Block wavelet transform for sub-image coding/decoding
Il Kyu Eom, Yoon-Soo Kim, Jae Ho Kim · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1996
Wavelet transform is used efficiently for high compression ratio image coding. It is useful for a high resolution and color document image processing system. However, a large amount of memory is required in wavelet decompression for a large image. Conventional wavelet transform does not allow reconstructing a sub-region of the image. Therefore, it is hard to use wavelet transform in a color document image processing system. In this paper, a block wavelet transform method is proposed. An image is divided into blocks and the samples of the adjacent block are used to transform one block for removing the edge artifact. The required number of samples of the adjacent block are derived. By using the proposed method, the memory requirement for wavelet coding/decoding is reduced to that of the block size. Any targeted region of an image can be compressed or reconstructed. The proposed method can be used for a color document image processing system.