maximum pixel intensity of image

My current project is based on CCD and LASER. i want to calculate maximum intensity of laser strip on ccd.. so please give me a code to find maximum intensity pixel and location of that pixel as row and column..

Answer 1

[Image Analyst]

Try this:

% Generate sample data
imageArray = [ 3 4 5 5 4 4 5 5 3; 5 4 5 5 3 3 3 3 4];
% Find the max value.
maxValue = max(imageArray(:))
% Find all locations where it exists.
[rowsOfMaxes colsOfMaxes] = find(imageArray == maxValue)

That said, this is probably not what you want to do to find the laser spot. You probably want to either do a spatial filter or a threshold, and then binarize and find the centroid of the binary blob. There are some laser tracking programs in the File Exchange: http://www.mathworks.com/matlabcentral/fileexchange/32492-laser-dot-isolation, http://www.mathworks.com/matlabcentral/fileexchange/33666-simple-particle-filter-demo, http://www.mathworks.com/matlabcentral/fileexchange/17960-particle-filter-color-tracker, http://www.mathworks.com/matlabcentral/fileexchange/31463-simple-demo-program-for-color-based-tracking, etc. etc.

Answer 2

[Matt J]

[maxval,idx]=max(image(:));

[row,col]=ind2sub(size(image), idx);

Answer 3

[Lalit Patil]

This gives one irritating figure and gives only value of one pixel... The response of this code is same for all figures.. ... and in my image there is more than one pixel that contains same maximum intensity... So, please give modification or anothe code...

Answer 4

[Lalit Patil]

Thank you Image Analyst... This thing works me... Now I want to generate Image array from image in terms of row and column as you have shown.. I tried imread but it gives M*N*3 array... and i require only M*N array.. So please give code or suggestion..

[Lalit Patil]

Ok... Thank you image analyst... It has been solved... I = imread('Image'); i = I(:,:,3);

[Image Analyst]

Yes, taking the blue channel will give you the best contrast for a red laser. Of course that doesn't solve the location (centroid) problem.

[Nonu 007]

Hey I am doing same analysis. But now i want a cross-section line of beam at highest intensity. Can you suggest me what to do for that... Please reply asap. thanks in advance.

[Image Analyst]

Try improfile().

[Nonu 007]

Hello Image Analyst. I am trying that too but I am not getting a single line of cross section in 2D at highest Peak. Here i am attaching a fig. May be from that you can help me.

I want a cross section line like this from the image at max intensity.

Answer 5

[Shel]

Hi, I am using max(I(:)) on my image but the error "Index exceeds matrix dimensions. " shows up ... do you know what the problem is?

[Matt J]

You've probably created a variable named 'max' previously in your workspace, which Matlab is trying to index.