Hough Transform for circle detectoin - getting information out

In summary, to perform circle detection using the hough transform, you need to make a 2-dimensional histogram of the hough transforms and find the cell with the highest count, which will give you the center of your circle. This is a helpful tool for finding circles in noisy images.
  • #1
thomas49th
655
0
Hi, I am using the hough transform to perform circle detection. I am able to perform a hough transform and plot the results, but how exactly do I now take my hough transform to actually get meaningful information. I know the size of the my circle (it's radius), but what information am I looking for in the hough transform?

Thanks
Thomas
 
Physics news on Phys.org
  • #2
don't know much about hough transforms, but i assume to detect a circle you'll need to parameterise the likelihood of a circle in terms of a radius and centre point. The highest likelihoods, will be most likely to be a circle (sounds obvious, but hopefully it helps)

can you describe the form of the hough transform?
 
Last edited:
  • #3
thomas49th said:
Hi, I am using the hough transform to perform circle detection. I am able to perform a hough transform and plot the results, but how exactly do I now take my hough transform to actually get meaningful information. I know the size of the my circle (it's radius), but what information am I looking for in the hough transform?

Thanks
Thomas

You need to make a 2-dimensional histogram of the hough transforms.
The hough transform gives all possible values for the x- and y- values of the center of your circle.
When you put those measurements in a 2-dimensional histogram, somewhere there will be a cell with the highest count. Your circle center will be in this cell.

For a more accurate measurement, you'll need to do more calculations, but the hough transform helps you to find the center of your circle in a picture that contains lots of noise and that may contain only part of your circle.
 

1. What is the Hough Transform and how does it work?

The Hough Transform is a computer vision algorithm used for detecting simple shapes, such as circles, in images. It works by converting the image space into a parameter space, where each point in the parameter space represents a possible shape in the image. The algorithm then searches for the most common shape parameters, which correspond to the detected circles in the original image.

2. What information can be obtained from the Hough Transform for circle detection?

The Hough Transform outputs the center coordinates and radius of detected circles in an image. It also provides a measure of confidence for each detected circle, which can be used to filter out false positives.

3. How accurate is the Hough Transform for circle detection?

The accuracy of the Hough Transform depends on several factors, such as the clarity and contrast of the image, the size and number of circles in the image, and the chosen parameters for the algorithm. In general, it can accurately detect circles with varying sizes and orientations, but may struggle with overlapping or partially obscured circles.

4. Is the Hough Transform for circle detection computationally expensive?

The Hough Transform can be computationally expensive, especially for larger images or images with many circles. However, there are optimizations and variations of the algorithm that can improve its efficiency, such as the Probabilistic Hough Transform.

5. Can the Hough Transform be used for detecting other shapes besides circles?

Yes, the Hough Transform can be adapted to detect other simple shapes, such as lines and ellipses. However, the algorithm may need to be modified and additional parameters may need to be considered for accurate detection of these shapes.

Similar threads

  • Calculus and Beyond Homework Help
Replies
11
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
786
  • Calculus and Beyond Homework Help
Replies
2
Views
1K
  • Calculus and Beyond Homework Help
Replies
9
Views
2K
  • Programming and Computer Science
Replies
4
Views
4K
  • Calculus and Beyond Homework Help
Replies
1
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
2K
  • Calculus and Beyond Homework Help
Replies
9
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
1K
  • Calculus and Beyond Homework Help
Replies
9
Views
1K
Back
Top