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| Frame-to-frame feature correlation |
The correlation-based mice rely heavily on the processing power and, at given power, are more limited in speed and resolution. The more modern mice are based on the laser speckle patterns, according to EDN article:
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| Surface irregularities (left) and the speckle produced (right) |
"In order to analyze such a speckle, a different type of optical sensor is used which has a unique configuration of the photodiode arrays. This configuration is primarily aimed at producing a minimal number of output signals, in contrast to the large number of pixels used in image correlation technique. The reduced number of output signals reduces the processing requirements of the DSP, hence reducing the power consumption and system cost."
This review paper is not in depth. We should mention the Marble technology developed by CSEM commercialized by Logitech and also the first HP analog correlator smart pixel based motion sensor used in the very first optical mouse commercialized by Logitech equally. Personally I conserve this optical mouse. The chip used inside is huge, about 8mmx8mm!
ReplyDeleteThey didn't mention the first work at Xerox by Lyon on a CMOS smart mice sensor by using NMOS process.
-yang ni