Coordinate positioning system and method with in-the-air positioning function

• US 20090046063A1
• Filed: 08/14/2008
• Published: 02/19/2009
• Est. Priority Date: 08/14/2007
• Status: Active Grant

• Current Assignee: Sunplus Mmedia Incorporated
• Original Assignee: Sunplus Mmedia Incorporated
• Inventors: Chen, Li-Ming
• Granted Patent: US 8,159,459 B2
• Time in Patent Office: Days
• US Class Current: 345/158
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

A coordinate positioning system with in-the-air positioning function includes an illuminator and an image sensor. The illuminator produces a directional light. The image sensor receives the directional light produced by the illuminator and produces an image corresponding to the directional light to accordingly analyze the image and obtain a rotating angle corresponding to the directional light.

Claims

1. A coordinate positioning system with in-the-air positioning function for an LCD display unit, comprising:

an illuminator, which produces a directional light; and

an image sensor, which senses the directional light and produces an image corresponding to the directional light to accordingly analyze the image to obtain a rotating angle corresponding to the directional light, wherein the image sensor includes;

an image sensing unit, which converts the directional light into an electrical signal, and produces an image corresponding to the directional light according to the electrical signal; and

a processing unit, which is connected to the image sensing unit, in order to perform a bi-level image pre-processing to thereby produce a bi-level image and to capture image objects corresponding to directional light from the bi-level image to accordingly produce the rotating angle corresponding to the directional light.

2. The system as claimed in claim 1, wherein the processing unit comprises:

a bi-level image processor, which is connected to the image sensing unit, in order to perform the bi-level image pre-processing on the image and to further produce the bi-level image;

an image object capturing device, which is connected to the bi-level image processor in order to capture the image objects corresponding to the directional light from the bi-level image and to produce a working image object; and

a computation device, which is connected to the image object capturing device, in order to compute a direction of the working image object to accordingly produce the rotating angle corresponding to the directional light.

3. The system as claimed in claim 2, wherein the computation device produces the rotating angle according to the direction and a predetermined vector.

4. The system as claimed in claim 3, wherein the rotating angle θ

is expressed as;

$\mathrm{\theta <br><br>}={\cos }^{-1}\left(\frac{\stackrel{\to <br><br>}{A}·<br><br>\stackrel{\to <br><br>}{B}}{<br><br>\stackrel{\rightharpoonup <br><br>}{A}<br><br><br><br><br><br>\stackrel{\rightharpoonup <br><br>}{B}<br><br>}\right),$

where ‘

{right arrow over (A)}’

indicates a vector of the direction, ‘

{right arrow over (B)}’

indicates the predetermined vector, ‘

{right arrow over (A)}’

indicates a length of the vector, ‘

|{right arrow over (B)}|’

indicates a length of the predetermined vector, and ‘



’

indicates an inner product operation.

5. The system as claimed in claim 1, wherein the image sensing unit is a complementary metal oxide semiconductor (CMOS) image sensor.

6. The system as claimed in claim 4, wherein the illuminator is comprised of a first LED and a second LED to accordingly produce the directional light, and the size of first LED is larger than the size of second LED.

7. The system as claimed in claim 6, wherein a center of the image object of the first LED is defined as a start point while a center of the image object of the second LED is defined as an end point, and thus the vector of the direction is defined by connecting from the start point to the end point.

8. The system as claimed in claim 1, wherein the illuminator is comprised of an L-shaped LED to produce the directional light.

9. The system as claimed in claim 1, wherein the illuminator is comprised of a first LED with a pre-determined shape and a second LED with a shape different from the first LED to produce the directional light.

10. A coordinate positioning system with in-the-air positioning function for an LCD display unit, the method comprising:

a receiving step, which uses an image sensor to sense a directional light produced by an illuminator;

an imaging step, which converts the directional light into an electrical signal and produces an image corresponding to the directional light according to the electrical signal;

a bi-level image processing step, which performs a bi-level image pre-processing on the image to thereby produce a bi-level image;

an image object capturing step, which captures image objects corresponding to the directional light from the bi-level image and accordingly produces a working image object; and

a computing step, which computes a direction of the working image object to thereby obtain a rotating angle.

11. The method as claimed in claim 10, wherein the computing step produces the rotating angle according to the direction and a predetermined vector.

12. The method as claimed in claim 11, wherein the rotating angle θ

is expressed as;

$\mathrm{\theta <br><br>}={\cos }^{-1}\left(\frac{\stackrel{\to <br><br>}{A}·<br><br>\stackrel{\to <br><br>}{B}}{<br><br>\stackrel{\to <br><br>}{A}<br><br><br><br><br><br>\stackrel{\to <br><br>}{B}<br><br>}\right),$

where ‘

{right arrow over (A)}’

indicates a vector of the direction, ‘

{right arrow over (B)}’

indicates the predetermined vector, ‘

|{right arrow over (A)}|’

indicates a length of the vector, ‘

|{right arrow over (B)}|’

indicates a length of the predetermined vector, and ‘



’

indicates an inner product operation.

13. The method as claimed in claim 10, wherein the image sensing unit is a CMOS image sensor.

14. The method as claimed in claim 12, wherein the illuminator is comprised of a first LED and a second LED to accordingly produce the directional light, and the size of first LED is larger than the size of second LED.

15. The method as claimed in claim 14, wherein a center of the image object of the first LED is defined as a start point while a center of the image object of the second LED is defined as an end point, and thus the vector of the direction is defined by connecting from the start point to the end point.

16. The method as claimed in claim 10, wherein the illuminator is comprised of an L-shaped LED to produce the directional light.

17. The method as claimed in claim 10, wherein the illuminator is comprised of a first LED with a pre-determined shape and a second LED with a shape different from the first LED to produce the directional light.