Processing

In CCTV systems the obtained image undergoes additional processing inside camera or other equipment. On the tab it is possible to set image processing parameters.

Some elements on this panel are duplicated in the Main menu of 3D Video.

According to camera parameters

Click to expand

According to camera parameters

Images from different cameras can be processing by various means and consequently for different cameras the processing parameters can be different.

If this box is checked, processing parameters are set according to processing parameters of the active camera. As a result activation of other camera, processing parameters will be changed according to processing parameters of this camera. Manual changing processing parameters will be disabled.

If this box is not checked, processing parameters could be specified manually. The set parameters will not be changed during activation of different cameras.

The According to camera parameters checkbox on the Processing tab is marked automatically when closing the Image parameter panel to avoid confusion with the resolution of active and inactive cameras.

See also: Save to camera

Image size

Video signal received from an analog camera, comes to DVR or multiplexer input, where it is processed by analog-to-digital convertor.

Analog-to-digital conversion does not coincide with number of pixels of camera image sensor. As a result, the output image size, as a rule, does not coincide with number of pixels of the image sensor. Because of such mismatch, there are distortions.

In IP cameras the number of pixels on the output image also differs from number of pixels of the image sensor.

In thermal cameras, the size of the output image exceeds resolution of the image sensor.

In the combo boxes it is possible to set the horizontal and vertical number of pixels of output image.

A button with a cross between combo boxes with horizontal and vertical numbers of pixels is intended for fast calculation of vertical number of pixels from the specified horizontal number of pixels and on the contrary. Calculation is carried out using the Aspect Ratio.

You can save frames with size in pixel exciting Windows screen size. See Real frame size.

Criteria of person detection, identification and license plate reading, pixel density depend on vertical number of pixel. Therefore Vertical number of pixels influences person detection, identification and license plate reading areas, positions of pixel density regions and image examples in the Pixel density box.

For criteria calculation minimal number of pixels from parameters of camera image sensor and parameters of output image is used.

Number of pixels of image sensor is specified on the Sensitivity and Resolution box.

If number of pixels is not set (N/A), calculation is performed for vertical 576 pixels (or horizontal 768 pixels), what corresponds to analog camera.

If a camera is rotated around its axis by an angle more than 45 degrees, when calculating person detection and identification, license plate reading areas, the parameters: minimum vertical resolution (pixel/meter, pixel/ft), the minimum vertical size of face image ( pixels ), the minimum vertical size of license plate ( pix) are calculated based on the number of pixels along the horizontal, instead of the number of pixels along the vertical, as in this case the vertical side of the field of view is located along the horizontal.

When calculating pixel density, the influence of rotation of the camera around its axis on the position of the vertical and horizontal in the frame is determined using the When rotating camera around its axis or in corridor mode, bind horizontal/ vertical combobox in the Options box.

The positions of the boundaries of pixel density and the sample images in the Pixel density box are affected by the number of pixels in vertical or horizontal direction depending on the position of the Vert. / Hor switch in settings of a pattern of pixel density, assigned to the camera.

If the According to camera parameters box is marked on the View tab of the Image parameters panel, Image size the in the 3D Video becomes equal to the image size specified in these boxes.

One field

If this box is checked, the vertical resolution of the image sensor is reduced in half.

Vertical resolution decreases, if video signal from a camera with interlace scan is captured by fields (half frames), instead of full frames. For example, 768x288 pixels.

For progressive scan cameras this box should not be marked.

See also: Interlace

Brightness

Using this slider the image brightness can be chosen.

Contrast

Using this slider the image contrast can be chosen.

Compression

Using this combo box an image compression level can be chosen.

Compression levels may differ from the compression levels in the settings of different DVR or IP cameras. To determine a correspondence use the visual image comparison.

Obtained image compress by the JPEG algorithm for approximating the image in the 3D Video to the real image from video cameras to exactly estimation the possibilities of detection, identification and reading

Using in your DVR algorithms different from JPEG is not generally an obstacle for compression modeling with the help of JPEG algorithm. Although other algorithm artifacts differ from JPEG artifacts, the general amount of information correspondence that can be determined by the careful visual image comparison is enough for modeling.

Sharpness

Using the sliders it is possible to set additional sharpness or smoothing of the image.

Move the sliders right to increase sharpness, move the sliders left to increase smoothing.

Additional sharping is applied to approximate the image in the 3D Video to real images from cameras for evaluation of their possibilities.

Principal causes of sharpness variation:

•	Sharpness increasing results from effect of aperture correctors in cameras and in other CCTV equipment.

•

Horizontal smoothing appears as the result of losses of the videosignal high-frequency component on long lines of communication or other components of the CCTV system. The horizontal smoothing also will be necessarily present at the color videosignal capture by chips without comb filters of chrominance (for example, Bt878) or black-and-white signal by the same chips without disconnection of noth filters with the horizontal discretization more than 500 pixels. Horizontal smoothing is in the case of recording on VHS videorecorder.

•	Vertical smoothing appears when working some algorithms of deinterlacing (the process of removing interlacing effects from the image).

•	Total smoothing can appear as the result of lens adjustments errors (especially with Auto iris lenses), optic pollution or as the result of working some algorithms of smoothing. Effect of some digital processing systems in low light conditions can lead to smoothing.

You can evaluate the resolution visually using the Test chart.

Save to camera

Clicking Save button, the processing parameters, specified on the Processing tab, will be saved in parameters of the active camera.

Later on, if the According to camera parameters box is marked, the saved processing parameters will be loaded at each activation of this camera.

During modeling monitors and images for the PDF report the scene parameters saved in cameras is always used.

If at clicking Save button the Save to selected cameras box is marked, processing parameter set on the Processing tab will be saved in all selected cameras.

Help URL: http://www.cctvcad.com/videocad_help/index.html?3dparamprocess.htm