Frame grabbers are required for cameras that output analog video, camera Link, Coexpress, HS LINK, HD SDI etc. Frame grabbers and video capture cards on PCI and PCI Xpress slots are available for desktops and Capture cards with PCMCIA and EXPRESS slots are available for Laptops. Video processors and Vision processors are also available for different inputs and different applications that include creating embedded systems with processors and FPGA. Frame grabbers that support different operating systems like Windows, Linux, MAC etc are available.
A frame grabber is an electronic device that captures (i.e., "grabs") 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. Early frame grabbers typically had only enough memory to store a single digitized video frame, hence the singular "frame" in the device name, whereas modern frame grabbers often can store multiple frames.
Historically, frame grabber expansion cards were the predominant way to interface cameras to PCs. Other interface methods have emerged since then, with frame grabbers (and in many case, cameras themselves) connecting to computers via interfaces such as USB, Ethernet and IEEE 1394 ("FireWire").
Modern frame grabber devices often perform functions beyond capturing a single video input. They also have different I/O ports to facilitate triggering cameras, acquisition start/end, communicate the results to external events, help to synchronize multiple camera acquisition etc. Modern Frame grabbers contain huge memory to store and also do some preprocess of video captured from camera by adding ASICs/FPGA/Controlle r/processor etc.
Frame grabbers are available in PCI Xpress x1, x4, x8 form factors and also in PCI/104 and also available as laptop supported PCMCIA ports etc. Frame grabbers have software support on Windows, Linux and other platforms also. These Frame grabbers are supplied with Software development kits to understand the camera, set acquisition parameters, memory, display, controls etc. C.C++.C#, VB are generally supported languages for programming.
Analog frame grabbers, which accept and process analog video signals, include these circuits:
- Input signal conditioner that buffers the analog video input signal to protect downstream circuitry
- Video decoder that converts SD analog video (e.g., NTSC, SECAM, PAL) or HD analog video (e.g., AHD, HD-TVI, HD-CVI) to a digital format
Digital frame grabbers, which accept and process digital video streams, include these circuits:
- Digital video decoder that interfaces to and converts a specific type of digital video source, such as Camera Link, CoaXPress, DVI, GigE Vision, LVDS, RS-422, or SDI
Circuitry common to both analog and digital frame grabbers:
- Memory for storing the acquired image (i.e., a frame buffer)
- A bus interface through which a processor can control the acquisition and access the data
- General purpose I/O for triggering image acquisition or controlling external equipment