Methods for input-output calibration and image rendering

• US 9,122,346 B2
• Filed: 03/22/2012
• Issued: 09/01/2015
• Est. Priority Date: 03/22/2012
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Wu, Chi-Ling, Tsai, Yu-Pao, Chen, Chia-Ping, Chen, Yu-Ting
• Primary Examiner(s): Karimi, Pegeman
• Application Number:
  US13/426,604
• Publication Number:
  US 20130249864A1
• Time in Patent Office: 1,258 Days
• Field of Search: 345/173, 345/175, 345/176
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/042 by opto-electronic means

Abstract

One of the embodiments of the invention provides an input-output calibration method performed by a processing unit connected to an output device and an input device. The output device and the input device correspond to an output device coordinate system and an input device coordinate system, respectively. The processing unit first derives M calibration points'"'"' coordinates in the input device coordinate system by using the input device to sense a viewer specifying the M calibration points'"'"' positions, wherein M is a positive integer. Then, the processing unit uses the M calibration points'"'"' coordinates in the output device coordinate system and coordinates in the input device coordinate system to derive the relationship between the output device coordinate system and the input device coordinate system.

Claims

1. An input-output calibration method performed by a processing unit connected to an output device and an input device, wherein the output device and the input device correspond to an output device coordinate system and an input device coordinate system, respectively, the method comprising:

using the input device to derive a plurality of lines in the input device coordinate system for M calibration points by sensing a viewer specifying the M calibration points'"'"' positions, wherein the plurality of lines are between the M calibration points and the viewer'"'"'s different positions, and M is a positive integer equal to or larger than three;

deriving the M calibration points'"'"' coordinates in the input device coordinate system according to the plurality of lines; and

using the M calibration points'"'"' coordinates in the output device coordinate system and coordinates in the input device coordinate system to derive the relationship between the output device coordinate system and the input device coordinate system.

2. The method of claim 1, wherein for each of the M calibration points, the step of deriving the calibration point'"'"'s coordinates in the input device coordinate system comprises:

deriving two lines in the input device coordinate system for the calibration point by using the input device to sense the viewer specifying the calibration point'"'"'s position from two different positions; and

using the two lines to derive the calibration point'"'"'s coordinates in the input device coordinate system.

3. The method of claim 2, wherein the step of deriving the two lines in the input device coordinate system for the calibration point comprises:

deriving a first reference point and a first vector in the input device coordinate system by using the input device to sense the viewer pointing at the calibration point from one of the two different positions; and

deriving a second reference point and a second vector in the input device coordinate system by using the input device to sense the viewer pointing at the calibration point from the other of the two different positions;

wherein the first reference point and the first vector define one of the two lines for the calibration point and the second reference point and the second vector define the other of the two lines for the calibration point.

4. The method of claim 2, wherein the step of deriving the two lines in the input device coordinate system for the calibration point comprises:

deriving a first reference point and a first vector in the input device coordinate system by using the input device to sense the viewer gazing at the calibration point from one of the two different positions; and

deriving a second reference point and a second vector in the input device coordinate system by using the input device to sense the viewer gazing at the calibration point from the other of the two different positions;

wherein the first reference point and the first vector define one of the two lines for the calibration point and the second reference point and the second vector define the other of the two lines for the calibration point.

5. The method of claim 1, wherein the processing unit uses a coordinate transformation matrix to represent the relationship between the output device coordinate system and the input device coordinate system.

6. A method performed by a processing unit connected to an output device and an input device, wherein the output device and the input device correspond to an output device coordinate system and an input device coordinate system, respectively, the method comprising:

determining the relationship between the output device coordinate system and the input device coordinate system, wherein the step of determining the relationship between the output device coordinate system and the input device coordinate system comprises;

using the input device to derive a plurality of lines in the input device coordinate system for M calibration points by sensing a viewer specifying the M calibration points'"'"' positions, wherein the plurality of lines are between the M calibration points and the viewer'"'"'s different positions, and M is a positive integer equal to or larger than three;

deriving the M calibration points'"'"' coordinates in the input device coordinate system according to the plurality of lines; and

using the M calibration points'"'"' coordinates in the output device coordinate system and coordinates in the input device coordinate system to derive the relationship between the output device coordinate system and the input device coordinate system;

deriving an object'"'"'s spatial information with respect to the input device coordinate system by using the input device to sense the object; and

deriving the object'"'"'s spatial information with respect to the output device coordinate system based on the spatial information of the object with respect to the input device coordinate system and the relationship between the output device coordinate system and the input device coordinate system.

7. The method of claim 6, wherein for each of the M calibration points, the step of deriving the calibration point'"'"'s coordinates in the input device coordinate system comprises:

deriving two lines in the input device coordinate system for the calibration point by using the input device to sense the viewer specifying the calibration point'"'"'s position from two different positions; and

using the two lines to derive the calibration point'"'"'s coordinates in the input device coordinate system.

8. The method of claim 7, wherein the step of deriving the two lines in the input device coordinate system for the calibration point comprises:

deriving a first reference point and a first vector in the input device coordinate system by using the input device to sense the viewer pointing at the calibration point from one of the two different positions; and

deriving a second reference point and a second vector in the input device coordinate system by using the input device to sense the viewer pointing at the calibration point from the other of the two different positions;

wherein the first reference point and the first vector define one of the two lines for the calibration point and the second reference point and the second vector define the other of the two lines for the calibration point.

9. The method of claim 7, wherein the step of deriving the two lines in the input device coordinate system for the calibration point comprises:

deriving a first reference point and a first vector in the input device coordinate system by using the input device to sense the viewer gazing at the calibration point from one of the two different positions; and

deriving a second reference point and a second vector in the input device coordinate system by using the input device to sense the viewer gazing at the calibration point from the other of the two different positions;

wherein the first reference point and the first vector define one of the two lines for the calibration point and the second reference point and the second vector define the other of the two lines for the calibration point.

10. The method of claim 6, wherein the processing unit uses a coordinate transformation matrix to represent the relationship between the output device coordinate system and the input device coordinate system.

11. The method of claim 6, wherein the object comprises a user'"'"'s hand, and the step of detecting the object'"'"'s spatial information with respect to the output device coordinate system comprises:

detecting the user'"'"'s gesture with respect to the output device coordinate system based on the spatial information of the object with respect to the input device coordinate system and the relationship between the output device coordinate system and the input device coordinate system.

12. The method of claim 11, wherein the user'"'"'s gesture comprises a push gesture made by the user toward a screen of the output device.

13. The method of claim 6, wherein the object comprises a user'"'"'s head, and the step of detecting the object'"'"'s spatial information with respect to the output device coordinate system comprises:

tracking the angle or distance from which the user is viewing a screen of the output device based on the spatial information of the object with respect to the input device coordinate system and the relationship between the output device coordinate system and the input device coordinate system.

14. The method of claim 6, wherein the step of detecting the object'"'"'s spatial information with respect to the output device coordinate system comprises:

tracking the object'"'"'s orientation, location, or movement with respect to the output device coordinate system based on the spatial information of the object with respect to the input device coordinate system and the relationship between the output device coordinate system and the input device coordinate system.

15. The method of claim 6, further comprising:

rendering images for the output device based on the object'"'"'s spatial information with respect to the output device coordinate system.

16. The method of claim 15, wherein the step of rendering the images for the output device based on the object'"'"'s spatial information with respect to the output device coordinate system comprises:

determining the orientation, position, or moving path of a visual object in the images based on the object'"'"'s spatial information with respect to the output device coordinate system.