how to extract pixels from a image {black and white only }

I want to extract pixels [black and white ] above image ,how to get it ? and give me answer below questions ? Thanks Advance .........

1. find the horizontally number of ON pixels in each row..?[on=white pixels]

2. find the horizontally number of OFF pixels in each row and column as well..?[off=black pixels]

3. Plot the histogram in y direction for the ON pixel

4 how to display histogram for that pixels only .......

Answer 1

[Voss]

data = imbinarize(rgb2gray(imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/160786/image.jpeg')));

% 1. find the horizontally number of ON pixels in each row..?[on=white pixels]
n_white_per_row = sum(data,2)

n_white_per_row = 111×1

1 2 3 9 10 7 5 16 18 13

% 2. find the horizontally number of OFF pixels in each row and column as well..?[off=black pixels]
n_black_per_row = sum(~data,2)

n_black_per_row = 111×1

235 234 233 227 226 229 231 220 218 223

n_black_per_column = sum(~data,1)

n_black_per_column = 1×236

108 107 111 111 109 107 106 107 108 106 105 102 105 102 99 101 100 97 90 95 98 93 92 93 89 87 81 89 92 91

% 3. Plot the histogram in y direction for the ON pixel
barh(n_white_per_row,'EdgeColor','none','BarWidth',1)
set(gca(),'YDir','reverse','YLim',[0.5 size(data,1)+0.5])

% 4 how to display histogram for that pixels only .......
% I don't know what "that" means.