crub

has anyone had definitive success with keeping multiple blobs sorted over time when they are moving in an unrestricted way? there are a number of posts in the archives that discuss cv.jit.blobs.sort, but tracking multiple objects reliably still seems problematic (overlap causing blob fusing, messed up labels, etc).

if there is somebody who has a persistent cv sorting technique that works very well with multiple objects i'd love to hear about it. perhaps a combination of different approaches? alternatively, if camera tracking is not the best way to do this i'd be very curious to hear what other approaches you've used successfully (ultrasound, sensor nets, etc).

need-help-with-reliable-blob-sorting

Looks like the new cv.jit package may have the answer, I have had the same issues with camera/IR LED tracking. Try the new package and look at cv.jit.touches, it appears to solve exactly this---the "swapping" of blob labels when they cross over each other's X axes, due to how cv.jit.label assigns its labels.

have been dealing with this problem for ages (and time's almost running out, grin)

just downloaded the new cv.jit package. deus ex machina, here it finally is

oh, this is so great =)
have been dealing with this problem for ages (and time's almost running out, grin)

Yes I was pretty excited to see cv.jit.touches, except that the requirement to indicate the maximum radius didn't work for me, since my application deals with blobs of very different sizes.

I have in the past tried using cv.jit.blobs.sort but noticed that sometimes it gave the same number back twice or more (the numbers indicate how to re-order your cv.jit.centroids.blobs list so therefore should be unique). I noticed that someone else on this list mentioned the same issue. I was wondering if the new cv.jit package included a fix to cv.jit.sort. Jean-Marc, if you are tracking this forum (pun alert!) can you let us know if there has been a change to that code? I tried running a sample patch and didn't find any repeats but, naturally, it is hard to know if it won't happen in a slightly different circumstance.

I wish I could use cv.jit.touches as the interface is so easy to implement! The cv.jit.centroids.blobs/cv.jit.blobs.sort method is more awkward, it involves using the sort data to re-order the blobs data (which I can do fairly easily if I cheat and use javascript). I loved that cv.jit.touches gives you all you need without the need for post-processing.

In any case, I am extremely grateful to have at my disposal the cv.jit package, which is fantastic and essential to the patches I am creating. Thanks again Jean-Marc and thanks especially for the great update!

Yes I was pretty excited to see cv.jit.touches, except that the requirement to indicate the maximum radius didn't work for me, since my application deals with blobs of very different sizes.
I have in the past tried using cv.jit.blobs.sort but noticed that sometimes it gave the same number back twice or more (the numbers indicate how to re-order your cv.jit.centroids.blobs list so therefore should be unique). I noticed that someone else on this list mentioned the same issue. I was wondering if the new cv.jit package included a fix to cv.jit.sort. Jean-Marc, if you are tracking this forum (pun alert!) can you let us know if there has been a change to that code? I tried running a sample patch and didn't find any repeats but, naturally, it is hard to know if it won't happen in a slightly different circumstance.
I wish I could use cv.jit.touches as the interface is so easy to implement! The cv.jit.centroids.blobs/cv.jit.blobs.sort method is more awkward, it involves using the sort data to re-order the blobs data (which I can do fairly easily if I cheat and use javascript). I loved that cv.jit.touches gives you all you need without the need for post-processing.
In any case, I am extremely grateful to have at my disposal the cv.jit package, which is fantastic and essential to the patches I am creating. Thanks again Jean-Marc and thanks especially for the great update!

Need help with reliable blob sorting