Example 22 Visualization of cameras' control area projections and spatial resolution inside them
Example 22 Visualization of cameras' control area projections and spatial resolution inside them |
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Example 22 Visualization of cameras' control area projections and spatial resolution inside them |
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Read before: Shadow, 
Spatial resolution 
, Spatial resolution box 
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 spatial resolution 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 using 3ds max.
See: Import of 3D models and scenes from 3ds max to VideoCAD
Through the 3ds max you can import 3D models from Google SketchUp. See: Importing 3D models from Google SketchUp
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 Shadow 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 
Spatial resolution 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 Spatial resolution 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 spatial resolution, the camera vertical resolution (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 Vertical resolution of camera combo box.
See details: Spatial resolution box.
Don't close the Spatial resolution 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 Spatial resolution box opened.
It is convenient to keep the Spatial resolution box opened during the analysis of spatial resolution in the Graphics window. Comparing color of regions on the layout with colors in the Table of regions in the Spatial resolution 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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