DE102004035102A1

DE102004035102A1 - 3 D object measurement projector has real or virtual point light sources with separate spectral intensity distributions strip modulated by cylindrical lens

Info

Publication number: DE102004035102A1
Application number: DE200410035102
Authority: DE
Inventors: Ulrich Krackhardt; Jochen Baehr
Original assignee: Bahr Jochen Dr
Current assignee: Bahr Jochen Dr
Priority date: 2004-07-20
Filing date: 2004-07-20
Publication date: 2006-02-16

Abstract

A 3 D object measurement projector has real or virtual point light sources with completely separate spectral intensity distributions illuminating the measurement object through a parallel cylindrical lens strip modulator to give a linearly polarised sinusoidal pattern. Independent claims are included for versions of the projector using an additional light source to create a Gray code giving absolute position on the measurement object and for procedures using the projector for 3 D object measurement.

Description

Berührungsfrei arbeitendes optisches Verfahren zur Ermittlung der 3D-Koordinaten von Oberflächen im Raum. Eine Aufnahmeapparatur, im weiteren „Sensor" genannt, besteht mindestens aus einem bildgebenden optischen Detektor (z.B. einer elektronischen Kamera) und mindestens einer Beleuchtungsapparatur (z.B. einem Projektor).contactless working optical method for determining the 3D coordinates of surfaces in the room. A recording apparatus, hereinafter referred to as "sensor", consists of at least one imaging optical detector (e.g., an electronic camera) and at least one lighting device (e.g., a projector).

Die Auswertung der 3D-Form basiert auf einer Phasenauswertung wie aus der Phase-Sampling-Interferometry (PSI) bekannt: Ein auf die Szene projiziertes Muster (z.B. Sinus-Streifen) wird hier durch die Tiefenvariation der Objektkoordinaten lokal verformt. Diese Verformung wird als Phasenveränderung gedeutet und durch Auswertung einer Sequenz von mindestens 3 Einzelbildern für jeden Bildpunkt ermittelt. Die Einzelbilder unterscheiden sich dabei in einer kontrollierten globalen Phasenverschiebung des aufprojizierten Musters. Mit Kenntnis der Sensorgeometrie (innere Orientierung) kann die lokale Phasenveränderung in 3D-Koordinaten umgerechnet werden.The Evaluation of the 3D shape is based on a phase evaluation like out Phase Sampling Interferometry (PSI): A projected onto the scene Pattern (e.g., sinusoidal stripes) here is represented by the depth variation the object coordinates are locally deformed. This deformation is called phase change interpreted and by evaluation of a sequence of at least 3 individual images for each Pixel determined. The single images differ in one controlled global phase shift of the projected pattern. With knowledge of sensor geometry (inner orientation), the local phase change be converted into 3D coordinates.

Zur Realisierung eines Echtzeit-Systems wird die Sequenz von aufprojizierten Einzelbildern bezüglich der Wellenlänge des Beleuchtungslichtes codiert: Die aufprojizierten Muster verschiedener globaler Phasenlage unterscheiden sich damit zudem in der Wellenlänge (physiologischer Eindruck im sichtbaren Bereich: die Farbe). Dadurch ist es prinzipiell möglich, beliebig viele Einzelbilder zu codieren, solange die Spektren der Lichtquellen für die Einzelbilder hinreichend voneinander separiert sind.to Realization of a real-time system is the sequence of projected on Single images with respect to the wavelength of the illumination light: the projected patterns of various global phase position thus also differ in the wavelength (physiological Impression in the visible area: the color). This makes it possible in principle, arbitrarily many frames to encode as long as the spectra of the light sources for the Frames are sufficiently separated from each other.

Im Hinblick auf eine kostengünstige Lösung, die auch auf vorhandene Bauelemente zurückgreift, können folgende Einstellungen gewählt werden:
Drei Einzelbilder, mit Projektionsmustern codiert im sichtbaren Bereich mit den Farben Rot, Grün und Blau (R, G, B). Als Detektor wird eine handelsübliche 3-Chip-Kamera verwendet. Die Spektren der Projektionsmuster werden jeweils so gewählt, dass ein Übersprechen in die anderen „Farb"-Kanäle minimiert ist.With regard to a cost-effective solution, which also uses existing components, the following settings can be selected:
Three frames, with projection patterns coded in the visible area with the colors red, green and blue (R, G, B). As a detector, a commercially available 3-chip camera is used. The spectra of the projection patterns are each chosen so that crosstalk in the other "color" channels is minimized.

Der erfindungsgemäße Projektor besteht aus mindestens 3 reellen oder virtuellen Lichtquellen, einem Modulationselement zur Erzeugung des Projektionsmusters und einem Objektiv. Die Lichtquellen sind so angeordnet, dass ein festeingestellter globaler Phasenversatz zwischen den Einzelmustern im Messvolumen erzielt wird. Der globale Phasenversatz ist definiert durch den örtlichen Abstand der Lichtquellen zueinander. Die Lichtquellen können je nach Ausführung auch faseroptisch realisiert werden. Mit diesen Eigenschaften weist der Projektor keinerlei mechanisch bewegliche Teile auf.Of the Projector according to the invention consists of at least 3 real or virtual light sources, one Modulation element for generating the projection pattern and a Lens. The light sources are arranged so that a fixed global phase offset between the individual patterns in the measurement volume is achieved. The global phase offset is defined by the local phase offset Distance between the light sources. The light sources can vary depending on execution also be realized fiber optic. With these features points the projector has no mechanical moving parts.

Zusätzlich wird durch die Verwendung spezieller optischer Komponenten das Projektionslicht mit hoher Schärfentiefe moduliert. Dadurch muss bei der Platzierung des Sensors in einer Szene lediglich auf die Einhaltung der Schärfentiefe hinsichtlich der Abbildung auf den Detektor geachtet werden.In addition will through the use of special optical components, the projection light with high depth of field modulated. This must be done when placing the sensor in one Scene only on the maintenance of the depth of field in terms of Pay attention to the detector.

Stand der Technik:State of the art:

In der bildgebenden optischen 3D-Meßtechnik (Topometrie) wird die zu untersuchende Objektoberfläche mit einem ortsvarianten Intensitätsmuster beleuchtet (strukturierte Beleuchtung). Die Szene wird aus einer zur Beleuchtungsrichtung unterschiedlichen Richtung beobachtet. Die Tiefeninformation des Messobjektes ist dann in einer lokalen Verzerrung des aufprojizierten Musters codiert. Die lokale Verzerrung wird unter Verwendung von Algorithmen aus der Phase-Sampling-Intereferometry (PSI) in eine ortsvariante Phase umgerechnet. Dazu ist eine Sequenz von mindestens 3 Einzelbildern mit zueinander global verschobenen Projektionsmustern von typischerweise sinusförmiger Intensitätsvariation nötig. Nach dem Prinzip der Triangulation wird daraufhin die 3D-Information über das Objekt gewonnen.In 3D imaging optical metrology (topometry) the object surface to be examined with a location variant Illuminated intensity pattern (structured lighting). The scene turns into an illumination direction observed in different directions. The depth information of the DUT is then in a local distortion of the projected Pattern coded. The local distortion is calculated using Algorithms from Phase Sampling Intereferometry (PSI) into one Variant phase converted. This is a sequence of at least 3 single frames with globally shifted projection patterns of typically sinusoidal intensity variation necessary. According to the principle of triangulation then the 3D information about the Object won.

Die nach diesem Verfahren gewonnenen 3D-Daten sind relativ, d.h. die Entfernung von Messpunkten zum Sensor kann nur bis auf ein ganzzahliges Vielfaches einer Konstanten, der sog. Empfindlichkeit, angegeben werden. Dies rührt von der Tatsache, dass periodische Muster mit z.B. sinusförmigem Verlauf, aufprojiziert werden und lokale Verschiebungen mit Vielfachen einer Periode nicht unterscheidbar sind.The 3D data obtained by this method is relative, i. the Distance from measuring points to the sensor can only be up to an integer Multiple of a constant, the so-called sensitivity, indicated become. This is touching from the fact that periodic patterns with e.g. sinusoidal course, be projected and local shifts with multiples of one Period are indistinguishable.

Für absolute Messwerte ist daher eine andere Codierung des Messvolumens erforderlich. Typischerweise kommt für die absolute Codierung der Gray-Code zum Einsatz, der eine minimale Hamming-Distanz und damit eine Möglichkeit zur Erkennung von Fehlern bei der Detektion des Projektionsmusters bietet. Hierzu wird eine Sequenz von unterschiedlichen Mustern auf das Objekt aufprojiziert. Die Wahl der Muster geschieht derart, dass für jedes beobachtete Oberflächenelement des Objektes nach Überlagerung der Einzelbilder ein eindeutiger numerischer Wert vorliegt. Durch Vergleich der Lage dieses Wertes im bildgebenden Detektor mit der Lage des selben numerischen Wertes bei einem bekannten Objekt, typischerweise ein planes Objekt, kann unter Kenntnis der Sensorgeometrie auf die Tiefe des Messpunktes geschlossen werden. Der eindeutige numerische Wert wird dabei durch einen typischerweise 6- bis 8-stelligen Bit-Wert repräsentiert. Dies bedeutet, dass zur Erzeugung des entsprechenden Gray-Codes 6-8 Einzelbilder aufprojiziert werden müssen.For absolute Measured values therefore require a different coding of the measuring volume. Typically comes for The absolute coding of the Gray code is used, which is a minimum Hamming distance and thus a possibility to detect errors in the detection of the projection pattern offers. For this purpose, a sequence of different patterns the object is projected on. The choice of patterns happens in such a way that for every observed surface element of the object after superposition the frames have a unique numeric value. By Comparison of the position of this value in the imaging detector with the Location of the same numeric value in a known object, typically a plan object, knowing the sensor geometry on the Depth of the measuring point to be closed. The unique numeric Value is given by a typically 6- to 8-digit bit value represents. This means that to generate the corresponding Gray code 6-8 frames must be projected.

Wegen der fundamentalen Limitierung des (Orts-)Bandbreiteproduktes stellt eine Absolutcodierung zwar ein Verfahren mit größerer Tiefenausdehnung, aber geringerer Genauigkeit als die o.g. Relativcodierung dar.Because of the fundamental limitation of (Local) Bandwidth product is an absolute coding Although a method with greater depth extension, but lower accuracy than the above Relativcodierung represents.

In praktischen absolut messenden Systemen werden daher die beiden o.g. Verfahren kombiniert. Dies hat zur Folge, dass ca. 9-11 unterschiedliche Muster auf das Objekt aufprojiziert werden müssen.In practical absolute measuring systems, therefore, the two o.g. Method combined. This has the consequence that about 9-11 different patterns must be projected onto the object.

Gemäß dem Stand der Technik werden die unterschiedlichen Muster in zeitlicher Abfolge aufprojiziert. Zwischen je zwei unterschiedlichen Mustern wird mittels des Detektors ein Intensitätsbild der Szene angefertigt. Die Muster werden entweder interferometrisch oder abbildend erzeugt.According to the state In technology, the different patterns are arranged in chronological order projected onto. Between each two different patterns is by means of of the detector an intensity image the scene made. The patterns become either interferometric or imaged.

Vor der Aufnahme muß eine Kalibrierung des optischen Abbildungssystems vorgenommen werden, um ein Bezugssystem zwischen den Koordinatensystemen der Aufnahmekamera, des Meßobjektes sowie des Projektionssystems herzustellen. Dazu werden eine Reihe von Eichmessungen durchgeführt, wobei wohlbekannte Objekte im Meßvolumen plaziert werden. Nach erfolgter Kalibrierung darf die Meßanordnung nicht mehr verändert werden.In front the recording must have a Calibration of the optical imaging system are made, a frame of reference between the coordinate systems of the recording camera, of the object to be measured and the projection system. This will be a series carried out by calibration measurements, where well-known objects are placed in the measuring volume. To After calibration, the measuring arrangement must not be changed.

Nachteile der bisherigen Verfahren:Disadvantages of the previous Method:

Während der gesamten Dauer der Sequenz muss das Objekt mindestens in den Grenzen der Sensorauflösung statisch sein, um unerwünschte Artefakte zu vermeiden. Dies hat zur Folge, dass entsprechend dynamische Objekte, Szenen oder Aufnahme-Geometrien (z.B. bewegter Sensor) nicht mit den gegenwärtig üblichen Verfahren erfasst werden können.During the Total duration of the sequence must be at least within the limits of the object the sensor resolution be static to unwanted To avoid artifacts. This has the consequence that correspondingly dynamic Objects, scenes or recording geometries (e.g., moving sensor) not with the current ones Procedure can be detected.

Zur Beleuchtung des zu vermessenden Objektes werden gegenwärtig gängige Projektionssysteme verwendet. Hierbei wird ein Dia mit dem entsprechenden Muster auf das Objekt abgebildet. Die typischerweise sehr geringe Tiefenschärfe dieser Abbildung beschränkt dabei die Tiefenausdehnung des Meßvolumens. Dies hat zwei schwerwiegende Nachteile zur Folge:

1. Zur Messung von Objekten mit hoher Tiefenausdehnung müssen mehrere Messungen von jeweils unterschiedlichen Tiefenbereichen angefertigt werden.
2. Das Projektionssystem muß zur Beleuchtung unterschiedlicher Tiefenbereiche jeweils nachfokussiert werden, wobei typischerweise der Vergrößerungsmaßstab der Projektion verändert wird, was eine erneute Kalibrierung nötig macht.

To illuminate the object to be measured currently common projection systems are used. In this case, a slide with the corresponding pattern is imaged on the object. The typically very shallow depth of field of this figure limits the depth of the measuring volume. This has two serious disadvantages:

1. To measure objects with high depth extension, multiple measurements of different depth ranges must be made.
2. The projection system must be refocused to illuminate different depth ranges, typically changing the magnification scale of the projection, necessitating recalibration.

Ziele der Erfindug:Objectives of the invention:

- optical Acquisition of 3D data for the relative and absolute measurement of surfaces in a single recording process.
- Relieved Sensor placement in the scene by creating a structured Measuring illumination with very high depth of field.

Vorteile der Erfindung:Advantages of the invention:

Mit dem erfindungsgemäßen Verfahren kann eine 3D-Szene mit einer einzigen Aufnahme erfasst werden. Damit ist es im Gegensatz zu allen bekannten Verfahren zur hochauflösenden, absoluten und bildgebenden optischen 3D-Formerfassung möglich, dynamische Szenen zu erfassen, wobei die Dynamik lediglich durch die minimale Belichtungsdauer des Bilddetektors limitiert ist, und damit im Rahmen der verfügbaren Technologien skalierbar ist. Um ganze Video-Sequenzen zu erfassen, können Datensätze mittels einer Speichervorrichtung, die mehrkanalige Video-Aufzeichnung bietet, für eine nachfolgende off-line Verarbeitung zur Errechnung von absoluten 3D-Daten erstellt werden.With the method according to the invention a 3D scene can be captured with a single shot. In order to it is in contrast to all known methods of high-resolution, absolute and imaging optical 3D shape detection possible, dynamic Capturing scenes, where the dynamics only by the minimum Exposure duration of the image detector is limited, and thus in the frame the available Technologies is scalable. To capture entire video sequences, can Records using a memory device that provides multi-channel video recording, for one subsequent off-line processing to calculate absolute 3D data to be created.

Durch Verwendung der erfindungsgemäßen Beleuchtungseinrichtung steht projektorseitig eine praktisch unbegrenzte Schärfentiefe zur Verfügung. Dadurch wird die Schärfentiefe des gesamten Sensors lediglich durch die Abbildung auf die bildgebenden Detektoren bestimmt. Ein Objekt muss also lediglich bzgl. der Detektoren korrekt platziert werden, die gleichzeitige Beachtung des Abstandes zur Projektorvorrichtung entfällt. Dies erleichtert die Einstellarbeiten hinsichtlich der Positionierung des Sensors relativ zur Szene auf ein Maß wie es in der Fotographie üblich ist. Weiterhin ermöglicht die praktisch unbegrenzte Schärfentiefe des Projektors eine Szene durch einen einzigen statisch positionierten Projektor und eine bewegliche oder mehrere bewegliche oder statisch positionierte erfindungsgemäße Detektorsysteme zu erfassen..By Use of the illumination device according to the invention Projector side has a virtually unlimited depth of field to disposal. Thereby will the depth of field of the entire sensor merely by imaging on the imaging Detectors determined. An object must therefore only with respect to the detectors be placed correctly, the simultaneous consideration of the distance to the projector device deleted. This facilitates the adjustment work in terms of positioning the sensor relative to the scene to a level as is customary in photography. Furthermore possible the practically unlimited depth of field of the projector a scene by a single statically positioned Projector and a movable or multiple movable or static positioned detector systems according to the invention capture..

Ausführungsbeispiele:EXAMPLES

Im Folgenden werden zwei erfindungsgemäße Ausführungsbeispiele nebst Varianten beschrieben. Zum Einen eine Ausführung, die eine simultane Aufnahme aller Daten für eine bildgebende absolute Oberflächenvermessung erlaubt (Ausführungsbeispiel I). Zum Zweiten eine Ausführung, die mit stark vermindertem konstruktiven Aufwand im Vergleich zu Ausführungsbeispiel I erlaubt, ebenfalls eine schnelle absolute Oberflächenvermessung durchzuführen, wobei hier allerdings drei sequentielle Bildaufnahmevorgänge benötigt werden (Ausführungsbeispiel II).in the Below are two embodiments of the invention and variants described. On the one hand an execution, the simultaneous acquisition of all data for an imaging absolute surface measurement allowed (embodiment I). Second, an execution the with greatly reduced design complexity compared to the embodiment I also allows a fast absolute surface measurement perform Here, however, three sequential image acquisition processes are needed (Embodiment II).

Für beide Ausführungsbeispiele werden jeweils die Projektionseinrichtungen zur Erzeugung des Signallichtes zur PSI-Auswertung und des Absolut-Codierungslichtes (im Folgenden Projektor genannt) beschrieben, weiterhin die Einrichtungen zur Bildaufnahme und Signalauswertung (im Folgenden Detektor genannt), sowie die Vorgehensweise der Signalauswertung für beide Ausführungsbeispiele.For both embodiments, the projection devices for generating the signal light for PSI evaluation and the absolute coding light (hereinafter referred to as the projector) are described in each case, furthermore the devices for image acquisition and signal evaluation (hereinafter Called detector), as well as the procedure of the signal evaluation for both embodiments.

Ausführungsbeispiel I:Embodiment I:

Absolut messend bei gleichzeitiger Aufnahme aller bildgebenden DatenAbsolutely measuring at the same time Recording of all imaging data

1. Projektor:1st projector:

a. 3 light sources (L1, L2 and L3) with each other well separated spectrum, so positioned in the optical structure that given the global phase shift of the pattern per light source is. The light of these light sources is uniform in a certain polarization state P1. The intensity modulation (eg sinusoidal Strip) is achieved by an optical phase element (see Image 1).
b. In another beam path in the same projector will be the same light sources used to provide lighting for To achieve color calibration. This will be a part of the light of under 1.a described light sources united to a common virtual light source. The light of this virtual light source is thrown unstructured on the object scene. This light (color calibration light) has a polarization state P2, orthogonal to the polarization state P1 from 1.a (picture 2).
c. The absolute encoding comes with another light source (L4) with one of the under 1.a. described light sources L1, L2 and L3 probably separated spectrum realized (Figure 2). With that Markers on the scene projected by the following procedure: i. Distinctive markers are projected on, wherein 1. the markers are individually coded to be followed by a subsequent one Image processing step to clearly identify. The coding can be through the intensity course, the form or the structuring of the marks are achieved. Second Markings not individual, but only groupwise distinguishable are. ii. Indistinguishable markers are projected where the absolute coding from the relative position of the markers can be derived to each other.
d. As an alternative to c, the absolute coding with k becomes further Light sources with each other and with respect to the 1.a. described Light sources L1, L2 and L3 well separated spectra realized. This will make a k-bit deep gray code in one step at a time projected as shown in I.1.a and I.1.b. The single ones k projection images are spectrally coded.

2. Detektor:2nd detector:

Für die bildgebenden Detektoren können handelsübliche Chips (CCD, C-MOS, o.ä.) verwendet werden. Entlang des Strahlenganges des eintreffenden Lichtes ist die Detektorkomponente des erfindungsgemäßen Sensors wie folgt aufgebaut (Bild 3):

a. Ein polarisierender Strahlteiler (PolBS) trennt das eintreffende Licht in zwei Kanäle auf. Der eine Kanal enthält das unter I.1.a beschriebene streifencodierte Licht, was nachfolgend auf eine handelsübliche Multi-Chip Kamera abgebildet wird.
b. Der zweite Kanal enthält das Licht zur Absolut-Codierung und zur Farb-Kalibrierung.
c. Die Trennung des Lichts zur Absolut-Codierung und zur Farb-Kalibrierung wird durch einen wellenlängensensitiven Strahlteiler (λ-BS) erreicht.
d. Das Farb-Kalibrierungssignal wird auf eine weitere Multi-Chip-Kamera abgebildet. Damit wird der spektrale Reflexionskoeffizient der Szene für jeden Bildpunkt ermittelt.
e. Das Absolut-Codierungslicht wird auf eine monochrome 1-Chip Camera abgebildet.
f. Alternativ, entsprechend der Ausführung des Projektors, wie in I.1.d beschrieben, wird der k-Bit tiefe Gray-Code durch k spektral unterschiedlich empfindliche Detektoren gleichzeitig erfaßt. Dazu können handelsübliche monochrome Kameras mit vorgeschaltetem Spektralfilter, alternativ eine geringere Anzahl von Multi-Chip Kameras verwendet werden.

Commercially available chips (CCD, C-MOS, etc.) can be used for the imaging detectors. Along the beam path of the incident light, the detector component of the sensor according to the invention is constructed as follows (Figure 3):

a. A polarizing beam splitter (PolBS) separates the incident light into two channels. The one channel contains the strip-coded light described under I.1.a, which is subsequently imaged on a commercially available multi-chip camera.
b. The second channel contains the light for absolute coding and color calibration.
c. The separation of the light for absolute coding and color calibration is achieved by a wavelength-sensitive beam splitter (λ-BS).
d. The color calibration signal is mapped to another multi-chip camera. This determines the spectral reflection coefficient of the scene for each pixel.
e. The absolute coding light is displayed on a monochrome 1-chip camera.
f. Alternatively, according to the design of the projector as described in I.1.d, the k-bit deep gray code is detected simultaneously by k spectrally different sensitive detectors. For this purpose, commercially available monochrome cameras with upstream spectral filter, alternatively a smaller number of multi-chip cameras can be used.

3. Auswertung:3. Evaluation:

a. To determine the color texture of the scene the color calibration signal described in I.2.d is used. This will be for determines each pixel three coefficients, the relative weighting of the 3 color channels (I.1.b) after reflection at the scene. This creates a Value table (look-up table) in which spatially resolved spectral object reflectivity is stored.
b. The strip light signal described in I.2.a is with the value table is calculated to obtain a constant spectral Objektreflektivität. After that the evaluation is carried out according to known PSI methods. As a result the relative phase position per pixel is present.
c. The absolute phase is derived from the lateral displacement of the Encoded points on the object obtained with the 1-chip camera. The absolute phase becomes location-dependent added as an offset to the relative phase (phase matching).

Ausführungsbeipiel II:Exemplary embodiment II:

Absolut messend, jedoch mit sequentieller Erzeugung des verschobenen StreifenmustersAbsolutely measuring, however with sequential generation of the shifted stripe pattern

1. Projektor:1st projector:

a. 3 light sources and optical design like described under I.1.a, but with a largely identical spectrum. The light sources are individually switchable. The single projection pictures with mutual global phase shift become sequential successively by sequentially turning on and off the light sources generated.
b. Alternatively as II.1.a., but with only one light source, a subsequent multi-beam splitter for dividing the intensity into three optical channels. The channels are switchable by active optical components.
c. Absolute coding as in I.1.c by another light source with well separated spectrum with respect to the light sources under II.1.a and marks for absolute coding as described under I.1.c.
d. Alternatively as II.1.c, but absolute coding with one Light source with similar Spectrum as II.1.a. additionally those under II.1.a. and the light source for the absolute coding one mutually orthogonal polarization states.

2. Detektor:2nd detector:

a. For the imaging detectors can commercial monochrome chips (CCD, C-MOS, etc.) be used. Along the beam path of the incoming light the detector component of the sensor according to the invention is constructed as follows (Photo 4): A beam splitter distributes the common signal (e.g. sinusoidal) modulated strip light and absolute coding light. Before the respective imaging detector is placed a wavelength filter that only that for desired detector Let light pass.
b. Like II.2.a, but with polarization dependent beam splitters, if Light sources according to II.1.d be used. The two outputs of the beam splitter become directed to a respective imaging detector.

3. Auswertung:3. Evaluation:

a. The (e.g., sinusoidally) coded stripe light is used for determining the local phase according to methods from the Phase Sampling Interferometry (PSI).
b. Determination of the absolute phase as described under I.3.c.

Literatur:Literature:

Roland Zumbrunn:, Device for measuring the surface of a Object by projection of stripe patterns, European patent 037909 B2. Filing date: 12.1.90
Breuckmann B .: "Image processing and optical metrology in industrial practice "Franzis-Verlag ISBN 3-7723-4861-0
Daniel Malacara, "Optical Shop Testing", 2nd Edition, John Wiley & Son, Inc. (1992)

Claims

The projector according to exemplary embodiment I is designed such that that it has at least three real or virtual light sources, the well-separated spectral intensity distributions have.

Light sources according to claim 1, arranged in such a way that they simultaneously illuminate the object to be measured.

Light sources according to claim 1, arranged in such a way that the light sources by constructive measures or design as punctiform or almost punctiform accomplished are.

The projector according to embodiment I, with a Modulation element is provided, when irradiated with light from the light sources mentioned in claim I.1 to I.3 a strip-shaped light distribution generated on the object to be measured, such that through the lateral arrangement of the individual light sources, corresponding to Requirements of the PSI method, laterally shifted stripe patterns generated on the object.

The projector of embodiment I with use a modulation element consisting of parallel cylindrical lenses consists, such that the individual cylindrical lenses a collimation of Perform light sources in a spatial direction and thus a deep-sharp Create line patterns for object lighting.

execution the modulation element according to claim 5, such that by special Design of phase and / or amplitude of the parallel cylindrical lenses a deep-sharp sinusoidal Light pattern is generated.

execution of the projector according to the embodiment I such that the generated light pattern is linearly polarized.

The projector according to exemplary embodiment II is designed such that that it has at least three light sources, which sequentially the illuminate the object to be measured.

The projector according to exemplary embodiment II is designed such that that he has a light source and a device for splitting the intensity at least three spatially separate channels having. The three channels be in their intensity modulated by switchable electro-optic, opto-electronic, magneto-optical, purely optical or mechanical components.

Light sources according to claim 8 or 9, wherein the light sources through constructive measures or by design as punctiform or almost punctiform accomplished are.

A projection device according to the embodiment II, which is provided with an optical modulation element, the when irradiated with light from the light sources mentioned in claim 8, 9 and 10 a strip-shaped Light distribution on the object to be measured generates such that by the virtual or real lateral arrangement of the individual Light sources, according to the requirements of the PSI method Strip pattern with different global phase shift in Direction of the strip grid vector can be generated on the object.

A projection device according to the embodiment II such that by constructive measures, such as a. at least a movable mirror and / or b. at least one mobile optical element of the projector and / or c. sequential spatial Moving at least one light source relative to the modulation element d. mechanical fixation at least three different virtual Light sources are generated, which correspond to the modulation element Claim 11.

A projection device according to the embodiment II using an optical modulation element such that the modulation element of parallel cylindrical lenses consists, wherein the individual cylindrical lenses a collimation of Perform light sources in a spatial direction and thus a deep-sharp Create line patterns for object lighting.

execution the modulation element according to claim 13 such that by special Design of phase and / or amplitude of the individual parallel cylindrical lenses a deep-focused sinusoidal light pattern is generated for object lighting.

execution the projection device according to embodiment I such that Light, composed of the spectral components of all light sources, which are used to generate the stripe pattern (according to claim 1 and 2), which illuminates the object to be measured homogeneously and unstructured, this light being a polarization state orthogonal to the stripe light having.

execution of the projector according to the embodiment I and II such that an encoding pattern for absolute determination the strip position is projected onto the object to be measured.

execution the projection device according to embodiments I and II such, a. that with the help of another light source whose spectrum is sufficient is separated from the spectra of the light sources used to generate the stripe pattern according to claims 1 and 2 and 8 and 9 and further outside the homogeneous object illumination according to claim 15, a coding pattern for the absolute determination of the strip position on the to be measured Object is projected. b. that with the help of k further light sources, whose spectra are sufficiently separated from the spectra of the light sources, for generating the stripe pattern according to claim 1 and 2 as well 8 and 9 and continue outside the homogeneous object illumination according to claim 15, a coding pattern in Shape of a k-bit deep Gray code for absolute determination of the strip position is projected onto the object to be measured.

execution the projection device according to embodiment II such that Alternatively to claim 17, the strip light and the light for absolute coding with different polarization directions P1 and P2, where P1 and P2 perpendicular to each other, aufprojiziert on the object to be measured become.

execution the coding illumination such that the light for absolute coding, according to claim 16 and 17 the same imaging optical Elements goes through like the strip light.

execution the absolute coding by pattern, either a. consisting of distinguishable markers for each single object point, b. consisting of distinguishable markings for each a group of object points, c. consisting of groups distinguishable markings, d. consisting of indistinguishable Markings with special arrangement, from which the positional shift the markings can be determined.

Realization of absolute coding as an alternative to Gray code through multi-valued discrete or continuous projection patterns.

Execution of the detector after execution in such a way that a polarization-sensitive beam splitter in the detector input splits the strip light onto a color-sensitive multi-chip camera, wherein the second output of the polarization-sensitive beam splitter includes the calibration light and the absolute coding light.

execution of the detector according to the embodiment I like that, a. that the light from the second output of the polarization-sensitive Beam splitter according to claim 22 by a further beam splitter once on another multi-chip camera, their individual photosensitive Components for the wavelengths the strip light are sensitive, and the second on a 1-chip Camera is headed for the wavelength the absolute coding light is sensitive. b. that the light from the second exit of the polarization-sensitive beam splitter according to claim 22 another beam splitter on the one hand to another multi-chip Camera, their individual photosensitive components for the wavelengths of the stripe light are sensitive, and the second on k spectrally sensitive 1-chip Cameras or correspondingly less multi-chip cameras.

execution of the detector according to the embodiment II such that an input-side beam splitter the common Signal from strip light and absolute coding light splits up a monochrome camera with wavelength filter for recording the pure strip light and on another monochrome camera with preferably also a wavelength filter for detecting the Absolutely encoding light.

execution of the detector according to the embodiment II such that a polarization-sensitive beam splitter the common Signal from strip light and absolute coding light, which according to claim 18 in its polarization state can be distinguished on divides two separate image sensors.

execution the evaluation according to Application Example I and II such that the Strip light using Phase Sampling Interferometry (PSI) techniques is evaluated to a local phase of the aufprojizierten pattern to investigate.

Evaluation method according to claim 26, additionally comprising a Standardization of the spectral reflection behavior of the to be measured Object performs.

Evaluation method according to claim 26 or 27, wherein the frames for the PSI method is extracted from a color image of the scene.

Evaluation method according to Application Example I and II such that from the lateral displacement of the coding points obtained on the object, the absolute phase or the absolute depth information is, by adding up the absolute and the relative strip light the high-resolution absolute depth data (phase matching).

Evaluation method as in claim 29, but with unambiguous absolute depth information (discrete-binary, discrete-multivalued, or continuously).