Calibrating apparatus and method

• US 20100079412A1
• Filed: 05/06/2009
• Published: 04/01/2010
• Est. Priority Date: 10/01/2008
• Status: Active Grant

• Current Assignee: Quanta Computer
• Original Assignee: Quanta Computer
• Inventors: Liu, Yun-Cheng, Chang, Chin-Kang, Chiang, Ching-Chun, Huang, Yi-Ming
• Granted Patent: US 8,243,047 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• 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 calibrating apparatus for an image processing apparatus is disclosed. The calibrating apparatus comprises a first operating module and a second operating module. The first operating module determines a third indicating point and a fourth indicating point according to a first indicating point, a second indicating point, and a specific point, and determines a calibration point (i.e. the predetermined position of a sensor) according to a first line through the first indicating point and third indicating point and a second line through the second indicating point and fourth indicating point. The second operating module forms reference lines according to reference points and the calibration point, forms reference angles according to the reference lines and a parallel line, generates reference coordinates of the reference points in an image and generates a calibration function according to the reference coordinates of the reference points and the reference angles.

Claims

1. A calibrating method for an image processing apparatus, the image processing apparatus comprising a panel and at least one light sensor, a first indicating point, a second indicating point, and a plurality of reference points, whose coordinates are known, being displayed on the panel, the light sensor being located at a predetermined position near a specific point on the circumference of the panel, the calibrating method comprising the steps of:

(a) determining a third indicating point and a fourth indicating point on the panel according to a first indicating point, a second indicating point, and the specific point;

(b) determining the predetermined position according to a first line which passes through the first indicating point and third indicating point and a second line which passes through the second indicating point and fourth indicating point;

(c) generating a base line which passes through the predetermined position and is parallel to the circumference of the panel;

(d) forming a plurality of reference lines according to the reference points and the predetermined position, and forming a plurality of reference angles according to the reference lines and the base line;

(e) generating a plurality of reference point coordinates which respectively corresponds to the reference points in an image of the at least one light sensor; and

(f) generating a calibration function according to the reference point coordinates and the reference angles.

2. The calibrating method of claim 1, wherein the at least one light sensor generates a first image according to the first indicating point, the second indicating point, the third indicating point, and the fourth indicating point, in the first image, a first observation point corresponding to the first indicating point and a second observation point corresponding to the second indicating point are different points, a third observation point corresponding to the third indicating point and the first observation point are the same points, a fourth observation point corresponding to the fourth indicating point and the second observation point are the same points.

3. The calibrating method of claim 1, wherein the at least one light sensor generates a second image according to the reference points, in the second image, a plurality of reference observation points corresponding to the reference points are all different points.

4. The calibrating method of claim 1, wherein step (a) comprises the steps of:

(a1) connecting the specific point to the first indicating point to form a first auxiliary line and connecting the specific point to the second indicating point to form a second auxiliary line;

(a2) determining a first auxiliary point and a second auxiliary point according to the first auxiliary line and determining a third auxiliary point and a fourth auxiliary point according to the second auxiliary line; and

(a3) determining the third indicating point according to the first auxiliary line, the first auxiliary point, and the second auxiliary point and determining the fourth indicating point according to the second auxiliary line, the third auxiliary point, and the fourth auxiliary point;

5. The calibrating method of claim 4, wherein in step (a2), the first auxiliary point and the second auxiliary point are located at two sides of the first auxiliary line, and the line which passes through the first auxiliary point and the second auxiliary point is perpendicular to the first auxiliary line, the third auxiliary point and the fourth auxiliary point are located at two sides of the second auxiliary line, and the line which passes through the third auxiliary point and the fourth auxiliary point is perpendicular to the second auxiliary line.

6. The calibrating method of claim 4, wherein in step (a3), the third indicating point is calculated according to the first auxiliary point, the second auxiliary point, and a first distance ratio, the fourth indicating point is calculated according to the third auxiliary point, the fourth auxiliary point, and a second distance ratio, the first distance ratio relates to the distance from the first auxiliary point to the first auxiliary line and the distance from the second auxiliary point to the first auxiliary line, the second distance ratio relates to the distance from the third auxiliary point to the second auxiliary line and the distance from the fourth auxiliary point to the second auxiliary line.

7. The calibrating method of claim 1, wherein in step (f), the calibration function is generated by fitting a curve with a method of curve-fitting, the curve relates to the reference point coordinates and the reference angles.

8. The calibrating method of claim 1, wherein the specific point is located at the apex at the upper right corner or the apex at the upper left corner of the panel.

9. The calibrating method of claim 1, further comprising the step of:

(g) calculating an included angle between a touch point and the base line according the calibration function.

10. A calibrating apparatus for an image processing apparatus, the image processing apparatus comprising a panel and a light sensor, a first indicating point, a second indicating point, and a plurality of reference points, whose coordinates are known, being displayed on the panel, the light sensor being located at a predetermined position near a specific point on the circumference of the panel, the calibrating apparatus comprising:

a first processing module being coupled to the panel, the first processing module determining a third indicating point and a fourth indicating point on the panel according to the first indicating point, the second indicating point, and the specific point, and determining the predetermined position according to the first line which passes through the first indicating point and third indicating point and a second line which passes through the second indicating point and the fourth indicating point; and

a second processing module being coupled to the first processing module and the panel, the second processing module forming a plurality of reference lines according to the reference points and the predetermined position and forming a plurality of reference angles according to the reference lines and a base line, generating a plurality of reference point coordinates which respectively corresponds to the reference points in an image of the light sensor, and generating a calibration function according to the reference point coordinates and the reference angles, wherein the base line passes through the predetermined position and is parallel to the circumference of the panel.

11. The calibrating apparatus of claim 10, wherein the light sensor generates a first image according to the first indicating point, the second indicating point, the third indicating point, and the fourth indicating point, in the first image, a first observation point corresponding to the first indicating point and a second observation point corresponding to the second indicating point are different points, a third observation point corresponding to the third indicating point and the first observation point are the same points, a fourth observation point corresponding to the fourth indicating point and the second observation point are the same points.

12. The calibrating apparatus of claim 10, wherein the light sensor generates a second image according to the reference points, in the second image, a plurality of reference observation points corresponding to the reference points are all different points.

13. The calibrating apparatus of claim 10, wherein the first processing module comprises:

a first processing unit for connecting the specific point to the first indicating point to form a first auxiliary line and connecting the specific point to the first indicating point to form a second auxiliary line;

a second processing unit, coupled to the first process unit, the second processing unit determines a first auxiliary point and a second auxiliary point which are respectively located at two sides of the first auxiliary line and a third auxiliary point and a fourth auxiliary point which are respectively located on two sides of the second auxiliary line, and determines the third indicating point according to the first auxiliary line, the first auxiliary point, and the second auxiliary point and determines the fourth indicating point according to the second auxiliary line, the third auxiliary point and the fourth auxiliary point; and

a third processing unit, coupled to the first process unit and the second processing unit, the third processing unit connects the first indicating point to the third indicating point to form the first line and connects the second indicating point to the fourth indicating point to form the second line, and the intersection point between the first line and the second line is determined to be the predetermined position.

14. The calibrating apparatus of claim 13, wherein the line which passes through the first auxiliary point and the second auxiliary point is perpendicular to the first auxiliary line, and the line which passes through the third auxiliary point and the fourth auxiliary point is perpendicular to the second auxiliary line.

15. The calibrating apparatus of claim 13, wherein the third processing unit determines the third indicating point according to the first auxiliary point, the second auxiliary point, and a first distance ratio and determines the fourth indicating point according to the third auxiliary point, the fourth auxiliary point, and a second distance ratio, the first distance ratio relates to the distance from the first auxiliary point to the first auxiliary line and the distance from the second auxiliary point to the first auxiliary line, the second distance ratio relates to the distance from the third auxiliary point to the second auxiliary line and the distance from the fourth auxiliary point to the second auxiliary line.

16. The calibrating apparatus of claim 10, wherein the second processing module generates the calibration function by fitting a curve with a method of curve-fitting, the curve relates to the reference point coordinates and the reference angles.

17. The calibrating apparatus of claim 10, wherein the specific point is located at the apex at the upper right corner or the apex at the upper left corner of the panel.

18. The calibrating apparatus of claim 10, wherein the calibration function calculates a first included angle between a touch point and the base line.

19. The calibrating apparatus of claim 18, further comprising a second light sensor, wherein the first processing module determines a predetermined position of the second light sensor, the second processing module generates a calibration function of the second light sensor, and the calibration function calculates a second included angle between the touch point and the base line.

20. The calibrating apparatus of claim 19, wherein the calibrating apparatus generates the coordinate of a touch point according to the first included angle, the second included angle and a distance between the first light sensor and the second light sensor according to the predetermined positions of the first light sensor and the second light sensor.