how to get random pixel index from binary image with value 1 ?

Question

bamini thavarajah 2017-12-4

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/370996-how-to-get-random-pixel-index-from-binary-image-with-value-1

评论： Walter Roberson 2018-9-16

I have a binary image of large size (256x256). In this image most of the pixel values are zero and some of them are 1. I need to get only 100 randomly chosen pixel coordinates with value 1 from image.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Guillaume 2017-12-4

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/370996-how-to-get-random-pixel-index-from-binary-image-with-value-1#answer_294607

在 MATLAB Online 中打开

pixels = [ones(1, 100), zeros(1, 256*256-100)];
img = reshape(pixels(randperm(numel(pixels))), 256, 256);

2 个评论
显示无隐藏无

Ahlam Benahmeida 2018-9-16

can you help me please, if I have a color image and I want to extract the random pixels value and save them in a new matrix?

Walter Roberson 2018-9-16

在 MATLAB Online 中打开

num_needed = 100;
[rows, cols, panes] = size(YourImage);
selected_indices = randperm(rows * cols, num_needed);
[r, c] = ind2sub([rows, cols], selected_indices(:));
random_pixel_r = YourImage(r, c, ones(num_needed,1));
random_pixel_g = YourImage(r, c, 2*ones(num_needed,1));
random_pixel_b = YourImage(r, c, 3*ones(num_needed,1));
random_new_image = cat(3, random_pixel_r, random_pixel_g, random_pixel_b);