Method of Tracing Touch Paths for a Multi-Touch Panel

• US 20120194444A1
• Filed: 07/04/2011
• Published: 08/02/2012
• Est. Priority Date: 01/31/2011
• Status: Abandoned Application

• Current Assignee: TPK Touch Solutions (Xiamen) Inc. (TPK Holding Co., Ltd.)
• Original Assignee: TPK Touch Solutions (Xiamen) Inc. (TPK Holding Co., Ltd.)
• Inventors: Chang, Ching-Yang, Wu, Hsiang-Cheng
• Application Number:
  US13/175,932
• Publication Number:
  US 20120194444A1
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04808 Several contacts: gestures triggering a specific function, e.g. scrolling, zooming, right-click, when the user establishes several contacts with the surface simultaneously; e.g. using several fingers or a combination of fingers and pen
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

A method of tracing touch paths for a multi-touch panel is disclosed. A basis touch point obtained from the multi-touch panel, a predicted touch point generated according to the basis touch point, and a detected touch point obtained from the multi-touch panel are provided. A reported touch point is then generated according to the basis touch point, the predicted touch point and the detected touch point based on a parametric curve.

Claims

1. A method of tracing touch paths, comprising:

providing a basis touch point obtained from a multi-touch panel,

generating a predicted touch point based on the basis touch point and a detected touch point obtained from the multi-touch panel; and

generating a reported touch point based on the basis touch point, the predicted touch point, and the detected touch point based on a parametric curve.

2. The method of claim 1, wherein the basis touch point is used as a starting point of the parametric curve, the detected touch point is used as a stopping point of the parametric curve, and the predicted point is used as a controlling point of the parametric curve.

3. The method of claim 2, wherein the parametric curve is Bezier curve.

4. The method of claim 3, wherein the Bezier curve is expressed as

R(t)=(1−

t)²B+2(1−

t)tP+t²D, t=0−

1

wherein R is the Bezier curve on which the reported touch point is disposed, t is a parameter of the Bezier curve, B is the basis touch point, P is the predicted touch point, and D is the detected touch point.

5. The method of claim 1, further comprising a step of inserting at least one inserted touch point by selecting a parameter of the parametric curve.

6. The method of claim 1, further comprising a step of storing the basis touch point, the predicted touch point, and the detected touch point in a memory device before generating the reported touch point.

7. A method of tracing touch paths, comprising:

obtaining a first touch point and a second touch point in sequence from a multi-touch panel;

determining whether a first distance between the first touch point and the second touch point is smaller than a predefined first value;

commencing a new touch path including the first and the second touch points if the first distance is smaller than the predefined first value;

generating a predicted touch point based on the first and the second touch points;

obtaining a detected touch point from the multi-touch panel;

determining whether a second distance between the predicted touch point and the detected touch point is smaller than a predefined second value; and

generating a reported touch point based on the second touch point, the predicted touch point, and the detected touch point based on a parametric curve if the second distance is smaller than the predefined second value.

8. The method of claim 7, further comprising a step of discarding the first touch point if the first distance is not smaller than the predefined first value.

9. The method of claim 7, further comprising a step of assigning a new contact identification number to the new touch path.

10. The method of claim 7, wherein a position X_n+1 of the predicted touch point at an expected time t_n+1 is generated based on velocity V_n, and acceleration a_n of the second touch point at time t_n, and is expressed as follows:

X_n+1=2V_n*dt+a_n*dt*dt

where

dt=t_n+1−

t_n,

V_n=(X_n−

X<sub>n−

1</sub>)/(t_n−

t<sub>n−

1</sub>),

a_n=(V_n−

V<sub>n−

1</sub>)/(t_n−

t<sub>n−

1</sub>)

where

V<sub>n−

1</sub>=(X<sub>n−

1</sub>−

X<sub>n−

2</sub>)/(t<sub>n−

1</sub>−

t<sub>n−

2</sub>),

V<sub>n−

1</sub>is a velocity of another previous touch point at time t<sub>n−

1</sub>, X<sub>n−

2</sub> is a position of a further previous touch point at time t<sub>n−

2</sub>.

11. The method of claim 7, further comprising a step of ending a current touch path if the second distance is not smaller than the predefined second value.

12. The method of claim 7, wherein the second touch point is used as a starting point of the parametric curve, the detected touch point is used as a stopping point of the parametric curve, and the predicted point is used as a controlling point of the parametric curve.

13. The method of claim 12, wherein the parametric curve is Bezier curve.

14. The method of claim 13, wherein the Bezier curve is expressed as

R(t)=(1−

t)²B+2(1−

t)tP+t²D, t=0−

1

wherein R is the Bezier curve on which the reported touch point is disposed, t is a parameter of the Bezier curve, B is the second touch point, P is the predicted touch point and D is the detected touch point.

15. The method of claim 7, further comprising a step of inserting at least one inserted touch point by selecting a parameter of the parametric curve.

16. The method of claim 7, further comprising a step of storing the first touch point, the second touch point, the predicted touch point, and the detected touch point in a memory device before generating the reported touch point.