Hi Guys.
Is it possible to detect a drawn convex hull that resides in another? If a convex hull is drawn inside a smaller one, I want to ignore it and only keep the bigger one.
Is there a way to do this?
Hi!
You can try this approach!
Add these smaller contours in merged_contour_points.
e.g merged_contour_points.push_back(contours[i]);// filtered smaller contours.
Lets say I have 4 areas of interest. After hulling, 2 of the areas appear as in the image attached (hull in hull) and the other two only have one bounding hull each.
I'm looking to somehow find a way to delete the smaller hull in the first two. Is it possible to get the coordinates of the hulls? Perhaps I can extract the coordinates of each hull and somehow see if one lies in another?
See this Image
Lets say the red boxes are my points of interest. Since I was unable to get a clean contour, I have in some cases 2 hulls (black lines) on one point while some have only one.
I wish to only have one hull for each point of interest. So where there are 2 hulls on one point of interest, I wish to only keep one. Either the bigger or the smaller of the two.
Yes, just see the parameters of findContours. To be more explicit, use :
cv::findContours(imageIn, contoursOut, hierarchyOut, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE);You can also see this for some info about the hierarchy, if you need it.
I tried using hierarchy but not all my points of interest have been identified to be on the same level. I'm assuming you mean only draw hull if (hierarchy[i][3] != -1) or similar right?
Is there another way to do this? I tried to hull my hull vector hoping it would just consume the smaller one and just output one that envelopes the two.
Asked: Sep 18 '14
Seen: 1,161 times
Last updated: Sep 19 '14
Can you explain it with a picture?
Sure! :) Here's the image: Image I know my lines are a bit thick but if you look closely you can see two rectangles. I wish to only keep the larger of the two rectangles each time this happens.
Is it possible?
Thank you!