how to plot coordinates of nonzero elements from matrix

hello, i want to ask something,

i have this binary image :

here is my code :

global A;
  global rx;
  global ry;
  A = handles.q; %#ok
  A = [500, 5000]; %#ok
  A = [450:500, ;]; %#ok
  [rx, ry] = size(A);
  for A = [:,1] > 0
      [rx,ry] = find(A[:,1] > 0);
  end
guidata(hObject,handles);
axes(handles.axes3); %#ok 
imshow(A);
msgbox('Process SUCCESSFUL !');

my question is :

how to find and plot coordinates of nonzero elements from the image?

please tell me if my code is wrong or not..

Thanks

Answer 1

[KSSV]

clc; clear all;
K = imread('your image') ;
K = K(:,:,1) ;
%  K = randi([0 1],[100 100]) ;  % 100x100 matrix
[r,c] = size(K) ;
x = 1:c ;
y = 1:r ;
[X,Y] = meshgrid(x,y) ;
% get indices of non zero
idx = (K>0) ;
% plot only ones
plot3(X(idx),Y(idx),K(idx),'.r')
view(2)

[Evan Weking]

ok i'll try, thanks

[Evan Weking]

i already try your code, and it does work

but it only works from different plot,

how can i put the code into my code above? in order i can execute it from GUI. Thanks

[KSSV]

Make it a function and call inside GUI...

[Guillaume]

The whole of

[r,c] = size(K) ;
x = 1:c ;
y = 1:r ;
[X,Y] = meshgrid(x,y) ;
% get indices of non zero
idx = (K>0) ;
% plot only ones
plot3(X(idx),Y(idx),K(idx),'.r')

can be replaced by

[Y, X, V] = find(K > 0);
plot3(X, Y, V, '.r');

and since K is binary, even simpler:

[Y, X] = find(K);
plot3(X, Y, 1, '.r');

[Evan Weking]

ok thank you Guillaume for the code

your first code is working, but the second code is showing error like this :

??? Error using ==> plot3
Vectors must be the same lengths.

Error in ==> coba at 6
plot3(X, Y, 1, '.r');

do you know why it's happen?

thanks

[Guillaume]

replace the 1 by ones(size(X)):

plot3(X, Y, ones(size(X)), '.r');