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How can I find the full width at half-maximum?

Hello,

I have run into a problem that I hope you can help me with: I need to find the Full Width at Half-Maximum.
I have an array of pixel intensities and have found the peaks and valleys using Peak Detector.vi, but I can not figure out a way to find the full width at half-maximum (the width of the 'hill' at one-half of its maximum point).
Any help you may provide would be greatly appreciated.

Jared Leisner
- Using LabVIEW 6.1/Vision 6.0
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Message 1 of 5
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Jared,

I had the same problem. One of the solutions I used was to use the was to
use "threshold 1D array.vi" from the array palette. You can use this to
iteratively get the uphill edge of the peak. To get the down hill edge, you
have to invert the array and then use the same VI. Then subract the uphil
position from the down hill position and your done.

You do however need to be careful depending on your image content. If the
image is noisy, then the "Peak Detector.vi" will have problems finding the
"real peak".

Steven Bloomberg
CISTech


"Jared Leisner" wrote in message
news:506500000008000000AE550000-1027480788000@exchange.ni.com...
> Hello,
>
> I have run into a problem that I hope you can help me with: I need
> to find the Full Width at
Half-Maximum.
> I have an array of pixel intensities and have found the peaks and
> valleys using Peak Detector.vi, but I can not figure out a way to find
> the full width at half-maximum (the width of the 'hill' at one-half of
> its maximum point).
> Any help you may provide would be greatly appreciated.
>
> Jared Leisner
> - Using LabVIEW 6.1/Vision 6.0
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Message 2 of 5
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Hi,
What about
"Functions->Analyze->Signal Processing->Time Domain->Pulse Parameters.Vi"
It returns the "duration" of the pulse which is actually the FWHM.

Good luck.

Oleg Chutko.
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Message 3 of 5
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Be careful when using the Pulse Parameters.vi. It may not return exactly what you are looking for in certain scenarios. There are certain criteria on the input sequence of this VI for it to work properly.
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Message 4 of 5
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Thanks for the help guys.
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Message 5 of 5
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