Help with Pixel intensity histogram and export

Hi everyone,

So I have a gray image, and I have created a matrix of the pixel intensity values. I then plotted these on a histogram to see the frequency of certain pixel intensities. Right now, I'm having trouble with two things:

• How do I export this data, getting the "bin" sizes from the x axis and the frequency on the y axis?
• How can I fit the behavior of the "tops" of the histogram via a non-normal distribution (the shape I have is like 3 mountains).

Here is my code:

clc grid on; imagename = 'blah.jpg'; I=imread(imagename); K=rgb2gray(I); imshow(K); [x,y]=size(K); X=1:x; Y=1:y; [xx,yy]=meshgrid(Y,X); i=im2double(K)

figure;mesh(xx,yy,i);colorbar; figure;h=pcolor(i);set(h,'Edgecolor','none'); figure;imhist(i,256); %256 since the range of gray pixel is 0 to 255 [hh,xxx]=hist(i,256);

Thanks!

[Geoff Hayes]

To get the histogram data, just do

 [counts,x]=imhist(…);

See http://www.mathworks.com/help/images/ref/imhist.html for details.

Answer 1

[Image Analyst]

You can use

[pixelCounts, grayLevels] = imhist(grayImage, 256);
bar(grayLevels, pixelCounts);

Not sure exactly what you mean by export but you can try fprintf(), save(), xlswrite(), writetable(), csvwrite(), dlmwrite(), etc.

Not sure how you want to fit 3 mountains. Maybe 3 Gaussians, maybe a 6th order polynomial (if the peaks are spaced evenly).