A Hybrid Image Compression Method For Medical Images
Yukihiro Nakagawa, Morito Shiohara, Toshiyuki Gotoh, Ryuichiro Ohta · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1988
This paper describes an efficient compression method for medical images. This method can compress images with small bit rates and generate reconstructed images of high quality. Discrete Cosine Transform (DCT) and Block Truncation Coding (BTC) are widely used in various fields. These methods, however, have the following problems. With the DCT method, the reconstructed image quality is quite good, except that the quality of sharp edges in the image is clearly inferior. The BTC method can reconstruct sharp edges, but the reconstruced image is not suitable for medical images. To solve these problems, we have proposed a new hybrid compression method. In this method an original image is divided into sub-images. The high frequency component of each sub-image is evaluated. If the component is small, DCT is performed on the sub-image. When the high frequency component is large, BTC is applied to the sub-image itself, then DCT is performed on the difference between the original and the reconstructed sub-images. In our experiments, this method proved to be effective.