Thursday, 18 May 2017

fly flight algorithm edge detection defeat mechanism

Anyone who has seen that Breaking Bad episode about the fly will understand a recent dilemma. Usually wasp or bumble-bee trapped indoors will co-operate with the homeowner, if shown a path back to the great outdoors.

Less so with some flies which will simply fly around available rooms in large figure of eights. I know I could find a swatter or some of that spray, but I decided to see if I could defeat the fly based upon its limited functions.

Three main ones, and I'd be concentrating on the flight one. My hypothesis was that the fly would have great flight processing, including brilliant edge detection and some sort of vector direction seeking, the latter based upon an inbuilt delay in one of the video channels which could ensure that the fly was flying in the intended direction. It would be similar to that Google effect when the images blur as one walks along a google map.

So I designed the fly flight algorithm defeat mechanism. Its a bottle, cut in half. The trick would be to find the fly at rest, approach slowly and then centre the bottle's cut edge over the fly's eyes. All 800 of them.

In practice, this was surprisingly easy. I suspect that the fly's flight algorithm is used to seeing surfaces expand as it gets closer (i.e. at landing time), so this bottle edge may have just been enough to confuse it.

Succinctly put, it was easy to surround the fly with the bottle and then trap it (in the way one traps a spider) with a bit of cardboard. An adjacent beermat, actually.

Turn bottle over. Walk outside and release. The fly is once again mobile food for the birds.

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