Measuring projector parameters |
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Measuring projector parameters |
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Measuring projector parameters
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Measuring projector parameters |
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Measuring projector parameters |
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See before: Illuminator calculation.
Problem
There is a visible light projector with close to round symmetrical light intensity distribution. It is necessary to create the model of this projector in VideoCAD.
Equipment:
| • | Luxmeter (a device for measuring illumination). Almost any kind of such a device with standard CIE spectral response will suit. |
| • | Measure by the luxmeter and write down the projector illumination on an axis of radiation at the distance not less than in 20 times more than the geometrical size of the radiant window. |
Order of work
1. Install the projector, supply it by nominal voltage.
2. Measure by the luxmeter and write down the projector illumination on an axis of radiation at the distance not less than in 20 times more than the geometrical size of the radiant window.
If the environment reflects the projector's light significantly, using small nontransparent object create shadow on the luxmeter sensor from the projector. Measure illumination created by the light reflected from the environment, and then deduct this illumination from the illumination on projector axis of radiation.
3. Open Illuminator calculation box 
. Enter:
| • | Lamp type - type of lamp in the projector; |
| • | Lamp power - consumed electric power of the lamp; |
| • | Lamp quantity - number of lamps in the projector; |
| • | Projector - mark; |
| • | Angle of radiation - radiation angle of the projector (0.5 light intencity); |
| • | Concentration - 0.5; |
If there is a specification with the light intensity curves, by choosing Concentration try to obtain close light intensity distribution.
| • | Distance - the distance on which the illumination has been measured in step 2. |
4. Choose the value in the efficiency factor box for obtaining value in the Illumination box, which is equal to the one measured in the step 2.
5. In this way we have obtained the model of the projector we have. Using obtained model we can get image models from different cameras at illumination produced by this projector with sufficient accuracy for the practice.
See also: Measuring camera sensitivity, IR illuminators.
External link: "The principles of CCTV design in VideoCAD. Part 4. Illumination and camera sensitivity in CCTV"(*.pdf) .