Retinex Image Processing--Publications--SPIE 2847, Denver, Colorado
Conference
A Multiscale Retinex For Color Rendition and Dynamic Range
Compression
Zia-ur Rahman, Daniel J. Jobson and, Glenn A. Woodell
Abstract
The human vision system performs the tasks of dynamic range compression
and color constancy almost effortlessly. The same tasks pose a very
challenging problem for imaging systems whose dynamic range is
restricted by either the dynamic response of film, in case of analog
cameras, or by the analog-to-digital converters, in the case of digital
cameras. The images thus formed are unable to encompass the wide
dynamic range present in most natural scenes (often > 500:1).
Whereas the human visual system is quite tolerant to spectral changes in
lighting conditions, these strongly affect both the film response for
analog cameras and the filter responses for digital cameras, leading to
incorrect color formulation in the acquired image. Our multiscale
retinex, based in part on Edwin Land's work on color constancy, provides
a fast, simple, and automatic technique for simultaneous dynamic range
compression and accurate color rendition. The retinex algorithm is
non-linear, and global---output at a point is also a function of
its surround---in extent. A comparison with conventional dynamic range
compression techniques such as the application of point non-linearities,
e.g. log(x,y), and global histogram equalization and/or modification
shows that the multiscale retinex simultaneously provides the best
dynamic range compression and color rendition. The applications of such
an algorithm are many; from medical imaging to remote sensing; and from
commercial photography to color transmission.
Download
Compressed Postscript (8.7M) or
Postscript (24.2M)
or
PDF (1.1M) version.
Retinex Publications Page