Adaptive image enhancement algorithm based on Bandelet transform
Jianying Wang · Journal of Computer Applications · 2008
A novel algorithm based on the Bandelet transform field for adaptive image enhancement was proposed.The algorithm reaches effective balance between noise limiting and detail enhancing with Bandelet transform's superiority in presenting the linear singularity and the surface singularity of planar image.First,the geometrical direction in each dyadic square was found according to the principle of the minimal approximation error,then the small dyadic squares were combined,which was based on the principle of Minimum Mean Square Error(MMSE),finally,the directions of image enhancement were determined.And according to the directions,the Bandelet blocks were classified into two sorts:the Bandelet blocks with geometrical directions and the Bandelet blocks without geometrical directions,and the different characteristics of the two sorts of Bandelet blocks were analyzed in order to distinguish the noise and signal,and the weak contrast features and the strong contrast features.Image enhancement was realized by a new strategy that can emphasize features with low contrast and protect the strong contrast features from distortions while restraining noise.Results of experiments show that this method offers significant improved performance in restraining noise and emphasizing features with low contrast over the conventional image enhancement algorithms.