Deviation-correction system for positioning of moving objects and motion tracking method thereof

• US 20070179710A1
• Filed: 12/22/2006
• Published: 08/02/2007
• Est. Priority Date: 12/31/2005
• Status: Active Grant

• Current Assignee: Nuctech Company Limited (Tsinghua Tongfang Co., Ltd.), Tsinghua University
• Original Assignee: Nuctech Company Limited (Tsinghua Tongfang Co., Ltd.), Tsinghua University
• Inventors: Wang, Zhiming, Liu, Yinong, Li, Yuanjing, Xing, Yuxiang, Zhang, Li, Xiao, Yongshun, Chen, Zhiqiang, Zhao, Ziran, Wang, Lijun
• Granted Patent: US 7,962,283 B2
• Time in Patent Office: Days
• US Class Current: 701/210
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means

Abstract

The present invention relates to the deviation-correction system for positioning of moving objects, and discloses a deviation-correction system for positioning of moving objects and the motion-tracking method thereof. The system includes a control system for receiving motion parameters required for deviation-correction, and sending commands to an actuator to control a moving object based on the motion parameters, the deviation-correction system for positioning of moving objects further comprising: a reference object which is set as a specified motion trail for the moving object; an image capturing system for acquiring successive digital image data upon the moving object moves; a motion tracking system for performing a motion tracking algorithm based on the digital image data transmitted by the image capturing system to judge whether the current motion state needs to be corrected and then transmitting the motion parameters required for deviation-correction to the control system.

Claims

1. A deviation-correction system for positioning of moving objects comprising a control system for receiving motion parameters required for deviation-correction, and sending commands to an actuator to control a moving object based on the motion parameters, the deviation-correction system for positioning of moving objects further comprising:

a reference object which is set as a specified motion trail for the moving object;

an image capturing system for acquiring successive digital image data upon the moving object moves; and

a motion tracking system for performing a motion tracking algorithm based on the digital image data transmitted by the image capturing system to judge whether the current motion state needs to be corrected and then transmitting the motion parameters required for deviation-correction to the control system.

2. The deviation-correction system for positioning of moving objects according to claim 1, wherein the reference object is a static reference object on the ground.

3. The deviation-correction system for positioning of moving objects according to claim 1, wherein the static reference object on the ground includes a color-identified line or strip which is same as the motion trail.

4. The deviation-correction system for positioning of moving objects according to claim 1, wherein the reference object includes two fixed specific reference objects at the start point or the finish point of the moving object.

5. The deviation-correction system for positioning of moving objects according to claim 1, wherein the reference object comprises a static scene at the finishing point.

6. The deviation-correction system for positioning of moving objects according to claim 1, wherein the image capturing system comprises:

one or more cameras;

an illuminator or a light compensation device for compensating illumination to enhance the quality of images captured by the cameras.

7. The deviation-correction system for positioning of moving objects according to claim 1, wherein the motion tracking system comprises:

a data acquisition card for acquiring image data;

a computer for processing image data and transmitting the processed image data to the control system; and

an interface to the control system for transmitting motion parameters.

8. A motion-tracking method in the deviation-correction system for positioning of moving objects according to claim 1, the motion tracking method comprising:

1) receiving images transmitted from an image capturing system;

2) extracting feature of reference object image from two images, to obtain a matching feature pair;

3) computing the relative motion parameters of a moving object, based on the positional relation between the matching features in two images;

4) transmitting motion parameters to a controller for deviation-correction if the motion parameters under current motion state exceed preset threshold values, otherwise adding the motion parameters into the history record of motion trail.

9. The motion tracking method according to claim 8, wherein the step 2) comprises:

positioning the reference objection in the images using an image processing method on the basis of the feature of the reference object.

10. The motion tracking method according to claim 9, wherein the image processing method determines the center axis of a straight line as matching feature if the straight line is taken as the reference object.

11. The motion tracking method according to claim 9, wherein the motion parameters include offset amount, direction and rotation.

12. The motion tracking method according to claim 8, wherein the preset threshold value is decided by the maximum deviation tolerable to the moving object.