How does an optical mouse detect movement?

Question

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Can anyone explain it ?

score 12 · Answer 1 · answered Feb 12 '11 at 15:28

The optical mouse has a chip that has a lo-res camera in it, with a DSP. The DSP picks off certain high-contrast bits of the image in one frame, and looks at how they've tracked across the field of view in the next image. From this it infers X and Y motion, and reports the position change to the computer through a USB interface. The LED provides illumination to increase contrast on the surface, so there will be more bright spots the DSP can pick off.

How does an optical mouse detect movement?

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