Quincunx Wavelet Image Compression: 2d Filter Design by Transformations of Variables and Quadtree Coding Approach

We study the compression performance of the quincunx discrete wavelet transform (DWT) and we compare it with the dyadic DWT in terms of PSNR and bit rate. The 2D non-separable quincunx wavelet filters are designed by making use of the ‘transformations of variables’ technique of Tay & Kingsbury starting from the 1D biorthogonal (9,7)-taps filters. The applied transformation functions are respectively based on the Kaiser and Chebyshev windows, and on the Lagrange halfband filters. The novelties of this work are in the evaluation of these filters for image compression and the usage of an embedded coder based on the quadtree approach for coding the quincunx subbands.