Polymap is similar to the Ismap function provides available on the Web except that it can be used to define arbitrary boundary of the image. This tool has been used extensively in the interactive teaching of 2D mammographic images, which is discussed in Section 4. At the moment, this routine is compatible with the Mosaic browser only. Work is progressing to extend the mapping for the Netscape browser. The other part of the visualization server consists of a distributed volume visualization tool, VIS, that can be used render and manipulate 3D volume data retrieved from the image database server.
Volume rendering algorithms require a significant amount of computational resources and time.
Section 5 describes the functions of VIS and illustrates the use of this tool to visualize 3D MR head images. In addition, the Web server contains software programs written in Perl that integrates all of the components above for particular applications. Perl programming language was chosen over others, such as C, because it is an interpreter language, providing the user with built-in functions for easy manipulation of processes, files, and networking tasks, and is available in the public domain. The next section describes a computer aided instruction program written in Perl for learning breast imaging cases on the Web. 4. The long term objective of this CAI program is to provide an interactive learning environment for breast imaging teaching file on the World Wide Web.