The study of imaging must begin necessarily with an investigation into light. An understanding of light in the context of imaging includes its function and interactions throughout the imaging chain: its emission from a light source, reflection and absorption by surfaces within a scene, detection and transformation by an image sensor (which may be the human eye) and finally its interpretation. Alongside physics, a number of other scientific disciplines are involved, including biology, physiology, chemistry and psychology, each of which has contributed to the various theories that have developed in the history of light theory.