# US 7,611,412 B2 · Orientation device and method for coordinate generation employed thereby

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- Number: US 7,611,412 B2
- Document ID: US7611412B2
- Status: Granted
- Kind: B2
- Application number: 12/008,596
- Filed: 2008-01-11
- Published: 2008-05-15
- Granted: 2009-11-03
- Earliest claimed: 2005-05-10
- Assignees: Pixart Imaging Inc.
- Inventors: Chih-Hsin Lin; Tzu-Yi Chao; Hsin-Chia Chen
- Web page: https://patentgrep.com/patent/US7611412B2

## CPC

- A63F 13/426: involving on-screen location information, e.g. screen coordinates of an area at which the player is aiming with a light gun
- A63F 13/213: comprising photodetecting means, e.g. cameras, photodiodes or infrared cells (A63F13/219 takes precedence)
- A63F 13/219: for aiming at specific areas on the display, e.g. light-guns
- A63F 13/5375: for graphically or textually suggesting an action, e.g. by displaying an arrow indicating a turn in a driving game
- A63F 13/837: Shooting of targets
- A63F 2300/1062: being specially adapted to a type of game, e.g. steering wheel
- A63F 2300/305: for providing a graphical or textual hint to the player
- A63F 2300/8076: Shooting
- A63F: CARD, BOARD, OR ROULETTE GAMES; INDOOR GAMES USING SMALL MOVING PLAYING BODIES; VIDEO GAMES; GAMES NOT OTHERWISE PROVIDED FOR

## Abstract

A method for coordinate generation to be implemented using an orientation device includes the steps of: providing at least three reference marks on a target; aiming the orientation device at a target point on the target, and operating the orientation device such that the orientation device is able to capture an image of the target that contains the reference marks; assigning absolute coordinates to the reference marks in the image captured by the orientation device; and determining relative coordinates of the target point in a coordinate space of the target with reference to the absolute coordinates assigned to the reference marks. An orientation device that performs the method is also disclosed.

## Claims

### Claim 1

A method for coordinate generation to be implemented using an orientation device that is provided with a sensor, said method comprising the steps of:
A) providing at least four reference marks on a target;
B) aiming the orientation device at a target point on the target, and operating the orientation device such that the sensor is able to capture an image of the target that contains the reference marks;
C1) computing coordinates of the reference marks in the image captured in step B) to obtain vector combinations;
C2) finding a pair of most parallel vectors from the vector combinations, and obtaining absolute coordinates of the reference marks projected onto the coordinate space of the target according to the pair of most parallel vectors; and
D) determining relative coordinates of the target point in a coordinate space of the target with reference to the absolute coordinates of the reference marks assigned in step C2);
E) aiming the orientation device at an arbitrary point on the target; and
F) operating the orientation device such that the sensor is able to capture an image of the target that contains the reference marks;
wherein step D) includes the sub-steps of:
D1) determining coordinates of the reference marks from the image captured in step F);
D2) performing projective transformation calculations upon the coordinates of the reference marks determined in sub-step Dl) to obtain a transformation matrix;
D3) correcting an image-capturing axis of the sensor of the orientation device with reference to the transformation matrix obtained in sub-step D2) and an established coordinate space relation between the target and the orientation device; and
D4) determining the relative coordinates of the target point with reference to the corrected image-capturing axis.

### Claim 2 (depends on 1)

The method as claimed in claim 1, further comprising the steps of:
G) aiming the orientation device at one of the reference marks;
H) operating the orientation device such that the sensor is able to capture an image of the target that contains the reference mark aimed in step G);
I) determining the coordinates of the reference mark aimed in step G) from the image captured in step H); and
J) correlating a coordinate space of the orientation device with a coordinate space of the target to thereby establish the coordinate space relation.

### Claim 3

A method for coordinate generation to be implemented using an orientation device that is provided with a sensor, said method comprising the steps of:
A) providing at least four reference marks on a target;
B) aiming the orientation device at a target point on the target, and operating the orientation device such that the sensor is able to capture an image of the target that contains the reference marks;
C1) computing coordinates of the reference marks in the image captured in step B) to obtain vector combinations;
C2) finding a pair of most parallel vectors from the vector combinations, and obtaining absolute coordinates of the reference marks projected onto the coordinate space of the target according to the pair of most parallel vectors; and
D) determining relative coordinates of the target point in a coordinate space of the target with reference to the absolute coordinates of the reference marks assigned in step, C2);
E) aiming the orientation device at one corner of the target, and operating the orientation device such that the sensor is able to capture an image of the target that contains the reference marks;
wherein step D) includes the sub-steps of:
D1) determining coordinates of the reference marks from the image captured in step E);
D2) performing projective transformation calculations upon the coordinates of the reference marks determined in sub-step D1) to obtain a transformation matrix;
D3) correcting an image-capturing axis of the sensor of the orientation device with reference to the transformation matrix obtained in sub-step D2); and
D4) determining the relative coordinates of the target point with reference to the corrected image-capturing axis.