The motion detection algorithm requires a contrast between the moving object and the background to ensure that the algorithm can effectively track and extract the moving object. The contrast between the moving object and the background is measured by the difference between the values of Y (brightness/grayscale) in the YUV color model. The value difference must be greater than or equal to 20 (256 levels in grayscale).
To measure the contrast in the current surveillance scenario, perform the following steps:
Choose Settings > Video/Audio/Image > Image Parameters. Under Day/Night Switch, set Mode to B/W.
Take a snapshot of the current surveillance scene on the View page.
Use the image editing software to open the snapshot.
Point the color picker to the foreground and check the Y value (grayscale value) in the color palette.
Repeat Step 4 and view the Y value of the background.
Calculate the grayscale difference between the foreground and background and determine whether the difference is greater than or equal to 20.
