+

WO2007065643A1 - Vibromètre - Google Patents

Vibromètre Download PDF

Info

Publication number
WO2007065643A1
WO2007065643A1 PCT/EP2006/011685 EP2006011685W WO2007065643A1 WO 2007065643 A1 WO2007065643 A1 WO 2007065643A1 EP 2006011685 W EP2006011685 W EP 2006011685W WO 2007065643 A1 WO2007065643 A1 WO 2007065643A1
Authority
WO
WIPO (PCT)
Prior art keywords
detector
vibrometer
vibrating object
micromirror
micromirrors
Prior art date
Application number
PCT/EP2006/011685
Other languages
German (de)
English (en)
Inventor
Joachim Barenz
Rainer Baumann
Hans Dieter Tholl
Original Assignee
Diehl Bgt Defence Gmbh & Co. Kg
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Diehl Bgt Defence Gmbh & Co. Kg filed Critical Diehl Bgt Defence Gmbh & Co. Kg
Publication of WO2007065643A1 publication Critical patent/WO2007065643A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
    • G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors

Definitions

  • the invention relates to a vibrometer according to the preamble of claim 1.
  • the invention further relates to the use of such a vibrometer and a method for generating a vibration image of a vibrating object.
  • a vibrometer of the type mentioned at the beginning can be found in the prospectus
  • Coherent light is generated in such a vibrometer, for example by means of a laser, and by means of a beam splitter into a measuring and a reference beam The measuring beam strikes a vibrating object, runs back from it and is caused to overlap with the reference beam based on the principle of an interferometer.
  • a characteristic overlay or interference pattern results, which indicates the oscillation behavior of the vibrating object If, for example, the intensity variation of the overlay pattern is observed over time by means of a detector, this variation can be used to draw direct conclusions about the oscillation frequency of the object or its illuminated surface tion frequency of the interference pattern is directly proportional to the speed of the vibrating object.
  • the object directed to a device for a vibrometer according to the preamble of claim 1 is achieved according to the invention in that a micromirror raster is arranged in the beam path of the returning measuring beam, with receiving optics for imaging the vibrating object onto the micromirror raster and imaging optics Image of the micromirror grid on the detector are provided.
  • the invention is based on the consideration that, in order to analyze the vibration behavior of the object to be examined, it should not be scanned by means of the measuring beam, but replaced by imaging the interference pattern on the detector. This eliminates the time-consuming scanning process, which not only reduces the measuring time, but also results in a simpler structure of the vibrometer.
  • the invention is based on the consideration that a simple and fast detector can be used to evaluate the interference pattern if a micromirror grid is used in the imaging beam path.
  • a micromirror raster which comprises micromirrors arranged in columns and rows, allows a selective selection of individual image sections, in that only the desired micromirrors are directed onto the detector.
  • the invention allows a vibration image of the object to be examined to be recorded, in which the measurement beam is not guided over the object in a time-consuming manner, but instead the object is selectively imaged on the detector.
  • the necessary measuring time is shortened by at least the part time that would be required to guide the measuring beam over the object.
  • the invention is not limits.
  • the structure can be the same as that of a known Michelson interferometer, with the measuring beam being reflected by the vibrating object in one branch and the reference beam being reflected by a mirror in the other branch.
  • the beam splitting can be carried out with conventional beam splitters, but also with non-linear optical elements. Mirrors, prisms and in particular also optical fibers can be used for beam guidance.
  • the necessary measuring time of the vibrometer depends on the desired resolution of the oscillation frequency and the number of evaluated measuring points.
  • the frequency resolution defines the measuring time per measuring point; the whole
  • Measuring time per area depends linearly on the number of measuring points.
  • the measurement time for a desired resolution of the oscillation frequency of 1 Hz is, for example, 1 second per measurement point. It takes N seconds to evaluate N measuring points. If the N measuring points could be observed in parallel with a mosaic of detector elements, the required one would be
  • a micromirror grid advantageously allows the use of a simple detector having a few grid elements, and in particular a single detector. For this purpose, only a selective mapping of the interference image onto the detector by aligning individual micromirrors needs to take place with the advantages described at the beginning with regard to the measuring time. With a micromirror grid, imaging of the vibrometer with an inexpensive detector is therefore possible with a reasonable measuring time.
  • a transmitting optic is provided for aligning the measuring beam running away with the oscillating object. This makes it possible, for example, to widen or focus the measuring beam.
  • the radiation source in such a way that the measuring beam striking the object already has a desired cross-sectional area.
  • a frequency shifter in particular a Bragg cell, is expediently arranged in the reference beam path.
  • a frequency shift In addition, which can in particular also be designed as a non-linear optical element, the frequency of the reference beam is shifted relative to the frequency of the measuring beam. In the case of the Bragg cell, this is done by a passing acoustic wave on which the reference beam is diffracted.
  • the beam splitter can be designed as a polarization-sensitive element.
  • the beam splitter can generally be designed as a partially reflective or diffractive element.
  • the measurement and reference beam can be superimposed on the detector itself.
  • a pixel of the vibrating object imaged by the micromirror raster in the detector interferes with the reference beam only in the detector.
  • the interference pattern already arises on the micromirror grid before it is imaged, in particular, selectively on the detector.
  • the second variant results in a simplified beam guidance, since the measuring beam and the reference beam are guided together in the optical system. However, image information can be deleted by interference.
  • a control unit for controlling the micromirror grid and a signal processing unit for evaluating the detector signals are expediently integrated in the vibrometer.
  • the control unit is set up to align the micromirrors individually one after the other in time at the detector, and the signal processing unit is set up to generate a spatially resolved vibration image of the vibrating object from the detector signals obtained in this way. In this way, pixels of the vibrating object with the possible switching frequency of the
  • Micromirror grids are imaged one after the other on the detector, so that their interference pattern can be observed with the reference beam.
  • the measurement time is shortened because there is no need to shift the measurement beam.
  • the measurement time can advantageously be reduced further if the micromirrors are aligned in succession with a frequency on the detector which is higher than a limit frequency required to resolve a maximum oscillation frequency. For example, if a maximum oscillation frequency of 10 Hz is to be detected at a resolution of 1 Hz, then the cut-off frequency required for the resolution is double the maximum oscillation frequency, namely 20 Hz, according to the Nyquist theorem.Therefore, each measurement point no longer has to be at a time interval are directed at the detector as 50 milliseconds over a period of 1 second in order to obtain the information necessary for the vibration pattern from the overlay pattern for each measurement point.
  • micromirrors are successively aligned with the detector at a higher frequency than the required cutoff frequency, this enables a reduction in the measurement time.
  • This succeeds in that in the time between two measuring cycles of a measuring point, with the micro mirror being aligned with the detector in each measuring cycle, further micro mirrors are aligned with the detector.
  • each micromirror is aligned with the detector with a time offset, each micromirror, viewed separately, aligned with the clocking of the cutoff frequency and the time interval between the alignment of successive micromirrors corresponds to a higher frequency, the maximum value of which is the maximum possible control frequency of the micromirror grid given is.
  • the measurement time can be significantly reduced.
  • the micromirror grid is controlled in such a way that the micromirrors are aligned with the detector in chronological succession in a respectively predetermined grouping, the signal processing unit using the mathematical transformation to generate a spatially resolved vibration image of the vibrating object from the detector signals obtained in this way.
  • groups of micromirrors are aligned together on the detector. In this way, several pixels of the overlay pattern are recorded together by the detector. If the micromirrors that are aligned jointly on the detector are specified accordingly, a mathematical transformation can be used to calculate back from the total of the detector signals recorded to the intensity curve in each individual pixel of the overlay pattern.
  • a Hadamard transformation is particularly suitable as a mathematical transformation for backward calculation. This is described, for example, in M. Harwit, Hadamard Transform Optics, Academic Press,
  • the respective vibration spectrum can be inferred from the intensity course of each individual image point of the superimposition pattern by means of a frequency analysis, for example by means of a Fourier transformation.
  • a frequency analysis for example by means of a Fourier transformation.
  • the micromirrors of the micromirror grid are designed such that they can each assume two tilt positions, each micromirror directing incoming radiation in the first tilt position onto the detector and in the second tilt position into a light trap. This configuration ensures that only that radiation reaches the detector that originates from micromirrors aligned with the detector. Scattered radiation from micromirrors not aligned with the detector is reduced by the light trap.
  • the object is achieved according to the invention in that the vibrometer described is used to identify a vibrating object or a significant property of the vibrating object on the basis of its vibration characteristics.
  • an active vehicle can be distinguished from a mere dummy by the vibration of a running engine.
  • the vibration characteristic of the object to be identified is specified in particular by a defined vibration device.
  • a specific vibration characteristic can be impressed on the objects to be identified, such as in particular vehicles, aircraft or buildings, by means of which they can be identified on the basis of their own side. With such a use, a friend-foe distinction is possible.
  • the task directed to a method is achieved by a method according to the
  • the preamble of claim 14 is achieved according to the invention in that the oscillating object is imaged on a micromirror grid by means of the measuring beam, and in that the micromirror grid is imaged on the detector. Further advantageous refinements can be found in the subclaims directed to a method.
  • FIG. 1 schematically shows a first variant of an imaging vibrometer with a micromirror grid
  • FIG. 2 schematically shows a second variant of an imaging vibrometer with a micromirror grid
  • FIG. 3 schematically shows the use of a vibrometer to identify a vibrating object.
  • a vibrometer 1 schematically shows a vibrometer 1, which comprises a laser 2, a beam splitter 4, a transmitting optic 5, a receiving optic 7, a micromirror laser 8, an imaging optic 9 and a detector 10 as the radiation source.
  • the laser 2 emits a coherent output beam 13 which is split into a measuring beam 14 and a reference beam 15 by the beam splitter 4.
  • the measuring beam 14 is widened by means of the transmitting optics 5 and onto the investigative vibrating object 17 directed.
  • the oscillating object 17 carries out oscillations, as indicated by the arrows.
  • the measuring beam 14 is reflected on the vibrating object 17.
  • the returning measuring beam 18 passes through the receiving optics 7, which images the illuminated surface of the vibrating object 17 onto the micromirror grid 8.
  • the micromirror laser 8 is imaged on the detector 10 by means of the imaging optics 9.
  • the part of the object image which is oriented by the micromirror grid 8 onto the detector interferes with the reference beam 15, so that the detector 10 observes the interference or superimposition pattern which is formed.
  • the detector 10 is connected to a signal processing unit 20.
  • the signal processing unit 20 is combined with a control unit 21 which is connected to the micromirror grid 8 for control purposes.
  • the control unit 21 controls the micromirror grid 8, for example, in such a way that individual micromirrors are aligned with the detector 10 one after the other in a respectively predetermined grouping. In a measurement cycle, a predetermined number of groups defined by the respective arrangement of the micromirrors in the micromirror grid 8 are aligned with the detector 10 at the actuation frequency possible by the micromirror laser 8.
  • a Hadamard transformation in the signal processing unit 20 is used to deduce the temporal intensity profile of the superimposition pattern of each imaging point defined by the size of the micromirror.
  • a spatially resolved vibration image of the vibrating object 17 is generated by a frequency analysis.
  • An alternative vibrometer 23 is shown schematically in FIG.
  • the vibrometer 23 differs from the vibrometer 1 shown in FIG. 1 in that the transmitting optics 5 are arranged in the output beam 13 and in that the beam splitter 4 directs the divided reference beam 15 onto the micromirror grid 8.
  • a Bragg cell 22 is also inserted into the reference beam 15, as a result of which the reference beam 15 experiences a frequency shift. This enables the direction of vibration to be detected.
  • the returning measuring beam 18 and the reference beam 15 are superimposed on the micromirror in the vibrometer 23. grid 8 instead.
  • one or more pixels of the interference pattern are imaged into the detector 10 by selective activation of the individual micromirrors of the micromirror grid 8.
  • the detectors 10 in the vibrometers 1 and 23 are each designed as individual detectors in the form of fast photomultipliers. The time course of the recorded intensity is recorded in each case.
  • FIG. 3 shows the use of the vibrometer 1 according to FIG. 1 for obtaining reconnaissance data.
  • a drone 24 flies over a site 26 with open vegetation 27 and trees 28.
  • a truck 29 is located in the site 26, from which it is unclear whether it is real or a dummy.
  • the drone 24 flying over the terrain 26 is one of a number of others
  • Sensors such as cameras and infrared detectors, are equipped with a vibrometer 1 according to FIG. 1.
  • the vibrometer 1 measures vibrations of the targeted object via the drawn beam path 30.
  • the vibrometer 1 detects an engine vibration of the truck 29, so that it can now be clearly concluded that a real truck 29 is present.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)

Abstract

L’invention concerne un vibromètre (1, 23), comprenant une source de rayonnement (par exemple 2) pour rayonnement cohérent, une lame séparatrice (4) permettant de décomposer le rayon de sortie (13) de la source de rayonnement (par exemple 2) en un rayon de mesure (14) pour observer un objet oscillant (17) et en un rayon de référence (15), un système de guidage de rayonnement pour la superposition du rayon de mesure (18) repartant de l’objet oscillant (17) avec le rayon de référence (15) et un détecteur (10) pour la réception à résolution temporelle et/ou géographique du modèle de superposition. Pour ce faire, un réseau microréflecteur (8) disposé dans la trajectoire du rayon de mesure de retour (18), une optique de réception (7) pour imager l’objet oscillant (17) sur le réseau microréflecteur (8) et une optique d’imagerie (9) pour imager le réseau microréflecteur (8) sont prévus sur le détecteur (10). Le vibromètre imagé (1, 23) se caractérise par un faible temps de mesure. L’invention concerne également un procédé de réalisation d’une image oscillante de l’objet oscillant (17) de même que l’utilisation du vibromètre (1, 23).
PCT/EP2006/011685 2005-12-09 2006-12-06 Vibromètre WO2007065643A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE102005058905.7 2005-12-09
DE102005058905 2005-12-09
DE102006003877.0 2006-01-27
DE102006003877A DE102006003877B4 (de) 2005-12-09 2006-01-27 Vibrometer

Publications (1)

Publication Number Publication Date
WO2007065643A1 true WO2007065643A1 (fr) 2007-06-14

Family

ID=37784716

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2006/011685 WO2007065643A1 (fr) 2005-12-09 2006-12-06 Vibromètre

Country Status (2)

Country Link
DE (1) DE102006003877B4 (fr)
WO (1) WO2007065643A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018114478A1 (de) * 2018-06-15 2019-12-19 Polytec Gmbh Verfahren zur Bestimmung des Strahlverlaufs eines Messstrahls einer interferometrischen Messvorrichtung und Messvorrichtung zur interferometrischen Vermessung eines Messobjekts

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007023826A1 (de) * 2007-05-21 2008-11-27 Polytec Gmbh Verfahren und Vorrichtung zur berührungslosen Schwingungsmessung
DE102008017119A1 (de) 2008-04-02 2009-10-08 Polytec Gmbh Vibrometer und Verfahren zur optischen Vermessung eines Objekts
DE102009049932B4 (de) 2009-10-19 2016-04-07 Polytec Gmbh Vorrichtung und Verfahren zur interferometrischen Schwingungsmessung an einem Objekt
DE102015003019A1 (de) 2015-03-06 2016-09-08 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Verfahren und Vorrichtung zur optischen Detektion einer Bewegung in einer biologischen Probe mit räumlicher Ausdehnung
DE102017112931A1 (de) 2017-06-13 2018-12-13 Prüftechnik Dieter Busch Aktiengesellschaft Mobiles Transportmittel zum Transportieren von Datensammlern, Datensammelsystem und Datensammelverfahren

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6081481A (en) * 1987-04-17 2000-06-27 Institute For Technology Development Method for detecting buried objects by measuring seismic vibrations induced by acoustical coupling with a remote source of sound
JP2000221077A (ja) * 1999-02-02 2000-08-11 Ono Sokki Co Ltd 振動計測装置
US20030218673A1 (en) * 2000-12-28 2003-11-27 Cameron Abnet Microscopic motion measuring
WO2004083795A2 (fr) * 2002-12-13 2004-09-30 Arete Associates Systeme optique
US20050157306A1 (en) * 2004-01-16 2005-07-21 Joanna Schmit Measurement of object deformation with optical profiler

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6388409A (ja) * 1986-10-01 1988-04-19 Mitsubishi Electric Corp レ−ザ振動計
GB2265514B (en) * 1992-03-28 1995-08-16 Marconi Gec Ltd A receiver-transmitter for a target identification system
JPH10503279A (ja) * 1994-07-08 1998-03-24 フォースクニングスセンター・リセー 光学的測定方法および装置
DE19801959A1 (de) * 1998-01-21 1999-07-22 Polytec Gmbh Optischer Aufbau zur berührungslosen Schwingungsmessung
DE19806240B4 (de) * 1998-02-16 2004-07-08 Polytec Gmbh Verfahren und Vorrichtung zur flächenhaften Schwingungsanalyse
JP4142532B2 (ja) * 2003-09-02 2008-09-03 シャープ株式会社 光学式速度計、変位情報測定装置および搬送処理装置
DE502004002547D1 (de) * 2004-06-22 2007-02-15 Polytec Gmbh Vorrichtung zum optischen Vermessen eines Objektes

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6081481A (en) * 1987-04-17 2000-06-27 Institute For Technology Development Method for detecting buried objects by measuring seismic vibrations induced by acoustical coupling with a remote source of sound
JP2000221077A (ja) * 1999-02-02 2000-08-11 Ono Sokki Co Ltd 振動計測装置
US20030218673A1 (en) * 2000-12-28 2003-11-27 Cameron Abnet Microscopic motion measuring
WO2004083795A2 (fr) * 2002-12-13 2004-09-30 Arete Associates Systeme optique
US20050157306A1 (en) * 2004-01-16 2005-07-21 Joanna Schmit Measurement of object deformation with optical profiler

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018114478A1 (de) * 2018-06-15 2019-12-19 Polytec Gmbh Verfahren zur Bestimmung des Strahlverlaufs eines Messstrahls einer interferometrischen Messvorrichtung und Messvorrichtung zur interferometrischen Vermessung eines Messobjekts
US12066321B2 (en) 2018-06-15 2024-08-20 Polytec Gmbh Method for determining the path of a measurement beam of an interferometric measuring device, and measuring device for interferometric measurement of an object under measurement
DE102018114478B4 (de) 2018-06-15 2024-09-19 Polytec Gmbh Verfahren zur Bestimmung des Strahlverlaufs eines Messstrahls einer interferometrischen Messvorrichtung und Messvorrichtung zur interferometrischen Vermessung eines Messobjekts

Also Published As

Publication number Publication date
DE102006003877B4 (de) 2007-10-31
DE102006003877A1 (de) 2007-06-14

Similar Documents

Publication Publication Date Title
EP3729137B1 (fr) Système lidar à impulsions multiples pour la détection multidimensionnelle d'objets
DE102019008989B3 (de) Verfahren zur Störungskorrektur und Laserscanningmikroskop mit Störungskorrektur
DE102004014048B4 (de) Vermessungseinrichtung und Verfahren nach dem Grundprinzip der konfokalen Mikroskopie
EP3298345B1 (fr) Caméra et procédé pour réaliser une mesure en 3d et une mesure de couleur d'un objet dentaire
EP2326915B1 (fr) Procédé et dispositif de détection de données de contour et/ou de propriétés optiques d'un objet semi-transparent tridimensionnel
DE102007003777B4 (de) Messvorrichtung und Verfahren zur optischen Vermessung eines Objektes
DE10225838A1 (de) Verfahren zur Scanmikroskopie, Scanmikroskop und Vorrichtung zum Codieren eines Beleuchtungslichtstrahles
DE102010049672B3 (de) Laser-Doppler-Linien-Distanzsensor zur dreidimensionalen Formvermessung bewegter Festkörper
WO2007065643A1 (fr) Vibromètre
DE112015001154T5 (de) Mikroskop und Mikroskopie-Verfahren
EP1870761B1 (fr) Microscope à balayage destiné à la mesure optique d'un objet
EP2557451A1 (fr) Procédé et dispositif pour la détection optique d'un échantillon éclairé
DE102008021465A1 (de) Entfernungsmesssystem
DE60036467T2 (de) Verfahren und vorrichtung zur dopplergeschwindigkeitsmessung
WO2019110206A1 (fr) Système lidar de perception de l'environnement et procédé pour faire fonctionner un système lidar
DD234340A3 (de) Automatische fokussiereinrichtung
EP1931970B1 (fr) Dispostif et procede d'enregistrement optique d'un echantillon avec une resolution en profondeur
DE102014108886B3 (de) Vorrichtung und Verfahren zur interferometrischen Abstandsbestimmung
EP2767797B1 (fr) Interféromètre à faible cohérence et procédé de mesure optique à résolution spatiale du profil de surface d'un objet
DE102010033951A1 (de) Anordnung und Verfahren zur mehrdimensionalen Messung von Schwingungen eines Objekts
EP2227671B1 (fr) Dispositif et procédé de détermination de la position et/ou de l' orientation de deux objets l'un par rapport à l'autre
DE102016215177B4 (de) Verfahren und Anordnung zur Erfassung von Bilddaten
DE112007002613T5 (de) Optisches Gattersystem, das das Moiré-Phänomen nutzt
DE3544558C1 (de) Laser-Sende/Empfangs-Abbildungssystem
DE102019203640A1 (de) Lidar-System mit holografischer Abbildungsoptik

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase

Ref document number: 06829324

Country of ref document: EP

Kind code of ref document: A1

点击 这是indexloc提供的php浏览器服务，不要输入任何密码和下载