Optical touch system having an image sensing module for generating a two-dimensional image and converting to a one-dimensional feature

• US 9,389,731 B2
• Filed: 10/23/2012
• Issued: 07/12/2016
• Est. Priority Date: 12/21/2011
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Su, Tzung-Min, Lin, Chih-Hsin, Ko, Yi-Hsien, Kao, Ming-Tsan
• Primary Examiner(s): Pham, Long D
• Application Number:
  US13/657,969
• Publication Number:
  US 20130162601A1
• Time in Patent Office: 1,358 Days
• Field of Search: 345/175
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

There is provided an optical touch system including at least one lighting unit, at least one image sensing module and a processing unit. The image sensing module is configured to capture light of a pointer and the lighting unit to generate a two-dimensional image and to convert entire of the two-dimensional image to a one-dimensional feature. The processing unit positions the pointer according to the one-dimensional feature.

Claims

1. An optical touch system, configured to position a pointer, the optical touch system comprising:

a touch surface;

at least one lighting unit disposed on the touch surface;

at least one image sensing module configured to

capture light of the touch surface, the pointer and the lighting unit to generate a two-dimensional image,

convert an entirety of the two-dimensional image, which has a plurality of pixel columns each having a plurality of pixels, to a one-dimensional feature by calculating intensities of the pixels of every pixel column to respectively obtain one calculated intensity corresponding to each of the pixel columns, wherein the calculated intensities of the pixel columns form the one-dimensional feature, and

output the one-dimensional feature formed by the calculated intensities of the pixel columns, without outputting the two-dimensional image to reduce an amount of data transmission; and

a processing unit configured to receive the one-dimensional feature and position the pointer according to the one-dimensional feature,

wherein the one-dimensional feature is an intensity array of the calculated intensities, and each of the calculated intensities is an intensity sum, an average intensity or a weighted average intensity of the pixels in the corresponding pixel column in the two-dimensional image.

2. The optical touch system as claimed in claim 1, wherein the processing unit is configured to define a ratio or an offset of the intensity array containing no pointer information as a threshold array.

3. The optical touch system as claimed in claim 2, wherein the processing unit is configured to compare the intensity array with the threshold array to identify at least one contact point, and position the pointer according to the contact point.

4. The optical touch system as claimed in claim 1, wherein

the at least one lighting unit comprises (i) one reflecting mirror and at least one light bar, or (ii) one reflecting mirror extending along two edges of the touch surface and one point light source;

and

the optical touch system comprises one image sensing module.

5. The optical touch system as claimed in claim 1, wherein

the at least one lighting unit comprises (i) three light bars, or (ii) one reflecting mirror extending along three edges of the touch surface;

and

the optical touch system comprises two image sensing modules.

6. The optical touch system as claimed in claim 1, wherein the image sensing module comprises a CMOS image sensor.

7. The optical touch system as claimed in claim 1, wherein each of the calculated intensities in the one-dimensional feature is an intensity sum of the pixels in the corresponding pixel column in the two-dimensional image.

8. The optical touch system as claimed in claim 1, wherein each of the calculated intensities in the one-dimensional feature is an average intensity of the pixels in the corresponding pixel column in the two-dimensional image.

9. The optical touch system as claimed in claim 1, wherein each of the calculated intensities in the one-dimensional feature is a weighted average intensity of the pixels in the corresponding pixel column in the two-dimensional image.

10. An optical touch system, configured to position a pointer, the optical touch system comprising:

a touch surface;

a reflecting mirror disposed on the touch surface;

at least one light bar disposed on the touch surface;

a CMOS image sensor configured to

capture light of the touch surface, the pointer, the reflecting mirror and the light bar to generate a two-dimensional image,

convert an entirety of the two-dimensional image, which has a plurality of pixel columns each having a plurality of pixels, to a one-dimensional feature by calculating intensities of the pixels of every pixel column to respectively obtain one calculated intensity corresponding to each of the pixel columns, wherein the calculated intensities of the pixel columns form the one-dimensional feature, and

output the one-dimensional feature formed by the calculated intensities of the pixel columns, without outputting the two-dimensional image to reduce an amount of data transmission; and

a processing unit configured to receive the one-dimensional feature and position the pointer according to the one-dimensional feature,

wherein the one-dimensional feature is an intensity array of the calculated intensities, and each of the calculated intensities is an intensity sum, an average intensity or a weighted average intensity of the pixels in the corresponding pixel column in the two-dimensional image.

11. The optical touch system as claimed in claim 10, wherein the processing unit is configured to define a ratio or an offset of the intensity array containing no pointer information as a threshold array.

12. The optical touch system as claimed in claim 11, wherein the processing unit is configured to compare the intensity array with the threshold array to identify at least one contact point, and position the pointer according to the contact point.

13. An optical touch system, configured to position a pointer, the optical touch system comprising:

a touch surface;

three light bars disposed on the touch surface;

two CMOS image sensors respectively configured to

capture a two-dimensional image looking across the touch surface and containing the pointer blocking the light bars,

convert an entirety of the two-dimensional image, which has a plurality of pixel columns each having a plurality of pixels, to a one-dimensional feature by calculating intensities of the pixels of every pixel column to respectively obtain one calculated intensity corresponding to each of the pixel columns, wherein the calculated intensities of the pixel columns form the one-dimensional feature, and

output the one-dimensional feature formed by the calculated intensities of the pixel columns, without outputting the two-dimensional image to reduce an amount of data transmission; and

a processing unit configured to position the pointer according to the one-dimensional feature received from the CMOS image sensors,

wherein the one-dimensional feature is an intensity array of the calculated intensities, and each of the calculated intensities is an intensity sum, an average intensity or a weighted average intensity of the pixels in the corresponding pixel column in the two-dimensional image.

14. The optical touch system as claimed in claim 13, wherein the processing unit is configured to define a ratio or an offset of the intensity array containing no pointer information as a threshold array.

15. The optical touch system as claimed in claim 14, wherein the processing unit is configured to compare the intensity array with the threshold array to identify at least one contact point, and position the pointer according to the contact point.

16. The optical touch system as claimed in claim 13, wherein the three light bars are combined as a single light bar extending along three edges of the touch surface.