Method for recording multiple three-dimensional images of a dental object

Patent metadata

Field	Value
Publication number	US-9456754-B2
Application number	US-201214236517-A
Country	US
Kind code	B2
Filing date	Aug 1, 2012
Priority date	Aug 1, 2011
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

A method and apparatus for forming an overall image of an object from a plurality of images. Each image includes three-dimensional data and color data and is segmented based on the color data to identify a first region with hard tissue and a second region with soft tissue. For each image, first and second weighting factors may be assigned. Points in the second region with a larger distance to a corresponding proximate part of the first region may have a smaller second weighting factor than a point with a smaller distance to a corresponding proximate part of the first region. The second weighting factor may be variable, with its value dependent upon a value of a first area section corresponding to the first region.

First claim

The invention claimed is:

1. A method of forming an overall image of an object from a plurality of images, the method comprising:
segmenting each image, of a plurality of images, to identify a first region with hard tissue and a second region with soft tissue, wherein each image includes three-dimensional data and color data, and each image is segmented based on the color data;
assigning for each image (i) a first weighting factor to the first region and (ii) second weighting factors to points within the second region, respectively,
wherein a point with a larger distance to a corresponding proximate part of the first region has a smaller second weighting factor than a point with a smaller distance to a corresponding proximate part of the first region; and

combining the plurality of images to form an overall image based on the first weighting factors and the second weighting factors assigned to the plurality of images.

2. The method according to claim 1 , wherein the first regions correspond to tooth substances or dental restorations, and the second regions correspond to gingiva or gingiva substitutes.

3. The method according to claim 1 , wherein points in the second region that border the first region are assigned second weighting factors with a value of 1.0, and
wherein a minimum value for the second weighting factors is 0.

4. The method according to claim 1 , further comprising:
identifying for each image a third region with soft tissue that is not assigned either to the first region or to the second region, the third region being a light region associated with glare or a dark region associated with inadequate illumination,
wherein the third region is not taken into account in the combining.

5. The method according to claim 1 , further comprising:
applying a blur filter to the color data in each of the plurality of images.

6. The method according to claim 1 , further comprising:
receiving each of the plurality of images from a dental handpiece that generates the three-dimensional data and the color data simultaneously or sequentially from the same imaging direction.

7. The method according to claim 6 , wherein the three-dimensional data is generated using a triangulation method and a strip projection method, and the color data is generated using a color camera.

8. The method according to claim 6 , wherein the three-dimensional data and the color data are generated sequentially within an interval of time that is between 0.2 ms and 100 ms.

9. An apparatus for forming an overall image of an object, comprising:
a computer configured to:
segment each image, of a plurality of images, to identify a first region with hard tissue and a second region with soft tissue, wherein each image includes three-dimensional data and color data, and each image is segmented based on the color data,
assign for each image (i) a first weighting factor to the first region and (ii) second weighting factors to points within the second region, respectively, wherein a point with a larger distance to a corresponding proximate part of the first region has a smaller second weighting factor than a point with a smaller distance to a corresponding proximate part of the first region, and
combine the plurality of images to form an overall image based on the first weighting factors and the second weighting factors assigned to the plurality of images.

10. The apparatus according to claim 9 , wherein the first regions of the plurality of images correspond to tooth substances or dental restorations, and the second regions of the plurality of images correspond to gingiva or gingiva substitutes.

11. The apparatus according to claim 9 ,
wherein points in the second region that border the first region are assigned second weighting factors with a value of 1.0, and
wherein a minimum value for the second weighting factors is 0.

12. The apparatus according to claim 9 , wherein the computer is further configured to:
identify for each image a third region with soft tissue that is not assigned either to the first region or to the second region, the third region being a light region associated with glare or a dark region associated with inadequate illumination,
wherein the third region is not taken into account when the plurality of images are combined.

13. The apparatus according to claim 9 , wherein the computer is further configured to:
apply a blur filter to the color data in each of the plurality of images.

14. The apparatus according to claim 9 , wherein the computer is further configured to:
receive each of the plurality of images from a dental handpiece that generates the three-dimensional data and the color data simultaneously or sequentially from the same imaging direction.

15. The apparatus according to claim 14 , wherein the three-dimensional data is generated using a triangulation method and a strip projection method, and the color data is generated using a color camera.

16. The apparatus according to claim 14 , wherein the three-dimensional data and the color data are generated sequentially within an interval of time that is between 0.2 ms and 100 ms.

17. A method of forming an overall image of an object from a plurality of images, the method comprising:
segmenting each image, of a plurality of images, to identify a first region with hard tissue and a second region with soft tissue, wherein each image includes three-dimensional data and color data, and each image is segmented based on the color data;
calculating (i) a first area section for each image that represents a percentage of a total area of the image identified as the first region, and (ii) a second area section for each image that represents a percentage of a total area of the image identified as the second region;
comparing the first area section for each image to a predetermined threshold,
wherein if an image has a first area section that is greater than a predetermined threshold, then a first weighting factor is assigned to the first area section and a second weighting factor is assigned to the second region,
wherein if an image has a first area section that is less than a predetermined threshold, then a first weighting factor is assigned to the first area section and a second variable weighting factor is assigned to the second region, and
wherein a value of the second variable weighting factor depends on a value of the first area section; and

combining the plurality of images to form an overall image based on the first and second weighting factors assigned to the plurality of images.

18. The method according to claim 17 , wherein the value of the second variable weighting factor increases as the value of the first area section decreases.

19. The method according to claim 18 , wherein the dependence of the value of the second variable weighting factor on the first area section is expressed by an exponential function.

20. The method according to claim 18 , wherein the dependence of the value of the second variable weighting factor on the first area section is expressed by a linear function.

21. An apparatus, comprising:
a computer configured to:
segment each image, of a plurality of images, to identify a first region with hard tissue and a second region with soft tissue, wherein each image includes three-dimensional data and color data, and each image is segmented based on the color data for the image;
calculate (i) a first area section for each image that represents a percentage of a total area of the image identified as the first re

Assignees

• Kocherscheidt Gerrit
• Adamson Anders
• Popilka Björn
• Thiel Frank
• Sirona Dental Systems Gmbh

Inventors

• Kocherscheidt Gerrit
• Adamson Anders
• Popilka Björn
• Thiel Frank

Classifications

• A61C9/006

  projecting one or more stripes or patterns on the teeth · CPC title

• G06T2207/30036

  Dental; Teeth · CPC title

• A61B5/0064

  Body surface scanning · CPC title

• G06T7/33

  using feature-based methods · CPC title

• A61C9/0046

  Data acquisition means or methods · CPC title