METHOD FOR DETERMINING THE LOCATION OF A POINTER IN A POINTER INPUT REGION, AND INTERACTIVE INPUT SYSTEM EXECUTING THE METHOD

• US 20110115746A1
• Filed: 11/16/2009
• Published: 05/19/2011
• Est. Priority Date: 11/16/2009
• Status: Active Grant

• Current Assignee: Smart Technologies ULC (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Smart Technologies Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: WANG, YUNQUI (RACHEL), McGibney, Grant, Morrison, Gerald
• Granted Patent: US 8,446,392 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/042 by opto-electronic means

Abstract

An interactive input system comprises a touch surface, and imaging system associated with the touch surface and processing structure. The imaging system comprises an optical sensor array that spans at least a portion of the area of the touch surface, and the processing structure communicates with the imaging system and analyzes images received by the imaging system to determine whether at least one pointer is near to the touch surface and the location of the at least one pointer in respect of the touch surface based at least in part on the edge sharpness of the at least one pointer.

Claims

1. An interactive input system comprising:

a touch surface;

an imaging system associated with the touch surface and comprising an optical sensor array that spans at least a portion of the area of the touch surface; and

processing structure communicating with the imaging system and processing images received by the imaging system to determine whether at least one pointer is near to the touch surface and the location of the at least one pointer in respect of the touch surface based at least in part on the edge sharpness of the at least one pointer.

2. The interactive input system of claim 1, wherein the optical sensor array is embedded along with display pixels in a display panel.

3. The interactive input system of claim 2, wherein the display panel is a liquid crystal display (LCD).

4. The interactive input system of claim 3, wherein the LCD is an active matrix LCD (AMLCD).

5. The interactive input system of claim 1, wherein the processing structure determines whether the at least one pointer is within an input region of the interactive input system based at least in part on the edge sharpness of the at least one pointer.

6. The interactive input system of claim 5, wherein the processing structure determines whether the at least one pointer in the input region is in contact with the touch surface.

7. The interactive input system of claim 1, wherein the processing structure determines the distance of the at least one pointer from the touch surface based at least in part on the edge sharpness of the at least one pointer.

8. The interactive input system of claim 1, wherein the processing structure determines edge sharpness of the at least one pointer by generating histograms based on the received images and analyzing high frequency content in the histograms.

9. The interactive input system of claim 8, wherein the high frequency content is analyzed in power spectrums that are generated from the histograms.

10. An interactive input system comprising:

a pointer input region comprising a touch surface;

an imaging system associated with the touch surface and comprising an optical sensor array that spans at least a portion of the area of the touch surface; and

processing structure processing images received by the imaging system to determine whether at least one pointer is within the pointer input region and the location of the at least one pointer in the pointer input region based at least in part on the edge sharpness of the at least one pointer.

11. A method of determining the location of at least one pointer in a pointer input region of an interactive input system comprising a touch surface, the method comprising:

receiving images from an optical sensor array that is associated with and spans at least a portion of the area of the touch surface;

determining whether at least one pointer is within the pointer input region; and

in the event that at least one pointer is within the pointer input region, determining the location of the pointer within the pointer input region based at least in part on the edge sharpness of the at least one pointer.

12. The method of claim 11, wherein determining the location of the pointer within the pointer input region comprises determining whether the pointer is in contact with the touch surface based at least in part on the edge sharpness of the at least one pointer.

13. The method of claim 11, wherein determining the location of the pointer within the pointer input region comprises determining the distance of the pointer from the touch surface based at least in part on the edge sharpness of the at least one pointer.

14. The method of claim 11, further comprising tracking the at least one pointer across a sequence of received images and determining based on the tracking whether the at least one object is approaching or retracting from the touch surface.

15. The method of claim 14, wherein the at least one pointer is approaching the touch surface in the event that edge sharpness of the object is determined to be increasing across the sequence of received images.

16. The method of claim 14, wherein the at least one pointer is retracting from the touch surface in the event that edge sharpness of the object is determined to be decreasing across the sequence of received images.

17. The method of claim 11, wherein determining whether at least one pointer is within the pointer input region comprises removing background features, and determining whether substantial high frequency content remains in the image.

18. The method of claim 17, wherein in the event that no substantial high frequency content remains, determining that there is no pointer in the pointer input region.

19. The method of claim 17, comprising:

in the event that substantial high frequency content remains, determining from the high frequency content whether a pointer has touched the touch surface or is hovering within the pointer input region above the touch surface.

20. The method of claim 11, wherein edge sharpness of the at least one pointer is determined by analyzing the high frequency content in a power spectrum based on a histogram generated from the images.

21. The method of claim 11, wherein edge sharpness of the at least one pointer is determined by analyzing the edge energy of an edge map based on a wavelet decomposition of the images.

22. A method of determining the location of at least one pointer in a pointer input region of an interactive input system comprising a touch surface, the method comprising:

receiving an image from an optical sensor array that is associated with and spans at least a portion of the area of the touch surface; and

determining the location of the pointer within the pointer input region based at least in part on the relative position of shadows in the image.

23. A computer readable medium embodying a computer program for determining the location of at least one pointer in a pointer input region of an interactive input system comprising a touch surface, the computer program comprising:

program code for receiving images from an optical sensor array that is associated with and spans at least a portion of the area of the touch surface;

program code for determining whether at least one pointer is within the pointer input region; and

program code for, in the event that at least one pointer is within the pointer input region, determining the location of the pointer within the pointer input region based at least in part on the edge sharpness of the at least one pointer.

24. A computer readable medium embodying a computer program for determining the location of at least one pointer in a pointer input region of an interactive input system comprising a touch surface, the computer program comprising:

program code receiving an image from an optical sensor array that is associated with and spans at least a portion of the area of the touch surface; and

program code determining the location of the pointer within the pointer input region based at least in part on the relative position of shadows in the image.