Binary Image: Count number of pixels that are 1.
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The code below is a simplified version of the one part of a longer code that I am running into an error. In the code below, I successfully convert the gray scale image into a binary image. Then I try to count the number of pixels in the image that are 1 (by using the for loop and bin()). However, MATLAB says, "Undefined function or variable 'rows'." Then if I type a number instead of saying rows columns, I get the error, "if bin(i,j) == 1."
I've looked at the syntax of the bin command, and I have tried problem solving this. However, I don't know if the for loop knows to apply itself to the image. Please let me know how I can fix this for loop to work properly.
Code:
I = imread('rice.png');
figure; imshow(I);
bw = imbinarize(I);
figure; imshow(bw);
ctr= 0;
for i = 1 : rows
for j = 1 : columns
if bin(i,j) == 1
ctr = ctr + 1;
end
end
end
채택된 답변
Andrei Bobrov
2017년 7월 3일
May be so:
I = imread('rice.png');
figure; imshow(I);
bw = imbinarize(I);
figure; imshow(bw);
ctr= 0;
for i = 1 : rows
for j = 1 : columns
if bw(i,j) == 1
ctr = ctr + 1;
end
end
end
댓글 수: 8
oussama zayene
2022년 2월 1일
Image Analyst
2022년 2월 1일
I'm sure that after almost 2 years he did. It probably went something like this:
props = regionprops(bw, 'BoundingBox');
for k = 1 : numel(props)
thisBB = props(k).BoundingBox;
croppedImage = imcrop(bw, thisBB);
% Now do something with cropped image.....
end
추가 답변 (4개)
Jan
2017년 7월 3일
Alternatively without a loop:
bw = imbinarize(I);
ctr = sum(bw(:) == 1);
or even shorter for a binary image:
ctr = sum(bw(:));
Image Analyst
2018년 2월 4일
편집: Image Analyst
2022년 2월 1일
If you want to know why your code didn't work, the problem with your code is that you forgot to define rows and columns for your image. After imread(), you need this:
[rows, columns, numberOfColorChannels] = size(I);
But better, like Jan said, you can simply could the number of white/true/1 pixels with this:
numWhite = sum(BW(:)) % numWhite is what you called ambiguously called ctr ("counter", "centroid"?)
No nested for loop is even needed.
numWhite = nnz(bw);
댓글 수: 0
bipul
2018년 9월 23일
편집: bipul
2018년 9월 23일
function ctr = PixelCounter(bw)
%I = imread('rice.png');
%I = I(4:15, 18:29);
%figure; imshow(I);
%bw = im2bw(I)
%figure; imshow(bw);
ctr= 0;
[rows columns] = size(bw);
for i = 1 : rows
for j = 1 : columns
if bw(i,j) == 1
ctr = ctr + 1;
end
end
end
%fprintf('1 are: %d \n', ctr);
%disp(ctr);
end
댓글 수: 1
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