Radiological image compression
The movement toward digital images in radiology presents the problem of how to conveniently and economically store, retrieve, and transmit the volume of digital images. Basic research into image data compression is necessary in order to move from a film-based department to efficient digital-based department. Digital data compression technology consists of two types of compression technique: error-free and irreversible. Error-free image compression is desired; however, present techniques can only achieve compression ratio of form 1.5:1 to 3:1, depending upon the image characteristics. Irreversible image compression can achieve a much higher compression ratio; however, the image reconstructed from the compressed data shows some difference from the original image. This dissertation studies both error free and irreversible image compression techniques. In particular, some modified error-free techniques have been tested and the recommended strategies for various radiological images are discussed. A full-frame hit-allocation irreversible compression technique has been derived. A total of 76 images which include CT head and body, and radiographs digitized to 2048 x 2048, 1024 x 1024, and 512 x 512 have been used to test this algorithm. The normalized mean-square-error (NMSE) on the difference image is used as a global measurement on the quality of the reconstructed image. The NMSE's of total of 380 reconstructed and 380 difference images are measured and the results tabulated. Three complex compression methods are also suggested to press images with special characteristics. Finally, various parameters which would effect the quality of the reconstructed images are discussed.
- Research Organization:
- California Univ., Los Angeles (USA)
- OSTI ID:
- 6935044
- Country of Publication:
- United States
- Language:
- English
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