Positioning module, optical touch system and method of calculating a coordinate of a touch medium

• US 9,213,448 B2
• Filed: 12/05/2013
• Issued: 12/15/2015
• Est. Priority Date: 11/29/2012
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Lin, Yu-Chia, Lu, Chun-Yi, Lin, Chun-Sheng, Huang, Yu-Hsiang, Cheng, Hsin-Chi
• Primary Examiner(s): Lao, Lun-Yi
• Assistant Examiner(s): McLoone, Peter D
• Application Number:
  US14/097,257
• Publication Number:
  US 20140146019A1
• Time in Patent Office: 740 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0428 by sensing at the edges of the touch surface the interruption of optical paths, e.g. an illumination plane, parallel to the touch surface which may be virtual sensing beam interruptions in a planar beam grid of an optical touch-screen G06F3/0421

Abstract

A method of calculating a coordinate of a touch medium is disclosed in the present invention. The method includes obtaining a first image to determine whether the first image overlaps a first threshold, generating a first interceptive boundary when the first image overlaps the first threshold, obtaining a second image to generate a second interceptive boundary by overlap of the second image and a second threshold, determining whether the first interceptive boundary overlaps the second interceptive boundary, and confirming a status of the touch medium according to determination.

Claims

1. A method of calculating a coordinate of a touch medium, the method comprising:

obtaining a first image to determine whether the first image overlaps a first threshold;

generating a first interceptive boundary when the first image overlaps the first threshold;

obtaining a second image to generate a second interceptive boundary by overlap of the second image and a second threshold; and

confirming the touch medium is at a hovering status when the first interceptive boundary does not overlap the second interceptive boundary.

2. The method of claim 1, wherein the method of confirming the status of the touch medium further comprises:

confirming the touch medium is at a touch status when the first interceptive boundary overlaps the second interceptive boundary; and

calculating a touch position of the touch medium according to the second image.

3. The method of claim 1, further comprising:

obtaining a first background image and a second background image to respectively set the first threshold and the second threshold.

4. The method of claim 3, wherein the first threshold is a percentage of the first background image, the second threshold is another percentage of the second background image, and the first threshold is substantially smaller than the second threshold.

5. The method of claim 1, wherein the method of obtaining the first image to determine whether the first image overlaps the first threshold further comprises:

receiving a raw image of the first image;

transforming the raw image into a profile; and

utilizing the profile of the first image to compare with the first threshold.

6. The method of claim 5, wherein the method of utilizing the profile of the first image to compare with the first threshold further comprises:

calculating a specific value of the profile; and

determining whether the specific value is lower than the first threshold, wherein the specific value is an average level or a minimal level.

7. The method of claim 1, wherein the first image is captured by an image detecting unit according to a first beam emitted from a first light source, the second image is captured by the image detecting unit according to a second beam emitted from a second light source, the first light source and the second light source are respectively disposed on a lateral side and an upper side of the image detecting unit.

8. A positioning module for calculating a coordinate of a touch medium, the positioning module comprises:

at least one image detecting unit, the image detecting unit being adapted to capture a first image generated by a first beam emitted from a lateral side of the image detecting unit, and further being adapted to capture a second image generated by a second beam emitted from an upper side of the image detecting unit; and

a processor electrically connected to the image detecting unit, the processor being adapted to generate a first interceptive boundary when the first image overlaps a first threshold, to generate a second interceptive boundary when the second image overlaps a second threshold, and to confirm the touch medium is at a hovering status when the first interceptive boundary does not overlap the second interceptive boundary.

9. The positioning module of claim 8, wherein the image detecting unit detects a first dark area because a part of the first beam is shadowed by the touch medium, and the processor determines the status according to an intensity of the first dark area on the first image.

10. The positioning module of claim 8, wherein the processor confirms the touch medium is at a touch status when the first interceptive boundary overlaps the second interceptive boundary, and calculates a touch position of the touch medium according to the second image.

11. The positioning module of claim 8, wherein the processor drives the image detecting unit to obtain a first background image and a second background image to respectively set the first threshold and the second threshold, the first threshold is substantially smaller than the second threshold.

12. The positioning module of claim 8, wherein the processor drives the image detecting unit to receive a raw image of the first image, transforms the raw image into a profile, and compares the profile of the first image with the first threshold.

13. The positioning module of claim 12, wherein the processor calculates a specific value of the profile to determine whether the specific value is lower than the first threshold, and the specific value is an average level or a minimal level.

14. The positioning module of claim 8, wherein the processor generates the second interceptive boundary and obtains the first image when the second image overlaps the second threshold.

15. An optical touch system for calculating a coordinate of a touch medium, the optical touch system comprising:

a panel; and

a positioning module disposed on the panel, the positioning module comprising;

at least one image detecting unit, the image detecting unit being adapted to capture a first image generated by a first beam emitted from a lateral side of the image detecting unit, and further being adapted to capture a second image generated by a second beam emitted from an upper side of the image detecting unit; and

a processor electrically connected to the image detecting unit, the processor being adapted to generate a first interceptive boundary when the first image overlaps a first threshold, to generate a second interceptive boundary when the second image overlaps a second threshold, and to confirm the touch medium is at a hovering status when the first interceptive boundary does not overlap the second interceptive boundary.

16. The optical touch system of claim 15, wherein the image detecting unit detects a first dark area because a part of the first beam is shadowed by the touch medium, and the processor determines the status according to an intensity of the first dark area on the first image.

17. The optical touch system of claim 15, wherein the processor confirms the touch medium is at a touch status when the first interceptive boundary overlaps the second interceptive boundary, and calculates a touch position of the touch medium according to the second image.

18. The optical touch system of claim 15, wherein the processor drives the image detecting unit to obtain a first background image and a second background image to respectively set the first threshold and the second threshold, the first threshold is substantially smaller than the second threshold.

19. The optical touch system of claim 15, wherein the processor drives the image detecting unit to receive a raw image of the first image, transforms the raw image into a profile, and compares the profile of the first image with the first threshold.

20. The optical touch system of claim 19, wherein the processor calculates a specific value of the profile to determine whether the specific value is lower than the first threshold, and the specific value is an average level or a minimal level.

21. The optical touch system of claim 15, wherein the processor generates the second interceptive boundary and obtains the first image when the second image overlaps the second threshold.

22. A positioning module for calculating a coordinate of a touch medium, the positioning module comprises:

at least one image detecting unit, the image detecting unit being adapted to capture a first image generated by a first beam emitted from a lateral side of the image detecting unit, and further being adapted to capture a second image generated by a second beam emitted from an upper side of the image detecting unit; and

a processor electrically connected to the image detecting unit, the processor driving the image detecting unit to capture the first image, and driving the image detecting unit to capture the second image if the first image overlaps a first threshold;

wherein the first image is used to determine a first interceptive boundary when the first image overlaps the first threshold, and the second image is used to determine a second interceptive boundary when the second image overlaps a second threshold;

wherein the processor is adapted to confirm the touch medium is at a hovering status when the first interceptive boundary does not overlap the second interceptive boundary.