Wavelet-based contrast computation and application to digital image watermarking
Pierre Vandergheynst, Martin Kutter, STEFAN S. WINKLER · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2000
We introduce an isotopic measure of local contrast for natural images that is based on analytic filters and present the design of directional wavelet frames suitable for its computation. We show how this contrast measure can be used within a masking model to facilitate the insertion of a watermark in an image while minimizing visual distortion.