PASCAL - Pattern Analysis, Statistical Modelling and Computational Learning

Unsupervised learning of dependencies between local luminance and contrast in natural images
Jussi Lindgren, Jarmo Hurri and Aapo Hyvärinen
In: IJCNN 2008, 01-06 Jun 2008, Hong Kong, China.


Separate processing of local luminance and contrast in biological visual systems has been argued to be due to the independence of these two quantities in natural image data. In this paper we examine spatial, retinotopic channels formed by these two quantities and use Independent Component Analysis to study the possible dependencies between the channels. As a result, oriented, localized bandpass filter pairs are learned, where one filter processes the luminance channel and the other the contrast channel. We study the relationship of the learned filters and their pairings, and show that these are due to dependencies existing between local luminance and contrast. Subsequently, our results suggest that the separate processing of local luminance and contrast can not be attributed to their independence in natural images.

EPrint Type:Conference or Workshop Item (Paper)
Project Keyword:Project Keyword UNSPECIFIED
Subjects:Machine Vision
Learning/Statistics & Optimisation
ID Code:3956
Deposited By:Jussi Lindgren
Deposited On:25 February 2008