Apparatus for controlling the position of a screen pointer based on projection data
View Patent ↗A device such as an optical mouse includes a light source for illuminating an imaging surface, thereby generating reflected images. The device also includes an optical motion sensor for generating one-dimensional projection data based on the reflected images, filtering the projection data, and generating movement data based on the filtered projection data. The movement data is indicative of relative motion between the imaging surface and the device.
1. An apparatus for controlling the position of a screen pointer, the apparatus comprising:
a light source for illuminating an imaging surface, thereby generating reflected images; and
an optical motion sensor for generating one-dimensional projection data based on the reflected images, filtering the projection data, and generating movement data based on the filtered projection data, the movement data indicative of relative motion between the imaging surface and the apparatus;
wherein the optical motion sensor comprises a first and a second one-dimensional array of elongated photodetectors for receiving the reflected images, and wherein the first one-dimensional array of elongated photodetectors generates analog projection data for a first axis, and the second one-dimensional array of elongated photodetectors generates analog projection data for a second axis;
wherein the elongated photodetectors in the first array have a length to width ratio in the range of five to one (5:1) to twenty to one (20:1), and wherein the elongated photodetectors in the second array have a width to length ratio in the range of five to one (5:1) to twenty to one (20:1).
2. The apparatus of claim 1 , wherein the light source is an at least partially coherent light source.
3. The apparatus of claim 2 , wherein the light source is a laser light source.
4. The apparatus of claim 1 , wherein the light source is a light-emitting diode (LED) source.
5. The apparatus of claim 1 , wherein the optical motion sensor further comprises an analog to digital converter coupled to outputs of the elongated photodetectors in the first and the second arrays for generating digital projection data based on outputs of the elongated photodetectors, and wherein the movement data is generated based on a correlation of the digital projection data.
6. The apparatus of claim 1 , wherein the elongated photodetectors in the first and the second arrays have a pitch in the range of about five to ten micrometers.
7. The apparatus of claim 1 , wherein the optical motion sensor includes a bandpass filter configured to filter out DC frequency components in the projection data and frequency components in the projection data that are at or near a Nyquist frequency for the apparatus.
8. A method of generating movement data with an optical pointing device, the method comprising:
illuminating an imaging surface with an at least partially coherent light source, thereby generating reflected images;
generating one-dimensional arrays of projection data based on the reflected images;
filtering the projection data;
generating movement data based on a correlation of the filtered projection data;
wherein the optical pointing device includes a first and a second one-dimensional array of elongated photodetectors for receiving the reflected images, the elongated photodetectors in the first array having a length to width ratio in the range of five to one (5:1) to twenty to one (20:1) and the elongated photodetectors in the second array having a width to length ratio in the range of five to one (5:1) to twenty to one (20:1), and wherein the step of generating one-dimensional arrays of projection data comprises:
generating analog projection data for a first axis with the first one-dimensional array of elongated photodetectors; and
generating analog projection data for a second axis with the second one-dimensional array of elongated photodetectors.
9. An optical motion sensor for generating movement data to control the position of a screen pointer, the sensor comprising:
first and second one-dimensional arrays of elongated photodetectors configured to sense reflected images from an imaging surface produced by an at least partially coherent light source;
an analog to digital converter for generating digital projection data based on outputs of the first and the second arrays; and
a processor for generating movement data based on the digital projection data;
wherein the elongated photodetectors in the first and the second arrays each have an aspect ratio in the range of five to one (5:1) to twenty to one (20:1).
10. The optical motion sensor of claim 9 , wherein the first and the second arrays are orthogonal, and are spatially separate structures.