How to count the number of occurrences of pixel intensities in an image without using for loop?
8 views (last 30 days)
Show older comments
I am to write a script for histogram equalisation and I need to work on each RGB plane separately. In the first step I count the number of occurrences of each intensity value in the range 0-255. As far as I know, using for loops makes MATLAB code super slow.
org_image = imread('image.jpg')
tot_pixel = size(org_image,1) * size(org_image,2)
R = org_image(:,:,1);
G = org_image(:,:,2);
B = org_image(:,:,3);
[R_val_ocurr,R_unique_val] = histcounts(R);
[G_val_ocurr,G_unique_val] = histcounts(G);
[B_val_ocurr,B_unique_val] = histcounts(B);
Now to have an array of size 256,with each index holding number of pixels corresponding to it what should my next step be? I'm trying to write down my logic :
for i = 0 to 255
if i is in R_unique_val
hist[i] = R_val_ocurr[i]
else
hist[i] = 0
Please tell me how to correctly and efficiently write this.
1 Comment
Stephen23
on 7 Sep 2018
This is confusing, because the first part of your code gets a histogram, in fact your even write this "In the first step I count the number of occurrences of each intensity value in the range 0-255". So each of R_val_ocurr, etc. is a histogram. Then what else do you have to do?
Accepted Answer
More Answers (0)
See Also
Categories
Find more on Histograms in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!