Video: High end consumer grade video devices, including video cameras, camcorders, and video cassette recorders (VCR), represent convenient, low-cost alternatives for providing image data to the computer environment. These devices operate according to television standards, supplying analog image data that conforms to either RS-170 (Black/White) or NTSC (Color) signal standards. A single image in these formats consists of two separate fields of lines, odd and even numbered, which interlace to form the displayed image. In the interlaced video signal, horizontal synchronization pulses control the orientation of video lines, and vertical synchronization pulses control the alignment of video fields. The fields are displayed at a rate of 60 per second. Consequently, complete images are displayed at a rate of 30 frames per second. This rate of 30 image frames per second is referred to as "real-time" video, and is the standard rate for recording and displaying action video sequences. Some video devices provide nonstandard video signals which are not compatible with the RS-170 or the NTSC formats. These devices (CAT scanners, scanning electron microscopes, and slow scan cameras) are most often used in medical or scientific applications which have unique image acquisition requirements. In order to incorporate these devices into an image management system, frame grab cards must be capable of variable synchronization settings (Molinari, 1989). Information Organization S-VHS Use of Video Effectiveness of Video Digital Cameras Digital Video Interactive (DVI)