multipe maxima

[retroscience]

hello,

I have a labview program that does the following;

- reads in a picture (the picture is of a beam spot)

- converts picture to array

- finds the maximum of the array array

Now, I want to do the following, and would like to a build a new program from scratch to do it.

- reads in a picture - but this time the picture is of many beam spots in a horizontal line

- converts picture to array

- finds all the maximum of the array

any ideas?

- maryam

[MikeS81]

Hi maryam,

do you use the vision toolkit? If not, then you can calculate a grey scale image of your data and use some edge detection algorithm, for example the Sobel operator.

Hope it helps.

Mike

[muks]

Hope you have vision tool kit.You can use the "Image to array function" first then try this vi attached.

Message Edited by muks on 08-28-2008 08:17 AM

[MikeS81]

Hi muks,

i think maxima is not equal to maximum value. The second maxima in your example could also be 53.

Mike 

Message Edited by MikeS81 on 08-28-2008 05:09 PM

[altenbach]

(Have you tried the "peak detector" from the "signal processing...signal operation" palette?)

Of course it seems you are dealing with a 2D array, here. Could you attach a typical array and tell us how many "peaks" there should be? Are they 2D gaussians? How much noise is there?

Message Edited by altenbach on 08-28-2008 09:07 AM

[muks]

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Hi muks,

i think maxima is not equal to maximum value. The second maxima in your example could also be 53.

Mike

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Mike u mean 43 right? the output array will show him how many times the maximum value occured in what index.

[altenbach]

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muks wrote:

Mike u mean 43 right? the output array will show him how many times the maximum value occured in what index.

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I am sure Mike meant 53. We have a 2D array with bright spots corrsponding to beam spots. It is very unlikely that each spot has exactly the same maximum value. Still we want to find the xy position of every bright spot in 2D, even if some are brighter than others. 😉

[muks]

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I am sure Mike meant 53. We have a 2D array with bright spots corrsponding to beam spots. It is very unlikely that each spot has exactly the same maximum value. Still we want to find the xy position of every bright spot in 2D, even if some are brighter than others

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Oh ok got it now.