Signal processing method for optical sensors
First Claim
1. A method for detecting motion of an optical sensor relative to a surface along a plurality of directions, the method comprising steps of:
- generating sets of signals responsive to motion along each of at least a first, second, and third direction, said directions not necessarily all different, each of said sets of signals consisting of a plurality of signals, said plurality including a main signal and one or more secondary signals, said main and secondary signals representing at least partially independent components of a complex signal whose complex phase changes in response to motion along one of said directions;
combining said sets of signals to generate a first complex signal for each of said directions at a first time;
combining said sets of signals to generate a second complex signal for each of said directions at a second time subsequent to said first time;
computing a third complex signal for each of said directions wherein each of said third complex signals is a predicted value for each of said second complex signals, said predicted signal depending on a number of values representing distance moved; and
determining the optimum values of said values representing distance moved by the step of minimizing the differences between said second and third complex signals.
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Abstract
A signal processing method is provided for sensing movement of an optical sensor relative to a surface. Generally, the method includes steps of: (i) generating sets of signals responsive to motion along each of a first, second, and third direction, the directions not necessarily all different, (ii) combining the sets of signals to generate a first complex signal for each direction at a first time; (iii) combining the sets of signals to generate a second complex signal for each direction at a second time subsequent to the first time; (iv) computing a third complex signal for each direction wherein each of the third complex signals is a predicted value for each of the second complex signals, the predicted signal depending on a number of values representing distance moved; and (v) determining optimum values of the values representing distance moved by minimizing differences between the second and third complex signals.
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Citations
20 Claims
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1. A method for detecting motion of an optical sensor relative to a surface along a plurality of directions, the method comprising steps of:
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generating sets of signals responsive to motion along each of at least a first, second, and third direction, said directions not necessarily all different, each of said sets of signals consisting of a plurality of signals, said plurality including a main signal and one or more secondary signals, said main and secondary signals representing at least partially independent components of a complex signal whose complex phase changes in response to motion along one of said directions;
combining said sets of signals to generate a first complex signal for each of said directions at a first time;
combining said sets of signals to generate a second complex signal for each of said directions at a second time subsequent to said first time;
computing a third complex signal for each of said directions wherein each of said third complex signals is a predicted value for each of said second complex signals, said predicted signal depending on a number of values representing distance moved; and
determining the optimum values of said values representing distance moved by the step of minimizing the differences between said second and third complex signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 14)
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11. A system for detecting motion along a plurality of directions, said system comprised of:
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means for generating main and secondary signals responsive to motion along a first, second, and at least third direction, said directions not necessarily all different;
means for combining said main and secondary signals to generate a first complex signal for each of said directions at a first time;
means for combining said main and secondary signals to generate a second complex signal for each of said directions at a second time subsequent to said first time;
means for computing a third complex signal for each of said directions wherein each of said third complex signals is a predicted value for each of said second complex signals, said predicted signal depending on a plurality of values representing distance moved; and
means for determining the optimum values of said values representing distance moved by the step of minimizing the differences between said second and third complex signals. - View Dependent Claims (12, 13, 15)
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16. A method for detecting movement of a surface relative to an optical sensor having an array of photosensitive elements, the method comprising steps of:
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generating at least two sets of signals responsive to motion of light received on the array in a first direction;
combining said sets of signals at a first time to generate a first complex signal;
combining said sets of signals at a second time subsequent to said first time to generate a second complex signal;
computing a predicted value for said second complex signal based on the first complex signal and a number of values representing distance moved; and
determining a value of distance moved in the first direction by minimizing the differences between said second complex signal and the predicted value for the second complex signal. - View Dependent Claims (17, 18, 19, 20)
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Specification