With the 4.1/185 firmware for IQeye cameras, a separate sensitivity setting was introduced for night-mode and day-mode.
This allows configurings a separate motion window sensitivity in night mode:
A motion detection window can be perfectly configured to detect motion during day time.
However, when the camera switches to night mode in low light situations, the camera applies a higher electronic gain to the signals from the imager chip.
This enhances images in low light scenes, but inevitable causes some noise in the image as well.
This noise can erroneously be interpreted as motion, and cause false motion detection alarms.
The new separate settings for sensitivity for day mode and night mode allows proper sensitivity settings at night, to avoid false motion detection, without affecting the day mode sensitivity.
Typically, the night mode sensitivity is a bit lower than the day mode sensitivity to compensate for the added noise in night mode.
Note: For most situations, the default values are OK. If adjustment is needed, it's best to start from the default setting, and make minor changes.
Note II: If making adjustments for the night mode sensitivity, make sure the camera is actually in night mode. Else it's difficult to predict the behavior.
From the on-camera help menu:
For each included motion detection window, set the sensitivity and size values.
sensitivity: sensitivity: specifies how much a pixel value must change in order for that change to be a motion trigger. Sensitivity values range between 0 and 255. Lower values increase sensitivity and higher values decrease it. A sensitivity value of 255 will only trigger with a change between absolute black and absolute white. Sensitivity values under 10 are not recommended as they often trigger from imager noise even when no motion is visible to the eye.
size: (default = 1) range is 0 to 100. Specifies what percentage of the pixels in a box must change (by the sensitivity) in order that "enough" change has occurred to trigger motion detection.
night sensitivity : sensitivity: specifies how much a pixel value must change in order for that change to be a motion trigger. Sensitivity values range between 0 and 255. Lower values increase sensitivity and higher values decrease it. A sensitivity value of 255 will only trigger with a change between absolute black and absolute white. Sensitivity values under 10 are not recommended as they often trigger from imager noise even when no motion is visible to the eye.
night size: (default = 1) range is 0 to 100. Specifies what percentage of the pixels in a box must change (by the sensitivity) in order that "enough" change has occurred to trigger motion detection.