Question

I have no background in computer vision, but I was curious to know how I could use OpenCV library to achieve the following:

I have a jar of spare buttons, assorted in colour, style and diameter. For the most part they are circular. I evenly scatter them on a piece of white paper, and under good lighting, take a fairly high resolution picture with your average digital camera. How would I got about slicing this image to grab each button individually as a separate object/image?

Thanks in advance.

Answer 1

Two possible ways:

1) Using the circle hough transform
You run some edge detector (canny/sobel) and then the circle hough transform. You’ll get the circles.

2) Using contours
Seperate the button and background using thresholding. Detect contours in this thresholded image and you have the buttons!

Articles that might help:

• Contours: http://aishack.in/tutorials/an-introduction-to-contours/
• Thresholding: http://aishack.in/tutorials/thresholding/
• Hough circles: http://aishack.in/tutorials/hough-circles-in-opencv/

Disclaimer: Those are links to my website.