how to count pixel in binary image ?

34 次查看（过去 30 天）
ayrie
ayrie 2014-8-19
评论： Image Analyst 2021-2-27
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.

请先登录，再回答此问题。

采纳的回答

Image Analyst
Image Analyst 2014-8-19
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(:));
  2 个评论
sofia cirne
sofia cirne 2017-6-22
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
Image Analyst 2017-6-22
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.

请先登录，再进行评论。

更多回答（1 个）

Asad Alam
Asad Alam 2021-2-25
How can we count pixels of an image by satisfy a condition?
  1 个评论
Image Analyst
Image Analyst 2021-2-27
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);

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Image Processing and Computer Vision 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by