What does the following code do?

If we have,

 [row_num, col_num] = size(img);

What does the following code do?

function length_vec = compute_angular_length(row_num, col_num, amplitude_ang)
% function that calculates the maximum size in a diagonal image with
% inclination from 0 to 180° for each amp_ang degrees.
%
% length_vec = compute_angular_length (row_num, col_num, amplitude_ang)
%
% calculate the value of the angle for which I have the main diagonal
alpha_rad = atan2( row_num, col_num );
alpha = rad2deg(alpha_rad);  
n_ang = floor(180/amplitude_ang);  
length_vec = zeros(1, n_ang);

for i=1:n_ang
    ang = (i-1)*amplitude_ang;
    if (ang <= alpha || ang >= 180 - alpha )
        length_vec(1,i)= abs(col_num / cos( deg2rad(ang)));
    else
        length_vec(1,i)= abs(row_num / cos( deg2rad(90 - ang)));
    end;   
end;

What does it mean by angular length?

[Cedric]

What is it that you don't understand?

[Ba Ba Black Sheep!]

What does this code accomplish?

Answer 1

[Walter Roberson]

Imagine that you are starting from one corner of a rectangular matrix, and you are drawing a line from there to somewhere on one of the opposite edges. What is the length of the angled line segment? This routine computes that, in increments of amplitude_ang degrees.

[Ba Ba Black Sheep!]

Thanks a lot.