VideoCAD

Image parameter panel

 Camera

Hide Navigation Pane

Image parameter panel

 Camera

Previous topic Next topic No directory for this topic Expand/collapse all hidden text  

Image parameter panel

 Camera

Previous topic Next topic Topic directory requires JavaScript JavaScript is required for expanding text JavaScript is required for the print function Mail us feedback on this topic!  

 

This tab contains the tools for 3D modeling camera parameters associated with the modeling movement (frame rate, interlacing, exposure time, rolling shutter) and the depth of field.

Tools on this tab can be applied simultaneously to one image, but in this case time of image generation might increase in the tens or hundreds of times.

 

Camera sensitivity and resolution parameters, lens parameters are available in the Sensitivity and resolution box.

 

See more: about modeling moving 3D models, Rotakin.

See more: about the depth of field.

 


 

According to camera parameters

 

Frame rate

Interlace

Exposure (ms)

Rolling shutter

Depth-of-field panel

 

Save to camera

 

 

Click to expand
Click to expand

 

According to camera parameters

 

Different cameras can have different parameters.

 

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

 

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

 

See also: Save, Save to selected cameras

 

Frame rate

 

In this box you can specify the Frame rate of the Active camera in frames per second.

The Frame rate is taken into account when modeling animated images with moving 3D models and Rotakin.

 

If a 3D  model has non zero speed, then the velocity vector is displayed.

 

If 3D model is in the normal state, the length of the velocity vector equals to the distance which the 3D model passes for the period between successive frames of the active camera (black arrow).

 

If 3D model is selected then length of the velocity vector equals to the distance in meters (feet) which the 3D model passes per second (crimson arrow).

 

The length of the velocity vector of a 3D model in the normal state is inversely proportional to the frame rate of the active camera. Thus we can see how many times the moving 3D model gets into the frame of the active camera.

If a model is assigned to the active camera, and the model has set maximal frame rate, then value in this box can not exceed the maximal frame rate.

When approach to the maximal value, the box will become crimson.

You can change frame rate in wide range of cameras, which have not assigned model or the assigned model have not specified maximal frame rate.

 

See also: Selecting frame rate on the basis of known target's positions and velocities.

External link: "The principles of CCTV design in VideoCAD. Part 5. Video surveillance of moving objects"(*.pdf)

 

Interlace

 

The panel is intended for modeling distortion of moving 3D models and rotating Rotakin object arising from interlacing of analog cameras (comb effect).

 

Due to the interlaced scanning, the full frame is composed of two interlaced fields. The exposition of the fields is performed consistently at different times, but the full frame is displayed on a digital monitor at once, which causes a horizontal shift of lines of moving objects.

Analog monitors have interlaced scan, and the full frame is displayed on an analog monitor field by field sequentially, therefore on analog monitors the interlace effect is absent.

 

 

In the Time interval between fields box you can specify a period between two fields in the full frame.

 

In the PAL system this interval equals 20 millisecond (1/50 s), In the NTSC system this interval equals 16.5 millisecond (1/60 s).

 

If the Model box is checked the the Interlace will be modeled.

 

Modeling Interlace increases image generation time in several times.

 

See also: Simulating distortions of moving objects arising from Exposure time, Interlace scan and Rolling shutter, One field

External link: "The principles of CCTV design in VideoCAD. Part 5. Video surveillance of moving objects"(*.pdf)

 

Exposure (ms)

 

The panel is intended for modeling blur of moving 3D models and rotating Rotakin object arising from the exposure time (Motion blur).

 

The greater the exposure time and the greater the velocity of an object on the screen, the more the blur appear.

 

In the Exposure time box you can specify the exposure time of the active camera (shutter time, shutter speed) in millisecond.

 

Exposure time of standard analog cameras can not exceed the period between fields. (20ms (1/50s) for PAL, 16.5ms (1/60s) for NTSC). Automatic electronic shutter reduces actual exposure time in dependence of scene illumination, camera sensitivity and the aperture ratio of the lens. In low light conditions exposure time is maximal.

Exposure time of IP cameras and analog cameras with light accumulation can be up to 200-500ms and more. By increasing the exposure time  increasing the rated sensitivity of these cameras is achieved, but this leads to blurring of moving objects, for that it does not always pay attention.

 

If the Get from modeling box is checked, then the expected exposure time is calculated during modeling sensitivity.

 

Different cameras can have different regularities of variation of exposure depending on the light, so the possible error in calculating the expected time during modeling sensitivity. Before the practical use of this feature, you must check it with the camera in use and make the necessary corrections.

 

The Model button launch the modeling exposure time once.

 

If the Model perm. box is checked, then the exposure time will be modeled permanently.

 

VideoCAD offers a technique of measuring exposure time of cameras with an analog oscilloscope, see: Measuring exposure time of IP camera

 

Modeling Exposure time takes much time (depending on complexity of scene, video card's and computer's opportunities (from several seconds to several minutes), therefore it is not recommended to mark needlessly the item Model perm., otherwise the program will work very slowly.

 

Realism of modeling exposure can be adjusted by the Model Depth of Field and Shutter slider in the Options box.

Quality of modeling considerably depends on video card's opportunities and its adjustments. If modeling exposure does not work or works incorrectly, try to change adjustments of video card hardware acceleration.

If in your video card there is no hardware support of this function, exposure should be modeled at completely switched off hardware acceleration (the slider is moved to the left). However in this case quality of other parameters of image is worsened.

 

See also: Errors in rendering 3D images

 

See also: Simulating distortions of moving objects arising from Exposure time, Interlace scan and Rolling shutter.

External link: "The principles of CCTV design in VideoCAD. Part 5. Video surveillance of moving objects"(*.pdf)

 

Rolling Shutter

 

The panel is intended for modeling distortion of moving 3D models and rotating Rotakin object arising from the rolling shutter effect.

 

As a result of Rolling Shutter work, exposure of different rows of the image sensor begins and ends sequentially at different times, which causes a horizontal shift of moving objects.

This effect occurs with many IP cameras with CMOS image sensor and usually doesn't occur with cameras with CCD image sensor.

In the Row time box you can specify the time period (in microsecond) between the beginning of exposure of adjacent rows. Unfortunately this parameter is not given in the cameras' specification. To elucidate the value of the parameter you should contact the manufacturer or measured this time in practice.

 

VideoCAD offers a technique of measuring row time of rolling shutter with an analog oscilloscope, see: Measuring rolling shutter row time of IP camera

The Row time may vary slightly under different settings of the same camera.

The Up checkbox switches direction of scanning strings by the Rolling shutter. Top-down or Down-top.

 

The Model button launch modeling Rolling Shutter once.

If the Model perm. box is checked, then the Rolling Shutter will be modeled permanently.

Modeling Rolling Shutter takes much time (depending on complexity of scene, video card's and computer's opportunities (from several seconds to several minutes), therefore it is not recommended to mark needlessly the item Model perm., otherwise the program will work very slowly.

 

Realism of modeling can be adjusted by the Model Depth of Field and Shutter slider in the Options box.

Quality of modeling considerably depends on video card's opportunities and its adjustments. If modeling Rolling Shutter does not work or works incorrectly, try to change adjustments of video card hardware acceleration.

If in your video card there is no hardware support of this function, Rolling Shutter should be modeled at completely switched off hardware acceleration (the slider is moved to the left). However in this case quality of other parameters of image is worsened.

 

See also: Errors in rendering 3D images

See also: Simulating distortions of moving objects arising from Exposure time, Interlace scan and Rolling shutter.

External link: "The principles of CCTV design in VideoCAD. Part 5. Video surveillance of moving objects"(*.pdf)

 

Depth of Field

 

On the panel you can invoke modeling depth-of-field and change depth-of-field parameters.

 

Parameters

 

Show Depth-of-field box. In this box it is possible to change lens parameters (lens focal length, aperture and focus distance).

 

Auto Iris lens

 

If the box is checked, at depth of field calculation the aperture value, computed during 3D modeling illumination, will be used. If the box is not checked, the aperture value, specified in the  box Aperture (F number) in the Depth-of-field box, is used.

 

Model

 

Run depth-of-field modeling once. Initial data (lens focal length, aperture and focus distance) are set in Depth-of-field box. Clicking the item Parameters it is possible to display this box.

 

If the Model perm. box is checked, then the Depth of Field will be modeled permanently.

 

Modeling Depth of Field takes much time (depending on complexity of scene, video card's and computer's opportunities (from several seconds to several minutes), therefore it is not recommended to mark needlessly the item Model perm., otherwise the program will work very slowly.

 

Realism of modeling can be adjusted by the Model Depth of Field and Shutter slider in the Options box.

Quality of modeling considerably depends on video card's opportunities and its adjustments. If modeling Depth of Field does not work or works incorrectly, try to change adjustments of video card hardware acceleration.

If in your video card there is no hardware support of this function, Depth of Field should be modeled at completely switched off hardware acceleration (the slider is moved to the left). However in this case quality of other parameters of image is worsened.

 

See also: Errors in rendering 3D images

 

Save to camera

 

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

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

At modeling monitors the parameters saved in cameras is always used.

 

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