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1 May 1992 Effect of block size on image quality for compressed chest radiographs
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Data compression can improve imaging system efficiency by reducing the required storage space and the image transmission time. Transform compression methods have been applied to digital radiographs with good results. Block transform compression is usually based on 8 X 8 or 16 X 16 transform blocks for the sake of simplicity and speed. Compression with these small sizes tends to require accurate coefficient representations to prevent blocking artifacts. Weighted quantization of block transform coefficients can reduce the blocking effects and improve compression performance. Full frame compression has the advantage of eliminating blocking effects but the disadvantage of heavy demand for computing resources. Small block compression can retain local variation better and has a simpler and faster implementation. We have evaluated the performance tradeoffs for different block sizes and their effects on the image quality of chest radiographs. The results showed that there is no significant difference in root-mean-square error nor in power spectra between different block sizes for visually lossless compression (at about 10:1 compression ratio).
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ji Chen and Michael J. Flynn "Effect of block size on image quality for compressed chest radiographs", Proc. SPIE 1653, Medical Imaging VI: Image Capture, Formatting, and Display, (1 May 1992);

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