The image sensor format can be only chosen from the list: 1/4", 1/3.6" ,1/3.2", 1/3", 1/2.7", 1/2", 1/1.8", 1/1.7", 2/3", 1", 4/3". Choose in this box a value given in the camera specification.

The most popular formats are 1/4" (for the mini- and DOME-cameras), 1/3" (for the better part of cameras) and 1/2" (for the certain cameras of extended quality). Formats 1/3.6" ,1/3.2", 1/2.7", 1/1.8", 1/1.7", 4/3" are used in IP cameras and digital photo cameras.

The image sensor format influences all the calculated parameters.

When moving the cursor to the image sensor box the information on horizontal and vertical view angles of lens appears.

In case of modeling camera has image sensor format, which is absent in the list, use the Special sensor size button to activate Special sensor size box. In this box it is possible to specify any image sensor size, view angles and aspect ratio.

If the special sensor size is assigned to the camera, sensor sizes in millimeters are displayed in this box.

The values can be chosen from the list or typed from keyboard, e.g. when using the varifocal lenses.

Choose a value given in the lens specification in this box.

It is assumed that the lens format equal to or larger than the camera image sensor format is used.

The lens focal length influences all the calculated parameters.

When moving the cursor to the lens focal length box the information on lens view angles appears.

If in lens' specification there are view angles which are different from standard ones, you can choose focal length value in order to get view angles that are close to the angles in the specification.

It is possible to specify special sensor size. To do this open Special sensor size box by clicking Special sensor size button. In this box you can specify any image sensor size using specification values of view angles.

Often wide-angle lenses have larger view angles than the standard ones because of optical distortion on the image edges.

Focal length can be chosen from the list or typed into this box or duplicate boxes on the Tool bar of the Graphics window and on the 3D window.

If a model is assigned to the camera, and the model has fixed focal length lens, then you can not change the focal length.

If a model is assigned to the camera, and the model has a lens with limited variable focal length, then you can change focal length within the limits only. When approach to the limit values, the box will become crimson.

You can change focal length in wide range of 0.5-1000mm of cameras, which have not assigned model or the assigned model have not specified limits of the lens focal length.

You can choose Aspect ratio (ratio of the horizontal image size to the vertical size): 4:3 or 16:9.

All analog cameras with standard video signal have 4:3 Aspect ratio.

Some IP cameras have 16:9 Aspect ratio (wide-screen image).

Some IP cameras allow to switch Aspect ratio between 16:9 & 4:3.

In case of modeling camera has image sensor format, which is absent in the list, use Special sensor size button to activate Special sensor size box. In this box you can specify any image sensor size using specification values of view angles.

If non standard Aspect ratio or sensor format is assigned to a camera, "custom" is displayed in this box and the box becomes inaccessible. To make it accessible choose any standard sensor format.

For correct calculation of person detection, identification and license plate reading areas and spatial resolution, after changing the Aspect ratio it is necessary to check and adjust vertical number of pixels in the Sensitivity and Resolution box and Image size on the Processing tab on the Image parameter panel.

Clicking this button will open Special sensor size box. In the box it is possible to specify any image sensor size and Aspect ratio.

See more: Special sensor size

Height of installation can be chosen from the list or typed. The height of installation influences all calculated parameters.

Camera tilt angle is a calculated parameter and can not be edited directly. The camera tilt angle is an angle between the main optical axis of camera lens and a horizontal.

Though in most of the cases the camera tilt angle is not interesting to designer, VideoCAD is displaying it for information.

The height of view area upper bound can be chosen from the list or typed. In the horizontal projection of the calculated view area the space above the upper bound height is not taken into consideration. Together with view area upper bound distance it completely determines a camera tilt angle and all calculated parameters through it.

The height of view area upper bound influences the projections of the person detection, identification and the license plate reading areas only through changing the camera tilt angle. The individual values of lower and upper bounds are customized in these projections' calculation criteria. For instance, when identifying a person the default lower bound is 1.5 m and the upper one is 2.2 m.

       Height of calculating Spatial resolution, Shadows and Depth of Field

The height of view area lower bound can be chosen from the list or typed. In the horizontal projection of the calculated view area the space below the lower bound height is not taken into consideration.

The height of view area lower bound influences the following calculated parameters:

View area lower bound distance

View area lower bound width

The height of view area lower bound doesn't influence the projections of the person detection, identification and license plate reading areas. The individual values of lower and upper bounds are customized in these projections calculation criteria. For instance, when identifying a person the default lower bound is 1.5 m and the upper one is 2.2 m.

       Height of calculating Spatial resolution, Shadows and Depth of Field

When a camera is located above the view area upper bound, a view area upper bound distance is the maximal distance of surveillance. The view area upper bound distance is chosen from the list or typed. The view areas are calculated up to this distance. Together with the height of view area upper bound, the view area upper bound distance completely determines the camera tilt angle and all the calculated parameters through it.

When the view area upper bound distance is less than the view area lower bound distance, the maximal distance of surveillance becomes the view area lower bound distance.

The view area upper bound distance influences the projections of the person detection, identification and the license plate reading areas only through changing the camera tilt angle. The maximal distances of the person detection, identification and the license plate reading can differ from the lower and upper bounds distance both to a smaller or larger extent.

The view area lower bound distance is a calculated parameter and can not be edited.

The view area lower bound distance doesn't influence the person detection, identification and the license plate reading area projections. The minimal distances of the person detection, identification and the license plate reading can differ from the lower and upper bounds' distance both to a smaller or larger extent.

The view area projection length is a calculated parameter and can not be edited. When there is an actual view area projection, the view area projection length displays the absolute value of difference between the upper and the lower bound distances of view area projection.

When there is no actual view area projection, the parameter doesn't have any sense and is not displayed. The parameter displaying enhances the convenience in use when it is required to obtain the length of view area projection.

The width of view area projection upper bound is a calculated parameter and can not be edited.

According to the "Projection" switcher state the width of view area projection upper bound displays the camera view area width at the point of intersection between the camera view area bound and the view area projection upper bound, or the view area projection edge width between the lower bound and the upper one.

The width of view area projection lower bound is a calculated parameter and can not be edited.

According to the "Projection" switcher state the width of view area projection lower bound displays the camera view area width at the intersection point between the camera view area bound and the view area projection lower bound, or the view area projection edge width between the lower bound and the upper one.

A "Projection" is a switcher determining a way of calculation:

When the switcher is checked, the view area bound distance and width are calculated according to narrower level of the view area opposite bound. In this case all the points of the calculated view area horizontal projection from the lower bound up to the upper one hit in the camera view area.

When the switcher is not checked, the distance up to the camera view area bound intersection with the upper or lower bounds and the width of this bound are calculated.

When the view area is not narrowing towards the opposite bound, the switcher doesn't have any sense and is not displayed.

Quality level is a set of criteria according to which VideoCAD calculates person detection, identification and license plate reading areas.

The criteria values for each quality level can be adjusted using the Quality level box.

It is convenient to open the Quality level box using pop-up menu of the Quality level combo box.

It is recommended to adjust quality level criteria according to your requirements.

See also: Recommendations on the program use, Quality level box

External link: "The principles of CCTV design in VideoCAD. Part 2. Person detection area, person identification area, license plate reading area. Spatial resolution."(*.pdf).