The "vfeature" module is comprised of commands to facilitate the management and analysis of feature vector data. There is a simple k-nearest neighbor classifier in VisionX (vclasf). For other classifiers the VisionX commnads facilitate the generation and management of feature vectors in native format and their export in text format for use with other classifiers.

Feature vector data are stored in a VisionX file with the structure listed below. The commands can be separated into several broad categories: import/export to other systems and classifiers, feature vector file manipulation, and classification. The converion program vxltovf converts between teh VisionX binary feature vector format and comma separated value text files; it facilitates the linking between VisionX and other external classifiers.

File Structure

All the programs utilize the VisionX feature vector file format. Feature vectors are stored in framed VisionX files according to the following structure (for each frame):

A header is only allowed once per frame; it consists of a text lsit of all the feature names. Only one ID, class, and description are allowed for each feature vector; the programs assume that the ID and class will be present immediately preceding the feature vector in the specified order, the description is optional and is a free form description with only one constraint -- it can not contain "tab" or "," characters. Within a frame, all the feature vectors must have the same length. i

Output files from the standard nearest neighbor classification program (vclasf) have the following structure (for each frame):