Radiology, Vol 170, 453-455, Copyright © 1989 by Radiological Society of North America
Comparison of information-preserving and information-losing data- compression algorithms for CT images
JM Bramble
Department of Diagnostic Radiology, University of Kansas Medical Center, Kansas City 66103.
Data compression increases the number of images that can be stored on
magnetic disks or tape and reduces the time required for transmission of
images between stations. Two algorithms for data compression are compared
in application to computed tomographic (CT) images. The first, an
information-preserving algorithm combining differential and Huffman
encoding, allows reconstruction of the original image. A second algorithm
alters the image in a clinically acceptable manner. This second algorithm
combines two processes: the suppression of data outside of the head or body
and the combination of differential and Huffman encoding. Because the final
image is not an exact copy, the second algorithm is information losing.
Application of the information- preserving algorithm can double or triple
the number of CT images that can be stored on hard disk or magnetic tape.
This algorithm may also double or triple the speed with which images may be
transmitted. The information-losing algorithm can increase storage or
transmission speed by a factor of five. The computation time on this system
is excessive, but dedicated hardware is available to allow efficient
implementation.
