Colour in Context
Research group
Computer Vision Center

The Chromatic Induction Wavelet Model (CiWaM) online






CiWaM is a wavelet-based computational model that attempts to reproduce the perceptual processes involved in visual chromatic induction. (Otazu X, Vanrell M, Parraga CA, "Toward a unified chromatic induction model" , Journal of Vision, 10(12):5, 2010)

CIWaM takes an input image and considers it to be the stimulus received by the observer. The model then generates an output image that is a prediction of the perceptual image of the observer. We would like to stress that, since this output image corresponds to the perceived image, the input and output images look very different because *YOUR* perceptual visual system is observing two different images. You will not see two identical images. As a result, the useful information provided by this output image is contained in its numerical values (LMS or sRGB values), rather than in the actual appearance of the image.

The user simply has to upload a color image in any common image file format and specify the color space of the image (LMS or sRGB). The system will output the perceptual image in the same color space.


Select files to upload
Max file size = 5 MB



Color space:  LMS sRGB          Maximum contrast factor:   (default value 1.000 , rang value [0.00 -2.00])

Select the option to fill the parameters

Choosing the first option, the BIWaM considers you are looking the image on the *ACTUAL* monitor you are right now. Introduce the distance at which you are looking the image and the monitor diagonal size in inches.


Option 1

Distance of monitor (cm):      
Monitor diagonal size (inch):

Option 2

Image width visual angle (degrees)




Note : This program accept many format of images (.gif,.jpg,.jpeg,.png,.tif,.bmp,.ppm) but we recomend (.tif,.png,.ppm) because the other formats may have lost color. The program always returns the .png format.