System for adaptive three-dimensional scanning of surface characteristics

• US 8,284,240 B2
• Filed: 07/30/2009
• Issued: 10/09/2012
• Est. Priority Date: 08/06/2008
• Status: Active Grant

• Current Assignee: Creaform, Inc. (Ametek Incorporated)
• Original Assignee: Creaform, Inc. (Ametek Incorporated)
• Inventors: Saint-Pierre, Éric, Tubic, Dragan, Hebert, Patrick
• Primary Examiner(s): Patel, Jay
• Assistant Examiner(s): PRINCE, JESSICA MARIE
• Application Number:
  US13/055,030
• Publication Number:
  US 20110134225A1
• Time in Patent Office: 1,167 Days
• Field of Search: 348 25-172, 3483841-4401, 348699-702, 348818-843, 382/154
• US Class Current: 348/47
• CPC Class Codes: G01B 11/03 by measuring coordinates of points
• CPC Class Codes: G01B 11/25 by projecting a pattern, e.g. one or more lines, moiré fringes on the object G01B11/255 takes precedence ; image analysis for depth or shape recovery G06T7/50
• CPC Class Codes: G01B 11/30 for measuring roughness or irregularity of surfaces
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light

Abstract

There are provided systems and methods for obtaining a three-dimensional surface geometric characteristic and/or texture characteristic of an object. A pattern is projected on a surface of said object. A basic 2D image of said object is acquired; a characteristic 2D image of said object is acquired; 2D surface points are extracted from said basic 2D image, from a reflection of said projected pattern on said object; a set of 3D surface points is calculated in a sensor coordinate system using said 2D surface points; and a set of 2D surface geometric/texture characteristics is extracted.

Claims

1. A system for obtaining data representing surface points of an object, said system comprising:

a sensing device having a pattern projector for providing a projected pattern on a surface of said object, at least one basic camera for acquiring basic 2D image data representing a basic 2D image of at least a portion of said object at a basic resolution, and a characteristic camera for acquiring characteristic image data representing a characteristic image of at least a portion of said object, said characteristic camera being at least one of a texture camera and a high resolution camera, said texture camera being a camera adapted to capture characteristic texture information about said portion of said object, said high resolution camera being a camera adapted to capture high resolution information about said portion of said object at a high resolution, said high resolution being higher than said basic resolution, said projected pattern being apparent on said basic image, at least part of said projected pattern being apparent on said characteristic image, a spatial relationship of said basic camera, said pattern projector and said characteristic camera in a sensor coordinate system being known, said characteristic camera and said basic camera being synchronized to allow said basic camera and said characteristic camera to respectively capture said basic 2D image data and said characteristic image data simultaneously while said pattern is projected on said surface of said object by said pattern projector;

a basic image processor for extracting, from said basic 2D image data, 2D point data representing at least one set of 2D surface points provided from a reflection of said projected pattern on said surface;

a 3D surface point calculator for calculating a set of 3D surface points in said sensor coordinate system using said 2D point data representing set of 2D surface points;

a characteristic image processor for

mathematically projecting said set of 3D surface points onto said characteristic image data to obtain a location of said 3D surface points in said characteristic image data,

guiding an extraction of characteristic data for said set of 3D surface points using said projected 3D surface points in said characteristic image data, said guiding including local image processing if said characteristic camera is said high resolution camera and said guiding avoiding interference by said projected pattern on said extracted characteristic data if said characteristic camera is said texture camera, and

obtaining, using said characteristic data of said extraction, at least one of a refined position of said 3D surface points if said characteristic camera is said high resolution camera and a texture of said 3D surface points if said characteristic camera is said texture camera.

2. The system as claimed in claim 1, further comprising

a positioning system for obtaining transformation parameters, said transformation parameters representing a spatial relationship between said sensor coordinate system and a global coordinate system;

and

a 3D surface point transformer for transforming said set of 3D surface points into a set of transformed 3D surface points in said global coordinate system using said transformation parameters.

3. The system as claimed in claim 2, wherein the positioning system comprises:

a set of target positioning features on said object, each of said target positioning features being provided at a fixed position on said object, a global coordinate system being defined using said target positioning features, at least a portion of said set of target positioning features being apparent on said basic 2D image, said set of target positioning features to be extracted from said basic 2D image by said image processor; and

wherein said system further comprises

a 3D positioning calculator for calculating said transformation parameters using said positioning system.

4. The system as claimed in claim 3, further comprising:

a surface reconstructor for cumulating the set of transformed 3D surface points and said characteristic data for said 3D surface points to provide a 3D surface model of said object.

5. The system as claimed in claim 4, wherein said surface reconstructor comprises a model resolution adjuster for adjusting a resolution of said cumulating the set of transformed 3D surface points.

6. The system as claimed in claim 4, further comprising:

a local tangent plane calculator for calculating a set of local tangent planes from the set of transformed 3D surface points in the global coordinate system,

said surface reconstructor using said local tangent planes to provide said 3D surface model of said object.

7. The system as claimed in claim 6, wherein said local tangent plane calculator comprises a tangent plane resolution adjuster for adjusting a resolution of said calculating a set of local tangent planes.

8. The system as claimed in claim 1, wherein said characteristic camera is a texture camera, said characteristic image is a texture image, wherein said characteristic image processor comprises a texture image processor and wherein said characteristic data is texture data obtained in texture patches.

9. The system as claimed in claim 6, wherein said characteristic camera is a texture camera, said characteristic image is a texture image, wherein said characteristic image processor comprises a texture image processor and wherein said characteristic data is texture data obtained in image texture patches.

10. The system as claimed in claim 9, further comprising:

a texture integrator for mapping and accumulating the set of texture patches onto the set of local tangent planes to produce one of a set of 2D texture maps and a set of local textured tangent planes.

11. The system as claimed in claim 1, wherein said characteristic camera is a high resolution camera, said characteristic image is a high resolution 2D image, wherein said characteristic image processor comprises a high resolution image processor, and wherein said characteristic data is high resolution 2D surface points.

12. The system as claimed in claim 1, wherein said characteristic camera is a high resolution texture camera, said characteristic image is a high resolution texture image, wherein said characteristic image processor comprises a texture image processor and a high resolution image processor and wherein said characteristic data comprises high resolution 2D surface points and texture data obtained in image texture patches.

18. The system as claimed in claim 1, wherein said pattern projector of said sensing device is a laser pattern projector.

13. A method for obtaining data representing surface points of an object, said method comprising:

obtaining basic 2D image data representing a basic 2D image of at least a portion of said object using at least one basic camera at a basic resolution, a projected pattern projected on a surface of said object being apparent on said basic image;

obtaining characteristic image data representing a characteristic image of at least a portion of said object using a characteristic camera, at least part of said projected pattern projected on said surface of said object being apparent on said characteristic image, said characteristic camera being at least one of a texture camera and a high resolution camera, said texture camera being a camera adapted to capture characteristic texture information about said portion of said object, said high resolution camera being a camera adapted to capture high resolution information about said portion of said object at a high resolution, said high resolution being higher than said basic resolution;

extracting, from said basic 2D image data, 2D point data representing at least one set of 2D surface points provided from a reflection of said projected pattern on said surface;

calculating a set of 3D surface points in a sensor coordinate system using said 2D point data representing set of 2D surface points, a spatial relationship of said basic camera, said pattern projector and said characteristic camera in said sensor coordinate system being known; and

mathematically projecting said set of 3D surface points onto said characteristic image data to obtain a location of said 3D surface points in said characteristic image data;

guiding an extraction of characteristic data for said set of 3D surface points using said projected 3D surface points in said characteristic image data, said guiding including local image processing if said characteristic camera is said high resolution camera and said guiding avoiding interference by said projected pattern on said extracted characteristic data if said characteristic camera is said texture camera, and

obtaining, using said characteristic data of said extraction, at least one of a refined position of said 3D surface points if said characteristic camera is said high resolution camera and a texture of said 3D surface points if said characteristic camera is said texture camera.

14. The method as claimed in claim 13, wherein said basic 2D image and said characteristic image are obtained using a sensing device having a pattern projector for providing said projected pattern on said surface of said object, at least one basic camera for acquiring a basic 2D image of said object, and a characteristic camera for acquiring a characteristic image of said object, a spatial relationship of said basic camera, said pattern projector and said characteristic camera in a sensor coordinate system being known, said characteristic camera and said basic camera being synchronized to allow said basic camera and said characteristic camera to respectively capture said basic 2D image data and said characteristic image data simultaneously while said pattern is projected on said surface of said object by said pattern projector.

15. The method as claimed in claim 13, further comprising

obtaining transformation parameters, said transformation parameters representing a spatial relationship between said sensor coordinate system and a global coordinate system,

transforming said set of 3D surface points into a set of transformed 3D surface points in said global coordinate system using said transformation parameters.

16. The method as claimed in claim 15, further comprising:

cumulating the set of transformed 3D surface points to provide a 3D surface model of said object.

17. The method as claimed in claim 16, further comprising:

calculating a set of local tangent planes from the set of transformed 3D surface points in the global coordinate system,

using said local tangent planes to provide said 3D surface model of said object.