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Feature Request: Histogram Array Variable(s)
from United States  [214 posts]
9 years
Hi STeven,

I continue to be amazed at the breadth and depth of RoboRealm.  One feature I could use down the road, assuming I'm not missing it somewhere already:  I was wondering if you could make the "View Histogram" module return the histogram values as four 256-dimensional arrays?  Like you do for the Blob_Filter and the BLOBS array.  I read an interesting paper (http://www.cs.cmu.edu/~iwan/localization.htm)  that uses color histograms of 360-degree images to determine the current location of a robot.  Since I will soon be setting up a parabolic 360-degree mirror vision system, I'd love to try out their algorithm.

Thanks!
patrick
from United States  [214 posts] 9 years
P.S. I'd be using the array variables via the RoboRealm API in a C# program as opposed to within the RR GUI, in case that makes any difference.

--patrick

Anonymous 9 years
pirobot,

Have you gotten the panoramic camera yet? The algorithm you link to is quite nice. It would be probably easier just to get the image from Roborealm via C# and create the histograms yourself since histogram creation is not a very taxing or difficult thing to do.

It is worth noting that the link you describe is very similar to our largely undocumented Image Matching module. It seems to perform about the same as the document you referred to above but we also found it to be very sensitive to changes in the environment ... namely, moving people and were not happy with the performance.

Nevertheless, it is a useful and fast technique. The Image matching module should work for you out of the box without any need to create a hand specified map. It can also handle quite a few images.

STeven.
from United States  [214 posts] 9 years
Hi STeven,

Many thanks for the tip regarding the Image_Match module.  I almost gave up on trying to do the panoramic vision thing.  First I picked up an 8" truck mirror which is perfect except it is just too big and heavy for a mobile robot.  Then I tried those little stick-on wide-angle rear view mirrors but they are too shallow so they don't have a good horizontal perspective.  Then I tried a Christmas ornament but the image was a little too small and not quite sharp enough...

And then a friend told me about something I had never heard of before: a garden gazing ball.  They look perfect on the web so I have two sizes on order (4" and 6").  They should be here any day now and I'll let you know how it goes.  Here's a link to the ones I ordered:

http://www.krupps.com/Gazing-Balls/1_PricePromo_35_3_mol409990sil_3_3

BTW, the reason I asked about the Histogram arrays is that I thought you might already have those arrays defined in your Histogram module seeing as you plot the 256 points for each channel.  All I would need is to have them exposed to the RR API which is what I am using in my C# program (as you probably surmised).  Otherwise, like you said, I can probably recreate the histogram arrays fairly easily from the raw image.

Thanks!
patrick
Anonymous 9 years
They look really nice! Seems like they might work. Let us know when you get a chance to post an image on what that looks like. We fiddled around a bit with the Polar unwrap and the Radial Distortion modules to see what the image they have on the website looks like. Seems that it should work with the polar unwrap ...

STeven.

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