The Affine Transforms for Image Enhancement in the Context of   Logarithmic Models
  The logarithmic model offers new tools for image processing. An efficient method for image enhancement is to use an affine transformation with the logarithmic operations: addition and scalar multiplication. We define some criteria for automatically determining the parameters of the processing and this is done via mean and variance computed by logarithmic operations. 
Vasile Patrascu, Vasile Buzuloiu
cs.CV