Moving Stimuli Define the Shape of Stationary Chromatic Patterns

Perception ◽  
1997 ◽  
Vol 26 (11) ◽  
pp. 1413-1422 ◽  
Author(s):  
Naokazu Goda ◽  
Yoshimichi Ejima
Keyword(s):  
Visual System ◽  
Capture Effect ◽  
Moving Stimuli ◽  
Imaginary Line ◽  
As If

A study is reported of phenomena involved in perceptually unified organisation of a stationary chromatic pattern and a moving black outline or dot pattern. When the corners of the outline pattern were temporally oscillated on a stationary chromatic square, the chromatic border appeared to follow the moving outline, as if captured by it. This capture effect was also observed with moving dots: the chromatic border was defined by an imaginary line connecting the moving dots. Both capture effects occur over a region that becomes wider with increasing velocity of the oscillation. These observations suggest that the visual system effectively uses information from moving features to define the shape of overlapping chromatic image regions.

scholarly journals Computational experiment of error diffusion dithering for depth reduction in images

2020 ◽  
Vol 1 (2) ◽  
pp. 9-13
Author(s):  
Leonardo Rezende Costa
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Computational Experiment ◽  
White Paper ◽  
Error Diffusion ◽  
Visual Effect ◽  
Black And White ◽  
Halftone Images ◽  
Depth Reduction ◽  
As If

The halftone technique is a process that employs patterns formed by black and white dots to reduce the number of gray levels in an image. Due to the tendency of the human visual system to soften the distinction between points with different shades, the patterns of black and white dots produce a visual effect as if the image were composed of shades of gray and dark. This technique is quite old and is widely used in printing images in newspapers and magazines, in which only black (ink) and white (paper) levels are needed. There are several methods for generating halftone images. In this article we explore dithering with error diffusion and an analysis of different halftone techniques is presented using error diffusion to change the depth of the image. The results showed that the depth of the image changes 1/8 per channel, this halftone technique can be used to reduce an image weight, losing information but achieving good results, depending on the context. ontext.

scholarly journals Why Do Line Drawings Work? A Realism Hypothesis

Perception ◽  
2020 ◽  
Vol 49 (4) ◽  
pp. 439-451 ◽  
Author(s):  
Aaron Hertzmann
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Line Drawing ◽  
Natural World ◽  
Human Observer ◽  
Object Identity ◽  
Line Drawings ◽  
3D Shape ◽  
Realistic Images ◽  
As If

Why is it that we can recognize object identity and 3D shape from line drawings, even though they do not exist in the natural world? This article hypothesizes that the human visual system perceives line drawings as if they were approximately realistic images. Moreover, the techniques of line drawing are chosen to accurately convey shape to a human observer. Several implications and variants of this hypothesis are explored.

Six-Month-Old Infants' Perception of the Hollow Face Illusion: Evidence for a General Convexity Bias

Perception ◽  
10.1068/p7689 ◽  
2014 ◽  
Vol 43 (11) ◽  
pp. 1177-1190 ◽  
Author(s):  
Sherryse L Corrow ◽  
Jordan Mathison ◽  
Carl E Granrud ◽  
Albert Yonas
Keyword(s):  
Visual System ◽  
Binocular Viewing ◽  
Viewing Condition ◽  
Binocular Condition ◽  
General Convexity ◽  
As If

Corrow, Granrud, Mathison, and Yonas (2011, Perception, 40, 1376–1383) found evidence that 6-month-old infants perceive the hollow face illusion. In the present study we asked whether 6-month-old infants perceive illusory depth reversal for a nonface object and whether infants' perception of the hollow face illusion is affected by mask orientation inversion. In experiment 1 infants viewed a concave bowl, and their reaches were recorded under monocular and binocular viewing conditions. Infants reached to the bowl as if it were convex significantly more often in the monocular than in the binocular viewing condition. These results suggest that infants perceive illusory depth reversal with a nonface stimulus and that the infant visual system has a bias to perceive objects as convex. Infants in experiment 2 viewed a concave face-like mask in upright and inverted orientations. Infants reached to the display as if it were convex more in the monocular than in the binocular condition; however, mask orientation had no effect on reaching. Previous findings that adults' perception of the hollow face illusion is affected by mask orientation inversion have been interpreted as evidence of stored-knowledge influences on perception. However, we found no evidence of such influences in infants, suggesting that their perception of this illusion may not be affected by stored knowledge, and that perceived depth reversal is not face-specific in infants.

The Two-Body Inversion Effect

2017 ◽  
Vol 28 (3) ◽  
pp. 369-379 ◽  
Author(s):  
Liuba Papeo ◽  
Timo Stein ◽  
Salvador Soto-Faraco
Keyword(s):  
Visual System ◽  
Intermediate Level ◽  
Inversion Effect ◽  
Configural Processing ◽  
Relative Positioning ◽  
Body Perception ◽  
Social Actions ◽  
Multiple Object ◽  
As If

How does one perceive groups of people? It is known that functionally interacting objects (e.g., a glass and a pitcher tilted as if pouring water into it) are perceptually grouped. Here, we showed that processing of multiple human bodies is also influenced by their relative positioning. In a series of categorization experiments, bodies facing each other (seemingly interacting) were recognized more accurately than bodies facing away from each other (noninteracting). Moreover, recognition of facing body dyads (but not nonfacing body dyads) was strongly impaired when those stimuli were inverted, similar to what has been found for individual bodies. This inversion effect demonstrates sensitivity of the visual system to facing body dyads in their common upright configuration and might imply recruitment of configural processing (i.e., processing of the overall body configuration without prior part-by-part analysis). These findings suggest that facing dyads are represented as one structured unit, which may be the intermediate level of representation between multiple-object (body) perception and representation of social actions.

scholarly journals Predictability of sinusoidally moving stimuli does not improve the accuracy of the accommodative response

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Antonio J. Del Águila-Carrasco ◽  
Iván Marín-Franch
Keyword(s):  
Visual System ◽  
Research Work ◽  
Target Motion ◽  
Phase Lag ◽  
Average Amplitude ◽  
Accommodative Response ◽  
Sinusoidal Movement ◽  
Moving Stimuli ◽  
Temporal Phase

AbstractPrevious research work suggests that predictable target motion such as sinusoidal movement can be anticipated by the visual system, thereby improving the accommodative response. The validity of predictable motion for studying human dynamic accommodation is sometimes put into question. The aim of this work was to assess the effect of anticipation along with learning (and motivation, etc.) and fatigue (and boredom, loss of attention, etc.) on dynamic accommodation experiments from a practical perspective. Specifically, changes in amplitude and temporal phase lag were estimated within and between trials as 9 adult observers were instructed to focus on a stimulus that oscillated sinusoidally towards and away from the eye at specific temporal frequencies. On average, amplitude decreased whereas phase increased within trials. No evidence of anticipation or learning was observed either within or between trials. Fatigue consistently dominated anticipation and learning within the course of each trial. Even if the eye is equipped by a prediction operator as it is often assumed, fatigue confounds the results from dynamic accommodation experiments more than anticipation or learning.

scholarly journals ‘Seeing’ proximal representations: Testing attitudes to the relationship between vision and images

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256658
Author(s):  
Steven Samuel ◽  
Klara Hagspiel ◽  
Geoff G. Cole ◽  
Madeline J. Eacott
Keyword(s):  
Visual System ◽  
Perspective Taking ◽  
Present Experiment ◽  
Retinal Images ◽  
Visual Perspective ◽  
Size Constancy ◽  
Original Response ◽  
Adult Participants ◽  
The Relationship ◽  
As If

Corrections applied by the visual system, like size constancy, provide us with a coherent and stable perspective from ever-changing retinal images. In the present experiment we investigated how willing adults are to examine their own vision as if it were an uncorrected 2D image, much like a photograph. We showed adult participants two lines on a wall, both of which were the same length but one was closer to the participant and hence appeared visually longer. Despite the instruction to base their judgements on appearance specifically, approximately half of the participants judged the lines to appear the same. When they took a photo of the lines and were asked how long they appeared in the image their responses shifted; now the closer line appeared longer. However, when they were asked again about their own view they reverted to their original response. These results suggest that many adults are resistant to imagining their own vision as if it were a flat image. We also place these results within the context of recent views on visual perspective-taking.

Author response for "The brain of the African wild dog. IV . The visual system"

2020 ◽  
Author(s):  
Samson Chengetanai ◽  
Adhil Bhagwandin ◽  
Mads F. Bertelsen ◽  
Therese Hård ◽  
Patrick R. Hof ◽  
...  
Keyword(s):  
Visual System ◽  
Author Response ◽  
African Wild Dog ◽  
Wild Dog ◽  
The Brain

Digital differential hysteresis iimage processing displays what the microscope acquires but the eye can't see

1995 ◽  
Vol 53 ◽  
pp. 642-643
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
Image Processing ◽  
Visual System ◽  
High Precision ◽  
Image Data ◽  
Processing Technology ◽  
Output Data ◽  
Contrast Resolution ◽  
Pixel Intensity ◽  
Data Reading ◽  
Hysteresis Properties

Differential hysteresis processing is a new image processing technology that provides a tool for the display of image data information at any level of differential contrast resolution. This includes the maximum contrast resolution of the acquisition system which may be 1,000-times higher than that of the visual system (16 bit versus 6 bit). All microscopes acquire high precision contrasts at a level of <0.01-25% of the acquisition range in 16-bit - 8-bit data, but these contrasts are mostly invisible or only partially visible even in conventionally enhanced images. The processing principle of the differential hysteresis tool is based on hysteresis properties of intensity variations within an image.Differential hysteresis image processing moves a cursor of selected intensity range (hysteresis range) along lines through the image data reading each successive pixel intensity. The midpoint of the cursor provides the output data. If the intensity value of the following pixel falls outside of the actual cursor endpoint values, then the cursor follows the data either with its top or with its bottom, but if the pixels' intensity value falls within the cursor range, then the cursor maintains its intensity value.

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