Predictive image coding with Pseudo-Lapacian edge detector

Several edge-adaptive dual-mode Predictive coding systems are proposed for encoding monochrome video signals. These algorithms use the Pseudo-Laplacian edge detector to switch between the textural coding and the edge coding. The one-dimensional Song DM coder and the two-dimensional weighted average prediction DM coder were used as the textural coding. The edge coding was done with either normal two-dimensional Song DM coder, DPCM schemes of Graham, or DPCM coder developed by the author. Nine different combinations of texture and edge coding techniques were developed and simulated. The bit rates of all the schemes were compared and the range varied between 2.28 - 3.46 bits/pixel without further compression of the edge information bits nor the correction bits. The subjective test on the selected images obtained with the developed schemes was carried out. The result showed that most of the pictures obtained with the techniques in this paper are superior to the pictures coded by the Song mode normal two-dimensional DM coder alone.