hough transform for circle in matlab

To perform the Hough transform for circle detection in MATLAB, follow these steps:

1. Read or load the image using imread or a similar function.

main.m
img = imread('example_image.png');
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2. Convert the image to grayscale using rgb2gray or a similar function.

main.m
gray_img = rgb2gray(img);
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3. Apply some preprocessing to the image, such as blurring, to improve the circle detection accuracy.

main.m
blurred_img = imgaussfilt(gray_img, 5);
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4. Determine the minimum and maximum radius values that you want to detect circles for.

main.m
min_radius = 10;
max_radius = 50;
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5. Run the imfindcircles function to detect the circles in the image using the Hough transform.

main.m
[centers, radii, metric] = imfindcircles(blurred_img, [min_radius max_radius], 'ObjectPolarity', 'dark', 'Sensitivity', 0.9);
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6. Visualize the detected circles by overlaying them on the original image.

main.m
figure, imshow(img);
viscircles(centers, radii, 'EdgeColor', 'b');
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This will display the original image with the detected circles plotted on top of it. Note that the 'Sensitivity' parameter can be adjusted to control the detection threshold and get better results.