Problem with Arclength function
I used Arclength to calculate curve length, but I found that the results are much larger than the real length. So is the perimeter for closed contour, I think. I wonder whether the area calculation is correct or not.
Can you describe your problem with a Sample(Image)? & your results?
Have you seen the closed parameter? Have you tried to use it? Does it works, or the length is the same no matter if the flag is set or not?
Thanks for your reply, I tried it, both closed and not closed. However, it didn't work. I guess it is because of the data storing structure in contour. Too many repeated pixels and the storing order is not strict neighbor to neighbor. I manually coded to calculate the length.
It is known that the area function is not the real area but the Green function, as discussed in this topic, so yes it can deviate from the actual area in pixels.