On the Classification of Colored Textures From a Texture-Ranking Experiment: Observers Ability of Discrimination Quantification

This paper is devoted to the construction of Fechnerian scales on a physical dimension of investigated colored textures. For this purpose, we considered the extension of the Mallows-Bradley-Terry model for the analysis of the data collected from a contrast-sorting experiment. A likelihood ratio test procedure was proposed in order to choose between the two following hypotheses- discrimination and non-discrimination between the investigated stimuli. In addition, post-hoc analyzes allowed us to find out which of the stimuli differ from the others. Our findings indicate that the subjective attribute of visual contrast appears to be a psycho physical scale that maps to the physical scale corresponding to the Michelson contrast. Mainly, the estimates of the model index of discrimination parameter of the stimuli show that the ability of the observers to discriminate between the textures according to the visual contrast varies with respect to the color ranges and the textures types. According to the luminance contrasts ability of discrimination, the Isotropic texture type is the best, followed by the Random-dots texture type, then by the Horizontal grating type and the Vertical grating type is the least. The Fechnerian scales on the physical dimension of the Michelson contrast of the colored textures depend on the chromaticness of the colored textures phases and the texture types. The psycho physical method of identification would be the best when determining the related thresholds.