Compression Vs. Breast Cancer
Posted by Mark Nelson on 20th December 2005 | Permanent Link
Reasearchers at Purdue are finding that compression improves a mammogram. You might be inclined to think that the smoothing and noise removal in image compression would be a bad thing when hunting for tiny anomolies, but this is apparently not the case.
Researcher Bradley J. Lucier started tinkering with compression in order to make it easier to transmit massive mammogram data files by phone:
“I began experimenting with file-compression algorithms to see if we could shrink files to the point where they could be sent over standard phone lines,” he said. “Some communities do not have easy access to broadband Internet yet, and my colleagues and I wanted to work around that issue.”
Lucier found that one well-tested algorithm - a short set of instructions that can be repeated many times - did the trick after a bit of tweaking. Though the basic mathematics has been around for more than a decade, he said, its finer points required some adjusting.
“I wanted the algorithm to make all the features important to radiologists degrade at the same rate - both the edges of large tumors and the smallest calcium deposits,” Lucier said. “I tried several approaches and eventually got a balance that seemed reasonable, based on what radiologists tell me they want.”
His methods have evidently paid off: On seven of nine measures of diagnostic accuracy, radiologists interpret the compressed images more accurately than they interpret the original images, even though the compressed images contain, on average, only 2 percent of the information in the originals.
I can’t find an online copy of the paper - so I don’t know what algorithm is actually employed. Email sent to Messr. Lucier with a query.