How many particles pass through the circle(or the line)

Draw a circles

Hello everyone, there is a metal particle currently being analyzed.

I want to measure how many particles pass through the circle. The test has no results for a long time.

I have tried the method of the website, but how to present the border and turn it into an irregular curve?

08/17 : I have an idea. The number of red circles and black focal points divided by two is the number of grains that the circle passes through. But if there is a U-shaped particles, there will be one more particles. Could the system distinguish whether it is the same particles?


I looks like your particles are well segmented by the black lines. In which case the cells can be labels by connected components labelling and the number of unique cells can found by getting the pixel values around the roi.

Upload an example image (without the roi) and I’ll show you the steps.