An inexpensive microcomputer-based image digitizer

An inexpensive (under $600) microcomputer-controlled image analysis system that uses commercially available components is described. Both programming and construction details are provided, as well as a discussion of the utility of the apparatus in studies of animal behavior. The system has been used to record position preferences and activity in animal groupings of various size. Simply by changing the distance between the target and the camera, animals and/or arenas of differing size can be monitored.