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.

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.

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

2001 ◽  
Vol 204 (14) ◽  
pp. 2391-2399 ◽  
Author(s):  
Adrian G. Dyer
Keyword(s):  
Ultraviolet Radiation ◽  
Visual System ◽  
Human Visual System ◽  
Visual Pigment ◽  
No Reduction ◽  
Human Observer ◽  
Colour Discrimination ◽  
Colour Constancy ◽  
Visual Systems ◽  
Spectral Spacing

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.

Can the non-pre-whitening model observer, including aspects of the human visual system, predict human observer performance in mammography?

2016 ◽  
Vol 32 (12) ◽  
pp. 1559-1569 ◽  
Author(s):  
R.W. Bouwman ◽  
R.E. van Engen ◽  
M.J.M. Broeders ◽  
G.J. den Heeten ◽  
D.R. Dance ◽  
...  
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Observer Performance ◽  
Human Observer ◽  
Model Observer

scholarly journals sketcher: An R package for converting a photo into a sketch style image

2020 ◽  
Author(s):  
Hiroyuki Tsuda
Keyword(s):  
Image Processing ◽  
Visual Perception ◽  
Visual System ◽  
Line Drawing ◽  
R Package ◽  
Specific Research ◽  
Line Drawings ◽  
Processing Effects

Line drawings have been useful stimuli for visual perception, cognition, and related fields, because edges play an important role in the visual system. Although there are many datasets of line drawing stimuli available for research, we often need a new set of stimuli for specific research purposes. Here I provide an R implementation of image processing effects where a photo is converted to a line drawing image. Drawing style, such as lineweight, texture smoothness, and the inclusion of shading can be controlled by adjusting the parameters of this algorithm. With this tool, line drawing stimuli can easily be created with just a few lines of script, and will be useful for various research applications.

Sign in / Sign up

Export Citation Format

Share Document