We present a morphological filter for lossless image subsampling for a given downsampling-upsampling strategy. This filter is applied in a multiresolution decomposition and results in a more efficient scheme for image coding purposes than other lossy sampling schemes. Its main advantage is a greatly reduced computational load compared to multiresolution schemes performed with linear filters.
Casas, J., Torres, L. Morphological filter for lossless image subsampling. A: IEEE International Conference on Image Processing. "Proceedings 1994 International Conference on Image Processing". Austin, Texas: IEEE Computer Society, 1994, p. 903-907.