Add some tests on different variations of Hough algorithm.

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

diff --git a/src/Tests_hough/HTCircleGradient.m b/src/Tests_hough/HTCircleGradient.m
new file mode 100644 (file)
index 0000000..fe20e20
--- /dev/null
+++ b/src/Tests_hough/HTCircleGradient.m
@@ -0,0 +1,42 @@
+% Hough Transform for circles with gradient.
+% img : gradient image
+% radius_range is a vector : [min, max]
+function [acc_votes, acc_radius] = HTCircleGradient(img, radius_range)
+
+    [rows, columns] = size(img);
+    
+    acc_votes = zeros(rows, columns);
+    acc_radius = zeros(rows, columns);
+    
+    phi_range = linspace(0, 2 * pi, 100);
+    phi_range(end) = [];
+    
+    indexes_non_zero = find(img)';
+    s = size(img);
+    
+    for r = radius_range(1):radius_range(2)
+        acc = zeros(rows, columns);
+        for i = indexes_non_zero            
+            [y, x] = ind2sub(s, i);  
+            for phi = phi_range
+                x0 = round(x - r * cos(phi));
+                y0 = round(y - r * sin(phi));
+                if x0 < columns && x0 > 0 && y0 < rows && y0 > 0
+                    acc(y0, x0) = acc(y0, x0) + img(y, x);
+                end
+            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_radius(y, x) = r;
+                end
+            end
+        end        
+    end
+    
+    acc_votes = imgaussfilt(acc_votes, 1.0);
+end
+