Should BM3D be in nonfree?

[tholzmann]

Hi,

the BM3D algorithm implemented in OpenCV [1] is only build in case the nonfree option is activated.

However, I didn't find a strong evidence that the original BM3D algorithm[2] is patented. I only found two patents[3,4] which are an extension to the original algorithm in my opinion.

Maybe the contributors to this code (@LaurentBerger @bpawlik) can comment on why this code is marked as nonfree.

Thanks!
Thomas

[1] https://github.com/opencv/opencv_contrib/blob/master/modules/xphoto/src/bm3d_image_denoising.cpp
[2] http://www.cs.tut.fi/~foi/GCF-BM3D/BM3D_TIP_2007.pdf
[3] https://patents.google.com/patent/CN107292851A/en?q=BM3D&oq=BM3D
[4] https://patents.google.com/patent/US9230161

[bpawlik]

Hi,

We had some discussion about it in the pull request for this change: #733

I think the non-free compiler flag is just for playing safe, but it'd be good to check with legal on that.

Thanks,
Bartek

[tholzmann]

Hi Bartek,

Thanks for the info.

To summarize: The code is completely written by you and you asked Prof. Foi if it is ok to include your implementation in OpenCV. He answered that there are no legal obstacles for non-profit purposes.

However, as long as there are no existing patents on the algorithm, there should be also no legal obstacles for commercial usage and the nonfree flag could be removed, right?

I will do a further patent research later this week and let you know about my results.

Best,
Thomas

[bpawlik]

Hi Thomas,

All above is correct.

As far as I know, BM3D algorithm in [2] is not patented, therefore non-free flag could be removed. Please go ahead and complete your patent research and let me know about your findings.

Cheers,
Bartek

[tholzmann]

There is a patent on the Non-Local Means algorithm[1]. Might this be too tightly related to BM3D?

[1] https://patents.google.com/patent/US20100141804

[bpawlik]

Even though BM3D builds on the idea of non-local similarities, it's a very different algorithm from NLM, this patent cannot cover it for sure.

If there's nothing else that came up in your search, I'd vote for removing of the non-free flag.

[mshabunin]

Maybe its covered by one of these patents: https://patents.google.com/?inventor=Alessandro+Foi&oq=Alessandro+Foi

[bpawlik]

It doesn't look like any of these can cover BM3D. The first one on the list comes closest, but it addresses FPN (fixed pattern noise) and it gathers blocks by motion estimation in video, instead of using non-local similarities as BM3D does.

Still voting for dropping the non-free flag.

[mshabunin]

Prof. Foi said that: "There are no legal obstacles if you implement BM3D based on the description in the paper and for non-profit purposes."

This statement implies algorithm is non-free. Can anyone contact original authors for explanation and more details, like patent ID?

[ShannonZ]

Is BM3D free for commercial use?