Method and apparatus for registering a known digital object to scanned 3-D model

• US 7,471,821 B2
• Filed: 05/01/2002
• Issued: 12/30/2008
• Est. Priority Date: 04/28/2000
• Status: Expired due to Term

• Current Assignee: Orametrix Incorporated
• Original Assignee: Orametrix Incorporated
• Inventors: Weise, Thomas, Imgrund, Hans, Rubbert, Rüdger, Sporbert, Peer, Maetzel, Stephan
• Primary Examiner(s): Dang; Duy M
• Application Number:
  US10/136,607
• Publication Number:
  US 20030021453A1
• Time in Patent Office: 2,435 Days
• Field of Search: 382/154, 382128-132, 382/282, 382/285, 382/294, 382/313, 382/126, 345/415, 345/653, 345/664, 345/419, 356/12, 433/3, 433/24, 433/223, 433/29, 702/159, 702/167, 700/163, 250/310
• US Class Current: 382/154
• CPC Class Codes: A61B 5/1178 using dental data
• CPC Class Codes: A61B 5/4547 Evaluating teeth
• CPC Class Codes: A61C 7/00 Orthodontics, i.e. obtaining or maintaining the desired position of teeth, e.g. by straightening, evening, regulating, separating, or by correcting malocclusions
• CPC Class Codes: A61C 7/002 Orthodontic computer assisted systems
• CPC Class Codes: A61C 7/146 Positioning or placement of brackets; Tools therefor
• CPC Class Codes: A61C 9/006 projecting one or more stripes or patterns on the teeth
• CPC Class Codes: A61F 2002/30953 using a remote computer network, e.g. Internet
• CPC Class Codes: B33Y 50/00 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: G06T 17/00 Three dimensional [3D] modelling, e.g. data description of 3D objects
• CPC Class Codes: G06T 2207/30036 Dental; Teeth
• CPC Class Codes: G06T 7/75 involving models
• CPC Class Codes: H02K 3/22 consisting of hollow conductors
• CPC Class Codes: H02K 3/24 with channels or ducts for cooling medium between the conductors
• CPC Class Codes: H02K 3/487 Slot-closing devices

Abstract

Method and apparatus for registering an object of known predetermined geometry to scanned three dimensional data such that the object'"'"'s location may be verified. Such a known object may comprise a less than ideal three-dimensional (3-D) digital object such as a tooth, a dental appliance (e.g., as a tooth bracket model) or other like object, including portions thereof. Knowledge of such an object'"'"'s location is generally helpful in planning orthodontic treatment, particularly where the location of the object needs to be determined or confirmed or where incomplete or poor scan data is obtained. Aspects of the present invention provide methods of effectively verifying dental appliance location and displaying appliance locations using a computer and three-dimensional models of teeth.

Claims

1. A method of constructing a virtual three-dimensional model of an object, wherein said object comprises a first object attached to a second object, comprising the steps of:

scanning said object;

creating a scanned virtual three-dimensional model of said object from a point cloud obtained from said scanning step with the aid of a computer, said scanned virtual three-dimensional model having a first portion thereof corresponding to scanning of said first object, wherein said first object is of a known structure, said known structure of predetermined three-dimensional configuration, wherein said first portion is a less than an ideal three-dimensional representation of said known structure;

retrieving a pre-existing three-dimensional digital model from a memory, said three-dimensional digital model corresponding to said known structure;

registering said pre-existing three-dimensional digital model to a portion of said point cloud corresponding to said first portion to form a three-dimensional surface;

wherein said registering step comprises calculating minimum distance vectors from every point in said portion of said point cloud to said pre-existing three-dimensional digital model and excluding those points from said three dimensional surface whose minimum distance vectors exceed a predefined value; and

forming said virtual three-dimensional model of said object from said scanned virtual three-dimensional model of said object, said virtual three-dimensional model including said three-dimensional surface.

2. The method of claim 1, wherein said pre-existing three-dimensional digital model comprises a pre-existing three-dimensional digital model of an orthodontic appliance.

3. The method of claim 2, further comprising the steps of storing a library of pre-existing three-dimensional digital models of orthodontic appliances and selecting one of said pre-existing three-dimensional digital models of orthodontic appliances for said step of registration.

4. The method of claim 1, wherein said step of scanning is performed with a hand-held scanner using a projection pattern and an image pick-up to acquire three-dimensional information as to said object.

5. The method of claim 1, wherein said second object comprises an anatomical structure.

6. The method of claim 5, wherein said anatomical structure comprises teeth and wherein said known structure comprises an orthodontic appliance.

7. The method of claim 6, wherein said orthodontic appliance comprises an orthodontic bracket.

8. The method of claim 1, further comprising the steps of deleting said first portion and replacing said first portion with said three-dimensional surface resulting from said registration step.

9. The method of claim 1, further comprising the step of deleting said first portion and forming a second virtual three-dimensional model of said object by replacing said first portion with a second three-dimensional surface representing said object without said known structure.

10. The method of claim 1, wherein said object comprises at least one tooth and a bracket, and wherein said known structure comprises said bracket.

11. A workstation adapted to form a virtual three-dimensional model of an object, wherein said object comprises a first object attached to a second object, comprising:

a central processing unit;

a memory storing a scanned virtual three-dimensional model of said object in the form of a point cloud obtained from scanning said object, said scanned virtual three-dimensional model having a first portion thereof corresponding to scanning of said first object, wherein said first object is of a known structure;

said known structure of predetermined three-dimensional configuration, wherein said first portion is a less than an ideal three-dimensional representation of said known structure;

said memory further storing a pre-existing three-dimensional digital model corresponding to said known structure; and

software executable by said central processing unit for registering said pre-existing three-dimensional digital model to a portion of said point cloud corresponding to said first portion to form a three-dimensional surface;

wherein said software for registering comprises software for calculating minimum distance vectors from every point in said portion of said point cloud to said pre-existing three-dimensional digital model and excluding those points from said three dimensional surface whose minimum distance vectors exceed a predefined value; and

for forming the virtual three-dimensional model of said object from said scanned virtual three-dimensional model of said object, said virtual three-dimensional model of said object including said three-dimensional surface.

12. The workstation of claim 11, wherein said pre-existing three-dimensional digital model comprises a pre-existing three-dimensional digital model of an orthodontic appliance.

13. The workstation of claim 12 wherein said memory further comprises a library of pre-existing three-dimensional digital models of orthodontic appliances and selecting one of said pre-existing three-dimensional digital models of orthodontic appliances for registering said pre-existing three-dimensional digital model to said first portion.

14. The workstation of claim 11, further comprising a hand-held scanner using a projection pattern and an image pick-up to acquire three-dimensional information as to said object.

15. The workstation of claim 11, wherein said second object comprises an anatomical structure.

16. The workstation of claim 15, wherein said anatomical structure comprises teeth and wherein said known structure comprises an orthodontic appliance.

17. The workstation of claim 16 wherein said orthodontic appliance comprises a tooth bracket.

18. The workstation of claim 11, wherein said software executable by said central processing unit includes instructions for deleting said first portion and and instructions for replacing said first portion with said three-dimensional surface resulting from said registration step.

19. The workstation of claim 11, wherein said software executable by said central processing unit includes instructions for deleting said first portion, and instructions for replacing said first portion with a second three-dimensional surface representing said object without said known structure, thereby forming a second three-dimensional virtual model of said object.

20. The workstation of claim 11, wherein said object comprises at least one tooth and a bracket, and wherein said known structure comprises said bracket.

21. An apparatus for constructing a virtual three-dimensional model of an object, wherein said object comprises a first object attached to a second object, comprising:

means for scanning said object;

means for creating a scanned virtual three-dimensional model of said object in the form of a point cloud from said scanning step with the aid of a computer, said scanned virtual three-dimensional model having a first portion thereof corresponding to scanning of said first object, wherein said first object is of a known structure, said known structure of predetermined three-dimensional configuration, wherein said first portion is a less than an ideal three-dimensional representation of said known structure;

means for retrieving a pre-existing three-dimensional digital model from a memory, said pre-existing three-dimensional digital model corresponding to said known structure;

means for registering said pre-existing three-dimensional digital model to a portion of said point cloud corresponding to said first portion to form a three-dimensional surface;

wherein said means for registering comprise means for calculating minimum distance vectors from every point in said portion of said point cloud to said pre-existing three-dimensional digital model and excluding those points from said three dimensional surface whose minimum distance vectors exceed a predefined value; and

means for forming said virtual three-dimensional model of said object from said scanned virtual three-dimensional model of said object, said virtual three-dimensional model including said three-dimensional surface.

22. The apparatus of claim 21, wherein said pre-existing three-dimensional digital model comprises a pre-existing three-dimensional digital model of an orthodontic appliance.

23. The apparatus of claim 21, further comprising a library of stored pre-existing three-dimensional digital models of orthodontic appliances, wherein one of said pre-existing three-dimensional digital models of orthodontic appliances is selected for registering said pre-existing three-dimensional digital model to said first portion to form a three-dimensional surface.

24. The apparatus of claim 21, further comprising a hand-held scanner using a projection pattern and an image pick-up to acquire three-dimensional information as to said object.

25. The apparatus of claim 21, wherein said second object comprises an anatomical structure.

26. The apparatus of claim 21, wherein said anatomical structure comprises teeth and wherein said known structure comprises an orthodontic appliance.

27. The apparatus of claim 26, wherein said orthodontic appliance comprises an orthodontic bracket.

28. The apparatus of claim 21, further comprising means for deleting said first portion and means for replacing said first portion with said three-dimensional surface resulting from said registration step.

29. The apparatus of claim 21, further comprising means for deleting said first portion, means for replacing said first portion with a second three-dimensional surface representing said object without said known structure, thereby forming a second three-dimensional virtual model of said object.

30. The apparatus of claim 21, wherein said object comprises at least one tooth and a bracket, and wherein said known structure comprises said bracket.

31. A method of constructing a virtual three-dimensional model of an object having a predefined geometry from a scanner, a data processing system, and at least one machine-readable memory accessible to the data processing system, comprising the steps of:

(a) scanning the object with the scanner and responsively obtaining a three-dimensional surface of said object in the from a point cloud;

wherein said three-dimensional surface of said object is a less than an ideal three-dimensional representation of said object;

(b) obtaining a pre-existing three-dimensional digital model of said object from said memory; and

(c) registering said three-dimensional surface in the from said point cloud to said pre-existing three-dimensional digital model to thereby produce the virtual three-dimensional model of said object;

wherein said registering step comprises calculating minimum distance vectors from every point in said point cloud to said pre-existing three-dimensional digital model and excluding those points from said three dimensional surface whose minimum distance vectors exceed a predefined value.

32. A method of constructing a virtual three-dimensional model of an object having a predefined geometry from a scanner, a data processing system, and at least one machine-readable memory accessible to the data processing system, comprising the steps of:

(a) scanning the object with the scanner and thereby obtaining a first and a second two-dimensional images of the object, wherein during scanning the scanner and object are moved relative to each other;

(b) processing the first and second images with the data processing system so as to convert the two-dimensional images into a data set representing a point cloud comprising individual points, each point comprising a location in a three-dimensional coordinate system;

(c) obtaining a pre-existing three-dimensional digital model of the object; and

(d) further processing the data set representing the point cloud with the data processing system so as to register the point cloud relative to the pre-existing three-dimensional digital model to thereby produce the virtual three-dimensional model of the object;

wherein said registering step comprises calculating minimum distance vectors from every point in said point cloud to said pre-existing three-dimensional digital model and excluding those points from said virtual three-dimensional model of the object whose minimum distance vectors exceed a predefined value.

33. The method of claim 32, wherein a spatial transformation relationship is derived for the point cloud and stored in the memory, the spatial transformation relationship indicating how the points in the point cloud should be translated and rotated in a three-dimensional coordinate system to register the point cloud relative to the pre-existing three-dimensional digital model.

34. The method of claim 32, wherein in step (d) an operator manipulates the virtual three-dimensional model of said object.

35. The method of claim 32, wherein step (d) is initiated by placing a virtual marker on a representation of the object.

36. The method of claim 32 wherein said object comprises an orthodontic appliance, and wherein said two-dimensional images of said object are obtained during a monitoring scan initiated after the orthodontic treatment using the orthodontic appliance has commenced.

37. The method of claim 32 wherein the pre-existing three-dimensional digital model is retrieved from a digital library comprising a plurality of pre-existing three-dimensional digital models.

38. The method of claim 32, wherein the scanner comprises a hand-held scanning device and the object is scanned by moving said hand-held scanning device over said object.

39. The method of claim 32, wherein the object comprises a dental appliance.

40. The method of claim 39, wherein the dental appliance comprises a bracket.

41. The method of claim 32, wherein the data processing system is incorporated into a workstation for said scanner.

42. A method of determining a location of a virtual three-dimensional model of an object of known geometry, comprising the steps of:

a) scanning said known object and generating a set of images;

b) converting said set of images into a point cloud;

c) retrieving said virtual three-dimensional model of said object from memory; and

d) registering said point cloud to said virtual three-dimensional model of said object to thereby verify in three-dimensional space the position of said virtual three-dimensional model of said object;

wherein said registering step comprises calculating minimum distance vectors from every point in said point cloud to said virtual three-dimensional model of said object and excluding those points from said virtual three-dimensional model of said object whose minimum distance vectors exceed a predefined value.

43. A method of registering a first digital model of a dental appliance to a three-dimensional representation of said dental appliance as a result of scanning, comprising the steps of:

p1 a) scanning said dental appliance and generating a first set of images;

b) converting said first set of images into a three-dimensional representation of said dental appliance in the form of a point cloud;

c) retrieving said first digital model of said dental appliance from a digital library;

d) fitting said three-dimensional representation in the form of said point cloud to said first digital model to thereby register said first digital model to said three-dimensional representation and generate a revised three dimensional representation of the dental appliance;

wherein said registering step comprises calculating minimum distance vectors from every point in said point cloud to said first digital model of said object and excluding those points from said three-dimensional representation whose minimum distance vectors exceed a predefined value.

44. The method of claim 43 further comprising the steps of

scanning a second known object and generating a second set of images;

converting said second set of images into a second point cloud;

deleting said registered first digital model from said revised three dimensional representation;

retrieving a second digital model of said second known object from a digital library;

performing a best fit analysis of said second point cloud to said second digital model to thereby register said second digital model to said second point cloud and generate a second revised three dimensional representation.

45. The method of claim 44 wherein said second digital model is a virtual digital tooth model.