouflage

Perception ◽  
1997 ◽  
Vol 26 (11) ◽  
pp. 1367-1380 ◽  
Author(s):  
Carol M Cicerone ◽  
Donald D Hoffman
Keyword(s):  
Visual System ◽  
Apparent Motion ◽  
Stimulus Display ◽  
Background Field ◽  
The Other ◽  
White Background ◽  
High Luminance ◽  
Low Luminance ◽  
Random Placement ◽  
Multiple Frames

‘Color from motion’ describes the perception of a spread of subjective color over achromatic regions seen as moving. The effect can be produced in a display of multiple frames shown in quick succession, each frame consisting of a fixed, random placement of colored dots on a high-luminance white background with color assignments of some dots, but not dot locations, changing from frame to frame. Evidence is presented that the perception of apparent motion and the spread of subjective color can be activated by binocular combination of disjoint signals to each eye. The dichoptic presentation of every odd-numbered frame of the full stimulus sequence presented to one eye and, out of phase, every even-numbered frame to the other eye produces a compelling perception of color from motion equal to that seen with the full sequence presented to each eye alone. This is consistent with the idea that color from motion is regulated in sites at or beyond the convergence of monocular pathways. When the background field in the stimulus display is of low luminance, an amodally complete object, fully colored and matching the dots defining the moving region in hue and saturation, is seen to move behind a partially occluding screen. Observers do not perceive such an object in still view. Hence, color from motion can be used by the visual system to produce amodal completion, which suggests that it may play a role in enhancing the visibility of camouflaged objects.

The Ternus Effect

2017 ◽  
Author(s):  
Elisabeth Hein
Keyword(s):  
Twentieth Century ◽  
Eye Movements ◽  
Visual System ◽  
Apparent Motion ◽  
Perceptual Grouping ◽  
The Other ◽  
The World ◽  
Motion Display ◽  
In The Beginning ◽  
Insight Into

The Ternus effect refers to an ambiguous apparent motion display in which two or three elements presented in succession and shifted horizontally by one position can be perceived as either a group of elements moving together or as one element jumping across the other(s). This chapter introduces the phenomenon and describes observations made by Pikler and Ternus in the beginning of the twentieth century. Next, reasons for continued interest in the Ternus effect are discussed and an overview of factors that influence it offered, including low-level image-based factors, for example luminance, as well as higher-level scene-based factors, for example perceptual grouping. The chapter ends with a discussion of theories regarding the mechanisms underlying the Ternus effect, providing insight into how the visual system is able to perceive coherent objects in the world despite discontinuities in the input (e.g., as a consequence of eye movements or object occlusion).

Transient—Sustained Input to Directionally Selective Motion Mechanisms

Perception ◽  
1996 ◽  
Vol 25 (11) ◽  
pp. 1263-1280 ◽  
Author(s):  
Walter F Bischof ◽  
Adriane E Seiffert ◽  
Vincent Di Lollo
Keyword(s):  
Apparent Motion ◽  
Motion Sensor ◽  
Motion Sensors ◽  
Single Image ◽  
High Luminance ◽  
New Model ◽  
Low Luminance ◽  
Directional Motion ◽  
Combined Images ◽  
Psychophysical Studies

The characteristics of the sustained input to directionally selective motion sensors were examined in three human psychophysical studies on directional-motion discrimination. Apparent motion was produced by displaying a group of dots in two frames (F1 and F2), where F2 was a translated version of F1. All stimuli included parts that contained both F1 and F2 (combined images) and parts containing only F1 or F2 (single images). All displays began with a single image (F1), continued with the combined image, and ended with F2. Six durations of single and of combined images (10, 20, 40, 80, 160, or 320 ms) were crossed factorially. As the duration of the single image was increased, perception of directional motion first improved, and then declined at longer durations. This outcome contrasted with the monotonic increment obtained in earlier studies under low-luminance conditions. To account for the entire pattern of results, earlier models of the Reichardt motion sensor were modified so as to include a mixed transient – sustained input to one of the filters of the sensor. Predictions from the new model were tested and confirmed in two experiments carried out under both low-luminance and high-luminance viewing conditions.

Illusory Color Spread from Apparent Motion

2017 ◽  
Author(s):  
Carol M. Cicerone ◽  
Donald D. Hoffman
Keyword(s):  
Apparent Motion ◽  
Natural Scenes ◽  
Test Region ◽  
Stereoscopic View ◽  
Random Placement ◽  
Multiple Frames ◽  
As If

Color from motion describes the perception of subjective color that spreads over physically achromatic regions that are seen in apparent motion. Multiple frames are shown in quick succession, each frame composed of a random placement of differently colored dots on an achromatic background. From frame to frame, the locations of all dots are fixed, whereas the color assignments of dots in the test region change. Subjective color can be measured by color matches to and cancellation by real lights, can be seen with chromaticity differences alone in test and surround dots, and is independent of contour formation. In stereoscopic view, the perception of depth, as well as color and form, can be recovered in tandem with seeing motion. This chapter suggests that in natural scenes, mechanisms triggered by motion may reconstruct the depth, color, and form of partially obscured objects so they can be seen as if in plain view.

Colour Constancy as Measured by Least Dissimilar Matching

2011 ◽  
Vol 24 (5) ◽  
pp. 407-452 ◽  
Author(s):  
Alexander D. Logvinenko ◽  
Rumi Tokunaga
Keyword(s):  
Visual System ◽  
Stimulus Display ◽  
Statistical Test ◽  
The Other ◽  
Colour Constancy ◽  
Exact Match ◽  
Match Rate ◽  
Black Paper ◽  
Colour Match

AbstractAlthough asymmetric colour matching has been widely used in experiments on colour constancy, an exact colour match between objects lit by different chromatic lights is impossible to achieve. We used a modification of this technique, instructing our observers to establish the least dissimilar pair of differently illuminated coloured papers. The stimulus display consisted of two identical sets of 22 Munsell papers illuminated independently by neutral, yellow, blue, green and red lights. The lights produced approximately the same illuminance. Four trichromatic observers participated in the experiment. The proportion of exact matches was evaluated. When both sets of papers were lit by the same light, the exact match rate was 0.92, 0.93, 0.84, 0.78 and 0.76 for the neutral, yellow, blue, green and red lights, respectively. When one illumination was neutral and the other chromatic, the exact match rate was 0.80, 0.40, 0.56 and 0.32 for the yellow, blue, green and red lights, respectively. When both lights were chromatic, the exact match rate was found to be even poorer (0.30 on average). Yet, least dissimilar matching was found to be rather systematic. Particularly, a statistical test showed it was symmetric and transitive. The exact match rate was found to be different for different papers, varying from 0.99 (black paper) to 0.12 (purple paper). Such a variation can hardly be expected if observers' judgements were based on an illuminant estimate. We argue that colour constancy cannot be achieved for all the reflecting objects because of mismatching of metamers. We conjecture that the visual system might have evolved to have colour constant perception for some ecologically valid objects at a cost of colour inconstancy for other types of objects.

Neurobiological correlates of apparent motion perception in the human visual system using magnetoencephalography

NeuroImage ◽  
2001 ◽  
Vol 13 (6) ◽  
pp. 893
Author(s):  
C.I. Horenstein ◽  
R.R. Ramirez ◽  
E. Kronberg ◽  
U. Ribary ◽  
R.R. Llinas
Keyword(s):  
Visual System ◽  
Motion Perception ◽  
Apparent Motion ◽  
Human Visual System

scholarly journals Optical axes of catadioptric systems including visual, Purkinje and other nonvisual systems of a heterocentric astigmatic eye

2010 ◽  
Vol 69 (3) ◽  
Author(s):  
W. F. Harris
Keyword(s):  
Visual System ◽  
Optical Axis ◽  
The Other ◽  
Optical Systems ◽  
Numerical Examples ◽  
Straight Line ◽  
Optical Axes ◽  
Catadioptric Systems ◽  
Reflecting Surfaces ◽  
Special Case

For a dioptric system with elements which may be heterocentric and astigmatic an optical axis has been defined to be a straight line along which a ray both enters and emerges from the system.  Previous work shows that the dioptric system may or may not have an optical axis and that, if it does have one, then that optical axis may or may not be unique.  Formulae were derived for the locations of any optical axes.  The purpose of this paper is to extend those results to allow for reflecting surfaces in the system in addition to refracting elements.  Thus the paper locates any optical axes in catadioptric systems (including dioptric systems as a special case).  The reflecting surfaces may be astigmatic and decentred or tilted.  The theory is illustrated by means of numerical examples.  The locations of the optical axes are calculated for seven optical systems associated with a particular heterocentric astigmatic model eye.  The optical systems are the visual system, the four Purkinje systems and two other nonvisual systems of the eye.  The Purkinje systems each have an infinity of optical axes whereas the other nonvisual systems, and the visual system, each have a unique optical axis. (S Afr Optom 2010 69(3) 152-160)

Local-Level and Global-Level Form Characteristics in Apparent-Motion Correspondence

Perception ◽  
1995 ◽  
Vol 24 (11) ◽  
pp. 1233-1245 ◽  
Author(s):  
Terry Palmer ◽  
Ovid J L Tzeng ◽  
Sheng He
Keyword(s):  
Apparent Motion ◽  
Motion Detection ◽  
Local Level ◽  
The Other ◽  
Correspondence Problem ◽  
Global Level ◽  
Global Precedence ◽  
Detection Mechanism ◽  
Motion Display ◽  
Motion Correspondence

This study addressed the ‘correspondence’ problem of apparent-motion (AM) perception in which parts of a scene must be matched with counterparts separated in time and space. Given evidence that AM correspondence can be mediated by two distinct processes—one based on a low-level motion-detection mechanism (the Reichardt process), the other involving the tracking of objects by visual attention (the attention-based process)—the present study explored how these processes interact in the perception of apparent motion between hierarchically structured figures. In three experiments, hierarchical figures were presented in a competition motion display so that, across frames, figures were identical at either the local or the global level. In experiment 1 it was shown that AM occurred between locally identical figures. Furthermore, with the Reichardt AM component eliminated in experiments 3 and 4, no preference was obtained for either level. While evidence from previous studies suggests that form extraction for hierarchically structured figures proceeds from the global to the local level, the present results indicate the irrelevance of such a global precedence in AM correspondence. In addition, it is suggested that Reichardt AM correspondence between local elements constrains attention-based AM correspondence between global figures so that both components move in the same direction. It is argued that this constraining process represents an elegant means of achieving AM correspondence between objects undergoing complex transformations.

scholarly journals Transmission of ocular media in labrid fishes

2000 ◽  
Vol 355 (1401) ◽  
pp. 1257-1261 ◽  
Author(s):  
Ulrike E. Siebeck ◽  
N. Justin Marshall
Keyword(s):  
Visual System ◽  
Great Barrier Reef ◽  
Florida Keys ◽  
The Other ◽  
Barrier Reef ◽  
Functional Roles ◽  
Shallow Reef ◽  
Transmission Properties ◽  
Ocular Media ◽  
Transmission Measurements

Wrasses (Labridae) are the second largest family of fishes on the Great Barrier Reef (after the Gobiidae) and, in terms of morphology and lifestyle, one of the most diverse. They occupy all zones of the reef from the very shallow reef flats to deep slopes, feeding on a variety of fauna. Many wrasses also have elaborately patterned bodies and reflect a range of colours from ultraviolet (UV) to far red. As a first step to investigating the visual system of these fishes we measured the transmission properties of the ocular media of 36 species from the Great Barrier Reef, Australia, and Hawaii, California and the Florida Keys, USA. Transmission measurements were made of whole eyes with a window cut into the back, and also of isolated lenses and corneas. Based on the transmission properties of the corneas the species could be split into two distinct groups within which the exact wavelength of the cut–off was variable. One group had visibly yellow corneas, while the corneas of the other group appeared clear to human observers. Five species had ocular media that transmitted wavelengths below 400 nm, making a perception of UV wavelengths for those species possible. Possible functional roles for the different filter types are discussed.

Motion Segmentation and Matting by Graph Cut

2012 ◽  
pp. 95-117
Author(s):  
Jiangjian Xiao
Keyword(s):  
Video Sequence ◽  
Graph Cut ◽  
The Other ◽  
Robust Approach ◽  
Alpha Matting ◽  
Optical Flow Field ◽  
Segmentation Boundary ◽  
Clustering Approach ◽  
Multiple Frames ◽  
Layer Segmentation

Given a video sequence, obtaining accurate layer segmentation and alpha matting is very important for video representation, analysis, compression, and synthesis. By assuming that a scene can be approximately described by multiple planar or surface regions, this chapter describes a robust approach to automatically detect the region clusters and perform accurate layer segmentation for the scene. The approach starts from optical flow field or small corresponding seed regions and applies a clustering approach to estimate the layer number and support regions. Then, it uses graph cut algorithm combined with a general occlusion constraint over multiple frames to solve pixel assignment over multiple frames to obtain more accurate segmentation boundary and identify the occluded pixels. For the non-textured ambiguous regions, an alpha matting technique is further used to refine the segmentation and resolve the ambiguities by determining proper alpha values for the foreground and background, respectively. Based on the alpha mattes, the foreground object can be transferred into the other video sequence to generate a virtual video. The author’s experiments show that the proposed approach is effective and robust for both the challenging real and synthetic sequences.

If vision is “veridical hallucination,” what keeps it veridical?

2003 ◽  
Vol 26 (4) ◽  
pp. 426-427
Author(s):  
Peter Ulric Tse
Keyword(s):  
Visual System ◽  
Reference Frame ◽  
Physical Stability ◽  
The Other ◽  
Data Loss ◽  
Missing Information

If perception is constructed, what keeps perception from becoming mere hallucination unlinked to world events? The visual system has evolved two strategies to anchor itself and correct its errors. One involves completing missing information on the basis of knowledge about what most likely exists in the scene. For example, the visual system fills in information only in cases where it might be responsible for the data loss. The other strategy involves exploiting the physical stability of the environment as a reference frame with respect to which the eyes and body can move.

Sign in / Sign up

Export Citation Format

Share Document