VideoCAD calculates results on the base of laws of geometrical optics, video sensor's characteristics, lighting engineering and radiometry. Mathematical precision in VideoCAD calculations is not less than ±1 %.

At the same time, parameters of real cameras and lenses are not so precise.

The difference with reality depends on the accuracy of the input data.

A big influence on the accuracy of camera modeling has accuracy of specifying image sensor sizes. For wide-angle lens consideration of lens distortion is very important.

Nobody can guarantee that just your camera and lens have no significant inequality of focal length value with the one declared in the specification. It is advisable to test a camera with a lens practically in especially crucial cases.

If not performing such a test, it is recommended to leave a reserve about 10-15 % in the results.

See also: About camera sensitivity, Measuring real view angles, Specifying active area size of the image sensor, About lens distortion

Horizontal projections of person detection, identification and license-plate reading areas are calculated strictly according to the criteria numerical values specified. In case the projection sizes are not suitable, it is recommended to understand, which criteria might cause the restrictions. Probably, in your case it is possible to sacrifice some values and obtain a sufficient projection with a less capacity of detection, identification or reading.

See also: Pixel density.

Criteria themselves are very subjective and depend on a number of external factors.

For instance, the license plate reading capacity, beside lighting, depends on weather conditions, road down-grade, etc. The person identification might depend on such factors as, whether people in a place of surveillance are looking upwards or downwards, whether the familiar or unfamiliar people are being identified, whether people in a place of surveillance wear headgear, etc. The numerical values specified in the program by default are rough and are given with some reserve. It is recommended to formulate your own numerical values of criteria proceeding from your requirements, type them in VideoCAD and apply them according to actual conditions in a place of surveillance.

With the help of 3D modeling video surveillance scenes and image quality you can make own criteria values, having several examples of images from your video system.  

In more detail the process of determination own criteria is viewed in the Example 6  Determining person identification criteria by a real image.

Eventually, you would be able to estimate the required quality level for each individual case.

Please start your acquaintance with the program with the overview tutorial article First project with VideoCAD, step by step. The article describes beginning of practical work with VideoCAD 11 Professional.

Other teaching articles are based on previous versions of VideoCAD. They lack new tools, but particular topics are considered in detail.

To master the program it will be very useful to get acquaintance with The principles of CCTV design in VideoCAD articles. See also Examples of work with VideoCAD,

See video tutorials on CCTVCAD Software on Youtube