AN INEXPENSIVE VIDEOPROJECTION DIGITIZATION SYSTEM FOR BEHAVIORAL-RESEARCH

We present an inexpensive approach to image analysis of spatial coordi nates for behavioral research. Image analysis of still video images (f reeze frames) with current technology can be prohibitively expensive, as well as time consuming. The system outlined here provides an accura te, inexpensive, and fast approach to acquiring information from video tape. It consists simply of a video monitor, bellows, large diameter l ens, and a digitizing tablet. The images are projected onto a digitizi ng tablet, and data acquisition is controlled with a series of three f unctions written in APL. We used this system to acquire positional inf ormation on fish responding to the threat of aerial predation. We disc uss several approaches to design and construction of this system, as w ell as provide computer listings for initiation of communication with digitization boards.