How to count the number of white pixels
53 views (last 30 days)
Show older comments
filename = 'untitled.jpg';
I = imread(filename);
figure, imshow(I);
sum(I(:) == 255)
ans = 592185
and
filename = 'untitled2.jpg';
I = imread(filename);
figure, imshow(I);
sum(I(:) == 255)
ans = 626229
....
This is strange that figure1 has much lower white pixels, because i'm agricultural student, so i do not know well about matlab, coding,,,
What is wrong about my script??
0 Comments
Accepted Answer
Chunru
on 13 May 2022
First, you should use gray scale image.
Second you have a large white margin in your data (which is not seen from imshow). You can see the margin if you use imagesc instead.
If you need to count the white pixels inside. You can clip the image to remove the white margin first.
filename = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/996375/image.jpeg';
I = imread(filename);
I = rgb2gray(I);
figure, imagesc(I); colorbar; %imshow(I);
sum(I(:) >= 250)
sum(I(200:600, 200:600)>250, 'all')
figure; histogram(I(:))
%whos
filename = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/996380/image.jpeg';
I = imread(filename);
I = rgb2gray(I);
figure, imagesc(I); colorbar; %imshow(I);
figure; histogram(I(:))
sum(I(:) >= 250)
sum(I(200:600, 200:600)>250, 'all')
More Answers (0)
See Also
Categories
Find more on Interactive Control and Callbacks 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!