User's Manual

Operation Manual
102
object in the image should be no less than 15 × 15 pixels (CIF image). The target height and
width should no more than a third of the image height and width. The recommended target
height is 10% of the image height.
● The brightness difference of the target and the background should be no less than 10 gray
levels.
● The target should be continuously present in the image for no less than two seconds, and
the moving distance of the target should be larger than its width and no less than 15 pixels
(CIF image) at the same time.
● Reduce the complexity of surveillance scene as much as you can. Intelligent analysis
functions are not recommended to be used in scene with dense targets and frequent
illumination change.
● Avoid areas such as glass, reflective ground, water surface, and areas interfered by branch,
shadow and mosquito. Avoid backlight scene and direct light.
8.4.1 Global Configuration
Set global rules for IVS, including anti-disturb, depth of field calibration, and valid motion
parameter for targets.
Calibration Purpose
Determine corresponding relationship between 2D image captured by the camera and 3D
actual object according to one horizontal ruler and three vertical rulers calibrated by the user
and the corresponding actual distance.
Applicable Scene
● Medium or distant view with installation height of more than three meters. Scenes with
parallel view or ceiling-mounted are not supported.
● Calibrate horizontal plane, not vertical walls or sloping surfaces.
● This function is not applicable to scenes with distorted view, such as the distorted views
captured by super wide-angle or fisheye camera.
Notes
● Calibration Drawing
◇
Calibration area: The calibration area drawn should be on one horizontal plane.
◇
Vertical ruler: The bottom of three vertical rulers should be on the same horizontal plane.
Select three reference objects with fixed height in triangular distribution as vertical rulers,
such as vehicle parked at roadside or road lamp poles. Arrange three persons to draw at
each of the three positions in the monitoring scene.
◇
Horizontal ruler: Select reference object with known length on the ground, such as sign
on the road, or use a tape to measure the actual length.
● Calibration Verification
After setting the ruler, draw a straight line on the image, check the estimated value of the
straight line, and then compare this value with the value measured in the actual scene to
verify calibration accuracy. In case of major difference between the estimated value and the
actual one, fine-tune or reset parameters until the error requirement is met.