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1407 black reference

How does one determine the range of black reference values for the 1407 and 1409 monochrome frame grabbers?

Neither manual says anything except "The level that represents the darkest an image can get."

MAX allows any value to be entered, but of course the system complains when it is out of range.

I have the same question of the white reference.

 

Thanks.

Brian Smith
Advanced Light Source
Lawrence Berkeley National Laboratory
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I'm not sure what the range of acceptable values are, but I can tell you how I adjusted them when I used analog cards.

 

I started by covering the lens with the lens cap to get a black image.  I displayed the histogram, then adjusted the black level until the peak was just a hair above zero or equal to zero.  The next step was to point the camera at a bright light to get a white image, then adjust until the peak hit 255 (or whatever the largest possible intensity is).

 

Don't really know if this is the type of information you are looking or not.

 

Bruce

Bruce Ammons
Ammons Engineering
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Hello BVSmith,

 

For the 1409, both white and black level can be between 0V and 1.4V (with black less than white).  For the 1407, black can be between 0V and 0.5V, and white can be between 0V and 1.26V, again with black less than white.

 

I hope this helps,

 

Jeff

 

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Thanks, Jeff.  That is exactly what I wanted to know, but where did you find those numbers?

They don't appear to be in any documentation, either the 1407(&1409) manual or the Imaq manual.

 

Brian

Brian Smith
Advanced Light Source
Lawrence Berkeley National Laboratory
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Hi Brian,

 

To be honest, I cheated - I went and looked at the code for the driver.  I haven't worked on IMAQ for nearly a decade now, so I'm no longer familiar with the documentation set.  Since I am the architect of the current plugin board IMAQ driver, when I have a question, I go to the code instead of the docs.

 

I'll let the documentation team know that you were unable to find this information, though.

 

-Jeff

 

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Thanks, Jeff. 

 

Brian Smith
Advanced Light Source
Lawrence Berkeley National Laboratory
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