Retinex Image Processing--Publications--SPIE 4388, Orlando, Florida
Conference
Information Content in Nonlinear Local Normalization Processing of
Digital Images
Nesim Halyo, Zia-ur Rahman, Stephen K. Park
Abstract
In this paper, we investigate the rate at which information is
transferred from the scene to the digital processed image in imaging
systems using nonlinear Local Normalization. While a formula for the
Rate of Information has been used in many studies of linear systems with
Gaussian (Normal) signals [1-6], a formula applicable to
nonlinear/non-Gaussian systems has not been available until now. We
discuss a new formula for the Rate of Information[7] developed by the
authors for systems with nonlinear Local Normalization processing. The
Local Normalization algorithm, which is similar to the Retinex
algorithm, is formulated and discussed. As the name implies, this
algorithm forms a local average signal and normalizes the detail (high
spatial frequency) scene signal by the local average. The scene detail
information transferred to the locally normalized image is seen to be at
least as high as that transferred to the acquired digital image. Thus,
no information loss occurs in using Local Normalization. A case study
of the new Rate of Information formula shows that designing the
image-gathering system cut-off frequency near or slightly below the
Nyquist frequency maximizes the scene detail information transferred to
the locally normalized image for all the conditions considered.
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