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Artificial Retinas Can Balance a Pencil On Its End
mikejuk writes "A team of researchers has built a neural information system that is good enough and fast enough to balance a pencil in real time. If you think it's an easy task, try it! The Institute of Neuroinformatics, ETH / University Zurich have used what look like video cameras to do the job but in fact they are analog silicon retinas. They work so fast that even with fairly basic hardware they can balance a pencil."
September 26, 2008
Wrong. Read TFA, and if necessary read their paper, and try again. They used a relatively simple feedback mechanism and simple algebra, not Lagrange equations.
I have seen this demo in person and chatted at length with its creator. It uses a custom sensor chip that does some analog temporal filtering and thresholding of light intensity at each pixel, sending events when the threshold is crossed. The intent of the authors seems to be to mimic the human visual system in silicon, even if it makes no engineering sense whatsoever. The demo was extremely sensitive to fluorescent lighting; the author had to run out and buy an incandescent desk lamp to get it to work at all. The event-based image representation makes it incompatible with everything that has been learned in computer vision over the last decade.
That is precisely my point. To clarify my own statement a little: the last time I was discussing this topic here on /., someone (I don't remember who) was trying to tell me that it was not possible to do this with a relatively simple feedback mechanism, no matter how fast, and that in fact it was necessary to use Lagrange equations as linked to there, or similar, to solve the problem.
My argument was that using advanced math was not necessary, as long as your feedback and control loop was fast enough. This experiment seems to bear out my side of the argument, since according to their paper they did not use anything beyond what might be considered middle-school math in their solution.