object counting in a video using python

I have come across a problem when doing object counting in a video. I have some particles in the video. I created a line and see if the particle passes through the line my count will add 1.

And I used the following statement in a for loop:

 if element[2] > 200:
     # print("_____")
   count += 1

However, every time the video refreshes, it gives me a count plus 1. Is there anyway to do this correctly? Thanks!