'improfile' is a missing function in octave, what other options could I use to make my loop works?

imshow(matrix(:,:,1))
%identify axes
[x, y] = ginput(2);
% preallocate matrices
cog = zeros(size(matrix,3),1);
% loop start
for i = 1:size(matrix,3)
    I = matrix(:,:,i);
    %what to do to make this code works in octave
    test = improfile(I,[x(1) x(2)],[y(1) y(2)]);
    
    cog(i) = sum((1:length(test)).*test')/sum(test); 
    % loop end
end
scog = (cog - min(cog)) / (max(cog) - min(cog));

[Jan]

This is a Matlab forum. The code runs successfully in Matlab. What about asking this question in an Octave forum?

improfile is a 2D interpolation along a line. So get the coordinates of the line and call interp2.

[BA]

I substitue the code with 'test = interp2(I, 2); instead of 'test = improfile(I,[x(1) x(2)],[y(1) y(2)]); and it works but not sure if it is right.

[Jan]

@Bilal Alsharif: Do you see the set of icons above the field for typing the text in the forum? They help you to apply a nice formatting. I've formatted the code for you in the question already. Please use these formatting tools to distinguish text, Matlab code and programs.

[Jan]

@Image Analyst: I've re-opened the question. Although Octave is off-topic, the answer works for Matlab users without the Image Processing Toolbox.

Answer 1

[Jan]

The command interp2(I, 2) does not consider the selected line. Better:

n = ceil(norm([diff(x), diff(y)]));  % A rough estimation of number of points
test = interp2(I, 2, linspace(x(1), x(2), n), linspace(y(1), y(2), n));

[Walter Roberson]

improfile figures out whether the row difference is greater than the column difference, and does the interp2 along the longer dimension.