Field of View (FOV) and Resolution Requirements
Frame rate in conjunction with resolution and the number of bytes per pixel determine the amount of data that needs to be transferred and processed. For example, a camera with a 1280 x 1024 (SXGA) resolution at 30 frames per second (fps) and 8bits (or 1 Byte) per pixel will require
a data bandwidth of approximately 50MBytes/sec. This is below the PCI bus limit (~100MB/sec) and is within the capabilities of 1394.b or Gigabit Ethernet interfaces. Anything beyond 100MB/sec will require a frame grabberbased system with Camera Link® interface and PC with PCI Express® bus.
Another important factor that comes into play when choosing the interface is cost. Analog cameras on average cost less than digital cameras and are built utilizing a single, well-established interface. Typically, the more cameras that are required to perform a single vision task, a frame grabber-based solution becomes most cost effective. On the other hand, with systems using digital cameras, the advantages are features and performance: high resolution options, high frame rate capability and image quality. The cost of cabling cost is also becoming an advantage with non-frame grabber digital interfaces. Overall, the cost gap between these two technologies is rapidly closing.