Find coordinate of non zero element in image .

I have a binary Image . and I want to get the coordinates(x1,y1) for first non zero element and coordinates of last non zero element (x1,y2) from each column of the image . and then want to plot them . can any one help me.

Answer 1

[KSSV]

I = imread('assd.jpg') ;
% I = imcrop(I) ;
I1 = rgb2gray(I) ;
[y,x] = find(I) ;

imshow(I1)
hold on
plot(x,y,'.r')

YOu may have to crop the image, if you want to remove the unnecessary white background around the image.

[Alina tom]

Sir I want to get the coordinates of 1st and last non zero elements from each column .

[KSSV]

I = imread('image.jpg') ;
I = imcrop(I) ;
I1 = rgb2gray(I) ;
[m,n] = size(I1) ;
hold on
for i = 1:m
    [y,x] = find(I1(i,:)) ;
    if ~isempty(x)
        plot(x(1),i,'.r') ;
        plot(x(end),i,'*b') ;
    end

end