Retinex Image Enhancement Technique

There are often serious discrepancy existing between the images and the direct observation of the real scenes. The human perception has natures of dynamic range compression and color rendition⁹ on the scenes. It can compute the details across a large range of spectral and lightness variations. So it is color constant. By comparison, the recorded films and other electric cameras, have no such computations before the scenes are recorded in the dynamic range limited media. Even with wide dynamic range imaging systems, the recorded images will not be seen same as real observation. This is because the dynamic range compression for perception of the recorded images is weaker than that for the scene itself. This could be explained as that in the real world, the wider angular extent helps to improve the dynamic range compression.