Method and apparatus for using rotational movement amount of mobile device and computer-readable recording medium for storing computer program

• US 20050137750A1
• Filed: 09/08/2004
• Published: 06/23/2005
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kwon, Woong, Roh, Kyung-shik, Han, Woo-sup, Shim, Young-bo
• Granted Patent: US 7,747,348 B2
• Time in Patent Office: Days
• US Class Current: 700/245
• CPC Class Codes: G05D 1/0253 extracting relative motion information from a plurality of images taken successively, e.g. visual odometry, optical flow determining position or orientation from images G06T7/70
• CPC Class Codes: G05D 1/027 comprising intertial navigation means, e.g. azimuth detector inertial navigation G01C21/16; inertial navigation combined with non-inertial navigation instruments G01C21/165
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00
• CPC Class Codes: Y10S 700/90 Special robot structural element

Abstract

Provided is a method of using a rotational movement amount of a mobile device including obtaining images at two different points on a path along which the mobile device moves, searching for matching points with respect to the obtained images and obtaining an image coordinate value of each of the matching points, sensing linear movement of the mobile device and obtaining a linear movement amount using a result of sensing, and obtaining the rotational movement amount using the image coordinate values and the linear movement amount.

Claims

1. A method of using a rotational movement amount of a mobile device comprising:

obtaining images at two different points on a path along which the mobile device moves;

searching for matching points with respect to the obtained images and obtaining an image coordinate value of each of the matching points;

sensing linear movement of the mobile device and obtaining a linear movement amount using a result of sensing; and

obtaining the rotational movement amount using the image coordinate values and the linear movement amount.

2. The method as claimed in claim 1, further comprising updating posture of the mobile device using the linear movement amount and the rotational movement amount.

3. The method as claimed in claim 2, further comprising determining whether to correct posture of the mobile device, wherein if it is determined that the posture of the mobile device needs to be corrected, the images are obtained.

4. The method as claimed in claim 2, wherein the mobile device moves from a time at which the image coordinate value is obtained until the posture is updated.

5. The method as claimed in claim 3, wherein the mobile device stops from a time at which the image coordinate value is obtained until the posture is updated.

6. The method as claimed in claim 2, further comprising:

starting movement of the mobile device;

initializing the posture of the mobile device and proceeding to obtaining the images; and

determining whether the mobile device arrives at a target position after the posture of the mobile device is updated and, if it is determined that the mobile device does not arrive at the target position, proceeding to obtaining the images.

7. The method as claimed in claim 3, further comprising:

starting movement of the mobile device;

initializing the posture of the mobile device and proceeding to determining whether to correct the posture; and

determining whether the mobile device arrives at a target position after the posture of the mobile device is updated and, if it is determined that the mobile device does not arrive at the target position, proceeding to determining whether to correct the posture.

8. The method as claimed in claim 7, further comprising moving the mobile device and proceeding to determining whether the mobile device arrives at the target position if it is determined that the posture of the mobile device does not need to be corrected.

9. The method as claimed in claim 1, wherein an interval between the two points are set to be narrow

10. The method as claimed in claim 1, wherein the number of the matching points are 8 that is the number of a minimum required matching point.

11. The method as claimed in claim 1, wherein the number of the matching points are 2 that is the number of a minimum required matching point.

12. The method as claimed in claim 10, wherein the number of the matching points are set to be an integral multiple of the number of a minimum required matching point.

13. The method as claimed in claim 3, wherein the pass formed by the two points is a straight line.

14. The method as claimed in claim 1, wherein the rotational movement amount of the mobile device is obtained using a conversion matrix (R_1,2) that is obtained as follows,

$\begin{array}{c}[\frac{\stackrel{\_}{u_{i,1}}}{f_{\mathrm{sx}}}\end{array}$

a i ⁢

v i , 1 _ f sy ] ·

R 2 , 1 ·

[ u i , 2 f sx ⁢

1 ⁢

v i , 2 f sy ] T = 0 , wherein ⁢

 

[ u i , 1 _ f sx ⁢

a i ⁢

v i , 1 _ f sy ] = [ u i , 1 f sx ⁢

1 ⁢

v i , 1 f sy ] ⁢

s ⁡

( t 1 , 2 1 )

and i=1, . . . , I, I denotes the number of the minimum required matching points, t_1,2 denotes a linear movement amount and ¹t_1,2 denotes a linear movement amount expressed as Coord. 1, u_i,2, u_i,1, v_i,1, and v_i,2 denote the image coordinate values, s( ) denotes a skew-symmetric matrix defined to express the cross product calculation of a vector, R_2,1 is an inverse matrix of R_1,2,,

$f_{\mathrm{sx}}=\frac{f_1}{s_x},f_{\mathrm{sy}}=\frac{f_2}{s_y},$

f₁ and f₂ denote focal distances from the two points, s_x and s_y denote scale factors, T denotes a transposed matrix, and a₁ denotes a constant.

15. An apparatus for using a rotational movement amount of a mobile device comprising:

an image obtaining portion which obtains images from two different points on a path along which the mobile device moves;

a coordinate value generating portion which searches for matching points with respect to the obtained images and generates an image coordinate value for each of the matching points;

a sensing portion which senses linear movement of the mobile device; and

a movement amount generating portion which generates a linear movement amount from a result of sensing and generates the rotational movement amount from the image coordinate values and the linear movement amount.

16. The apparatus as claimed in claim 15, further comprising a posture updating portion which updates posture of the mobile device from the linear movement amount and the rotational movement amount generated by the movement amount generating portion and outputs an updated result.

17. The apparatus as claimed in claim 16, further comprising a correction checking portion which checks whether to correct the posture of the mobile device, wherein the image obtaining portion obtains the images in response to a result of checking.

18. The apparatus as claimed in claim 16, further comprising:

a control portion which generates a movement control signal, a posture initialization signal, and an obtainment control signal; and

a position checking portion which checks whether the mobile device arrives at a target position in response to an update completion signal that indicates completion of update and is received from the posture updating portion,

wherein the mobile device moves in response to the movement control signal, the posture updating portion initializes the posture in response to the posture initialization signal, and the image obtaining portion obtains the image in response to the obtainment control signal and a result of checking by the position checking portion.

19. The apparatus as claimed in claim 17, further comprising:

a control portion which generates a movement control signal, a posture initialization signal, and a correction control signal; and

a position checking portion which checks whether the mobile device arrives at a target position in response to an update completion signal that indicates completion of update of the posture and is received from the posture updating portion,

wherein the mobile device moves in response to the movement control signal, the posture updating portion initializes the posture in response to the posture initialization signal, and the correction checking portion checks whether to correct the posture in response to the correction control signal or a result of checking checked by the position checking portion.

20. The apparatus as claimed in claim 19, wherein the control portion generates the movement control signal in response to a result of checking by the correction checking portion and controls a checking operation of the position checking portion.

21. A computer-readable recording medium for storing at least one computer program to control an apparatus for using a rotational movement amount of a mobile device, the computer program comprises:

obtaining images at two different points on a path along which the mobile device moves;

searching for matching points with respect to the obtained images and generating an image coordinate value of each of the matching points;

sensing linear movement of the mobile device and generating a linear movement amount using a result of sensing; and

generating the rotational movement amount using the image coordinate values and the linear movement amount.

22. The computer-readable recording medium as claimed in claim 21, wherein the computer program further comprise updating posture of the mobile device using the linear movement amount and the rotational movement amount.

23. The computer-readable recording medium as claimed in claim 22, wherein the computer program further comprises determining whether to correct the posture of the mobile device, wherein, if it is determined that the posture of the mobile device needs to be corrected, proceeding to obtaining the images.