first of all your create account for Math Works ,

how to create the math work link on below,

https://in.mathworks.com/ ,

first create and what you want you get it , here n number of code is there just refer it and some ideas, help full for you do your work in best level

Tim Elberfeld suggestion seems like a most elegant solution for the task.

To sum up:

mat=rgb2gray(imread('path/to/image.png'));

[row,col] =ind2sub(size(mat),find(mat));

Tim Elberfeld: Thanks a lot. It works :)

Yevgeniy Kadranov : Thanks!

I guess it will work fine, not sure about the syntax along with its time taking,

for i=1:height

for j=1:width

if(matrix(i,j)==1)

[r,c]=[i j]

end