Professors Margaret Fleck and David Forsyth are looking for ways of putting their Naked People Finder - a search engine of nude figures - to commercial use.

While most existing image-finding programs use a mix of image analysis and caption-text analysis to find specific images, the two researchers have developed a program that uses image analysis alone, making it possible to refine pictorial retrieval techniques based on image content.

The program could be developed as a product for anyone who wants to avoid or seek out certain types of pictures on the Net, said Fleck, a faculty member in the Computer Science Department at the University of Iowa. "It's up to the end user how to apply this general-purpose tool. Central authorities don't have to make these decisions for us." She and Forsyth already have been contacted by a couple of parties interested in commercializing the program, but wouldn't say who they were.

The Naked People Finder begins by looking for images with regions that have colors and texture resembling skin of any pigment. It then runs its limb-detecting algorithm on the skin-like regions of pictures. "If it finds a skin-colored cylinder, it looks for another cylinder nearby," said Forsyth, an assistant professor at UC Berkeley's computer science department.

The ultimate goal of Fleck and Forsyth's research is to create a program that can examine an image file and then "tell you what's in it - if it contains a person, or two jaguars, or something else," said Forsyth.

He decided to use naked people for his first test application because of "the large sample set - I got it from the Net." Another reason is "nobody is going to get interested in a program that finds pictures of horses."

The program does a pretty good job. In a test set of 4,854 images (565 images of naked people and 4,289 control images) "the system marked 43 percent of the naked people images as containing naked people. By contrast, it marked only 4 percent of the other images as containing naked people," explained Fleck.

The 4 percent mistake batch included images "with the right color and elongated shapes," Fleck said, such as "stalactites, pumpkins, and desserts - especially pinkish-colored ones."