Color Restoration and Enhancement in the Compressed Domain
The quality of an image captured by a camera is influenced primarily by three main factors; namely, the three-dimensional (3D) scene consisting of the objects present in it, the illuminant(s) or radiations received by the scene from various sources, and the camera characteristics (of its optical lenses and sensors). In a typical scenario, the 3D scene and the camera may be considered as invariants, whereas the illumination varies depending on the nature of the illuminant. For example, the same scene may be captured at different times
of the day. The pixel values of these images then would be quite different from each other and the colors may also be rendered differently in the scene.