SPIHT Modification for Edge Preserving Wavelet Lossy Image Coding: An Application for Automatic Inspection

In this paper, we address the problem of design a wavelet lossy image coder that allows preservation of image features such as edges using a modified version of SPIHT algorithm. The modification is made by changing the concept of pixel significance, a coefficient is selected not only by magnitude but as part of a Feature Of Interest (FOI) map obtained with SUSAN edge detector and mapping the correspondent positions to the wavelet domain. The bit rate spends mores bits in those important zones, and finally the bit stream is entropy coded. We show experiments in which is demonstrated the edge preserving by using the decompressed images as inputs to quality automatic inspection process using the commercial software “Vision Builder”. Key-Words: Image coding, edge preserving, wavelet, SPIHT, parent-child relationship, automatic inspection.