OBJECT DETECTION CALIBRATION SYSTEM OF AN OPTICAL TOUCH SCREEN AND METHOD THEREOF

• US 20100328270A1
• Filed: 06/29/2010
• Published: 12/30/2010
• Est. Priority Date: 06/30/2009
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Lin, Chih-Hsin, Lin, Cho-Yi, Su, Tzung-Min
• Granted Patent: US 8,462,137 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 first image sensor captures a first image of a panel of a touch screen. The first image includes a first object, a second object, a first set of reference marks, a second set of reference marks, and a first boundary mark. The touch screen establishes relationships of relative positions among the first image sensor, the first object, the second object, and the reference marks according to positions of the first object, the second object, and the reference marks in the first image. And the touch screen calculates a relative position between the first image sensor and the panel according to the relationships of relative positions among the first image sensor, the first object, the second object, and the reference marks and relative positions among the first object, the second object, and the panel.

Claims

1. An object detection calibration system comprising:

a touch screen comprising;

a control panel comprising a first side, a second side, a third side, and a fourth side; and

at least one first image sensor positioned at a corner region joining the first side and the second side; and

an auxiliary reference device comprising a plurality of reference marks comprising at least a first set of reference marks, a second set of reference marks, and a first boundary mark, wherein the first set of reference marks is positioned on the third side, the second set of reference marks is positioned on the fourth side, and the first boundary mark is positioned at a corner region joining the third side and the first side;

wherein the first image sensor is utilized for capturing a first image of at least a first object and the plurality of reference marks, and the touch screen determines relative position relationships between the first image sensor, the first object, and the plurality of reference marks according to positions of the first object and the plurality of reference marks in the first image.

2. The object detection calibration system of claim 1, wherein the first image captured by the first image sensor is further of a second object, positions of the first object and the second object relative to the control panel are known, the touch screen determines relative position relationships between the first image sensor, the first object, the second object, and the plurality of reference marks according to positions of the first object, the second object, and the plurality of reference marks in the first image, and the touch screen calculates relative position relationship between the first image sensor and the control panel according to the relative position relationships between the first image sensor, the first object, the second object, and the plurality of reference marks and the relative positions of the first object, the second object, and the control panel.

3. The object detection calibration system of claim 1, wherein the touch screen further comprises a second image sensor positioned at a corner region of the control panel joining the second side to the third side, the plurality of reference marks of the auxiliary reference device further comprises a third set of reference marks positioned on the first side, and a second boundary mark positioned at a corner region joining the fourth side to the first side, wherein the second image sensor is utilized for capturing a second image of the first object and the plurality of reference marks, and the touch screen determines relative position relationships of the second image sensor, the first object, and the plurality of reference marks according to positions of the first object and the plurality of reference marks in the second image.

4. The object detection calibration system of claim 1, further comprising at least one projected light source for lighting the control panel.

5. The object detection calibration system of claim 1, further comprising an image coordinates generator device for generating image coordinates of the first object relative to the first image sensor and image coordinates of the second image sensor according to positions of the first object in the first image and the second image.

6. The object detection calibration system of claim 5, wherein the touch screen locates coordinates of the first object on the control panel according to image coordinates of the first object relative to the first image sensor and the second image sensor, image coordinates of the first image sensor, and image coordinates of the second image sensor.

7. A method of performing object detection calibration for a touch screen, the method comprising:

a first image sensor capturing a first image of a first object, a second object, and a plurality of reference points comprising a first set of reference marks, a second set of reference marks, and a first boundary mark;

the touch screen determining relative position relationships of the first image sensor, the first object, the second object, and the plurality of reference points according to position of the first object and the second object in the first image and position of the plurality of reference marks in the first image; and

the touch screen calculating relative position relationship of the first image and the control panel according to the relative position relationships of the first image sensor, the first object, the second object, and the plurality of reference marks, and positions of the first object and the second object relative to the control panel;

wherein the positions of the first object and the second object relative to the control panel are known.

8. The method of claim 7, further comprising:

a second image sensor capturing a second image of the first object, the second set of reference marks, a third set of reference marks, and a second boundary mark on the control panel; and

the touch screen determining relative position relationships of the second image sensor, the first object, and the plurality of reference marks according to positions of the first object and the plurality of reference marks in the second image.

9. The method of claim 7, further comprising:

an image coordinates generator device generating image coordinates of the first object relative to the first image sensor and image coordinates of the second image sensor according to positions of the first object in the first image and the second image.

10. The method of claim 9, further comprising:

the touch screen locating coordinates of the first object on the control panel according to image coordinates of the first object relative to the first image sensor and the second image sensor, image coordinates of the first image sensor, and image coordinates of the second image sensor.

11. The method of claim 7, further comprising:

the first image sensor capturing a third image of a plurality of objects, the first set of reference marks, the second set of reference marks, and the first boundary mark on the control panel;

the second image sensor capturing a fourth image of the plurality of objects, the second set of reference marks, the third set of reference marks, and the second boundary mark on the control panel;

the touch screen determining relative position relationships of the first image sensor, the plurality of objects, and the plurality of reference marks according to positions of the plurality of objects and the plurality of reference marks in the third image;

the touch screen determining relative position relationships of the second image sensor, the plurality of objects, and the plurality of reference marks according to positions of the plurality of objects and the plurality of reference marks in the fourth image; and

the touch screen calculating relative position relationships of the first image sensor, the second image sensor, and the control panel according to the relative position relationships of the first image sensor, the second image sensor, the plurality of objects, and the plurality of reference marks, and positions of the plurality of objects relative to the control panel;

wherein the positions of the plurality of objects relative to the control panel are known.