how to count pixel in binary image ?
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ayrie
am 19 Aug. 2014
Kommentiert: Image Analyst
am 27 Feb. 2021
Hi, i'm trying to counting a binary image on handwritting. how to count a high string using pixel? example for counting high of alphabet A.
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Image Analyst
am 19 Aug. 2014
To get the number of pixels in the entire image
numberOfPixels = numel(binaryImage);
To get the number of white/1/true pixels only , and NOT the number of black/0/false pixels:
numberOfTruePixels = sum(binaryImage(:));
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sofia cirne
am 22 Jun. 2017
Hello! im doing the same thing apresented above and i used your code to count the black picels and the total number of pixels, but when i submit a completly black image, the number of black pixels is different from the total. Can you help me please?
Image Analyst
am 22 Jun. 2017
Bizarre. Of course my code does not count black pixels but I assume you made the obvious alterations (but maybe not). What do you get for this example:
blackImage = false(240, 320);
numberOfPixels = numel(blackImage)
numberOfBlackPixels = sum(~blackImage(:))
The two numbers should be identical.
To know what you're doing wrong, I'll have to see what you're doing, because, as I've said, you're not doing what I posted because I did not post code to count black pixels.
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Asad Alam
am 25 Feb. 2021
How can we count pixels of an image by satisfy a condition?
1 Kommentar
Image Analyst
am 27 Feb. 2021
You can use length() and pass your condition in as a mask. Like if your condition is the pixel value is less than 100, you'd do
condition = yourImage < 100; % tru or false values - a logical 2-d matrix.
pixelsLessThan100 = yourImage(condition); % These are a list (1-d vector) of gray level values.
% Count the number of pixels.
count = length(pixelsLessThan100);
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