Just got back from taking ARPool to London England (wow what a trip!) I’ll write a blog about my trip later but right now I just want to focus on ARPool.
On Thursday Chris and Alex from North One Television were about an hour late picking us up at our hotel so we were starting to set up behind schedule. I’m pretty thankful that the schedule was changed so that filming was late afternoon on Friday rather than morning or we would have been very pressed for time. I had to help build the Truss – so much for this being a show up and plug in a computer gig, anyways it wasn’t too big a deal and at least I didn’t have to carry and assemble a pool table like past events. We got the structure up and mounted the camera and projector (I am a wizard with zip-ties!) and fired up the calibration.
Things were not as smooth as I had expected – the table calibration step, the final step that creates the transformation matrices was giving us grief - the final image after the transformation was either rotated 90 degrees or had some really strange jagged distortion. I thought I had fixed this step but it needs more work – I expect the problem is in the line intersection code possible a bad solution or an overflow problem. It is really weird because you can perform this step multiple times without altering the code and it can give wildly different results. I think that drawing more intermediate images will fix this problem especially during the line intersection process.
* edit * The week after we got back I added more intermediate debugging visuals which are nice to confirm the calibration is doing what we expect but didn’t solve the issue. Still can’t believe this but our source of grief was from Qt being unable to display images with an odd number of rows or columns. That alone makes sense but what still confounds me is how this hadn’t come before…
Anyways thanks to the randomness of the table calibration procedure it eventually worked for us and we moved on to finish the calibration. We skipped ball training and simply ran the system, surprisingly the classifier was still able to get the cue ball!
The filming process was very interesting, there were tons of crew members and I could never really figure out who was in charge with the exception of the director. I got to briefly explain to Stephen Fry and Jeremy Clarkson how the system worked and how to use it before they played a game on film. Stephen Fry got to use ARPool while Jeremy was on his own. The shoot went pretty well but after the first shot Stephen Fry sort of forgot how to use it and didn’t have the cue close enough to the cue ball for it to detect the shot. They also both kept bumping into the truss which of course can throw off the whole calibration -wince! After their game we filmed a few sequences of Stephen using ARPool which were set up and I was there to guide him through making the shot. ARPool isn’t quite a hands off demo at this point! We got a few more shots after the celebrities left and everyone was pretty happy with how it went and I am sure that it will look great!