Posted by
Gluender-2 on
Jan 30, 2009; 10:52am
URL: http://imagej.273.s1.nabble.com/Laser-Beam-Profile-Analysis-in-ImageJ-tp3693862p3693865.html
>We are trying to use ImageJ for laser beam profile analysis. Thus, we want
>to accurately measure power in the beam, and use multiple methods to
>calculate beam diameter. Also, we are analyzing field tests where the
>background changes from frame-to-frame due to clouds, sun movement, and
>other environmental effects.
>
>So far, I have not found any "laser beam profile" specific plug-ins. Does
>anyone on the list know of any that have been written? I have found the
>"Moment Calculator" which calculates the second moment, and thus can be
>turned into a "4 Sigma" beam width. We are also looking to calculate the
>1/e^2 width when the distribution is summed in the x and y directions, as
>well as the "90/10" beam width.
>
>Background subtraction is also a problem for us as the built-in "Rolling
>ball" method does not work well for beam images. Other background
>subtraction methods also do not work as well since we have a dynamic
>background, and we want to preserve the pixel counts in the beam area for
>accurate measurement, and not just make a pretty picture. Right now we are
>taking two regions of interest per frame, and approximating the background
>as constant over the frame. However, we would like to fit a well-behaved
>function to the background, and subtract off the background on a
>frame-by-frame basis for an entire stack. We would like to do it sort of
>like it's done in the "A_Posteriori" plug-in, but using a region of
>interest, doing it on an entire stack, and subtracting the background
>without renormalizing the output.
>
>If anyone has any ideas of ImageJ plug-ins that might implement some of
>these measurements, we would really appreciate it. ImageJ is so much better
>and faster than the Ophir/Spiricon BeamStar software we were using. After
>fighting BeamStar, we are very happy with ImageJ.
>
As being aware of the specific requirements for laser beam profiling
and having worked with some professional profiling software, I should
like to point out that ImageJ mailny is thought for off-line or batch
processing of images. Although you may capture images from a number
of digital cameras, life image processing is not directly supported
and AFAIK not really intended.
The latter, however is desirable for laser beam profiling.
If you are happy with off-line image evaluation ImageJ can easily
perform the usual profiling tasks with Gauss-fitting etc. Just write
the appropriate macros or plug-ins, both of which is really easy.
Furthermore and from my experience, a better than 8 bit
grey-resolution camera is of advantage.
Just my 2 cents
--
Herbie
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