SmarTek Systems SVS-1 User Guide-Part B - Manual (Page 45)

SVS-1 – Setting Light Reference Parameters and Visibility Parameters
Light Reference Detection Threshold– Specifies the threshold that the position of the dominant image histogram
peak is compared to for determining lighting conditions (day or night). The Light Reference Threshold value is set
slightly below the position of the image histogram dominant peak during day time light conditions. The default
value is 140.
Light Reference Smoothing Alpha – Specifies the smoothing filter coefficient for the image histogram. The
default value is 0.0005.
Visibility Time Out – Specifies the amount of time to wait when there are no vehicle detections before determining
visibility conditions. The default value is 5 minutes.
Visibility Threshold – Specifies the threshold for comparing the visibility measurement variable (low value for no
visibility and high value for good visibility). Setting the threshold too high may cause visibility false alarms. During
a “No Visibility” condition, all Output Relay states are set to active indicating failure. The default value for the
Visibility Threshold is 3.
Show Visibility Reference Grid – Specifies whether to show the Visibility Reference Grid in the
Output Video signal. The Visibility Reference Grid shows up as 5 green horizontal lines in the
output video display. Default is unchecked to NOT show the grid.
The parameters for the Light and Visibility Reference are displayed to the right of the camera image. Choose the Light
Reference by clicking LR option button in the Zone Select Frame (below the image). The following section provides detailed
descriptions for each of the Light Reference and Visibility parameters.