Zone Analysis Pseudo Algorithm
The primary goal of this algorithm is to determine if the current image snapshot has changed from the previous image snapshot (or reference image).
Secondary to this goal, is the need to make this determination as soon as possible, to reduce the amount of computation (comparisons). This will ease the load on the box. So, we seek to prove the image has not changed, and as soon as we make that determination, we stop the analysis.
On the zone configuration page, there is an "Alarm Check Method" parameter, and depending on this setting, a series of analysis are performed:
If Alarm_Check_Method is "Alarmed Pixels". Then the first analysis is done. If this analysis determines a not-changed state, then we exit with that conclusion.
If Alarm_Check Method is "Filtered Pixels", then after processing the "Alarmed Pixels" tests (and getting a result that the image has changed), another processing is done, based on the Filtering Parameters. If this analysis determines a not-changed state, then we exit with that conclusion.
If Alarm_Check Method is "Blobs", then after processing the "Filtered Pixels" tests above (and getting a result that the image has changed), another processing is done, based on the blob parameters. If this analysis determines a not-changed state, then we exit with that conclusion.
Otherwise, we have a changed image, and an alarmed condition, and the images are captured.
