Optical navigation device and method thereof
An optical navigation device and a method thereof, wherein the optical navigation device comprises a pair of linear sensor arrays which are arranged non-parallel to each other for detecting light signal. Furthermore, an algorithm including correlation and vector analysis is processed by a computation unit to determine velocity and displacement according to present and previous light signal data sequences. Hence, the linear sensor arrays adapted to be the approach of navigation device can achieve the goal of reducing the computing data, increasing operation speed effectively and reducing hardware cost because of its fewer optically sensitive elements.
1. An optical navigation device, comprising:
a singular light source adapted to illuminate a surface and a reflected light reflected by the surface adopted to be a light signal;
a first linear sensor array adapted to passively detect the light signal according to a system timing clock;
a second linear sensor array arranged non-parallel with the first sensor linear sensor array to passively detect the light signal according to the system timing clock; said second linear sensor array detecting the light signal independently of and simultaneously to the first linear sensor array; wherein, said first and second linear sensor arrays are independent of the singular light source;
a data storage unit adopted to store the light signal detected by the first linear sensor array and the second linear sensor array; and
a computation unit connected with the data storage unit and adopted to compute the velocity of the optical navigation device according to the light signal detected by the first linear sensor array and the second linear sensor array.
2. The optical navigation device as claimed in claim 1 , wherein both the first liner sensor array and the second linear sensor array have at least one optically sensitive element.
3. The optical navigation device as claimed in claim 1 , further comprising a sensor control unit which is connected with the first linear sensor array, the second linear sensor array, the data storage unit, and the computation unit, so as to provide the system timing clock.
4. The optical navigation device as claimed in claim 1 , wherein the light source is a coherent light source.
5. The optical navigation device as claimed in claim 4 , wherein the light source is a laser or a vertical cavity surface emitting laser (VCSEL).
6. The optical navigation device as claimed in claim 1 , wherein the light signal is a speckle image.
7. The optical navigation device as claimed in claim 1 , wherein the light source is a resonant cavity light emitting diode (RCLED).
8. The optical navigation device as claimed in claim 1 , wherein the light source includes an incoherent light source and a lens adapted to produce an image.
9. The optical navigation device as claimed in claim 8 , wherein the incoherent light source is a light emitting diode (LED).
10. The optical navigation device as claimed in claim 1 , wherein the two linear sensor arrays are perpendicular to one another.
11. An optical navigation method, comprising the steps of:
passively detecting a light signal by a first linear sensor array, and simultaneously passively detecting a light signal by a second linear sensor array, wherein the first linear sensor array and the second linear sensor array are arranged non-parallel to each other, said second linear sensor array detecting the light signal independently of and simultaneously to the first linear sensor array storing the first light signal data sequences and the second light signal data sequences respectively;
computing a correlation or an image comparison between present and previous light signal data sequences of the first linear sensor array and the second linear sensor array respectively, computing the vectors of displacement and velocity in both the parallel directions of the first linear sensor array and the second linear sensor array; and
processing the vectors of displacement and velocity produced from both the parallel directions of the first linear sensor array and the second linear sensor array to determine the final velocity and displacement of the optical navigation device.
12. The optical navigation method as claimed in claim 11 , further comprising a step that illuminating light on a surface and reflecting the light signals from the surface.
13. The optical navigation method as claimed in claim 11 , wherein the velocity in both the parallel directions of the first linear sensor array and the second linear sensor array are determined by an algorithm of the displacement and the system timing clock.
14. The optical navigation method as claimed in claim 13 , wherein the algorithm is a division operation or a differentiation operation.
15. The optical navigation method as claimed in claim 11 , wherein the correlation between present and previous light signal data arrays is:
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16. The optical navigation method as claimed in claim 11 , wherein the correlation between present and previous light signal data arrays is:
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wherein, the Cr is a correlation parameter, xi is a previously stored data array, and yi is a presently stored data array, is an average value of the previously stored data array and is an average value of the presently stored data array.