Indicators of colour image quality for ησλ-SPACES

We take the standing that a characterization of an image, together with a knowledge of the class the image belongs to, is required information to assess the quality of the image. We consider characterizations of images in colour spaces of the hue-saturation-luminance (ησλ for short) type. We use word descriptors, the entropy of hue circular histograms and other indexes that summarize the characterization process. We introduce two spaces of the type ησλ one is spherical; in the other, the saturation is not normalized by the luminance (unlike the HSV, HSL and HSI spaces).