Averaging brightness/fluorescent intensity in columns (y axis)

Hello, I'm trying to find the average brightness of the columns (y direction) of an image and have these for each column along the x direction. Then I'd like to plot this in some sort of graph.

I've gotten some good information through this forum:

    % 
grayImage = rgb2gray(Image);
meanGrayLevels = mean(grayImage(:));

I'm a little confused about how to set up the indices for the mean. And how do I set this in a loop to continue along the x direction of the image until the end of the image? Any help here would be much appreciated.

Thanks! Jane

Answer 1

[sixwwwwww]

just use

meanAlongEachColumn = mean(grayImage)

it will create an array of mean values. Each value in this row vector will be of each column. Is it what you need?

[Jane]

Yes this looks correct. Thank you!

[Image Analyst]

When you do (:) , that basically takes a multidimensional array and turns it into a 1D vector . So when you did that, the columns were "lost" and it just took the mean of all the pixels in the image, not column-by-column like mean() will do if you pass it a 2D array (instead of the 1D array like you passed it).