Optical Mouse as Angular Position Sensor



You might be able to turn that off in your settings dialogue (it didn't work too well for me (kensington retractable on weathered finished wood) but I'm not sure that I'm using acceleration (fvwm).

So that would eliminate the upper bound? (I think, if i'm following you.) I was thinking of straight black and white bars for the original poster's application. For such a highly constrained system I think this would work, sufficiently well for a slew rate that didn't exceed the framerate capabilities. And for microadjustment it would be sufficient to whatever unit of measure one pixel represents.
Yours,
CA
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Charles Abney
Polymorphism Research Laboratory
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At agilent's site, navigate to: Home > Products & Services > Semiconductor Products Home > Motion Control Design Center > Product Selection Results: Reflective Optical SMT
If encoding a 1 dimensional surface is all that is required.
Mike

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the
will
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There's a lot more noise in this system than in the original posters. He can control the features passing across the camera's field of view, and the direction is limited to two.
I think I'd bet on that one. In fact, if I ever get around to the hobby that never was, I might try using it for the encoder on that telescope I may never actually build.
CA
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Charles Abney
Polymorphism Research Laboratory
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The optical mouse has a 16 x 16 pixel camera inside it. It takes images (maybe 1500 fps?) and does a 2-D correlation between one image and the next. From this calculation, the maximum in the x and y correlations gives the displacement of the mouse between the two image captures. The algorithm works well on random surfaces having sufficient contrast. On the other hand, one can envision surfaces with patterns where the correlation algorithm gets "confused." For example, consider a surface with an "egg carton" pattern. Depending on the pitch of the peaks and valleys of the egg carton as well as the mouse velocity and camera resolution, the correlation may indicate the mouse didn't move between image captures. Crank up Matlab and compute the autocorrelation of a sinusoidal function, and you'll see what I mean - no unique maximum. Its a manifestation of aliasing.
There is almost no chance this will happen when using the mouse on the average surface.
Blueeyedpop wrote:

learned
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