High-resolution digital resampling using vector rational filters

Rational filters are extended to multichannel signal processing and applied to image interpolation. Two commonly used decimation schemes are considere d: a rectangular grid and a quincunx grid. For each decimation lattice, we propose a number of adaptive resampling algorithms based on the vector rati onal filter (VRF). These algorithms exhibit desirable properties such as ed ge and detail preservation and accurate chromaticity estimation. In these a pproaches, color image pixels are considered as three-component vectors in the color space. Therefore, the inherent correlation that exists between th e different color components is not ignored. This leads to better image qua lity compared to that obtained by componentwise or marginal processing. Ext ensive simulations show that multichannel image processing with the propose d algorithms (VRFL) and (VRFd) based on I-p-norm and directional processing , respectively; significantly outperform linear and some nonlinear techniqu es, e.g., vector FIR median hybrid filters (VFMH). Some images interpolated using VRFL and VRFd are presented for qualitative comparison. These images are free from blockiness and jaggedness, confirming the quantitative resul ts, (C) 1999 society of Photo-Optical instrumentation Engineers. [S0091-328 6(99)00105-1].