Ocular filtering of ultraviolet radiation and the spectral spacing of photoreceptors benefit Von Kries colour constancy

SUMMARY Ocular filters in the eyes of many vertebrates, including humans, absorb wavelengths shorter than approximately 400nm. These filters prevent the β-band of a visual pigment from being exposed to ultraviolet radiation, essentially narrowing the spectral sensitivity of the different photoreceptor classes. A comparison of different hypothetical visual systems is used to show that von Kries colour constancy is improved by ocular filtration of ultraviolet radiation, whilst there is no reduction in colour discrimination. Furthermore, it is shown that the asymmetric spectral spacing of different photoreceptor classes present in the human visual system may benefit colour constancy. The results are interpreted in relation to predictions of von Kries colour constancy for a standard human observer.

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Why Do Line Drawings Work? A Realism Hypothesis

Perception ◽

10.1177/0301006620908207 ◽

2020 ◽

Vol 49 (4) ◽

pp. 439-451 ◽

Cited By ~ 1

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.

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Technical Vision Model of the Visual Systems for Industry Application

Examining Optoelectronics in Machine Vision and Applications in Industry 4.0 - Advances in Computational Intelligence and Robotics ◽

10.4018/978-1-7998-6522-3.ch010 ◽

2021 ◽

pp. 288-310

Author(s):

Oleg Sytnik ◽

Vladimir Kartashov

Keyword(s):

Image Processing ◽

Pattern Recognition ◽

Visual System ◽

Mathematical Models ◽

Human Visual System ◽

Vision System ◽

Vision Systems ◽

Industrial Systems ◽

Visual Systems ◽

Technical Vision

The problems of highlighting the main informational aspects of images and creating their adequate models are discussed in the chapter. Vision systems can receive information about an object in different frequency ranges and in a form that is not accessible to the human visual system. Vision systems distort the information contained in the image. Therefore, to create effective image processing and transmission systems, it is necessary to formulate mathematical models of signals and interference. The chapter discusses the features of perception by the human visual system and the issues of harmonizing the technical characteristics of industrial systems for receiving and transmitting images. Methods and algorithms of pattern recognition are discussed. The problem of conjugation of the characteristics of the technical vision system with the consumer of information is considered.

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Image Content Enhancement Through Salient Regions Segmentation for People With Color Vision Deficiencies

i-Perception ◽

10.1177/2041669519841073 ◽

2019 ◽

Vol 10 (3) ◽

pp. 204166951984107 ◽

Cited By ~ 4

Author(s):

Alessandro Bruno ◽

Francesco Gugliuzza ◽

Edoardo Ardizzone ◽

Calogero Carlo Giunta ◽

Roberto Pirrone

Keyword(s):

Visual System ◽

Eye Tracking ◽

Color Vision ◽

Human Visual System ◽

Color Images ◽

Color Mapping ◽

Visual Systems ◽

Salient Regions ◽

Color Blind ◽

Color Vision Deficiencies

Color vision deficiencies affect visual perception of colors and, more generally, color images. Several sciences such as genetics, biology, medicine, and computer vision are involved in studying and analyzing vision deficiencies. As we know from visual saliency findings, human visual system tends to fix some specific points and regions of the image in the first seconds of observation summing up the most important and meaningful parts of the scene. In this article, we provide some studies about human visual system behavior differences between normal and color vision-deficient visual systems. We eye-tracked the human fixations in first 3 seconds of observation of color images to build real fixation point maps. One of our contributions is to detect the main differences between the aforementioned human visual systems related to color vision deficiencies by analyzing real fixation maps among people with and without color vision deficiencies. Another contribution is to provide a method to enhance color regions of the image by using a detailed color mapping of the segmented salient regions of the given image. The segmentation is performed by using the difference between the original input image and the corresponding color blind altered image. A second eye-tracking of color blind people with the images enhanced by using recoloring of segmented salient regions reveals that the real fixation points are then more coherent (up to 10%) with the normal visual system. The eye-tracking data collected during our experiments are in a publicly available dataset called Eye-Tracking of Color Vision Deficiencies.

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Are new vision standards and tests needed for military aircrew using 3D stereo helmet-mounted displays?

BMJ Military Health ◽

10.1136/bmjmilitary-2020-001493 ◽

2020 ◽

pp. bmjmilitary-2020-001493

Author(s):

Bonnie Noeleen Posselt ◽

M Winterbottom

Keyword(s):

Visual System ◽

Human Visual System ◽

Three Dimensional ◽

Testing Methods ◽

Flight Data ◽

Visual Systems ◽

Overall Performance ◽

New Vision ◽

Medical Vision ◽

Stereo Acuity

Visual standards for military aviators were historically set in the 1920s with requirements based on the visual systems of aircraft at the time, and these standards have changed very little despite significant advances in aircraft technology. Helmet-mounted displays (HMDs) today enable pilots to keep their head out of the cockpit while flying and can be monocular, biocular or binocular in design. With next generation binocular HMDs, flight data can be displayed in three-dimensional stereo to declutter information presented, improving search times and potentially improve overall performance further. However, these new visually demanding technologies place previously unconsidered stresses on the human visual system. As such, new medical vision standards may be required for military aircrew along with improved testing methods to accurately characterise stereo acuity.

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