cuda::connectedComponents random label numbers?

C++
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I want moments for the connected component having the greatest area, but I can’t see an elegant way to locate said component given label numbering seems to be random 32 bit integers. Any suggestions?

opencv 4.9.0

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I’m suprised I would have expected it to be the lowest indexed pixel in the blob.

If you need a structure similar to the CPU version I would use NPP, otherwise you have to write your own routine to compress the labels and extract the blob info. See NPP CompressedMarkerLabelsUFInfo for details.

Notes regarding NPP:

  1. You need to use CUDA 12.3 as there was a bug in the NPP routine which returned the info in earlier versions.
  2. The NPP version doesn’t label the background (0 intensity pixels) as 0 which is the expected behaviour in OpenCV.
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Thank you for the response.

That appears to be the background, which in my use case is indeed the largest area, but of no interest.

I’ll look at NPP: It would be really sweet if connectedComponents could be made to produce sequential labels starting at 0…