Feature Extraction and Image Processing for Computer Vision, 4th Edition

11.2. Colour image theory

11.2.1. Colour images

The representation of colour is based on the relationships between coloured light and perception. Light can be understood as an electromagnetic wave, and when these waves hit an object some light frequencies are absorbed whilst some others are reflected towards our eye and thus creating what we perceive as colours. Similarly, when the reflected light hits a camera's sensor, it obtains a measure of intensity by adding energy on a range of frequencies. In general, multi-spectral images maintain information about the absorption characteristics of particular materials by maintaining the measured energy over several frequencies. This can be achieved by using filters on the top of the sensors, ...