Feature Analysers, Optical Illusions, and Figural Aftereffects

Perception ◽  
1977 ◽  
Vol 6 (4) ◽  
pp. 401-406 ◽  
Author(s):  
Tadasu Oyama
Keyword(s):  
Interaction Model ◽  
Size Ratio ◽  
Absolute Distance ◽  
Test Circle ◽  
Optical Illusions ◽  
Tuning Width ◽  
The Absolute ◽  
Delboeuf Illusion

Simple displacement models cannot explain some aspects of optical illusions and figural aftereffects. The orientation-detector interaction model proposed by Blakemore and others is more suitable to explain many aspects of the Zöllner illusion, positive and negative illusions, the effect of gap between the inducing and test lines, and the anisotropy of illusions. If we hypothesize size detectors whose tuning width and distribution steps are proportional to logarithmic size, interactions between them explain well the fact that the Delboeuf illusion and figural aftereffects of circles are determined by the size ratio of the inducing to test circle, not by the absolute distance between the contours of these circles.

Gravity as a Monocular Cue for Perception of Absolute Distance and/or Absolute Size

Perception ◽  
1992 ◽  
Vol 21 (1) ◽  
pp. 69-76 ◽  
Author(s):  
John S Watson ◽  
Martin S Banks ◽  
Claes von Hofsten ◽  
Constance S Royden
Keyword(s):  
Wave Motion ◽  
Moving Objects ◽  
Formal Analysis ◽  
Free Fall ◽  
Absolute Distance ◽  
Absolute Size ◽  
The Absolute ◽  
Pendulum Wave

When the motion of an object is influenced by gravity (eg free fall, pendulum, wave motion), that influence may provide a cue to computing the absolute distance and/or size of the object. Formal analysis supports the claim that the distance and size of moving objects are generally computable with reference to the gravitational component of motion. Informal evidence from judgments of realism in films is consistent with this gravity-cue hypothesis.

scholarly journals Absolute distance interferometry for subaperture stitching of large freeform optics

2020 ◽  
Vol 238 ◽  
pp. 06011
Author(s):  
Jan Spichtinger ◽  
Michael Schulz ◽  
Gerd Ehret
Keyword(s):  
Measurement System ◽  
Optical Axis ◽  
Distance Measurement ◽  
Fizeau Interferometer ◽  
Absolute Distance ◽  
Local Surface ◽  
Surface Gradient ◽  
Freeform Optics ◽  
The Absolute ◽  
Subaperture Stitching

We are developing a form measurement system for the surfaces of freeform optics and large conventional optics. The specifications of the optics are diameters up to 1.5 m and radii of curvature down to 10 m. This includes optics like telescope mirror segments and synchrotron optics. Using a Fizeau interferometer, we propose a subaperture stitching method that involves vertically aligning the interferometer’s optical axis to the local surface gradient and measuring the absolute distance from the interferometer’s reference flat to the specimen. Experimental results for the absolute distance measurement are shown.

Geometric-Optical Illusions Under Isoluminance?

2017 ◽  
Author(s):  
Kai Hamburger ◽  
Thorsten Hansen ◽  
Karl R. Gegenfurtner
Keyword(s):  
Poggendorff Illusion ◽  
Ponzo Illusion ◽  
Ebbinghaus Illusion ◽  
Optical Illusions ◽  
Magnocellular System ◽  
Lyer Illusion ◽  
System P ◽  
Visual Areas ◽  
Parvocellular System ◽  
Delboeuf Illusion

This chapter briefly introduces nine classical geometric-optical illusions. These include the Delboeuf illusion, the Ebbinghaus illusion, the Judd illusion, the Müller-Lyer illusion, the Ponzo illusion, the vertical illusion, the Hering illusion, the Poggendorff illusion, and the Zoellner illusion. It then demonstrates that they persist under different luminance conditions and under isoluminance. The empirical findings show that our conscious percept is similarly affected by luminance conditions and isoluminance, suggesting that joint contour processing (chromatic and luminance) may extend well beyond early visual areas. The chapter further discusses these concepts in terms of the magnocellular system, the parvocellular system, and the koniocellular system.

Expanding Angles? Systematic Distortions of Space Involving Angular Figures

Perception ◽  
1977 ◽  
Vol 6 (5) ◽  
pp. 571-582 ◽  
Author(s):  
Simon Heywood ◽  
Karen Chessell
Keyword(s):  
Absolute Distance ◽  
Per Se ◽  
The Absolute

Using simple, single angular figures, including figures containing only one line, we have shown systematic misestimations of distance defined by these figures. These misestimations are not related to the absolute distance per se, but are related both to the size of the angle defining the distance, and to the part of the angle defining it. Some implications of these findings are discussed.

scholarly journals Optical Angle Sensor Technology Based on the Optical Frequency Comb Laser

2020 ◽  
Vol 10 (11) ◽  
pp. 4047 ◽  
Author(s):  
Yuki Shimizu ◽  
Hiraku Matsukuma ◽  
Wei Gao
Keyword(s):  
Femtosecond Laser ◽  
Frequency Comb ◽  
Angle Measurement ◽  
Optical Frequency Comb ◽  
High Peak Power ◽  
Optical Frequency ◽  
Absolute Distance ◽  
Angle Sensor ◽  
The Absolute ◽  
Optical Angle Sensor

A mode-locked femtosecond laser, which is often referred to as the optical frequency comb, has increasing applications in various industrial fields, including production engineering, in the last two decades. Many efforts have been made so far to apply the mode-locked femtosecond laser to the absolute distance measurement. In recent years, a mode-locked femtosecond laser has increasing application in angle measurement, where the unique characteristics of the mode-locked femtosecond laser such as the stable optical frequencies, equally-spaced modes in frequency domain, and the ultra-short pulse trains with a high peak power are utilized to achieve precision and stable angle measurement. In this review article, some of the optical angle sensor techniques based on the mode-locked femtosecond laser are introduced. First, the angle scale comb, which can be generated by combining the dispersive characteristic of a scale grating and the discretized modes in a mode-locked femtosecond laser, is introduced. Some of the mode-locked femtosecond laser autocollimators, which have been realized by combining the concept of the angle scale comb with the laser autocollimation, are also explained. Angle measurement techniques based on the absolute distance measurements, lateral chromatic aberration, and second harmonic generation (SHG) are also introduced.

Quantitative Endoscopy: Initial Accuracy Measurements

2000 ◽  
Vol 109 (2) ◽  
pp. 128-132 ◽  
Author(s):  
Theodore O. Truitt ◽  
Roger A. Adelman ◽  
Dan H. Kelly ◽  
J. Paul Willging
Keyword(s):  
Object Size ◽  
Absolute Distance ◽  
Image Size ◽  
Absolute Size ◽  
Actual Object ◽  
Endoscopic Images ◽  
Endoscopic Image ◽  
The Mean ◽  
The Absolute ◽  
Size Estimates

The geometric optics of an endoscope can be used to determine the absolute size of an object in an endoscopic field without knowing the actual distance from the object. This study explores the accuracy of a technique that estimates absolute object size from endoscopic images. Quantitative endoscopy involves calibrating a rigid endoscope to produce size estimates from 2 images taken with a known traveled distance between the images. The heights of 12 samples, ranging in size from 0.78 to 11.80 mm, were estimated with this calibrated endoscope. Backup distances of 5 mm and 10 mm were used for comparison. The mean percent error for all estimated measurements when compared with the actual object sizes was 1.12%. The mean errors for 5-mm and 10-mm backup distances were 0.76% and 1.65%, respectively. The mean errors for objects <2 mm and ≥2 mm were 0.94% and 1.18%, respectively. Quantitative endoscopy estimates endoscopic image size to within 5% of the actual object size. This method remains promising for quantitatively evaluating object size from endoscopic images. It does not require knowledge of the absolute distance of the endoscope from the object, rather, only the distance traveled by the endoscope between images.

A Comparative Analysis of Accelerometer and Time–Motion Data in Elite Men’s Hockey Training and Competition

2015 ◽  
Vol 10 (4) ◽  
pp. 446-451 ◽  
Author(s):  
Ted Polglaze ◽  
Brian Dawson ◽  
Daniel J. Hiscock ◽  
Peter Peeling
Keyword(s):  
Strong Relationship ◽  
Absolute Distance ◽  
Motion Data ◽  
Time Motion ◽  
Player Tracking ◽  
Hockey Players ◽  
Physiological Demands ◽  
The Absolute ◽  
Tracking Devices ◽  
The Relationship

Purpose:To determine the relationship between distance covered and player load (PL: sum of accelerations in all 3 planes of movement) in hockey training and competition.Methods:Elite male hockey players (N = 24) wore player-tracking devices in 7 international matches and 7 training sessions. Players were arranged in 4 positional groups (strikers, attacking midfielders, defensive midfielders, defenders) in competition but had generic roles in training. Relationships between distance and PL were assessed in both absolute (m, AU) and relative (m/min, AU/min) terms and were compared between matches and training and between positions within matches, using the Fisher Z test.Results:In competition, the absolute distance–PL relationship was very large overall (r = .868), with no differences between positions. The relative distance–PL relationship was moderate overall (r = .486) and weaker in strikers than in defensive midfielders (Z = 1.785, P = .037) and defenders (Z = 1.690, P = .045). In training, the absolute distance–PL relationship was very large (r = .742), and large (r = .633) in relative terms. The relationship was stronger in competition than training for absolute values (Z = 2.824, P = .005) but not different for relative values.Conclusions:The strong relationship between these variables suggests that PL in hockey is mostly accumulated through running and other locomotor actions, such that PL is not effective in quantifying other activities (evasion, low stance) that contribute to physiological demands, particularly in training.

Sign in / Sign up

Export Citation Format

Share Document