3D intraoral measurements using optical multiline method

• US 9,295,532 B2
• Filed: 11/10/2011
• Issued: 03/29/2016
• Est. Priority Date: 11/10/2011
• Status: Active Grant

• Current Assignee: Dental Imaging Technologies Corporation (Envista Holdings Corporation)
• Original Assignee: CareStream Health Incorporated
• Inventors: Milch, James R.
• Primary Examiner(s): Kelley, Christopher S
• Assistant Examiner(s): BEASLEY, DEIRDRE L
• Application Number:
  US13/293,308
• Publication Number:
  US 20130120532A1
• Time in Patent Office: 1,601 Days
• Field of Search: 348/45, 348/E13.074
• US Class Current: 1/1
• CPC Class Codes: A61C 9/006 projecting one or more stripes or patterns on the teeth
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns
• CPC Class Codes: G06T 2207/30036 Dental; Teeth
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light

Abstract

A method for mapping a sensor pixel array to an illumination pixel array according to a surface forms a group map by assigning each pixel on the sensor array to a corresponding group of an ordered set of groups, each group defined by a set of p adjacent pixels on the illumination pixel array by projecting and recording at least n projected images from a first set of n binary patterns, with transitions between pixels in each of the n binary patterns only at group boundaries. At least m images from a second set of m binary patterns are projected and recorded, with one or more transitions between pixels in each of the m binary pattern offset from group boundaries. At least p multiline images are projected and recorded. Lines in the recorded multiline images are correlated with lines in the multiline images according to the group map.

Claims

1. A method for mapping a sensor pixel array to an illumination pixel array according to a surface, comprising:

forming a group map by assigning each pixel in a plurality of pixels on the sensor array to a corresponding group of an ordered set of groups on an illumination pixel array, wherein each group is defined by a set of p adjacent pixels on the illumination pixel array and wherein each group is defined by a group boundary by;

(a) projecting and recording at least n images from a first set of n different binary patterns onto the surface, wherein a bright-to-dark or dark-to-bright transition between pixels in each of the n binary patterns occurs only at one or more of the group boundaries; and

(b) projecting and recording at least m images from a second set of m different binary patterns onto the surface, wherein one or more bright-to-dark or dark-to-bright transitions between pixels in each of the m binary patterns are offset from one or more of the group boundaries;

projecting and recording at least p different multiline images onto the surface, wherein each multiline image projects a line within each group;

correlating lines in the recorded multiline images with lines in the projected multiline images according to the group map; and

using the recorded at least p multiline images to form a surface contour image of the surface, wherein n and m are integers greater than or equal to 1 and p is an integer greater than or equal to 2.

2. The method of claim 1 further comprising storing the correlation in a computer-accessible memory, and generating surface contour data according to the stored correlation.

3. The method of claim 1 wherein the ratio of longest to shortest run lengths for the first set of n binary patterns is less than 2ⁿ⁻

4.

4. The method of claim 1 wherein the first set of n binary patterns is projected so that each successive pattern changes by only one bit from the previous pattern.

5. The method of claim 1 wherein the ratio of longest to shortest run lengths for the first set of n binary patterns is less than 2ⁿ⁻

4 and wherein the first set of n binary patterns is projected so that each successive pattern changes by only one bit from the previous pattern.

6. The method of claim 1 wherein the illumination pixel array is a liquid crystal device or a digital micromirror array device.

7. The method of claim 1, where patterns of the first set of different binary patterns, patterns of the second set of different binary patterns, and patterns of the at least p different multiline images are each different from each other.

8. The method of claim 1 wherein forming the group map further comprises obtaining and recording at least one dark field image and at least one flat field image.

9. The method of claim 2 further comprising displaying the surface according to the surface contour data.

10. A method for mapping a line of pixels in a sensor pixel array to a line of pixels in an illumination pixel array according to a surface, comprising:

defining an ordered sequence of groups, wherein each group is defined by a set of p pixels that are adjacent along the line on the illumination pixel array, wherein p is an integer greater than or equal to 2;

assigning pixels along the line of pixels in the sensor pixel array to the defined groups of p adjacent pixels along the line on the illumination pixel array by;

projecting and recording a first set of a plurality of different binary patterns including transitions indicative of boundaries between said groups of p adjacent pixels,

projecting and recording a second set of one or more different binary patterns wherein one or more transitions in the second set are offset from the group boundaries, and

projecting and recording at least one dark field image and at least one flat field image;

recording a third set of at least p multiline images projected onto the surface, wherein each of the projected different multiline images projects a single line of light at a time for each defined group of p adjacent pixels;

correlating lines in the recorded multiline images with lines in the projected multiline images according to the group assignment and the at least one dark and flat field images; and

storing the correlation as a mapping in a computer-accessible memory.

11. The method of claim 10 wherein the surface is a tooth.

12. The method of claim 10 wherein the first set of n binary patterns is projected so that each successive pattern changes by only one bit from the previous pattern.

13. The method of claim 10 wherein the ratio of longest to shortest run lengths for the first set of n binary patterns is less than 2ⁿ⁻

4 and wherein the first set of n binary patterns is projected so that each successive pattern changes by only one bit from the previous pattern.

14. The method of claim 10 wherein the illumination pixel array is a liquid crystal device or a digital micromirror array device.

15. The method of claim 10, where patterns of the first set of different binary patterns, patterns of the second set of different binary patterns, and patterns of the at least p different multiline images are each different from each other.

16. The method of claim 10 further comprising displaying the surface according to the stored mapping.

17. A method for forming a surface contour image, comprising:

forming a group map by assigning each pixel in a plurality of pixels on the sensor array to a corresponding group of an ordered set of groups on an illumination pixel array, wherein each group is defined by a set of p adjacent pixels in a row on the illumination pixel array, and wherein two adjacent groups share a group boundary;

by;

(a) projecting and recording at least n images from a first set of n binary patterns onto the surface, wherein a bright-to-dark or dark-to-bright transition between pixels in each of the n binary patterns occurs only at the group boundary; and

(b) projecting and recording at least m images from a second set of m binary patterns onto the surface, wherein one or more bright-to-dark or dark-to-bright transitions between pixels in each of the m binary patterns are offset from the group boundary;

projecting and recording a third set of at least p multiline images onto the surface, wherein each multiline image has, within each group of pixels in the ordered set of groups within the row on the illumination pixel array, a single bright pixel;

correlating lines in the recorded multiline images with lines in the projected multiline images according to the group map, wherein n and m are integers greater than or equal to 1 and p is an integer greater than or equal to 2;

storing the correlation in a computer-accessible memory;

using the at least p multiline images to form a surface contour image; and

displaying the surface contour image formed according to the stored correlation.

18. The method of claim 17 wherein the first set of n binary patterns is projected so that each successive pattern changes by only one bit from the previous pattern.

19. The method of claim 17 wherein forming the group map further comprises obtaining and recording at least one dark field image and at least one flat field image.