Visual Inter-Attribute Contour Completion

Perception ◽  
10.1068/p3222 ◽  
2001 ◽  
Vol 30 (7) ◽  
pp. 855-865 ◽  
Author(s):  
Leo Poom
Keyword(s):  
Binocular Disparity ◽  
Luminance Contrast ◽  
Second Order ◽  
Temporal Contrast ◽  
Pictorial Cues ◽  
Visual Phenomenon ◽  
Completion Process ◽  
Contour Completion

A new visual phenomenon, inter-attribute illusory (completed) contours, is demonstrated. Contour completions are perceived between any combination of spatially separate pairs of inducing elements (Kanizsa-like ‘pacman’ figures) defined either by pictorial cues (luminance contrast or offset gratings), temporal contrast (motion, second-order-motion or ‘phantom’ contours), or binocular-disparity contrast. In a first experiment, observers reported the perceived occurrence of contour completion for all pair combinations of inducing elements. In a second experiment they rated the perceived clarity of the completed contours. Both methods generated similar results—contour completions were perceived even though the inducing elements were defined by different attributes. Ratings of inter-attribute clarity were no lower than in either of the two corresponding intra-attribute conditions and seem to be the average of these two ratings. The results provide evidence for the existence of attribute-invariant Gestalt processes, and on a mechanistic level indicate that the completion process operates on attribute-invariant contour detectors.

Interaction between Transparency and Structure from Motion

1992 ◽  
Vol 4 (4) ◽  
pp. 573-589 ◽  
Author(s):  
Daniel Kersten ◽  
Heinrich H. Bülthoff ◽  
Bennett L. Schwartz ◽  
Kenneth J. Kurtz
Keyword(s):  
Visual System ◽  
Structure From Motion ◽  
Human Visual System ◽  
Binocular Disparity ◽  
Rigid Motion ◽  
Motion Information ◽  
Low Level ◽  
Visual Process ◽  
Pictorial Cues

It is well known that the human visual system can reconstruct depth from simple random-dot displays given binocular disparity or motion information. This fact has lent support to the notion that stereo and structure from motion systems rely on low-level primitives derived from image intensities. In contrast, the judgment of surface transparency is often considered to be a higher-level visual process that, in addition to pictorial cues, utilizes stereo and motion information to separate the transparent from the opaque parts. We describe a new illusion and present psychophysical results that question this sequential view by showing that depth from transparency and opacity can override the bias to see rigid motion. The brain's computation of transparency may involve a two-way interaction with the computation of structure from motion.

scholarly journals REPRESENTATION OF 3-D VOLUMETRIC OBJECT FROM THE PANTOMIME EFFECT AND SHADING CUES IN HUMAN BRAIN

2007 ◽  
Vol 21 (08) ◽  
pp. 1307-1322
Author(s):  
QI ZHANG ◽  
KEN MOGI
Keyword(s):  
Human Brain ◽  
Visual Processing ◽  
Visual Information ◽  
Binocular Disparity ◽  
Object Perception ◽  
Human Beings ◽  
Brain Areas ◽  
Human Ability ◽  
Visual Areas ◽  
Visual Phenomenon

Human ability to process visual information of outside world is yet far ahead of man-made systems in accuracy and speed. In particular, human beings can perceive 3-D object from various cues, such as binocular disparity and monocular shading cues. Understanding of the mechanism of human visual processing will lead to a breakthrough in creating artificial visual systems. Here, we study the human 3-D volumetric object perception that is induced by a visual phenomenon named as the pantomime effect and by the monocular shading cues. We measured human brain activities using fMRI when the subjects were observing the visual stimuli. A coordinated system of brain areas, including those in the prefrontal and parietal cortex, in addition to the occipital visual areas was found to be involved in the volumetric object perception.

scholarly journals Processing of first and second order binocular disparity by the human visual system

2012 ◽  
Vol 12 (9) ◽  
pp. 39-39
Author(s):  
C. Quaia ◽  
B. Sheliga ◽  
L. Optican ◽  
B. Cumming
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Binocular Disparity ◽  
Second Order

scholarly journals Seeing Depth with One Eye and Pictorial Space

2021 ◽  
Author(s):  
Paul Linton
Keyword(s):  
Binocular Disparity ◽  
3D Vision ◽  
Pictorial Space ◽  
Pictorial Cues

In my second post I questioned whether the integration of pictorial cues and binocular disparity occurs at the level of perception. In this third post, I push the argument further by questioning whether pictorial cues contribute to 3D vision at all.

scholarly journals First- and second-order contributions to depth perception in anti-correlated random dot stereograms

2018 ◽  
Author(s):  
Jordi M. Asher ◽  
Paul B. Hibbard
Keyword(s):  
Binocular Disparity ◽  
Second Order ◽  
Gap Size ◽  
Neural Responses ◽  
Random Dot Stereograms ◽  
Coarse Spatial Resolution ◽  
Correct Direction ◽  
Random Dot Stereogram ◽  
Circular Target ◽  
Detection Mechanisms

ABSTRACTThe binocular energy model of neural responses predicts that depth from binocular disparity might be perceived in the reversed direction when the contrast of dots presented to one eye is reversed. While reversed depth has been found using anti-correlated random-dot stereogram (ACRDS) the findings are inconsistent across studies. The mixed findings may be accounted for by the presence of a gap between the target and surround, or as a result of overlap of dots around the vertical edges of the stimuli. To test this, we assessed whether (1) the gap size (0, 19.2 or 38.4 arc min) (2) the correlation of dots or (3) the border orientation (circular target, or horizontal or vertical edge) affected the perception of depth. Reversed depth from ACRDS (circular no-gap condition) was seen by a minority of participants, but this effect reduced as the gap size increased. Depth was mostly perceived in the correct direction for ACRDS edge stimuli, with the effect increasing with the gap size. The inconsistency across conditions can be accounted for by the relative reliability of first- and second-order depth detection mechanisms, and the coarse spatial resolution of the latter.

Measurements of ‘Von Kries’ Contrast Colours

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 42-42 ◽  
Author(s):  
P Whittle ◽  
L Arend
Keyword(s):  
Luminance Contrast ◽  
Second Order ◽  
Logarithmic Function ◽  
Binocular Field ◽  
First Approximation ◽  
Cone Axis ◽  
Multiplicative Shift

At two previous ECVPs we showed demonstrations and preliminary measurements of contrast colours in a haploscopic display. Colours were presented in different uniform surrounds to the two eyes, superimposed in the binocular field so that they appeared to be in the same surround. Here we report more extensive matching experiments. The principal results are as follows: (1) To a first approximation, in a log MacLeod - Boynton space, perceived colour is determined by the surround-to-colour vector (SCV). The remaining results are second-order deviations from this von Kries scheme. (2) Increment colours are tinged with the hue of the surround, even though that surround hue cannot be seen. This effect of the sign of luminance contrast seems to be just a multiplicative shift: otherwise, increment and decrement data can be superimposed. (3) SCVs for a constant perceived colour shrink and expand slightly with movement along the S-cone axis, suggesting that the transform of S-cone excitation is less compressive than a logarithmic function. (4) SCVs show consistent small rotations, suggesting that L- M and S-( L+ M) axes are not completely independent.

scholarly journals Processing of first- and second-order motion signals by neurons in area MT of the macaque monkey

1998 ◽  
Vol 15 (2) ◽  
pp. 305-317 ◽  
Author(s):  
LAWRENCE P. O'KEEFE ◽  
J. ANTHONY MOVSHON
Keyword(s):  
Visual Motion ◽  
Luminance Contrast ◽  
Macaque Monkey ◽  
Small Sample ◽  
Second Order ◽  
Spatial Modulation ◽  
Motion Processing ◽  
Motion Sensors ◽  
Area Mt ◽  
First Order

Extrastriate cortical area MT is thought to process behaviorally important visual motion signals. Psychophysical studies suggest that visual motion signals may be analyzed by multiple mechanisms, a “first-order” one based on luminance, and a “second-order” one based upon higher level cues (e.g. contrast, flicker). Second-order motion is visible to human observers, but should be invisible to first-order motion sensors. To learn if area MT is involved in the analysis of second-order motion, we measured responses to first- and second-order gratings of single neurons in area MT (and in one experiment, in area V1) in anesthetized, paralyzed macaque monkeys. For each neuron, we measured directional and spatio-temporal tuning with conventional first-order gratings and with second-order gratings created by spatial modulation of the flicker rate of a random texture. A minority of MT and V1 neurons exhibited significant selectivity for direction or orientation of second-order gratings. In nearly all cells, response to second-order motion was weaker than response to first-order motion. MT cells with significant selectivity for second-order motion tended to be more responsive and more sensitive to luminance contrast, but were in other respects similar to the remaining MT neurons; they did not appear to represent a distinct subpopulation. For those cells selective for second-order motion, we found a correlation between the preferred directions of first- and second-order motion, and weak correlations in preferred spatial frequency. These cells preferred lower temporal frequencies for second-order motion than for first-order motion. A small proportion of MT cells seemed to remain selective and responsive for second-order motion. None of our small sample of V1 cells did. Cells in this small population, but not others, may perform “form-cue invariant” motion processing (Albright, 1992).

scholarly journals Possible significance of spatial heterogeneities of local visual features for face perception

F1000Research ◽  
2015 ◽  
Vol 4 ◽  
pp. 10
Author(s):  
Vitaly V. Babenko ◽  
Daria S. Alekseeva ◽  
Denis V. Yavna
Keyword(s):  
Spatial Heterogeneity ◽  
Random Sequence ◽  
Luminance Contrast ◽  
Second Order ◽  
Visual Features ◽  
Living Things ◽  
Spatial Frequencies ◽  
Average Luminance ◽  
Striate Neurons ◽  
Unfamiliar Faces

Second-order visual filters are the mechanisms which preattentively combine the rectified outputs of first-order filters (the linear striate neurons). This allows them to select the image areas which are characterized by spatial heterogeneity of the local visual features. The aim of our research is to determine whether information from these areas may be sufficient to detect unfamiliar faces and to distinguish their gender. In our experiments we used digital photos of real living things or artificial objects and faces. All these images were adjusted to an average luminance, contrast and size (7 angle degree) and were processed to extract the areas which differ the most in contrast, orientation, and spatial frequency in each of the six spatial frequencies (0.5, 1, 2, 4, 8, and 16 cpd). The other image parts were adjusted to the background. The obtained pictures were presented in a random sequence. The observer had to say what he/she saw after each presentation. When a face was presented the observer’s answer could be assigned to one of the categories: ‘it is not clear’, ‘head’, ‘human face’, ‘male / female’. We found that the information contained in the image areas with a spatial heterogeneity of the local features is sufficient not only for detecting a face, but also for distinguishing its gender. The best results were obtained at a carrier frequency of 2 cpd. The results were a little bit worse at 0.5 and 1 cpd. However, the information extracted from the high-frequency half of the spectrum was significantly less useful. The obtained results allow us to suggest that the information transmitted by the second-order visual filters may be used for pattern recognition.

scholarly journals Different latencies of edge detection cause the fluttering-heart illusion

2021 ◽  
Author(s):  
Masahiro Suzuki ◽  
Kazuhisa Yanaka
Keyword(s):  
Edge Detection ◽  
Luminance Contrast ◽  
Second Order ◽  
High Luminance ◽  
First Order ◽  
Low Luminance

AbstractWe studied the mechanism causing the fluttering-heart illusion in which the motion of an inner figure appears unsynchronized compared with that of the outer figure surrounding it although the motion of both figures is objectively synchronized in reality. Experiment 1 examined the effect of edges’ luminance contrasts. The illusion was measured under conditions where the luminance contrasts of the outer and inner figures’ edges were varied. The results indicated that the illusion occurred when the outer figure’s edge had a high luminance contrast and the inner figure’s edge had a low luminance contrast and that the illusion was reversed when the outer figure’s edge had a low luminance contrast and the inner figure’s edge had a high luminance contrast. Experiment 2 examined the effect of the first- and second-order edges. The illusion was measured under conditions where the first- and second-order edges coexisted or only the first-order edges existed. The results indicated that the illusion occurred when the outer figure had the first-order edge and the inner figure had the second-order edge, and that the illusion was reversed when the outer figure had the second-order edge and the inner figure had the first-order edge. These findings supported the hypothesis that the different latencies of edge detection cause the fluttering-heart illusion.

scholarly journals Flashing anomalous color contrast

2004 ◽  
Vol 21 (3) ◽  
pp. 365-372 ◽  
Author(s):  
BAINGIO PINNA ◽  
LOTHAR SPILLMANN ◽  
JOHN S. WERNER
Keyword(s):  
Luminance Contrast ◽  
Color Contrast ◽  
Foveal Vision ◽  
Stimulus Movement ◽  
Central Disk ◽  
Visual Phenomenon ◽  
Length Width ◽  
Central Gray ◽  
Simultaneous Color Contrast ◽  
Gray Disk

A new visual phenomenon that we call flashing anomalous color contrast is described. This phenomenon arises from the interaction between a gray central disk and a chromatic annulus surrounded by black radial lines. In an array of such figures, the central gray disk no longer appears gray, but assumes a color complementary to that of the surrounding annulus. The induced color appears: (1) vivid and saturated; (2) self-luminous, not a surface property; (3) flashing with eye or stimulus movement; (4) floating out of its confines; and (5) stronger in extrafoveal than in foveal vision. The strength of the effect depends on the number, length, width, and luminance contrast of the radial lines. The results suggest that the chromatic ring bounding the inner tips of the black radial lines induces simultaneous color contrast, whereas the radial lines elicit, in conjunction with the gray disk and the ring, the flashing, vividness, and high saturation of the effect. The stimulus properties inducing the illusion suggest that flashing anomalous color contrast may be based on asynchronous interactions among multiple visual pathways.

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