<title>Bit-rate control in overlapped transform coding of medical x-ray images</title>

Abstract

In previous papers, we presented an overlapped transform-coding method for efficient data compression of medical x-ray image series. The proposed method is a lossy compression method. The distortion that is introduced by the compression is determined by the step size with which the transform coefficients are quantized. The number of bits produced per image depends on the amount of detail in the image. In principle, highly detailed images produce higher bit rates than less detailed images. For applications in which only a small number of images are recorded, the amount of time needed to store or transmit these images may not be an essential factor. In that case, some fluctuation in the bit rate may be tolerable. But for applications in which image series have to be stored or transmitted in real time, a constant bit rate is often preferred. In this paper, we explain how compression at a constant bit rate can be achieved. We propose a bit-rate control method that is capable of realizing a constant number of bits per image with a homogeneous distribution of the quantization errors over the coded image.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.