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Instruction of IR Illuminator

To get excellent performance of the product, please read carefully
the following product instruction.
Relation between infrared illuminator and camera lens
The reasons for the importance of the camera lens in relation to the
infrared illuminator include the following:      
i. Luminous flux of lens (lumen)
ii. Angle of the lens and IR illuminator
iii. Dimension of the chipset
 
Solution
1. Luminous flux of the lens – to choose the lens with the least F- ratio that has the biggest luminous flux.
2. How to choose the angle of what the appropriate focus is,
according to the diagram, to work well with the infrared illuminator –
         a. If working with a fixed lens
       i. Measure the distance between the IR camera and object.
       ii. Select the lens with appropriate focus according to the diagram.
       iii. Double check the angle of the lens.
        b. If working with a zoom lens 
       i. Measure the nearest and farthest point of measurand from the camera.
       ii. Selective focus of the lens.
       iii. Double check the angle range of the lens.
       iv. Choose the IR illuminator which can cover the entire range. 
3. Computing the formula for focus of the lens, to display the ratio of
the measurand, how to select the dimension of a chipset of 1/3”or larger.
a. Focus of lens for 1/3” inch chipset:
             1.  F = 4.8 x L/W
             2.  F = 3.6 x L/H
b. Focus of the lens for 1/2” inch chipset:
             1.  F = 6.4 x L/W
             2.  F = 4.8 x L/H
4. For example: 50 m away from the camera there is a man, 1.7 m tall,
which occupies 1/4 height on the screen. F= 3.6 x 15m/1.7m x 1/4 = 8 mm;
where F = Focus, L = Distance between lens and measurand; H = height
of the measurand; W = weight of measurand.
 
 
      i. The computing formula is based on the measurand range filling the 
entire screen.  If it fills only 1/4 of the screen, multiply the focus by 1/4.
ii. Depending upon a reasonable price and cost, the angle range of
one infrared illuminator may not cover the expected range of the
zoom camera. The edge of the screen will be gloomy or fuzzy. The
solution is to combine IR illuminators with small angles or using
different illuminating distances - together with technical expertise.
 
Selection of camera
The camera should have day and night, color and black-and-white functions, or infrared (IR) function, and should be sensitive to 850 nm
infrared [IR] light. The dimension of the chipset should be up to 1/3 inch
and below 0.01 Lux. If using a regular colour camera, the IR filter should
be replaced with one that is penetrable to 850 nm IR light. If you only
remove the IR filter without replacing it, metachromatism will occur.
 
Matters that need attention
1. Adjustment of the Auto Iris Lens.  The auto iris lens has DC and video
drive modes. Adjust the ALC (automatic level control) to fit the IR
illuminator exactly; otherwise the illuminative distance will be markedly
affected.
2. The deviation angle of the mounting should be accurate within 2°
(in relation to the plane of the camera).
3. Operating temperature should be between -20° C and 50° C.
4. Optimum Distance. Halfway between the illuminate distance and the
IR illuminator is the optimum distance. (Test by 1/3 CCD, 0.01 Lux camera).
5. Voltage. Use according to the voltage rating of every product.
6. Debugging. IR illuminators need to debug before they are used, which,
in relation to the camera and other equipment, may need technical
assistance from a qualified technician.

 

Infrared illuminator angle
Optimum distance in relation to the focus and angle of the camera lens,
based on a person (1.7 m tall) occupying 1/4 height of the screen

 

 
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