Motion Detection and Changes in Illumination
Motion detection is triggered when there is a change in the illumination level of a specific pixel. The sensitivity of motion detection determines how easily the camera responds to these changes. The higher the sensitivity, the smaller the change in illumination required to trigger a motion detection event.
Why Changes in Illumination Can Trigger False Motion Events
A sudden change in illumination across the entire scene or a specific area can trigger motion detection even when there is no actual movement. For example:
Lightning strikes can suddenly change the illumination across the entire scene.
A vehicle passing by with headlights on can cause a sudden change in illumination in part of the scene.
When the camera detects such a change, it triggers a motion event. The Object Detection algorithm then analyses the motion detection area for objects. If the illumination of a sufficiently large portion of a stationary object changes, the algorithm may interpret the change as movement and report the object as a moving object.
Recommended Solution
To reduce false motion events caused by changes in illumination, it is recommended to use Line Crossing or Intrusion Detection instead of basic motion detection, where applicable.
These detection methods are based on an object's movement across a defined area or boundary rather than changes in pixel illumination. This significantly reduces the likelihood of illumination changes triggering unnecessary motion events and prevents the Object Detection algorithm from incorrectly identifying stationary objects as moving.
Sudden changes in illumination can trigger basic motion detection and may result in stationary objects being incorrectly reported as moving. Using Line Crossing or Intrusion Detection can help minimize these false detections.
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