Image quality in lossy compressed digital mammograms

The substitution of digital representations for analog images provides access to methods for digital storage and transmission and enables the use of a variety of digital image processing techniques, including enhancement and computer assisted screening and diagnosis. Lossy compression can further improve the efficiency of transmission and storage and can facilitate subsequent image processing. Both digitization (or digital acquisition) and lossy compression alter an image from its traditional form, and hence it becomes important that any such alteration be shown to improve or at least not damage the utility of the image in a screening or diagnostic application. One approach to demonstrating in a quantifiable manner that a specific image mode is at least equal to another is by clinical experiment simulating ordinary practice and suitable statistical analysis. In this paper we describe a general protocol for performing such a ∗P. C. Cosman is with the Department of Electrical and Computer Engineering, University of California at San Diego, La Jolla, CA 92093-0407. S. M. Perlmutter and K. O. Perlmutter are with Johnson-Grace Company, Inc., 2 Corporate Plaza, Suite 150, Newport Beach, CA. R. M. Gray, B. J. Betts, J. Li, and A. Aiyer are with the Department of Electrical Engineering, Stanford University, Stanford, CA 94305. C. N. Adams is with Apple Computer, 3515 Monroe St., MS: 70-IS, Santa Clara, CA 95015. R. A. Olshen is with the Division of Biostatistics of the Stanford University School of Medicine and the Department of Statistics of Stanford University, Stanford, CA 94305. D . Ikeda is with the Department of Radiology, Stanford University School of Medicine, Stanford, CA 94305. M. Williams and L. L. Fajardo are with the Department of Radiology, University of Virginia, Charlottesville, VA. This research was supported by the Army Medical Research and Materiel Command under Grant DAMD17-94-J-4354, Kodak, Inc., and by BMDO under contract F49620-95-1-0538.