From: "Jerry" 
To: "'James Lerch'" ,
        
Cc: "'ATM List'" 
Reply-To: "Jerry" 


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I don't like the idea of a slitless tester for this robo test. I think = you
will be measuring diffraction bands differing in intensity by effective = slit
size. The previous post of mine suggesting a method was regarding a slit
tester. You need to adjust exposure so that with the knife completely = out
of
the beam you are just under saturating the ccd pixels. "Grey" needs to = be
referenced to the same value or condition for all zones. One reference = is
black, when all light is blocked by the knife. Another is full = brightness,
when no light is blocked by the knife. I think if a slit were used, the
center of the slit image can be found for the knife and grey could be
determined to be a pixel value midway between full bright and full dark.
Then carry on with your technique.

The post by Dwight Elvey recommending determination by looking for
simultaneous motion opening pairs for a zone is correct. That is largely
what I do by eye. It may be no harder to automate. I think if this were =
done
it would result with the crossover point I spoke of in my last post = being in
agreement with the point of "simultaneous movement" in zone
openings. I think the crossover graph would be easiest to program.

=20

Jerry

 =20


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I
don’t like the idea of a slitless tester for this robo test. I = think you
will be measuring diffraction bands differing in intensity by effective = slit
size. The previous post of mine suggesting a method was regarding a slit
tester. You need to adjust exposure so that with the knife completely = out
of
the beam you are just under saturating the ccd pixels. =
“Grey” needs
to be referenced to the same value or condition for all zones. One = reference is
black, when all light is blocked by the knife. Another is full = brightness, when
no light is blocked by the knife. I think if a
slit were used, the center of the slit image can be found for the = knife
and grey could be determined to be a pixel value midway between full = bright and
full dark. Then carry on with your technique.

The post by Dwight Elvey recommending determination by =
looking for simultaneous
motion opening pairs for a zone is correct. That is largely what I do by = eye.
It may be no harder to automate. I think if this were done it would = result with
the crossover point I spoke of in my last post being in agreement with = the
point of “simultaneous movement” in zone openings. I think = the
crossover graph would be easiest to program.

 

Jerry

  









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