abhi m

I should recognise circle square rectangle but am struck... the code below is effecient in recognising circle but it is failing to recognise square and recatngle.. plz help me in improvising my code plz....

rgbImage = imread('test.jpg');
[rows columns numberOfColorBands] = size(rgbImage);
subplot(3, 2, 1);
imshow(rgbImage, []);
title('Original color Image');
set(gcf, 'Position', get(0,'Screensize')); % Maximize figure.

%STEP 2

%---------------------------------------------------Convert rgb image to grayscale-----------------------------------------

grayImage = rgb2gray(rgbImage);
subplot(3, 2, 2);
imshow(grayImage, []);
title('Converted to gray scale');

%STEP 3

%------------------------------------------------------Detection of edge by canny-------------------------------------------------------

cannyImage = edge(grayImage,'canny');
subplot(3, 2, 3);
imshow(cannyImage, []);
title('Canny Edge Image');

%STEP 4

%-------------------------------------------------------------dilation--------------------------------------------------------

windowSize = 5;
halfWidth = floor(windowSize/2);
dilatedImage = zeros(rows, columns);
for col = (halfWidth+1) : columns - halfWidth
    x1 = col - halfWidth;
    x2= col + halfWidth;
    for row = (halfWidth+1) : rows - halfWidth
        y1 = row - halfWidth;
        y2 = row + halfWidth;
        dilatedImage(row, col) = max(max(cannyImage(y1:y2, x1:x2)));
    end
end

%Displaying the dilated image

subplot(3, 2, 4);
imshow(dilatedImage, []);
caption = sprintf('Dilated with a window size of %d',windowSize);
title(caption);

%STEP 5

%------------------------------------------------------------Erosion-------------------------------------------------

windowSize = 5;
halfWidth = floor(windowSize/2);
erodedImage = zeros(rows, columns);
for col = (halfWidth+1) : columns - halfWidth
    x1 = col - halfWidth;
    x2= col + halfWidth;
    for row = (halfWidth+1) : rows - halfWidth
        y1 = row - halfWidth;
        y2 = row + halfWidth;
        erodedImage(row, col) = min(min(dilatedImage(y1:y2, x1:x2)));
    end
end

%Displaying eroded image

subplot(3, 2, 5);
imshow(erodedImage, []);
caption = sprintf('Eroded image with a window size of %d',windowSize);
title(caption);
[B,L] = bwboundaries(grayImage, 'noholes');

STATS = regionprops(L, 'all');

figure,
imshow(grayImage),
title('Results');
hold on
for i = 1 : length(STATS)
  W(i) = uint8(abs(STATS(i).BoundingBox(3)-STATS(i).BoundingBox(4)) < 0.1);
  W(i) = W(i) + 2 * uint8((STATS(i).Extent - 1) == 0 );
  centroid = STATS(i).Centroid;
  switch W(i)
      case 1
          plot(centroid(1),centroid(2),'wO');
          title('circle');
      case 2
          plot(centroid(1),centroid(2),'wX');
          title('rectangle');
      case 3
          plot(centroid(1),centroid(2),'wS');
          title('square');
  end
end
return