how to find a local minima for a continuous waveform ?

I am working on image processing. I want to find the local minima of a particular area in an image.

Thank you in advance.

Answer 1

[John Petersen]

min(min(X))

[Image Analyst]

That's a global min value, not a local min.

[John Petersen]

not if X is limited to the area of interest. but it does have to be rectangular-ish.

Answer 2

[Image Analyst]

You can find local min using the imregionalmin() function to produce a binary image of where the local mins are.

binaryImage = imregionalmin(grayImage);

Use find() or regionprops() if you want the row and column coordinates.

[rows columns] = find(binaryImage);

Use indexing if you want to know what the values at those min locations are.

localMinGrayValues = grayImage(binaryImage);