It is hypothesized that colour vision and opponent processing of colour signals in the visual system evolved as a means of overcoming the extremely unfavourable lighting conditions in the natural environment of early vertebrates. The significant flicker of illumination inherent in the shallow-water environment complicated the visual process in the achromatic case, in particular preventing early...

We have revealed a new role for colour vision in visual scene analysis: colour vision facilitates shadow identification. Shadows are important features of the visual scene, providing information about the shape, depth, and movement of objects. To be useful for perception, however, shadows must be distinguished from other types of luminance variation, principally the variation in object reflecta...

This study aimed at assessing the processing time of a natural scene in a fast categorization task of its context or``gist''. In Experiment 1, human subjects performed 4 go/no-go categorization tasks in succession with colour pictures of real-world scenes belonging to 2 natural categories: ``Sea'' and``mountain'', and 2 artificial categories: ``Indoor'' and``urban''. Experiment 2 used colour an...

Automated chromosome classification is an essential task in cytogenetics. The genetic disorders and abnormalities that occur to the future generation can be predicted through analysing the various characteristics of the chromosomes. The chromosome classification is mainly based on geometric and morphological features. An effective algorithm for chromosome geometric feature extraction is present...

The proximate functions of animal skin colour are difficult to assign as they can result from natural selection, sexual selection or neutral evolution under genetic drift. Most often colour patterns are thought to signal visual stimuli; so,their presence in subterranean taxa is perplexing. We evaluate the adaptive nature of colour patterns in nearly a third of all known species of caecilians, a...

Based on a model of transverse chromatic aberration (TCA) of the eye and perceptual effects previously discussed by the same author, it was predicted that colour induced binocular depth perception (chromostereopsis) is possible from images containing red or blue along with achromatic information (grey and black); that the direction of the perceived depth from certain colours should differ for t...

Enforcing a Shape Correspondence between Two Views of a 3D Non-rigid Object p. 163 A Colour Constancy Algorithm Based on the Histogram of Feasible Colour Mappings p. 171 Reconstruction of Surfaces from Cross Sections Using Skeleton Information p. 180 Extension of a New Method for Surface Reconstruction from Cross Sections p. 188 Imposing Integrability in Geometric Shape-from-Shading p. 196 Corr...

This article describes the way in which image is prepared for content-based image retrieval system. Our CBIR system is dedicated to support estate agents. In our database there are images of houses and bungalows. All efforts have been put into extracting elements from an image and finding their characteristic features in the unsupervised way. Hence, the paper presents segmentation algorithm bas...

In this paper we present a new method for the identification of specular reflectance in colour images. We have developed a bi-dimensional histogram which allows the exploitation of the relations between the signals of intensity and saturation of a colour image. Once the diagram has been constructed, it is possible to verify that the pixels of the specular reflectance are located in a well-defin...