Transform Coding of Arbitrarily Shaped Image Segments

Transform Coding of Arbitrarily Shaped Image Segments

A new transform coder for arbitrarily shaped image segments is proposed. In the encoder, a block-based DCT is applied to the resulting image block after shifting pixels within the image segment to block border and padding the mean value of the pixels to empty region. For reducing the transmission bit rate, the transform coefficients located in padded region are truncated and only the remaining transform coefficients arc transmitted to the decoder. In the decoder, the transform coefficients truncated in the encoder are recovered using received transform coefficients and a block-based inverse DCT is performed.