B. Frame Grabber Cards

NIH Image directly supports the Scion (www.scioncorp.com) LG-3, AG-5 and VG-5 frame grabber cards for acquiring images from video sources, such as TV cameras and VCR's. These cards allow brightness, contrast and pseudocolor to be adjusted during "live" capture. They support continuous histogram display and "live" paste, which can be useful for image alignment.

All of the Scion cards support software control of analog gain and offset and on-chip integration. The LG-3 features a frame buffer that can be expanded to 64MB using standard Mac SIMMS. The AG-5 supports video rate averaging and integration. The VG-5 is a short NuBus card that will fit in the Quadra 610 and PowerMac 6100. The PCI versions of the Scion cards, which are faster than the NuBus versions, can capture 30 full size frames per second to system RAM using the Make Movie command.

Using VDIGs (QuickTime Video Digitizer extensions), NIH Image also supports some QuickTime compatible video digitizers such as those built into "AV" Macs and the PowerMac7500/8500. The directly supported frame grabber cards, however, currently provide the following advantages:

  1. 30 frames per second capture (Scion PCI cards only)
  2. Ability to adjust gain and offset in "Live" capture mode
  3. External trigger support
  4. On-chip integration
  5. Use of pseudo-color LUTs during "Live" capture
  6. Highlighting of saturated pixels during "Live" capture
  7. Capture with virtual memory or Ram Doubler enabled
The newer ImageJ program, which runs on both Macs and Windows, supports frame grabber cards and Firewire cameras using plugins.

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