A device for optically scanning and measuring an environment is provided. The device includes a movable scanner having at least one first projector for producing at least one uncoded first pattern on an object in the environment. The scanner includes at least one camera for recording images of the object provided with the pattern and a controller coupled to the first projector and the camera. The device further includes at least one second projector which projects a stationary uncoded second pattern on the object while the scanner is moved. Wherein the controller has a processor configured to determine a set of three-dimensional coordinates of points on a surface of the object from a set of images acquired by the camera based at least in part on the first pattern. The controller is further configured to register the set of images relative based in part on the stationary second pattern.

Device for optically scanning and measuring an environment

We report on highly efficient transmission gratings in fused silica with a grating period of 800 nm generated by electron-beam lithography. At a wavelength of 1060 nm, 95% diffraction efficiency is achieved under Littrow conditions. The damage threshold, extremely enhanced compared with conventional gold-coated diffraction gratings, makes these gratings the key elements in high average power (>100 W) femtosecond fiber chirped-pulse amplification systems.

Highly efficient transmission gratings in fused silica for chirped-pulse amplification systems

Fiber- or rod-based optical source featuring a large-core, rare-earth-doped photonic-crystal device for generation of high-power pulsed radiation and method

A noncontact optical three-dimensional measuring device that includes a projector, a first camera, and a second camera; a processor electrically coupled to the projector, the first camera and the second camera; and computer readable media which, when executed by the processor, causes the first digital signal to be collected at a first time and the second digital signal to be collected at a second time different than the first time and determines three-dimensional coordinates of a first point on the surface based at least in part on the first digital signal and the first distance and determines three-dimensional coordinates of a second point on the surface based at least in part on the second digital signal and the second distance.

Three-dimensional coordinate scanner and method of operation

Spectrally beam-combined (SBC) laser systems, wherein multiple laser outputs are spectrally multiplexed into a single high-quality beam, are rapidly advancing the power scaling frontier for high-average-power beam-combined fiber lasers with near-perfect beam quality. We describe two- and three-channel SBC fiber lasers featuring 93% power-combining efficiency, near-diffraction-limited beam quality, average output powers in excess of 500 W, and excellent prospects for additional power scaling. To our knowledge, this level of optical performance represents the highest combination of beam quality and average power obtained so far for a beam-combined fiber laser system.

Spectrally Beam-Combined Fiber Lasers for High-Average-Power Applications

We report on reflection gratings produced entirely of dielectric materials. This gives the opportunity to enhance the laser damage threshold over that occurring in conventional metal gratings used for chirped-pulse-amplification, high-power lasers. The design of the system combines a dielectric mirror and a well-defined corrugated top layer to obtain optimum results. The rules that have to be considered for the design optimization are described. We optimized the parameters of a dielectric grating with a binary structure and theoretically obtained 100% reflectivity for the -1 order in the Littrow mounting for a 45° angle of incidence. Subsequently we fabricated gratings by structuring a low-refractive-index top layer of a multilayer stack with electron-beam lithography. The multilayer system was fabricated by conventional sputtering techniques onto a flat fused-silica substrate. The parameters of the device were measured and controlled by light scatterometer equipment. We measured 97% diffraction efficiency in the -1 order and damage thresholds of 4.4 and 0.18 J/cm2 with 5-ns and 1-ps laser pulses, respectively, at a wavelength of 532 nm in working conditions.

High-efficiency dielectric reflection gratings: design, fabrication, and analysis.

The invention relates to a device for the contactless detection of a three-dimensional contour, comprising a projector with an imaging element (1) and a projection lens (2) for depicting a stripe pattern that is generated on the imaging element (1) in an object space (3). The invention further comprises a camera arrangement for the surveillance of the object space (3) from two different directions, having two camera lenses (4). The projector and the camera arrangement are housed together in a measurement head that can be handheld. The invention further relates to a method for detecting a three-dimensional contour using said device.

Device and method for the contactless detection of a three-dimensional contour

Die
Erfindung betrifft eine Vorrichtung zum beruhrungslosen Erfassen einer
dreidimensionalen Kontur, umfassend einen Projektor mit einem bildgebenden
Element (1) und einem Projektionsobjektiv (2) zum Abbilden eines
auf dem bildgebenden Element (1) generierbaren Streifenmusters in
einen Objektraum (3) sowie eine zwei Kameraobjektive (4) umfassende
Kameraanordnung zur Beobachtung des Objektraums (3) aus zwei unterschiedlichen
Richtungen, wobei der Projektor und die Kameraanordnung gemeinsam
in einem als Handgerat verwendbaren
Messkopf untergebracht sind. Die Erfindung betrifft ferner ein mit
einer solchen Vorrichtung durchfuhrbares
Verfahren zum Erfassen einer dreidimensionalen Kontur.

Vorrichtung und Verfahren zum berührungslosen Erfassen einer dreidimensionalen Kontur

Here a new set-up of a 3D-scanning system for CAD/CAM in dental industry is proposed. The system is designed for direct scanning of the dental preparations within the mouth. The measuring process is based on phase correlation technique in combination with fast fringe projection in a stereo arrangement. The novelty in the approach is characterized by the following features: A phase correlation between the phase values of the images of two cameras is used for the co-ordinate calculation. This works contrary to the usage of only phase values (phasogrammetry) or classical triangulation (phase values and camera image co-ordinate values) for the determination of the co-ordinates. The main advantage of the method is that the absolute value of the phase at each point does not directly determine the coordinate. Thus errors in the determination of the co-ordinates are prevented. Furthermore, using the epipolar geometry of the stereo-like arrangement the phase unwrapping problem of fringe analysis can be solved.
The endoscope like measurement system contains one projection and two camera channels for illumination and observation of the object, respectively. The new system has a measurement field of nearly 25mm × 15mm. The user can measure two or three teeth at one time. So the system can by used for scanning of single tooth up to bridges preparations. In the paper the first realization of the intraoral scanner is described.

Intraoral 3D scanner

Up to now, Microdisplays are mainly used in multimedia applications or head-mounted displays. Due to their interesting properties, these displays open more and more alternative application fields, for example, in optical metrology. Projection lenses for this application area have to be specially designed, because the requirements for these systems differ completely from those for multimedia applications. The lenses must have very low geometrical image distortion and they have to be adapted to small objects and/or image distances. On the other hand, they often work with light sources with small spectral bandwidths; consequently they do not need to be corrected for chromatic aberrations. In addition, the numerical aperture (NA) has to be large enough to collect and transfer as much light as possible. Secondary the size of the projection lens has to be as small as possible to ensure compact measurement systems. All these requirements lead to a compromise in optical lens and system design. Within this paper, the development and realization of a 3D-scanner for the registration of dental surfaces directly inside the patient's mouth is presented. The advantages of such an intraoral scanning system are the reduced pain level for the patient and the absence of extensive intermediate steps. The production of prosthesis can be performed directly after measurement. Thus a quality improvement can be obtained as well as a reduction of the efforts in time and costs.

Martin Palme

Papers

High-efficiency dielectric reflection gratings: design, fabrication, and analysis.

Device and method for the contactless detection of a three-dimensional contour

Vorrichtung und Verfahren zum berührungslosen Erfassen einer dreidimensionalen Kontur

Intraoral 3D scanner

Microdisplay-Based Intraoral 3D Scanner for Dentistry