Circuit and method for determining motion with redundant comb-arrays
First Claim
1. A method for sensing displacement of an optical sensor relative to a surface, the optical sensor having at least a first and a second array, each array having a plurality of photosensitive elements, the method comprising:
- generating for each array a first set of quasi-sinusoidal signals at a first time and a second set of quasi-sinusoidal signals at a second time in response to motion of light received thereon in at least a first direction (x);
computing from said first and second sets of quasi-sinusoidal signals from each of said arrays a phase angle change (Δ
Ø
x1, Δ
Ø
x2) for said first and second sets of quasi-sinusoidal signals received from each of said arrays;
computing from said first and second sets of quasi-sinusoidal signals from each of said arrays radius values (Rx1, Rx2) for said first and second sets of quasi-sinusoidal signals received from each of said arrays; and
combining said phase angle changes (Δ
Ø
x1, Δ
Ø
x2) for each of said arrays using radius-weighted-averaging to provide a single weighted average phase angle change Δ
Ø
x resulting from said motion in the first direction.
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Abstract
A method is provided for sensing displacement of an optical sensor relative to a surface, the sensor having at least first and second arrays with a plurality of photosensitive elements. The method involves: (i) generating for each array first set of quasi-sinusoidal signals at a first time and a second set of quasi-sinusoidal signals at a second time in response to motion of light received thereon; (ii) computing from said first and second sets of signals phase angle changes for signals received from each array; (iii) computing from said first and second sets of signals radius values for signals received from each array; (iv) computing unwrapped phase angle changes for signals received from each array; and (v) combining said unwrapped phase angle changes for each of said arrays using radius-weighted-averaging to provide a single weighted average of unwrapped phase angle change resulting from said motion of light.
85 Citations
14 Claims
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1. A method for sensing displacement of an optical sensor relative to a surface, the optical sensor having at least a first and a second array, each array having a plurality of photosensitive elements, the method comprising:
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generating for each array a first set of quasi-sinusoidal signals at a first time and a second set of quasi-sinusoidal signals at a second time in response to motion of light received thereon in at least a first direction (x); computing from said first and second sets of quasi-sinusoidal signals from each of said arrays a phase angle change (Δ
Ø
x1, Δ
Ø
x2) for said first and second sets of quasi-sinusoidal signals received from each of said arrays;computing from said first and second sets of quasi-sinusoidal signals from each of said arrays radius values (Rx1, Rx2) for said first and second sets of quasi-sinusoidal signals received from each of said arrays; and combining said phase angle changes (Δ
Ø
x1, Δ
Ø
x2) for each of said arrays using radius-weighted-averaging to provide a single weighted average phase angle change Δ
Ø
x resulting from said motion in the first direction. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An optical navigation system for use in a data input device to sense displacement of the data input device relative to a surface, the system comprising:
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an optical sensor having at least a first and a second array, each array having a plurality of photosensitive elements; and a signal processing circuit comprising; means for generating for each array a first set of quasi-sinusoidal signals at a first time and a second set of quasi-sinusoidal signals at a second time in response to motion of light received thereon in at least a first direction (x); means for computing from said first and second sets of quasi-sinusoidal signals from each of said arrays a phase angle change (Δ
Ø
x1, Δ
Ø
x2) for said first and second sets of quasi-sinusoidal signals received from each of said arrays;means for computing from said first and second sets of quasi-sinusoidal signals from each of said arrays radius values (Rx1, Rx2) for said first and second sets of quasi-sinusoidal signals received from each of said arrays; and means for combining said phase angle changes (Δ
Ø
x1, Δ
Ø
x2) for each of said arrays using radius-weighted-averaging to provide a single weighted average phase angle change Δ
Ø
x resulting from said motion in the first direction. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification