Message Boards Message Boards

1
|
10006 Views
|
5 Replies
|
3 Total Likes
View groups...
Share
Share this post:

OpenCVLink insight?

Recent versions of Mathematica contain OpenCVLink, presumably for support of image processing routines in WL. Its internal nature means that it is, understandably, relatively incomplete and undocumented.

I have some optic flow calculations to do, and, indeed, I see that two CUDA implementations are available, 

$OpticalFlowFarneback

and

$OpticalFlowDualTVL1

but their parameters are not as easily decipherable as some of the other implementations ($Dilation for example).

I was wondering if anyone out there had successfully parsed the unparsable or, barring that, someone has a .mc link that uses OpenCV that I can just steal as a template.Maybe even WRI could think of releasing some of these incomplete undocumented links to the GitHub-o-verse where the public could enhance and refine them?
POSTED BY: Flip Phillips
5 Replies
Sort By:

Hi Flip.

I understand it would be useful to add usage to our OpenCVLink functions and we'll consider putting some effort in doing so. But, keep in mind that we have them so that we use them one way or the other with WL functions.

$OpticalFlowFarneback is the method used in ImageDisplacements. You can access $OpticalFlowDualTVL1 using the undocumented Method->"TotalVariation", but our tests show that this method is not giving results of consistent quality and that's why we haven't exposed it.
POSTED BY: Shadi Ashnai

Hi Shadi!

OK great, thank you- good to know about the Dual TVL 1... I know precisely what you're talking about re: consistency, seems that things have to be 'just right' for it to work. Also, I didn't know the Farneback is presently used in ImageDisplacements so I'll play around there also.

Thanks for getting back on this-

POSTED BY: Flip Phillips

Salam Shadi,

I hope everything is going well for you.
I tried to use the OpticalFlow for a small project and did something. I'm not sure whether I went the right way or not. May I get your help.?

All the best,
Mohammad
POSTED BY: M.A. Ghorbani

Sure. Please feel free to comment here or create a new post with your question. Either the community or myself should be able to help.
POSTED BY: Shadi Ashnai

Thank you, Shadi.

I came across this post that shows how optical flow is used in the tracking cell's motion.

As I am a hydrologist, I decided to use the optical flow for measuring river flow velocity. I recorded a short video (10 seconds) from the Sumida River, Japan. I did something and got the initial results. Please have a look at the enclosed notebook and the video. The main aim of this notebook is the extraction of velocity components.

Attachments:
Sumida River.nb
sumida.MP4
POSTED BY: M.A. Ghorbani
Reply to this discussion
Community posts can be styled and formatted using the Markdown syntax.
Tag limit exceeded
Note: Only the first five people you tag will receive an email notification; the other tagged names will appear as links to their profiles.
Reply Preview
Attachments
Remove
or Discard

Group Abstract Group Abstract