Three compression algorithms were compared by using contrast-detail (CD) analysis. Two phantoms were designed to simulate computed tomography (CT) scans of the head. The first was based on CT scans of a plastic cylinder containing water. The second was formed by combining a CT scan of a head with a scan of the water phantom. The soft tissue of the brain was replaced by a subimage containing only water. The compression algorithms studied were the full-frame discrete cosine (FDCT) algorithm, the Joint Photographic Experts Group (JPEG) algorithm, and a wavelet algorithm. Both the wavelet and JPEG algorithms affected regions of the image near the boundary of the skull. The FDCT algorithm propagated false edges throughout the region interior to the skull. The wavelet algorithm affected the images less than the other compression algorithms. The presence of the skull especially affected observer performance on the FDCT compressed images. All of the findings demonstrated a flattening of the CD curve for large lesions. The results of a compression study using lossy compression algorithms is dependent on the characteristics ofthe image and the nature of the diagnostic task. Because of the high density bone of the skull, head CT images present a much more difficult compression problem than chest x-rays. We found no significant differences among the CD curves for the tested compression algorithms.

Date of creation, presentation, or exhibit



Proceedings of the SPIE: Image Perception 2712 (1996) 128-137 Copyright 1996 Society of Photo-Optical Instrumentation Engineers. This paper was published in Proceedings of SPIE Volume 2712 Medical Imaging 1996: Image Perception, Harold L. Kundel, Editor, March 1996, pp. 128-137, and is madeavailable as an electronic reprint with permission of SPIE. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. The investigation was supported by a grant from Eastman Kodak Corporation, Rochester, NY and by the Clinical Radiology Foundation at KUMC. ISSN: 0277-786X Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type

Conference Proceeding

Department, Program, or Center

Chester F. Carlson Center for Imaging Science (COS)


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