Indicating minima points in a gray scale image

Hello all,

I have been recently working on a image processing project with no prior experience in the field and have a query regarding the same. Excuse my lack of expertise and assist me in any way possible. So I am doing an optical measurement and have 256(0-255) gray level patterns. I append a particular line(say 95) of each image and get a image like shown below,

Now my task is to find the minimas in a ROI for each line and plot it on the image. Also I would like to know the location of the minimas(the X,Y coordinates). So basically I need to find the lowest intensity pixel in the ROI, plot it on the image for the 256 lines and find its location.

I have been using improfile, impixel, impixelinfo but its tedious and with no certain result. Is there any way it can be done?

Thank you in advance.

R's Pratik

[Michael Hawks]

I think you might do better to think of it as a matrix of values rather than an image (i.e. you don't have to limit yourself to the image processing tools).

For example, have you tried something like this:

% If your data is in a 2D array named `Img`
idx = find( Img == min(Img(:)) );
%or 
idx = find( Img < quantile( Img(:), 0.02) );

Answer 1

[Image Analyst]

Try imregionalmin().