Tracing technique and recording media of object motion

• US 6,950,550 B1
• Filed: 09/26/2000
• Issued: 09/27/2005
• Est. Priority Date: 07/07/2000
• Status: Expired due to Term

• Current Assignee: Koji Kajimura, Stanley Electric Company Limited
• Original Assignee: Koji Kajimura, Stanley Electric Company Limited
• Inventors: Tomita, Fumiaki, Ishiyama, Yutaka, Sumi, Yasushi
• Primary Examiner(s): Werner, Brian
• Assistant Examiner(s): Patel, Shefali
• Application Number:
  US09/669,384
• Time in Patent Office: 1,827 Days
• Field of Search: 382/154, 382/107, 348/169, 345/418, 345/419
• US Class Current: 382/154
• CPC Class Codes: G06T 7/285 using a sequence of stereo image pairs
• CPC Class Codes: G06T 7/75 involving models
• CPC Class Codes: G06V 10/24 Aligning, centring, orientation detection or correction of the image
• CPC Class Codes: H04N 13/243 using three or more 2D image sensors

Abstract

After stereo image is inputted (S1), the tracing point corresponding to the silhouette of a curved object observed by the stereo image is selected on the basis of the information on the present position of the object (S2), using a three-dimensional geometric model. And the corresponding points on the silhouette corresponding to respective tracing points are sampled from the stereo image (S3), and their three-dimensional coordinates are measured (S4). Then, from the group of the three-dimensional coordinates of tracing points and corresponding points, the position/posture of the object concerned and the measurement error are determined (S5), to discriminate the error (S6). In case the error is not small enough, processes starting from (S2) are repeated, regarding the detected position/posture as a renewed present position, while, if the error is small enough, processes are repeated starting from (S1), regarding the detected position/posture as a renewed present position, thereby providing the technique for high-speed tracing of three-dimensional rigid body motion of an arbitrarily-curved and smooth faced object utilizing an object model, applying a stereo camera system as sensors.

Claims

1. An object motion tracing method for tracing the three-dimensional motion of an object having an arbitrarily curved and smooth surface, based on the stereo image of the object concerned obtained in time series, composed of:

an inputting step for inputting a stereographic image frame of the object concerned;

a selecting step for selecting tracing points on a three-dimensional object model corresponding to the silhouette of the object concerned in the inputted image frame based on the present position of the object concerned;

a sampling step for sampling points on the silhouette of the object in the image frame corresponding to respective tracing points on the three-dimensional object model;

a measuring step for measuring the three-dimensional coordinates of the sampled corresponding points; and

a detecting step for detecting the position/posture of the object from the three-dimensional coordinates of those respective tracing points and respective corresponding points and for detecting a detection error, wherein

if the detected error is not small enough, the three-dimensional motion of aforesaid object is traced by continuously repeating each process from the selecting step through the detecting step toward each frame of the stereo image obtained in time series, or

if the detected error is small enough, the three-dimensional motion of the aforesaid object is traced by continuously repeating each process from the inputting step through the detecting step toward each frame of the stereo image obtained in time series.

2. The object motion tracing method according to claim 1, wherein the three-dimensional geometric model of an object is used to select the tracing points on the selecting step.

3. The object motion tracing method according to claim 1, wherein the three-dimensional coordinates are measured by stereo vision applying stereo correspondence on the measuring step.

4. The object motion tracing method according to claim 1, wherein the three-dimensional coordinates are measured by monocular vision on the measuring step.

5. A computer readable medium wherein an object motion tracing program is recorded for tracing the three-dimensional motion of an object having an arbitrarily curved and smooth surface on the basis of the stereo image of the object obtained in time series, composed of:

an inputting step for inputting a stereographic image frame of the object concerned;

a selecting step for selecting the tracing point corresponding to the silhouette of the object concerned on the inputted image frame based on the present position of the object concerned;

a sampling step for sampling points on the silhouette of the object in the image frame corresponding to respective tracing points on the three-dimensional object model;

a measuring step for measuring the three-dimensional coordinates for the sampled corresponding points; and

a detecting step for detecting the position/posture of the object from respective the three-dimensional coordinates of the respective tracing points and respective sampled points and for detecting a detection error, wherein

if the detected error is not small enough, the program for executing the tracing of the three-dimensional motion of the object continuously repeats each process from the selecting step through the detecting step as mentioned above toward each frame of the stereo image obtained in time series, or

if the detected error is small enough, the program for executing the tracing of the three-dimensional motion of the object continuously repeats each process from the inputting step through the detecting step toward each frame of the stereo image obtained in time series.

6. The computer readable medium according to claim 5, wherein the program is recorded for executing the selection of the tracing point using the three-dimensional geometric model of an object on the selecting step.

7. The computer readable medium as according to claim 5, wherein

the program is recorded for executing the measurement of the three-dimensional coordinates by stereo vision applying stereo correspondence on the measuring step.

8. The computer readable medium according to claim 5, wherein the program is recorded for executing the measurement of the three-dimensional coordinates by monocular vision on the measuring step.

9. An object motion tracing method for tracing the three-dimensional motion of an object having an arbitrarily curved and smooth surface, based on the stereo image of the object concerned obtained in time series, composed of:

a selecting step for selecting tracing points corresponding to the silhouette of the object concerned in the stereo image of the object, wherein the rigid body motion parameters of an object between frames of inputted images in time series and the form of the silhouette varying every moment are estimated simultaneously;

a sampling step for sampling from the above-mentioned stereo image the corresponding points on the silhouette of the object corresponding to respective tracing points;

a measuring step for measuring the three-dimensional coordinates of the sampled corresponding points; and

a detecting step for detecting the position/posture of the object from the three-dimensional coordinates of those respective tracing points and respective corresponding points, wherein

the three-dimensional motion of aforesaid object is traced by continuously repeating each process from the selecting step through the detecting one toward each frame of the stereo image obtained in time series.