Color illusion by histogram compression
"A Javascript program to create images of color illusion by histogram compression in RGB"
made by Akiyoshi Kitaoka for
ECVP2021
Showtime!
(1) Choose an image from the pre-prepared images above, or select an image from your own folders.
(2) Set the following values (parameters) and press the button below.
R min
- max
G min
- max
B min
- max
(This transformed image can be downloaded by right-clicking on it.)
(original image)
For those who are still getting used to it:
This program can automatically determine the best parameter for you! (though not perfect:D)
Select the target color by clicking on the image above, and press the button below.
target color:    R
the color after change: R
Press the left button if all the histograms are not drawn.
magnification: x
Explanation
This color illusion production program takes advantage of the fact that
the human visual system behaves as if it is perceiving a distribution of
RGB values that is corrected to be in the range of 0 to 255.
References
Kitaoka, A. (2019). Two types of spatial color mixtures and color illusions.
EIP19 (Empirical Research in Psychology), Belgrade, Serbia, March 30, 2019.
Presentation (html)
Shapiro, A., Hedjar, L., Dixon, E., & Kitaoka, A. (2018). Kitaoka's
tomato: Two simple explanations based on information in the stimulus. i-Perception,
9(1), January-February, 1-9.
PDF (open access)
other pre-prepared images
The address of this webpage is available from:
Abstract
An electronic image is made up of pixels whose sub-pixels are RGB. Each
of RGB has a value of 256 gradations, where '0' means the darkest and '255'
means the brightest. In most cases, an image of an object or landscape
contains all gradations from 0 to 255 for each of RGB. When the range of
those gradations is narrowed, color illusion is likely to occur. My demo
is a Javascript program that creates color illusion by manipulating the
range of gradations of each of RGB. Here I name this manipulation 'histogram
compression.' Suppose you have an image of red strawberries. The R gradations
of the image are compressed downward, say from 0 to 128, and the G and
B gradations are compressed upward, say from 128 to 255. Then, pixels of
red hue disappear, but the strawberries will continue to look red. This
is a kind of color constancy phenomenon, but it is also a color illusion
in the sense that objects appear to be reddish even though there are no
red hue pixels. In my demo, I designed it so that you can try images of
various colors. The demo (shown below) is available to anyone who has access
to the web. Enjoy!
ECVP2021
(Staff only)