User manual

85XX Series Network DVR User Manual……………………………………………………………………….V1.0
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4.4.2.9 Camera Calibration
Camera calibration is required in order for the VCA engine to classify objects into different object classes.
Once the camera has been calibrated, the engine can infer real-world object properties such as speed, height
and area and classify objects accordingly.
4.4.2.9.1 Calibration Page Elements
The following describes the purpose of each element of the calibration page. To get started calibrating straight
away, see the Calibrating a Camera topic.
4.4.2.9.2 3D Graphics Overlay
During the calibration process, the features in the video image need to be matched with a 3D graphics overlay.
The 3D graphics overlay consists of a green grid that represents the ground plane. Placed on the ground plane
are a number of 3D mimics that represent the dimensions of a person with the current calibration parameters.
The calibration mimics are used for verifying the size of a person in the scene.
4.4.2.9.3 Mouse controls
The calibration parameters can be adjusted as follows:
 Click and drag the ground plane to change the tilt angle.
 Use the mouse wheel to adjust the camera height.
 Drag the slider to change the vertical field of view.
4.4.2.9.4 Other Graphical Tools
There are a number of other graphical tools that can be used to make the calibration process simpler and more
accurate.
4.4.2.9.5 Horizon Display
The horizon can be displayed by right clicking and checking the menu option. If the horizon is visible in the
video, it is possible to use this to set the tilt angle. Drag the grid until the horizon in the video matches the
graphical horizon.