Frame Grabber

A frame grabber is an electronic device that captures individual, digital still frames from an analog video signal or a digital video stream. It is usually employed as a component of a computer vision system, in which video frames are captured in digital form and then displayed, stored or transmitted in raw or compressed digital form. Historically, frame grabbers were the predominant way to interface cameras to PC's. This has substantially changed in recent years as direct camera connections via USB, Ethernet and IEEE 1394 ("FireWire") interfaces have become prevalent.

Early frame grabbers had only enough memory to acquire (i.e., "grab") and store a single digitized video frame, hence the name. Modern frame grabbers typically can store multiple frames and compress them in real time using algorithms such as MPEG2 and JPEG. Frame grabbers that perform compression on the video frames are referred to as "Active Frame Grabbers," while frame grabbers that simply capture raw video data are called "Passive Frame Grabbers." Technological demands in fields such as radar acquisition, manufacturing and remote guidance have led to the development of frame grabbers with the ability to capture images at high frame rates and resolutions.