Color Models and Illumination Changes

Color model representation allows characterizing in a quantitative manner, any defined color spectrum of visible light, i.e. with a wavelength between 400nm and 700nm. To accomplish that, each model, or color space, is associated with a function that allows mapping the spectral power distribution of the visible electromagnetic radiation, in a space defined by a set of discrete values that quantify the color components composing the model. Some color spaces are sensitive to changes in lighting conditions. Others assure the preservation of certain chromatic features, remaining immune to these changes. Therefore, it becomes necessary to identify the strengths and weaknesses of each model in order to justify the adoption of color spaces in image processing and analysis techniques. This chapter will address the topic of digital imaging, main standards and formats. Next we will set the mathematical model of the image acquisition sensor response, which enables assessment of the various color spaces, with the aim of determining their invariance to illumination changes.

I CONGRESSO JURÍDICO DE INVESTIGADORES LUSÓFONOS: não esqueça a lei!

Quando pessoas com as mais altas responsabilidades institucionais e políticas, em países da lusofonia, alegam “o desconhecimento da lei social e dos impostos”, nada melhor do que ir(em) assistir a um congresso em diversas áreas do Direito para aprenderem um pouco, com entrada gratuita e direito a perguntas e debate. § When people with the highest institutional and political responsibilities in Lusophone countries claim "ignorance of social law and taxation", nothing better than going (in) attend a convention in various areas of law to learn a little, with free admission and the right to question and debate.