Institute for Data Analysis and Visualization

We introduce TLHaar, an n-bit to n-bit reversible transform similar to the S-transform. TLHaar uses lookup tables that approximate the S-transform, but reorder the coefficients so they fit into n bits. TLHaar is suited for lossless compression in fixed-width channels, such as digital video channels and graphics hardware frame buffers. Tests indicate that when the incoming image data has lines or hard edges TLHaar coefficients compress better than S- transform coefficients. For other types of image data TLHaar coefficients compress up to 2.5% worse than those of the S-transform, depending on the data and the compression method used.