Classes of vision systems

• Video-rate systems: (Europe 25/50 Hz, US 30/60 Hz)
  • System is fast enough to process every frame.
  • Note distinction between processing time (Tp) and delay (Td).
  • Video rate Tp 25 Hz; Application can require Td to be small.

• Hard Real time systems :
  • System returns results within a fixed delay, , determined by the application.

• Soft Real time systems :
  • System returns a result with an average delay of .
  • Some frames may skipped.

• Continuously operating systems :
  • System is cyclic process.
  • Processing based on previous results.

• Purposive vision (Y. Aloimonos)
  • The visual computation is determined by the goals of the system.