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Modeling PTZ cameras

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Modeling PTZ cameras

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Modeling PTZ cameras

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The following tools can be used to simulate a PTZ camera in VideoCAD:

 

1. PTZ or Fisheye box for modeling full circular view area of PTZ camera. The view area is modeled with visualization of Shadow and pixel density in the Graphics window and in the 3D World window. When constructing the view area, the limiting angles of rotation and inclination up and down are taken into account.

2. List / Range of Lens focal length for modeling the range of Lens focal length of the PTZ camera.

3. Positions of active camera window for simulating PTZ presets.

 

 

Problem

 

There is AXIS Q6124-E camera. The camera is installed at height of 3 m in the center of a rectangular room 20 * 30 m. The height of the room is 10 m. It is necessary to make models of the view area of the camera in this room in the height range of 0.5-2 meters in horizontal projection and along the entire height of the walls in 3D.

It is required to obtain the projection of the view area, the view area in 3D, distribution of pixel density and get model of image from this camera.

 

Camera parameters according to the manufacturer's specifications, important for modeling the view area:

 

•Resolution in pixels 1280x720.
•Image sensor size 1/3".
•Lens ZOOM 4.3-129mm.
•Horizontal angle of view: 58.30 - 2.10
•Vertical angle of view: 34.90 - 1.30

 

Since the camera’s parameters give accurate angles of view, we can simulate the view area more accurately, taking into account the lens distortion and actual size of the active area of the Image sensor. In this example, big accuracy is not needed, so we will not use the angles of view in the model.

 

•Pan angle 3600
•Tilt angle +200 to -900

 

 

Order of work

 

1. Create a camera by clicking the New camera  button. In the camera creation dialog select the Camera icon outdoor/PTZ.

 

Assigning a special icon is optional. In the future, you can change the icon in the Camera list window.

 

If the camera model is present in the database of real camera models, then there is no need to enter the camera parameters manually, just select the model from the Active Camera Model list or in the Table of Camera Models. The manual input of parameters is described below, for a case this camera model is not available in the database of real models.

 

2. Set camera parameters in the Camera geometry box:

•Sensor size 1/3".
•Active pixels 1280*720.
•Aspect ratio 16:9.
•Lens focal length 4.3 mm.

 

•View area upper bound height - 2 m
•View area lower bound height - 0,5 m

 

 

 

3. Open the Sensor and Lens box.

 

Enter in the List / Range box the range of change of the lens focal length: 4.3-129

 

Click on the Save button.

 

4. Model a room 20 * 30 meters with 10 meters of height by the tool Wall. Place 3D models of  windows, doors and people for beauty images.

 

See Example

 

Place the camera in the center of the room.

 

Set the far bound of the view area at the inner edge of the room.

 

Enable modeling shadows by selecting Within projection, in the drop-down menu of the Shadow button.

 

5. Open the PTZ or Fisheye box.

 

Mark the PTZ switch and enter angles of panning and tilting Up and Down.

 

 

 

As a result, we get:

•In the Graphics window - the projection of the view area in the height range of 0.5-2 meters
•In the 3D World window - the distribution of pixel density on the room in 3D.

 

 

The pixel density corresponds to the set lens focal length - 4.3 mm. To obtain pixel density with a different focal length - change the focal length.

 

The maximum drawing distance of view area projections is determined by the Maximum distance of drawing view area.

 

       Modeling presets of PTZ camera

 

6. Open the Positions of active camera window.

 

Switch to Positions tab.

Click Add to save full view area of our PTZ camera to the first position.

 

Uncheck the Monitor column in the position table so that image from this position is not displayed in the 3D Video window.

 

To make the full view area faded select -2 in the Highlight column.

 

 

 

7. Open the 3D Video window to see the images from the presets.

 

8. Open the PTZ or Fisheye box.

 

Mark None switch.

 

Now the active camera is not PTZ. We will simulate the PTZ camera presets as normal cameras and save them as positions.

 

 

 

9. Direct the camera to the desired preset point (Pan and Tilt) and adjust the lens focal length (ZOOM).

 

Click Add in the Position of Active Camera / Multisensor window to save the preset to a new position.

 

Set up and save to positions as many presets as you need.

 

To hide names and icons of  positions, clear the checkboxes Show names and Show icons.

 

After filling the positions by presets, you can hide the image from the parent camera in the 3D Video window, leaving only images from the presets. To do this, right-click on the 3D Video window, select the Panoramic tab on the appeared Image parameter panel and mark the Show> Positions switch.

 

On the Positions of active camera window, you can turn the display of the PTZ view area on and off, hide and show positions, copy positions to the camera, change the camera and copy the modified camera to the position back and much more.

 

Below there are examples of pictures that can be obtained:

 

Images from presets of the PTZ camera in the 3D Video window

 

 

View area projection and presets of PTZ camera in the Graphics window

 

Presets of the PTZ camera in the 3D World window

 

 

 

See also: Modeling multisensor camera, Positions of active camera, Panoramic, PiP, Modeling megapixel images