Visualization of cameras' control area projections and pixel density inside them

 Visualization of cameras' control area projections and pixel density inside them Visualization of cameras' control area projections and pixel density inside them

Problem

We have a three-dimensional model of a complex environment.

We need to determine the areas controlled by cameras taking into account shadows arising from obstacles of the environment (camera control areas). Within the control areas, the pixel density of cameras must be visualized.

We should be able to estimate directly on the 2D site plan how people will look into the camera image at each point of the camera control area.

Order of work

1. Construct three-dimensional model of the environment using the tools of 3D modeling.

The constructions must be drawn by line types with marked Shadow box.

You can import the environment or its fragments in the form of one or several 3D models imported from other graphics formats.

If the environment contains 3D models,  shadows from which must be taken into account, you must:

 • enable calculation of shadows from 3D models in the Options box;
 • individually switch these 3D models into the editing state by double-clicking, then mark  the box on the Current construction parameter panel.

2. Place a camera. Activate it.

3. Choose Filling in the drop-down menu of the Fill projection button on the Tool bar.

View area projection will be filled by blend color.

The color of filling is determined by the line type of the camera.

4. Choose Discrete color in the drop-down menu of the Pixel density button on the Tool bar.

View area projection will be divided into the regions. The regions will be colored according to values of the criterion within the regions.

5. Open the Pixel density box.

In the Pattern criterion combo box you can see which criterion is chosen in the pattern assigned to the active camera.

In calculation of pixel density, the Vert.(Horiz.) number of pixel is taken into account.

In the Table of regions you can see what color corresponds to each range of the criterion value.

On the images in the Resolution column, you can see with which resolution people at the far bound of each region will be visible.

On the images in the Field of view column, you can see which part of the field of view people at the far bound of each region will cover.

Sample images are correct for the cameras with vertical resolution specified in the Vert.(Horiz.) number of pixel combo box.

See details: Pixel density box.

Don't close the Pixel density box.

6. Choose Within projection in the drop-down menu of the Shadow button on the Tool bar.

After a while VideoCAD calculates the control area projection, taking into account shadowing from obstacles in environment.

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7. Keep the Pixel density box opened.

It is convenient to keep the Pixel density box opened during the analysis of pixel density in the Graphics window. Comparing color of regions on the layout with colors in the Table of regions in the Pixel density box, on the images in the Resolution and Field of view columns you can immediately see the expected resolution and  field of view size at every point of view area of each camera.

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