Detecting finger orientation on a touch-sensitive device

• US 8,125,458 B2
• Filed: 09/28/2007
• Issued: 02/28/2012
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Keam, Nigel
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): CRAWLEY, KEITH L
• Application Number:
  US11/864,650
• Publication Number:
  US 20090085881A1
• Time in Patent Office: 1,614 Days
• Field of Search: 345173-178, 178 1801- 1811, 341/5, 341/22, 341 33- 34, 341/6, 382115-116, 382119-126, 382/181, 382/190, 382/199, 382/203, 382/195, 382/197, 382205-206, 382270-274, 382286-289, 382/291, 382295-296, 715730-737, 715750-759, 715/863
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04109 FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location
• CPC Class Codes: G06F 3/0425 using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected tracking a projected light spot to determine a position on a display surface G06F3/0386
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

The determination of an orientation of a finger touching a touch-sensitive device is disclosed. In one embodiment, a computing device comprises a display screen configured to display an image to a user, and an intensity-sensitive touch-sensing input mechanism configured to detect one or more objects touching the display screen. The device also comprises a controller configured to determine an orientation of a finger touching the screen from a direction between a center of a first set of touch data and a center of a second set of touch data, and to adjust an image on the display screen in response to a determined orientation of the finger.

Claims

1. A computing device, comprising:

a display screen configured to display an image to a user;

an intensity-sensitive touch-sensing input mechanism configured to acquire an array of touch intensity data and to detect one or more objects touching the display screen from the array of touch intensity data; and

a controller comprising a processor and memory containing instructions executable by the processor to determine an orientation of a finger touching the display screen from a direction between a center a first region of touch data of a higher intensity and a center of a second region of touch data of a lower intensity, and to orient an image on the display screen to correspond to a determined orientation of the finger touching the display screen.

2. The device of claim 1, wherein the instructions are executable to define the first region of touch data as touch data that exceeds a threshold intensity value.

3. The device of claim 2, wherein the threshold intensity value comprises a weighted average intensity of the array of touch intensity data.

4. The device of claim 3, wherein each intensity value in the weighted average intensity is weighted by a weighting factor comprising a gradient of the intensity value.

5. The device of claim 1, wherein the instructions are executable to determine the second region of touch data as having a preselected shape around the first region of touch data.

6. The device of claim 1, wherein the instructions are executable to determine the first region of touch data as data that exceeds a first threshold intensity value and the second region of touch data as data that exceeds a second threshold intensity value lower than the first threshold intensity value.

7. A computing device, comprising:

a display screen;

a touch-sensitive input configured to acquire a frame of touch intensity data comprising an array of touch intensity values and to detect one or more fingers touching the display screen from the frame of touch intensity data; and

a controller comprising a processor and memory containing instructions executable by the processor to determine an orientation of a finger detected on the display screen by detecting a first region of touch data in the frame of touch intensity data in which substantially all pixels have intensities that exceed a threshold intensity value, detecting a second region of touch data in the frame of touch intensity data that surrounds the first region of touch data, calculating a center of the first region of touch data, calculating a center of the second region of touch data, determining a direction between the center of the first region of touch data and the center of the second region of touch data, and orienting an image on the display screen to correspond to a determined orientation of the finger touching the display screen.

8. The device of claim 7, wherein the touch-sensitive input comprises an optical touch-sensing mechanism.

9. The device of claim 7, wherein the touch-sensitive input comprises one or more of a capacitive touch-sensing mechanism and a resistive touch-sensing mechanism.

10. The device of claim 7, wherein the instructions are executable to calculate the centers of the first and second regions of touch data as weighted centers of intensity by using an intensity at each pixel as a weighting factor.

11. The device of claim 7, wherein the instructions are executable to define an outer border of the second region as having an intensity a preselected amount lower than an outer border of the first region.

12. The device of claim 7, wherein the instructions are executable to define an outer border of the second region as having a preselected shape.

13. The device of claim 7, wherein the instructions are executable to determine the threshold intensity from a weighted average intensity of the touch data, and wherein a gradient at each pixel is used as a weighting factor for the intensity at that pixel.

14. In a computing device comprising a touch-sensitive input, a method of determining an orientation of a finger touching the touch-sensitive input, the method comprising:

acquiring an image comprising a two-dimensional array of touch data from the touch-sensitive input;

determining a first region of touch data in the image in which an intensity of each pixel exceeds a first threshold intensity;

determining a second region of touch data in the image that surrounds the first region of touch data and in which an intensity of each pixel exceeds a second threshold intensity;

calculating a weighted center of intensity of the first region of touch data;

calculating a weighted center of intensity of the second region of touch data;

determining a direction between the weighted center of intensity of the second region of touch data and the weighted center of intensity of the first region of touch data to determine an orientation of a finger; and

rotating an image displayed on the touch-sensitive input based upon the direction.

15. The method of claim 14, wherein the intensity at each pixel is used as a weighting factor in determining the weighted centers of intensity of the first and second regions of touch data.

16. The method of claim 14, wherein an outer border of the second region extends a preselected distance from an outer border of the first region.

17. The method of claim 14, wherein the second region has a preselected shape around an outer border of the first region.

18. The method of claim 14, wherein the first and second threshold intensities are determined from a weighted average intensity of the touch data weighted by a gradient at each pixel.

19. The method of claim 18, wherein the gradient at each pixel is determined via a Sobel filter.