SIZE/SCALE AND ORIENTATION DETERMINATION OF A POINTER IN A CAMERA-BASED TOUCH SYSTEM

• US 20120280943A1
• Filed: 07/20/2012
• Published: 11/08/2012
• Est. Priority Date: 11/15/2002
• Status: Active Grant

• Current Assignee: Smart Technologies ULC (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Smart Technologies ULC (Hon Hai Precision Industry Co., Ltd.)
• Inventors: MORRISON, GERALD, AKITT, TREVOR, SU, SCOTT
• Granted Patent: US 8,537,134 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• 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 touch system includes a touch surface and at least two cameras associated with the touch surface. The at least two cameras acquire images of the touch surface from different locations and having overlapping fields of view. A digital signal processor is associated with each camera. The digital signal processors process pixel data acquired by selected pixel subsets of the at least two digital cameras to generate pointer characteristic data when a pointer exists in the acquired images. The pointer characteristic data identifies edges of the pointer. A master digital signal processor triangulates the edge information in the pointer characteristic data to determine a bounding area that represents a pointer perimeter.

Claims

1. A method comprising:

acquiring images of a pointer proximate an input surface from different vantages;

processing pixel data of each image to determine edges of said pointer; and

triangulating an input area of said pointer based on said determined edges.

2. The method of claim 1 further comprising using the triangulated input area to control execution of an applications program.

3. The method of claim 2 further comprising updating a computer generated image presented on said input surface.

4. The method of claim 3 further comprising determining the center of the input area thereby to determine the center of said pointer.

5. The method of claim 3 further comprising examining the shape of the input area to determine the orientation of said pointer relative to said input surface.

6. The method of claim 4 further comprising examining the shape of the input area to determine the orientation of said pointer relative to said input surface.

7. The method of claim 1 wherein said input surface is generally rectangular, wherein said acquiring comprises acquiring an image looking generally across said input surface from each corner of said input surface, and wherein said triangulating comprises triangulating an input area based on said determined edges for different pairs of images and using the smallest triangulated input area to represent the size of said pointer.

8. The method of claim 7 further comprising averaging the centers of the triangulated input areas to determine the center of said pointer.

9. The method of claim 1 wherein said processing is performed at a rate greater than the rate at which said images are acquired.

10. The method of claim 1 further comprising superimposing a model over said triangulated input area.

11. The method of claim 10 further comprising determining the center of said model thereby to determine the center of said pointer.

12. The method of claim 10 further comprising examining the size of said model to identify non-pointer input.