VideoCAD

Image parameter panel

 Scene

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Image parameter panel

 Scene

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Image parameter panel

 Scene

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On the tab parameters of the scene in front of the active camera are presented. Scene parameters include illumination and visibility range. For day and night time separate scene parameter sets are specified.

 

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

 


 

According to camera parameters

Day and Night tabs

Background illumination panel

Lamp position

Model illumination

Background light source

Background illumination (lx)

Illuminators

Meteorological visibility

Save to camera

 

Click to expand
Click to expand

 

According to camera parameters

 

Different cameras can be in various conditions and consequently for different cameras scene parameters can be different.

 

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

 

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

 

The box is duplicated in the Main menu of the 3D Video.

 

See also: Save, Save to selected cameras

 

Day and Night tabs

 

 

During the day, scene of the same camera can be essentially changed. In daytime there is predominance of the natural illumination, and at night artificial one. In daytime the sky is much brighter than the ground, and at night it is darker (because of the predominance of artificial illumination).

Therefore for each camera 2 sets of scene parameters are specified: for day and night time.

If the Day tab is opened, scene parameters of day time is used. If the Night tab is opened, scene parameters of night time is used.

 

The effect of this tabs is applied to all cameras at once. Actually it is a switch of time in the project. The same switch is available in the Monitor window and in the Main menu of the 3D Video.

 

Background illumination panel

 

On the panel there are parameters of the Background light source. Background light source produces background illumination on the scene.

 

For simple modeling illumination it is enough to specify parameters of the background light for each camera. The Illumination produced by background light can be measure by the luxmeter during the site pre-design investigation.

 

In addition to the background light on the scene you can place Illuminators.

 

Lamp position

 

The item opens a submenu, in which the Lamp position relative to the active camera can be chosen.

Background light source produces background illumination on the scene.

In addition to the background light on the scene you can place Illuminators.

 

Model illumination

 

If this box is checked, during 3D image generation, scene illumination parameters, illuminators and camera sensitivity are considered.

 

Image generation time can considerably increase.

 

If the item is not checked, illumination is not considered, only camera view area is modeled.

 

Illumination modeling can be switched on separately for each camera, for day time or night time.

 

External link: "The principles of CCTV design in VideoCAD. Part 4. Illumination and camera sensitivity in CCTV"(*.pdf) .

 

Background light source

 

Using this combo box you can choose type of the Background light source.

 

The combo box is accessible only if illumination modeling is switched on.

 

Camera sensor spectral sensitivity to different types of light sources essentially differs from human eye (and luxmeter) spectral sensitivity. For example, luminescent and Incandescent lamps produce equal scene illumination according to luxmeter reading. But the image from a black-white camera directed on this scene will not be equal at scene illumination produced by different lamps. The difference in the equivalent illumination can reach four or more times. Color cameras are practically insensitive to IR illuminators, and black-white cameras have sensitivity depending on maximum wavelength of the IR illuminators.

 

VideoCAD considers this difference through in advance determined and experimentally verified spectral efficiency factors of different light sources for different types of cameras.

 

Choosing type of the light source, you automatically switch on an appropriate set of the spectral efficiency factors.

 

See also: Illuminator calculation, Measuring spectral efficiency of light source.

 

Background illumination (lx)

 

In the box it is possible to choose from the list or enter from keyboard scene illumination, created by background light.

Illumination is measured, according to the standard luxmeter reading, in luxes.

If background light source is an infra-red (IR) LED, the background illumination is measured in Watts/square meter (watt/m2). The IR illumination cannot be measured by an luxmeter. More in detail see Infra-red illuminators.

Background illumination does not decrease with distance, the scene is illuminated evenly.

Light source type is selected in the Background light source combo box, the light direction is selected in the Lamp position combo box.

 

The box is accessible and considered in 3D image modeling only if the illumination modeling is switched on.

 

Illuminators

 

If this box is checked, during 3D image generation, switched on illuminators, placed on the scene, are considered.

If the box is not checked, the illuminators are not considered.

 

The box is accessible and considered in 3D image modeling only if the illumination modeling is switched on.

 

Meteorological  visibility

 

Using this combo box you can model meteor, limiting visibility range (rain, snow, fog, sandy storms, etc.).

 

Meteorological Visibility is the greatest distance at which it is just possible to see with the unaided eye:

in the daytime, a prominent dark object against the sky at the horizon;
at night, a known, preferably unfocused, moderately intense light source.

This parameter is reported in a weather forecast, and can be also visually determined.

 

Rough values of Meteorological Visibility for various weather conditions according to data of meteorologists:

 

Rain, weak snowfall, smoke - 900-1000 m
Medium snowfall, weak fog - 500 m
Medium fog, strong snowfall - 100-500 m
Thick fog - less 100 m.

 

Pay attention to the following moments:

 

Meteorological Visibility does not coincide with the maximal person detection range. Meteorological Visibility is calculated in respect of black big size object against background of fog or sky. Maximal person detection range, limited by visibility, is 1.5-2 times less at the average depending on contrast between background and person's clothes.

 

At surveillance in the night time and at illumination from the camera the maximal detection range is considerably reduced due to light reflection from fog (rain or snow).

 

At modeling the threshold of eye contrast sensitivity 0.03 is accepted.

 

Quality of visibility range modeling has a great dependence from video card's opportunities and its adjustments. Modern 3D-accelerator allows getting excellent quality of modeling. At the same time without the accelerator, accurate modeling fog is insufficient.

 

See also: Errors in rendering 3D images

 

Save to camera

 

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

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

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

 

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