Add some tests on different variations of Hough algorithm.

[master-thesis.git] / src / Tests_hough / HTEllipse2.m

diff --git a/src/Tests_hough/HTEllipse2.m b/src/Tests_hough/HTEllipse2.m
new file mode 100644 (file)
index 0000000..bea1243
--- /dev/null
+++ b/src/Tests_hough/HTEllipse2.m
@@ -0,0 +1,75 @@
+% Hough Transform for circles.
+% img : logical image, zeros are the circles edges
+% radius_range is a vector : [min, max]
+function [acc_votes, acc_radius1, acc_radius2, acc_alpha] = HTEllipse2(x_dir, y_dir, edges, radius_range)
+
+    [rows, columns] = size(edges);
+    
+    acc_votes = zeros(rows, columns);
+    acc_radius1 = zeros(rows, columns);
+    acc_radius2 = zeros(rows, columns);
+    acc_alpha = zeros(rows, columns);
+    
+    alpha_range = linspace(0, pi / 2, 8);
+    alpha_range(end) = [];
+%     alpha_range = pi/8;
+        
+    indexes_edges = find(edges)';
+    s = size(edges);
+    
+    for alpha = alpha_range
+        rot_mat = [cos(alpha) -sin(alpha); sin(alpha) cos(alpha)];
+        rot_mat_inv = [cos(-alpha) -sin(-alpha); sin(-alpha) cos(-alpha)];      
+        for r1 = radius_range(1):radius_range(2)
+            for r2 = radius_range(1):radius_range(2)
+                acc = zeros(rows, columns);
+                for i = indexes_edges
+                    [y, x] = ind2sub(s, i);
+                    v = [-x_dir(i); -y_dir(i)];
+                    u = rot_mat_inv * v;
+                    if u(1) == 0
+                        if u(2) > 0
+                            theta = pi / 2.;
+                        else
+                            theta = 3. * pi / 2.;
+                        end
+                    elseif u(2) == 0
+                        if u(1) > 0
+                            theta = 0;
+                        else
+                            theta = pi;
+                        end
+                    elseif u(2) < 0
+                        t = u(2) / u(1);
+                        theta = 2*pi + 2 * atan(...
+                            (-r1 - r2*t*sqrt((r1^2+r2^2*t^2)/(r2^2*t^2)))...
+                            /(r2*t));
+                    else
+                        t = u(2) / u(1);
+                        theta = 2 * atan(...
+                            (-r1 + r2*t*sqrt((r1^2+r2^2*t^2)/(r2^2*t^2)))...
+                            /(r2*t));
+                    end
+                    C = round([x; y] - rot_mat * [r1*cos(theta); r2*sin(theta)]);
+                    if C(1) < columns && C(1) > 0 && C(2) < rows && C(2) > 0
+                        acc(C(2),C(1)) = acc(C(2),C(1)) + 1;
+                    end
+                end
+
+                for x = 1:columns
+                    for y = 1:rows
+                        if acc(y, x) > acc_votes(y, x)
+                            acc_votes(y, x) = acc(y, x);
+                            acc_radius1(y, x) = r1;
+                            acc_radius2(y, x) = r2;
+                            acc_alpha(y, x) = alpha;
+                        end
+                    end
+                end      
+            end
+        end
+    end
+    
+    acc_votes = imgaussfilt(acc_votes, 1.0);
+end
+