SENSOR POSITIONING FOR 3D SCANNING

• US 20140085429A1
• Filed: 06/07/2012
• Published: 03/27/2014
• Est. Priority Date: 06/07/2011
• Status: Active Grant

• Current Assignee: Creaform, Inc. (Ametek Incorporated)
• Original Assignee: Eric Saint-Pierre, Felix Rochette, Patrick Hebert
• Inventors: Hbert, Patrick, Tubic, Dragan, Gignac, Olivier, Saint-Pierre, ric, Rochette, Flix, Carette, Alexandre
• Granted Patent: US 9,325,974 B2
• Time in Patent Office: Days
• US Class Current: 348/46
• CPC Class Codes: G01S 5/163 Determination of attitude using inertial means G01C9/00; control of attitude G05D1/49
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 2207/30204 Marker
• CPC Class Codes: G06T 2207/30244 Camera pose
• CPC Class Codes: G06T 7/75 involving models
• CPC Class Codes: G06T 7/80 Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
• CPC Class Codes: H04N 13/275 from 3D object models, e.g. computer-generated stereoscopic image signals

Abstract

A method for obtaining a refined pose for a 3D sensor for online 3D modeling of a surface geometry of an object, the pose encompassing six degrees of freedom (DOF) including three translation parameters and three orientation parameters, the method comprising: providing the 3D sensor, the 3D sensor being adapted to capture 3D point measurements of the surface of the object from a viewpoint; providing a geometry model of at least part of the surface; observing a portion of the surface of the object with the 3D sensor; measuring an initialization pose for the 3D sensor by at least one of positioning device pose measurement, predicted pose tracking and target observation; finding a best fit arrangement of the 3D point measurements in the geometry model using the initialization pose; generating the refined pose for the 3D sensor using the best fit arrangement.

Claims

1. A method for obtaining a refined pose for a 3D sensor for online 3D modeling of a surface geometry of an object, said pose encompassing six degrees of freedom (DOF) including three translation parameters and three orientation parameters, the method comprising:

providing said 3d sensor, said 3d sensor being adapted to capture 3d point measurements of said surface of said object from a viewpoint;

providing a geometry model of at least part of said surface;

observing a portion of said surface of said object with said 3d sensor;

measuring an initialization pose for said 3d sensor by at least one of positioning device pose measurement, predicted pose tracking and target observation;

finding a best fit arrangement of said 3d point measurements in said geometry model using said initialization pose;

generating said refined pose for said 3d sensor using said best fit arrangement;

wherein said positioning device pose measurement includes;

providing a positioning device;

measuring sensor location information indicating a device pose of said 3d sensor relative to the geometry model using said positioning device;

wherein said predicted pose tracking includes;

retrieving a previous tracked pose from a previous instance of said capture of said 3d point measurements;

assigning a predicted pose to said initialization pose, said predicted pose being predicted using said previous tracked pose;

wherein said target observation includes;

providing at least one target on said object;

providing a target model for said object, said target model including previously observed targets;

said observing said surface including observing at least one currently observed targets;

matching said currently observed target with a corresponding previously observed target using said target model;

generating at least one additional initialization parameter for said initialization pose by attributing a value for said additional initialization parameter;

obtaining said initialization pose from said matched target, said additional initialization parameter and said target model.

2. The method for obtaining a refined pose as claimed in claim 1, further comprising generating missing initialization parameters for said initialization pose if said initialization pose includes less than said six degrees of freedom, wherein said generating missing initialization parameters includes attributing a value for said missing initialization parameter.

3. The method for obtaining a refined pose as claimed in claim 2, wherein said generating missing initialization parameters includes sampling a parameter space of said initialization pose and said finding said best fit arrangement includes using each sampled initialization parameters and selecting a converging best fit arrangement.

4. The method for obtaining a refined pose as claimed in claim 1, wherein said refined pose includes at least one parameter of said initialization pose.

5. The method for obtaining a refined pose as claimed in claim 1, wherein said finding a best fit arrangement includes weighting geometry surface points and target points to find said best fit arrangement.

6. The method for obtaining a refined pose as claimed in claim 1, wherein said initialization pose includes at least one parameter measured by said positioning device pose measurement and at least one parameter measured by said target observation.

7. The method for obtaining a refined pose as claimed in claim 1, wherein said target is at least one of affixed to said surface of said object, affixed to a solidary environment of said object, created on said surface of said object, created on said solidary environment of said object, part of a distinctive shape feature of said object and part of a distinctive shape feature of said solidary environment of said object.

8. The method for obtaining a refined pose as claimed in claim 1, wherein said target is at least one of a photogrammetric target, a retro-reflective target, a coded target, a circular target, a simply reflective target, a drawn mark and a distinctive shape feature.

9. The method for obtaining a refined pose as claimed in claim 1, wherein said positioning device is at least one of a referenced mechanical device, an optical tracking device, an electromagnetic system, an acoustic system and an inertial system.

10. The method for obtaining a refined pose as claimed in claim 1, wherein said obtaining said initialization pose from said matched target and said target model includes obtaining a surface normal for said target.

11. The method for obtaining a refined pose as claimed in claim 1, wherein two of said targets are currently observed targets, said target observation further comprising comparing a distance between said currently observed targets to distances between previously observed targets in said target model to eliminate candidate sites for said match.

12. The method for obtaining a refined pose as claimed in claim 1, wherein said target observation further comprises selecting a candidate site for said match in said target model based on a quantity of said currently observed targets;

wherein said matching includes sequentially testing, at each said candidate site, said currently observed targets for said match with a same number of previously observed targets in said target model and said finding said best fit arrangement includes using each tested match and selecting a converging best fit arrangement.