Passive Touch System And Method Of Detecting User Input

• US 20070002028A1
• Filed: 08/31/2006
• Published: 01/04/2007
• Est. Priority Date: 07/05/2000
• Status: Active Grant

• Current Assignee: Smart Technologies Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Smart Technologies Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Morrison, Gerald, Singh, Manvinder
• Granted Patent: US 8,203,535 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/042 by opto-electronic means
• 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 3/0428 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 passive touch system includes a passive 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 have overlapping fields of view. A processor receives and processes images acquired by the at least two cameras to detect the existence of a pointer therein and to determine the location of the pointer relative to the touch surface. Actual pointer contact with the touch surface and pointer hover above the touch surface can be determined.

Claims

1. An imaging assembly comprising:

a substantially rectangular frame to surround a region of interest in front of a display surface; and

a plurality of digital cameras mounted adjacent at least three comers of said frame, said digital cameras being oriented to capture overlapping images of said region of interest.

2. An imaging assembly according to claim 1, wherein each said digital camera comprises a CMOS digital camera.

3. An imaging assembly according to claim 2, wherein each digital camera has a selectable pixel array.

4. An imaging assembly according to claim 3, wherein said digital cameras are oriented so that the field of view of each digital camera extends beyond a peripheral edge of said frame.

5. An imaging assembly according to claim 4, further including a processor associated with each of said digital cameras, each digital camera and associated processor being mounted on a common board.

6. An imaging assembly according to claim 5, wherein a subset of pixels in the selectable pixel array of each digital camera provides pixel data to said associated processor.

7. An imaging assembly according to claim 6, wherein each pixel subset includes contiguous rows of pixels.

8. An imaging assembly according to claim 7, wherein the pixel subset of each digital camera is aligned so that the pixel subset looks along a plane substantially coplanar to said display surface.

9. An imaging assembly according to claim 8, wherein the row of pixels in the pixel subset of each digital camera, that acquires pixel data corresponding to a tip of said pointer within said region of interest, is determined to enable said processor to detect pointer contact and pointer hover over said display surface.