3D focus scanner with two cameras

Patent metadata

Field	Value
Publication number	US-9769455-B2
Application number	US-201113996739-A
Country	US
Kind code	B2
Filing date	Dec 21, 2011
Priority date	Dec 21, 2010
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A scanner for obtaining and/or measuring a 3D geometry of a surface of an object includes a camera having an array of sensor elements, a first device for generating a probe light, a device for transmitting the probe light rays towards the object, a device for transmitting light rays returned from the object to the array of sensor elements, an optical system for imaging with a first depth of field on the camera the transmitted light rays, a device for varying the position of the focus plane on the object, a device for obtaining at least one image from said array of sensor elements, a device for determining the in-focus position(s) of sensor elements, and a device for transforming the in-focus data into 3D coordinates.

First claim

The invention claimed is:

1. A scanner for obtaining and/or measuring a 3D geometry of at least a part of a surface of an object, said scanner comprising:
a first light source configured for generating probe light rays;
a first camera comprising an array of sensor elements, where said first camera is configured for obtaining at least one image from said array of sensor elements;
an arrangement of optical components configured for:
transmitting the probe light rays towards the object such that at least a part of the object can be illuminated;
transmitting light rays returned from the object to the array of sensor elements; and
imaging with a first depth of field at least part of the transmitted light rays returned from the object onto the array of sensor elements;

where the arrangement of optical components comprises focusing optics that defines a focus plane for the scanner, and where at least part of the optical components forms a first optical system that provides the imaging of light onto the array of sensor elements;
a positioning device configured for varying the position of the focusing optics, such that the position of the focus plane relative to the scanner is changed;
a data processing device, configured for:
determining the in-focus position(s) of:
each of a plurality of the sensor elements for a range of focus plane positions, or
each of a plurality of groups of the sensor elements for a range of focus plane positions,

and for transforming the in-focus data into 3D coordinates;

the scanner further comprising:
optics for selecting a portion of the light rays returned from the object, where the light rays have been transmitted through at least a part of the first optical system, and where the optics for selecting a portion of light rays returned from the object include a second optical element that is arranged in an aperture in the first optical system; and a second camera arranged to capture at least some of the selected light rays to provide a second depth of field image with a second depth of field, or
a third camera arranged to capture a portion of the light rays returned from the object, where the light rays have been transmitted through at least a part of the first optical system, to provide a second depth of field image with a second depth of field, where the third camera is arranged in the aperture in the first optical system; and

where a ratio between the second depth of field and the first depth of field is in the range of 10 to 2000, and a region of the aperture, where the light rays are selected from, is less than 30% of an area of the aperture.

2. The scanner according to claim 1 , wherein the second camera is adapted for forming at least one image in 1D and/or 2D of at least some of the selected light rays.

3. The scanner according to claim 1 , wherein the second depth of field image has the same perspective as the first depth of field image.

4. The scanner according to claim 1 , wherein the focusing optics is arranged outside the path of the selected portion of the returned light rays to the second camera such that the second depth of field image is unaffected by varying the position of the focus plane on the object.

5. The scanner according to claim 1 , wherein the optics for selecting a portion of light rays is arranged in front of the focusing optics such that the selected light rays are transmitted to the second camera without intersecting the focusing optics when returning from the object.

6. The scanner according to claim 1 , wherein the selected portion of light rays are directed to a second optical system for imaging onto the second camera, where the second optical system at least partly determines the second depth of field.

7. The scanner according to claim 1 , wherein the first camera and the second camera are adapted to operate simultaneously.

8. The scanner according to claim 1 , wherein the second optical element in the aperture is a mirror, a beam splitter, or a filter adapted to select light rays of one or more specific wavelengths.

9. The scanner according to claim 1 , wherein the probe light is white light.

10. The scanner according to claim 1 , wherein the scanner comprises a second light source for generating a probe light which is not used for determining the in-focus positions.

11. The scanner according to claim 10 , wherein the second light source generates white light.

12. The scanner according to claim 10 , wherein the second light source is LEDs of different colors.

13. The scanner according to claim 2 , wherein the points in the 1D image are spectrally analyzed.

14. The scanner according to claim 13 , wherein the 1D spectral analysis is performed on the second camera comprising a 2D array, where one axis of the camera array corresponds to a spatial coordinate on the object being scanned and the other axis of the camera array corresponds to a wavelength coordinate of the light returned from the object.

15. The scanner according to claim 13 , wherein the spectral analysis is performed by means of a diffractive optical component.

16. The scanner according to claim 15 , wherein the diffractive optical component comprises a grating, a prism or a color gradient film.

17. The scanner according to claim 1 , wherein the scanner is an intra-oral scanner for scanning of at least part of a patient's set of teeth, a scan of at least part of an impression of the patient's set of teeth, and/or a scan of at least part of a model of the patient's set of teeth.

18. A scanner for obtaining and/or measuring a 3D geometry of at least a part of a surface of an object, said scanner comprising:
a first camera comprising an array of sensor elements,
a first means for generating probe light rays,
means for transmitting the probe light rays towards the object thereby illuminating at least a part of the object,
means for transmitting light rays returned from the object to the array of sensor elements,
a first optical system for imaging with a first depth of field on the first camera at least part of the transmitted light rays returned from the object to the array of sensor elements,
means for varying the position of the focus plane on the object,
means for obtaining at least one image from said array of sensor elements,
means for determining the in-focus position(s) of:
each of a plurality of the sensor elements for a range of focus plane positions, or
each of a plurality of groups of the sensor elements for a range of focus plane positions, and

means for transforming the in-focus data into 3D coordinates;
the scanner further comprising:
means for selecting a portion of light rays returned from the object, where the light rays have been transmitted through at least a part of the first optical system, and where the means for selecting a portion of light rays returned from the object includes an optical element that is arranged in an aperture in the first optical system; and a second camera for capturing at least some of the selected light rays to provide a second depth of field, or
a third camera arranged to capture a portion of the light rays returned from the object, where the light rays have been transmitted through at least a part of the first optical system, to provide a second depth of field image with a second depth of field, where the third camera is arranged in the aperture in the first optical system; and
where a ratio between the second depth of field and the first depth of field is in the range of 10 to 2000, and a region of the aperture, where the light rays are selected from, is less

Assignees

• Fisker Rune
• Van Der Poel Mike
• 3Shape As

Inventors

• Fisker Rune
• Van Der Poel Mike

Classifications

• A61C9/0066

  Depth determination through adaptive focusing · CPC title

• A61B5/1076

  for measuring dimensions inside body cavities, e.g. using catheters (A61B3/1005 takes precedence) · CPC title

• A61B5/441

  Skin evaluation, e.g. for skin disorder diagnosis · CPC title

• A61B5/1079

  using optical or photographic means · CPC title

• A61B5/4542

  Evaluating the mouth, e.g. the jaw · CPC title