WO2012136238A1 - Verfahren und anordnung zur kurz-kohärenz-holografie - Google Patents
Verfahren und anordnung zur kurz-kohärenz-holografie Download PDFInfo
- Publication number
- WO2012136238A1 WO2012136238A1 PCT/EP2011/006546 EP2011006546W WO2012136238A1 WO 2012136238 A1 WO2012136238 A1 WO 2012136238A1 EP 2011006546 W EP2011006546 W EP 2011006546W WO 2012136238 A1 WO2012136238 A1 WO 2012136238A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- light
- short
- hologram
- frequency comb
- coherence
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 78
- 238000001093 holography Methods 0.000 title claims abstract description 66
- 230000003287 optical effect Effects 0.000 claims abstract description 140
- 238000001514 detection method Methods 0.000 claims abstract description 79
- 238000005259 measurement Methods 0.000 claims abstract description 38
- 238000000149 argon plasma sintering Methods 0.000 claims description 69
- 230000003595 spectral effect Effects 0.000 claims description 29
- 230000001427 coherent effect Effects 0.000 claims description 15
- 230000008569 process Effects 0.000 claims description 14
- 230000008859 change Effects 0.000 claims description 11
- 230000033001 locomotion Effects 0.000 claims description 9
- 230000015572 biosynthetic process Effects 0.000 claims description 8
- 230000005670 electromagnetic radiation Effects 0.000 claims description 7
- 230000010363 phase shift Effects 0.000 claims description 7
- 230000005855 radiation Effects 0.000 claims description 6
- 238000006073 displacement reaction Methods 0.000 claims description 4
- 238000000691 measurement method Methods 0.000 claims description 2
- 238000013459 approach Methods 0.000 abstract description 16
- 230000015654 memory Effects 0.000 abstract description 5
- 238000005210 holographic interferometry Methods 0.000 abstract 1
- 239000000835 fiber Substances 0.000 description 23
- 230000008901 benefit Effects 0.000 description 18
- 239000011159 matrix material Substances 0.000 description 12
- 238000005516 engineering process Methods 0.000 description 10
- 238000005286 illumination Methods 0.000 description 6
- 238000012546 transfer Methods 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000011156 evaluation Methods 0.000 description 5
- 238000005305 interferometry Methods 0.000 description 4
- 238000010009 beating Methods 0.000 description 3
- 210000001520 comb Anatomy 0.000 description 3
- 230000006378 damage Effects 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 238000003384 imaging method Methods 0.000 description 3
- 238000007689 inspection Methods 0.000 description 3
- 238000002211 ultraviolet spectrum Methods 0.000 description 3
- 230000003044 adaptive effect Effects 0.000 description 2
- 238000003491 array Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 238000001727 in vivo Methods 0.000 description 2
- 238000012623 in vivo measurement Methods 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 230000001902 propagating effect Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000008439 repair process Effects 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 230000002123 temporal effect Effects 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 241000282326 Felis catus Species 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000021615 conjugation Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000005339 levitation Methods 0.000 description 1
- 230000004807 localization Effects 0.000 description 1
- 230000010358 mechanical oscillation Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000386 microscopy Methods 0.000 description 1
- 230000002285 radioactive effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 230000029305 taxis Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012549 training Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/04—Processes or apparatus for producing holograms
- G03H1/08—Synthesising holograms, i.e. holograms synthesized from objects or objects from holograms
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/2441—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures using interferometry
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
- G01B9/02041—Interferometers characterised by particular imaging or detection techniques
- G01B9/02047—Interferometers characterised by particular imaging or detection techniques using digital holographic imaging, e.g. lensless phase imaging without hologram in the reference path
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
- G01B9/0209—Low-coherence interferometers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
- G01B9/021—Interferometers using holographic techniques
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/04—Processes or apparatus for producing holograms
- G03H1/0443—Digital holography, i.e. recording holograms with digital recording means
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/04—Processes or apparatus for producing holograms
- G03H1/08—Synthesising holograms, i.e. holograms synthesized from objects or objects from holograms
- G03H1/0866—Digital holographic imaging, i.e. synthesizing holobjects from holograms
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2203/00—Function characteristic
- G02F2203/54—Optical pulse train (comb) synthesizer
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2203/00—Function characteristic
- G02F2203/56—Frequency comb synthesizer
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/0005—Adaptation of holography to specific applications
- G03H2001/0033—Adaptation of holography to specific applications in hologrammetry for measuring or analysing
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/04—Processes or apparatus for producing holograms
- G03H1/0443—Digital holography, i.e. recording holograms with digital recording means
- G03H2001/045—Fourier or lensless Fourier arrangement
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/04—Processes or apparatus for producing holograms
- G03H1/0465—Particular recording light; Beam shape or geometry
- G03H2001/0467—Gated recording using pulsed or low coherence light source, e.g. light in flight, first arriving light
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H2210/00—Object characteristics
- G03H2210/62—Moving object
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H2222/00—Light sources or light beam properties
- G03H2222/10—Spectral composition
- G03H2222/13—Multi-wavelengths wave with discontinuous wavelength ranges
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H2222/00—Light sources or light beam properties
- G03H2222/20—Coherence of the light source
- G03H2222/22—Spatial coherence
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H2222/00—Light sources or light beam properties
- G03H2222/20—Coherence of the light source
- G03H2222/23—Temporal coherence
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H2222/00—Light sources or light beam properties
- G03H2222/20—Coherence of the light source
- G03H2222/24—Low coherence light normally not allowing valuable record or reconstruction
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H2222/00—Light sources or light beam properties
- G03H2222/33—Pulsed light beam
Definitions
- the short-coherence holography also represents an absolute measuring method whose potential and its advantages were already clearly recognized several years ago, sa technical essay "Applications of short-coherence digital holography in microscopy” by Lluis Martinez-Leon, Giancarlo Pedrini and Wolfgang Osten in Applied Optics of July 1, 2005, Vol. 44, No. 19, pages 3977 to 3984. [2]
- the object of the invention is to be able to measure objects in three spatial dimensions as quickly as possible with a resolution that can be adjusted by a wide scale. This object is achieved by a method and a device having the features specified in the independent claims. Preferred embodiments are subject of the dependent claims.
- the invention provides a method for short coherence holography of an at least partially light scattering object
- a holographic interferometer for generating a reference and an object light bundle
- a planar hologram detection area HDB in which at least one at least in spectral subranges spectrally integrally detecting, rasterized detector is arranged, and
- a holographic interferometer for generating a reference and an object light bundle, in which there is a mean, non-zero optical retardation Xm, and
- a planar hologram detection area HDB in which at least one at least in spectral subranges spectrally integrally detecting, rasterized detector is arranged, and
- the device preferably comprises an evaluation module which is designed to detect at least one short coherence hologram in the recording process by means of the spectrally integrally detecting, screened detector,
- the invention achieves in particular, measuring systems for the distance or distance measurement or for the extraction of 3D point clouds with a - depending on the needs - whskalig customizable resolution and thus generally wide-scale customizable measuring or sampling accuracy of economic use to supply.
- the inventive approach includes the possibility of depth resolution from the sub-micrometer to the centimeter range depending on the object distance and object depth extent and training of the components used and is thus learnskalig applicable.
- the invention makes it possible to obtain depth information from the depth of the object space by means of short-coherence holography.
- the depth resolution is very flexible adaptable.
- a particular advantage consists in being able to simultaneously obtain information about an at least partially light-scattering object from different depths of the object space.
- the registered short coherence holograms which are simultaneously formed by spherical waves from different depths of the object space, can be processed to a 3D point cloud by means of digitally performed hologram reconstructions.
- the present invention provides the advantage of scanning an object with a rung ladder having a plurality of ladder rungs that are gradually shifted over the object in depth, and thus optically scan that object, so that information can be obtained simultaneously from a plurality of depth regions of the object in the form of short coherence holograms, that is to say from the depth regions which are each optically cut by a ladder rungs region.
- Another particular advantage is to allow both the absolute detection of the object position and the determination of the object shape - even at a greater distance, for example, at an object distance of 10 meters, with relatively high resolution in the three spatial coordinates.
- the invention thus offers in particular a method for short coherence holography, in particular for a technical or biological, at least partially light-scattering object or for at least partially light-scattering object elements for obtaining a 2D or 3D point cloud in the microscopic, the mesoscopic, especially for the In vivo 3D detection of the shape of a tooth or even several teeth in the mouth of a human, or on the macroscopic scale or for endoscopic 2D or 3D metrology of technical or biological, at least partially light scattering objects with obtaining a 2D or 3D Point cloud or even only for distance measurement or depth determination of an at least partially light-scattering object.
- the method is carried out with a holographic interferometer for generating reference and object light - in which case light in the sense of electromagnetic radiation of terahertz, via IR, VIS, UV or EUV radiation is understood in particular.
- At the output of the holographic interferometer there is a planar Hologram detection area HDB. Furthermore, at least one short-coherence light source or at least one quasi-short coherence light source is arranged for illumination.
- an optical retardation X_k which is always clearly different from zero, in which case the holographic interferometer in its area hologram detection area HDB at a point DP of the hologram detection area HDB for an optically detected object point OP_k always has a clearly different from zero optical - object point-related - path difference x_OP_k_DP.
- At least one spectrally integrally detecting rasterized detector is arranged in this hologram detection area HDB, at least in spectral subranges.
- short-coherence holography is procedurally combined with the short-coherence frequency comb holography (SCFC-holography) frequency-comb technique by using a short-coherent or quasi-short-coherent holographic interferometer
- the inequality is the inequality
- x_OP_k_DP - n1 ⁇ Y1
- ⁇ Ic for at least one integer n1 with n1 1, 2, 3, ... and for at least one optically detected, at least partially light scattering object point OP_k fulfilled and thus creates a hologram in at least a portion of the screened detector with Ic as the coherence length of short-coherent or quasi-short coherent frequency comb light, which returns from the light scattering object point OP and contributes to hologram formation.
- x_OP_k_DP is the optical path difference at a point DP of the areal hologram detection area HDB for the optically detected, light-scattering object point OP_k.
- At least one short coherence hologram is digitally reconstructed and at least one intensity amplitude of a light scattering object point OP_k is determined from the reconstructed hologram above a threshold value IS.
- This is the criterion for the presence of a light-scattering object point OP_k of the object space, so that a plurality of light-scattering object points in the object space and thus a 3D point cloud can be determined by means of digital hologram reconstruction and application of the threshold criterion IS.
- the short-coherence light source may preferably have a coherence length Ic of the single-digit micrometer range down to the single-digit millimeter range.
- a quasi-short coherence light source may preferably have a coherence length Ic of the single-digit millimeter range down to the one or two-digit centimeter range.
- the inequality (1) can be satisfied if the mean optical path difference Xm in the holographic arrangement is set accordingly, for example also by means of a displaceable reference reflector .
- the coherence length Ic of the short-coherent light can be made comparatively large, for example in the range of a single-digit millimeter range, if it is all about checking or detecting the presence of an object point or an object at a greater distance, for example the presence of power cables or Also fine wires in a very confusing situation, in which the depth information in comparison to the high-resolution image acquisition is very useful.
- the delay length Y1 in generating frequency comb light is only a few millimeters, it is not necessary to know the integer number n1 in the inequality (1).
- the integer number n1 describes the integer number of delay lengths Y1, which fit into the optical path difference and x_OP_k_DP, thus derives from a quotient.
- an approximate knowledge of the number n1 suffices to be able to assign the recorded and reconstructed data.
- the knowledge of the number n1 is rather minor if the profile depth is significantly smaller than the delay length Y1.
- n1 is the number rounded to an integer number, the delay lengths Y1, which fits into the optical path difference of the holographic device.
- n1 is the number rounded to an integer number, the delay lengths Y1, which fits into the optical path difference of the holographic device.
- a generally invariable n1 is assumed for all touched object points, since this is a flat object - in relation to the existing delay length Y1 in the generation of frequency comb light.
- a frequency comb light source is superfluous, as this provides rather no apparent advantage.
- the exact location of this particular (zeroth) ladder rung depends, of course, on the position and design of the reference reflector in the reference arm of the Michelson interferometer as adopted herein. A shift of the reference reflector then also pushes the position of this zeroth rung with the sprouts ordinal number assigned by definition to zero.
- the light coming back from an object point OP_k which here is supposed to be modeled on the heavy beam of the illumination beam, is to propagate in the model as a beam parallel to the above-mentioned heavy beam.
- the ladder model quite well approximates the optical path length issue when the associated reference beam at the Michelson interferometer output coincides with the object beam returning from OP_k. It is clear that a spherical wave propagates from the light scattering object point OP_k and interference with the reference light occurs in the hologram detection plane.
- This reference light may preferably also be embodied as a spherical wave, wherein the center of the reference spherical wave should be modeled on the heavy beam of the beam propagating in the reference arm, so that here the case of Fourier holography is given.
- the interference of two spherical waves then occurs.
- the ladder model approximates the conditions particularly well if the reference wave is a spherical wave whose source point is optically conjugate to the object point OP_k, the latter - here in the model - lying on the heavy beam of the beam in the reference arm. In this case, the variation of the optical path difference in the hologram in the entire hologram detection area HDB approaches zero.
- the representation of the reference wave as a spherical wave with the object point OP_k optically conjugate spherical wave source point can be done by a correspondingly arranged paraboloid of revolution in the reference arm of a Michelson interferometer for performing the holography.
- the focal point of the paraboloid of revolution lies on the heavy beam of the incoming beam and the heavy beam coincides with the axis of symmetry of this paraboloid of revolution.
- the ladder rungs can be numbered up to the ordinal number n1_max.
- the thickness of these ladder rungs, ie their depth extent - here in the direction of light propagation - here in the model is then at least approximately equal to half the coherence length lc of the frequency comb light, ie lc / 2.
- the coherence length Ic is preferably adjustable within wide limits, whereby the thickness of these model ladder rungs is also variable within wide limits.
- the coherence length Ic of the short-coherent light may preferably be in the two-digit micron range.
- the coherence length Ic of the short-coherent light may even be in the single-digit micrometer range, ie the short-coherent light may then also be "white” in the visible spectral range.
- the screened detector can be designed as a monochrome matrix CCD or matrix CMOS camera or as a color matrix CCD or color CMOS camera, in a single-chip or multi-chip arrangement.
- a plurality of camera chips or a plurality of camera chips are arranged in matrix form.
- the rastered detector can preferably be formed by a multiplicity of camera chips in matrix form, it also being possible to arrange a plurality of chip arrays, for example one chip matrix each for a particular one Spectral range.
- a plurality of holograms in the form of a hologram stack, are preferably generated step by step and recorded by means of a rastered detector.
- ⁇ Ic (1) is satisfied.
- at least one hologram is formed - with Ic as the coherence length of the hologram forming frequency comb light, which comes back from at least one light scattering object point OP_k.
- x_OP_k_DP is the optical path difference at a point DP of the area hologram detection area HDB for an optically detected object point OP_k.
- the predetermined, as well as measured, multiple variation of the mean optical path difference Xm enables the person skilled in the art to obtain data from recorded holograms in order to determine the integer number nT exactly.
- several inequalities according to the inequality (1) are set up with immutable object position, but with variation of the mean optical path difference Xm.
- each delivering holograms preferably the mean optical path difference Xm must be changed stepwise or continuously, at least one hologram being recorded after each step.
- the phase shifting technique preferably three, four, or five - possibly even more - mutually phase-shifted holograms are recorded after each step.
- the change in the mean optical path difference Xm at each step may preferably be one-tenth of the frequency comb light forming the coherence length lc of the hologram, so that the "rungs areas" gradually overlap on the object in the depth direction an object point OP_k in the digitally reconstructed holograms multiple intensity amplitude values that may be on a Gaussian curve, whereby the skilled person skilled in the execution of well-known gravity evaluation for each object point OP_k is possible, which the Measurement uncertainty (accuracy) in the depth measurement usually improved significantly.
- the delay length Y1 of the delay line is changed, but this is considered technically more complex - compared to changing the mean optical path difference Xm in the holographic arrangement, for example in the reference arm of the holographic interferometer by pushing a final reflector.
- the frequency combs must therefore have very sharp "needles" and equidistant needles, ie have a low half-width with respect to the frequency spacing of the individual maxima (frequency comb needles) .
- This requirement increases with the quotient of the mean optical path difference Xm and the delay length Y1 of some kind This is best achieved in the prior art and best knowledge with frequency comb lasers and best for optically to be touched objects in the near range, where the above quotient is comparatively small.
- the number n1 can also be expressed by the multiple variation of
- Xm be determined from a hologram stack.
- the mean optical path difference Xm is preferably changed gradually, thus addressing different depth ranges in the storage volume, and thus dots in the volume of the holographic memory or a three-dimensional signature carrying the digital information are present (L situation) or absent (O situation) detected.
- a multiplicity of holograms j in the form of a hologram stack, that is to say gradually generated in j situations, are recorded by means of a rastered detector.
- a multiplicity of holograms j in the form of a hologram stack, that is to say gradually generated in j situations, are recorded by means of a rastered detector.
- the first inequality (2) describes the case of changing the mean optical path difference Xm in the holographic interferometer in j steps and the second inequality (3) the case of changing the delay length Y1 of the delay path for frequency comb generation in holographic interferometer in j steps.
- Ic is the coherence length of the hologram forming frequency comb light returning from at least one light scattering object point OP_k.
- x_OP_kJ_DPJ and x_OP_k_DP respectively represent the optical path difference at a point DP of the area hologram detection area HDB for an optically detected object point OP_k and a situation j.
- the value x_OP_k_j_DPJ is to be assumed when the average optical path difference is predeterminedly varied.
- the value x_OP_k_DP is to be assumed when the optical delay length Y1 of the delay line for frequency comb generation is changed.
- Y1 or Y1J - the latter in the case of varying the delay length - represent the respective optical delay length of the frequency comb light source.
- the image of the rung ladder clarifies the facts quite clearly here as well, in that in a first phase with a rung ladder the individual ladder rungs (with their center lines) have half the distance of the delay length Y1, ie Y1 / 2, of the frequency comb light source from one another second phase, the half distance of the delay length Y2, so Y2 / 2, the frequency comb light source from each other.
- the rung ladder in the model is displaced in depth, preferably in equal steps, well below the coherence length lc of the frequency comb light for hologram formation. This should be done here in the model - starting in each of the two phases, each in the same starting position (O position) - down.
- the response of a point in the form of a hologram in different step positions j of the ladder assumed here in the model is generally carried out. From this, the depth position within a beat region Ys can be reliably determined for the person skilled in the art, for example also in analogy to the ladder model also used in the two-wavelength technique, which is determined by the two frequency comb light sources with the respective delay lengths Y1 and Y2 and on the basis thereof Difference delta_Y is given here.
- the difference (j1 - j2) gives the number 2, and thus also the information that the 10 "answering" object point OP_k in the depth of 2.2 Length units - based on half the delay length Y1 / 2 - seen from the zero position - is located.
- This "fractional method”, shown here in a simplified manner, is well-known to experts in the field of two-wavelength technology or, generally, in the two-period technique.
- the beat approach is based here on the basis of measurement information based on the calculation of stretched or compressed reference lengths, here the delay lengths Y1 and Y2, and preferably further delay lengths Yi.
- At least one second short-coherent or quasi-short-coherent light with frequency-comb characteristic with the frequency spacing Af2 c / Y2 in a spectral range delta_sigma2, which is completely separated from the spectral range delta_sigma1, preferably also occurs for the same object depth range of the object space with the same light scattering object points OP_k generating and detecting holograms with the number j2.
- the reference spherical wave source point is preferably carried out in the Fourier holography with reference spherical wave, so that the reference spherical wave source is located as close as possible in the environment of the object points to be measured, in which case the optical conjugation of reference space and object space applies.
- the reference spherical wave source point is thus positioned, for example, by precise sliding of optical components such as rooftops, triple mirrors or even curved individual mirror or mirror systems so that the reference spherical wave source point coincides with an object point, the large one Interest is, for example, an object point in the immediate vicinity of a real or suspected crack of a container, a tub or a tank.
- a holographic deformation measurement with this holographic arrangement or with optical components thereof can be performed to get more information about a defective component.
- light of other laser light sources for example double-pulse laser
- other cameras such as high-speed cameras can be used as well as optical components exchanged, removed or added.
- means are preferably also arranged which enable a predetermined movement of optical components, such as roof-edge, triple-mirror or even curved mirror components.
- means for measuring this movement of components are preferably also arranged in a preferably comparatively large volume.
- the method of short coherence holography employs in-line holography. This usually significantly reduces the pixel pitch size requirements for rasterized detectors.
- the short-coherence holography method employs phase-shifting holography.
- phase-shifting holography This can usually improve the signal-to-noise ratio significantly.
- the phase shift can preferably also be effected by means of micro-scanning on a low-mass mirror in a frequency comb light source. This works - taking into account the resonator geometry of the frequency comb light source - like a Phase shift in the reference arm of a holographic interferometer.
- At least one short coherence light source or one quasi-short coherence light source is arranged upstream of the arrangement for short coherence holography.
- light is understood in particular in terms of electromagnetic radiation of terahertz, via IR, VIS to UV and EUV radiation.
- the holographic interferometer In its planar hologram detection area HDB, the holographic interferometer always has an optical path difference x_OP_k_DP which differs in particular clearly from zero at a point DP of the HDB for an optically detected object point OP_k.
- At least one spectrally integrally detecting rasterized detector is arranged in this hologram detection area HDB, at least in spectral subregions.
- the screened detector can be designed as a monochrome matrix CCD or matrix CMOS camera or as a color matrix CCD or color CMOS camera, in a single-chip or multi-chip arrangement.
- a plurality of camera chips or a plurality of camera chips are arranged in matrix form.
- the rasterized detector may preferably be implemented by a variety of camera chips Matrix form may be formed, wherein also preferably the arrangement of a plurality of chip matrices is possible, for example one for a particular spectral range.
- At least one short coherence light source or / and at least one quasi-short coherence light source with a frequency comb characteristic are formed and assigned to the holographic interferometer. If several short coherence light sources with frequency comb characteristics are used, which supply light to the holographic arrangement, in particular in separate spectral regions, each spectral region can be assigned its own rastered detector or a matrix of rastered detectors. In this case, the individual short-coherence light sources with frequency-comb characteristics preferably each have a different optical delay length, so that a different frequency spacing results in the frequency domain for each short-coherence light source with frequency-comb characteristics. These short coherence light sources with frequency comb characteristics and in each case different spectral range can be operated simultaneously.
- a frequency comb laser which can be used in particular for holography in the microscopic and possibly also in the mesoscopic scale, is a monolithic torodial microresonator with an optical retardation length Y1 of about 400 micrometers and a coherence length Ic in the middle This is described in the paper "Optical frequency comb generation from a monolithic microresonator" by P.
- two monolithic torodial microresonators for example, having a first optical retardation length Y1 of about 500 microns in size and a second optical retardation length Y2 of about 555 microns in size and one coherence length Ic in the mid single-digit micrometer range, respectively Central wavelength of about 1550 nm and a spectral range of about 400 nm, a two-frequency comb technique, ie as a frequency comb technique with two frequency combs, for micro-profile detection or 3D miniature form detection can be performed.
- the two monolithic, torodial microresonators can be switched on alternately.
- centroid wavelengths 1350 nm for the first microresonator and 1650 nm for the first microresonator have, for example, the centroid wavelengths 1350 nm for the first microresonator and 1650 nm for the first microresonator.
- the uniquely addressable object depth range Ys / 2 results in analogy to the two-wavelength technique from the beat delay length Ys
- Ys Y1 * Y2 / (delta_Y), so that the uniquely addressable object depth range Ys / 2 is about 2.52 millimeters.
- a very compact arrangement for single-shot testing of three-dimensional optical micro-signatures can be constructed, which can ensure a high safety standard.
- an arrangement (device) for short coherence holography means for varying the delay length Y1, Y2 or Yi at least one frequency comb light source are arranged.
- the delay length is comparatively easily feasible in the case of frequency comb lasers having a significantly longer delay length than microresonators, for example with delay lengths Y1 of around 300 mm or 1000 mm.
- phase shift which are very advantageous or even absolutely indispensable in inline holography.
- means for varying the mean optical path difference Xm of the holographic interferometer are arranged in order to generate holograms.
- This is particularly preferred in order to be able to detect holographically completely also objects with comparatively great depth extent, in particular when the coherence length Ic is comparatively small in the interest of a better depth resolution, for example only 10 micrometers for holography in the microscopic scale.
- the holographic interferometer is designed as a Michelson interferometer. This is object lighting light and the returning and for the hologram formation used light at least approximately coaxial, which can be a very big advantage in the inspection of holes and craters narrow.
- a spherical mirror or a rotation paraboloid mirror is arranged with its focal plane in the reference beam space.
- the focal plane of the spherical mirror or a rotational paraboloid mirror is preferably at least approximately parallel to the input wavefronts, which are preferably planar.
- means for lateral displacement of the spherical mirror or the rotational paraboloid mirror are arranged.
- This is advantageous, in particular for the near range and for a comparatively large object field.
- the paraboloid of revolution is displaced laterally in the Michelson interferometer so that the Fourier case can be approximated well even for object points far out in the field.
- the object spherical waves of external object points in the field assigned to a reference ball wave which is well adapted to the position of its source point, so even with a small coherence length Ic still a rasterized detector fully hiding over the hologram - then always with only a few stripes.
- a spherical mirror or an off-axis rotational paraboloid mirror is arranged with a miniaturized end mirror, which is arranged at least approximately in the focus of the mirror. This is a Cat's eye arrangement that can be very beneficial.
- the miniaturized end mirror is assigned means for highly dynamic phase shifting. This is due to the low mass of the miniaturized end mirror a significant advantage in terms of achievable dynamics in the phase position.
- These means are preferably designed as a piezoelectric actuator.
- the holographic interferometer is formed as an interferometer with a location for the beam splitting and with a location for the beam combination, these locations being spatially completely separated from one another.
- the holographic interferometer with U-arrangement in the reference beam path and V-arrangement in the object beam path is formed.
- this is arranged at the end of a U-ray path in the reference arm of the holographic arrangement.
- there may be a cat's-eye arrangement, which can be a significant advantage.
- the holographic interferometer for object light in the propagation direction is for detection associated with a beam cross-section reducing optical system.
- This bundle cross-section-reducing optical system in the object beam path can be adapted to the size of the rastered pixelated pixel detector with a very small pixel pitch in order to adapt a laterally extended object beam coming from a far-reaching, light-scattering object point.
- the depth resolution with a correspondingly short coherence length can also be in the single-digit millimeter range.
- the rasterized detector can have 100 million pixels. By contrast, these parameters are in no way achievable in the prior art with commercially available runtime cameras.
- the holographic arrangement is formed as an in-line arrangement with a beam cross-sectional reduction optical system for returning object light.
- This beam cross-section shrinking optical system in the return light beam path may also be adapted to match a laterally extended backward object beam of a far-flung, light-scattering object point to the size of the very high pixel pitch rastered pixelated detector.
- each individual mirror of a mirror array can also be assigned its "own" camera chip
- a wavefront-forming optical system can preferably also be arranged in front of the input to the holographic arrangement, which can preferably also serve the optimal illumination of the object field.
- wavefront shaping in the reference arm can also preferably be carried out.
- the Fourier holography and the short-coherence technique with the frequency comb light source technology fit together particularly well, because in this combination, the rasterized detector with a well-modulated hologram at Application of a short-coherence light source - at least for relatively small object fields - can be filled.
- This hologram tends not to have extremely high densities of the interference fringes, which is a significant technical advantage.
- the invention provides a teaching of methods and arrangements which can in particular also make a contribution to increasing the security in space, in particular also to identify on the basis of the profile or the shape of moving objects, which for others Space objects, for inhabited areas or for the natural environment on the earth's surface can pose a threat.
- the invention also makes it possible, in this preferred embodiment, to generate optical signals in the form of short-coherence holographic holograms from fast-moving or oscillating objects, which may also be located at greater distances, which are suitable for being picked up by available screened detectors become.
- optical signals in the form of short-coherence holographic holograms from fast-moving or oscillating objects, which may also be located at greater distances, which are suitable for being picked up by available screened detectors become.
- the profile or the shape of the moving or oscillating object should be at least partially displayed.
- a holographic method by means of a holographic measuring arrangement, which can be used in particular for optical sectioning (optical cutting) on moving objects, in particular also in outer space.
- the term light is used in particular as a synonym for electromagnetic radiation from the terahertz, over the infrared to the deep UV spectrum.
- the holographic measuring arrangement contains in particular at least one frequency comb light source with comparatively short coherence length Ic in relation to the object extent and with controllable frequency comb light by predetermined change of the optical path length L1 in its integrated or in at least one of these frequency comb light source associated cavity.
- at least one short-coherence light source and / or quasi-short coherence light source already described above can be used, wherein the latter can now be controlled to increase the frequency comb light by changing the optical path length according to the procedure described here Taxes.
- the measuring arrangement also contains an unbaianciertes two-beam interferometer with a reference and an object arm, which acts on the moving object with measuring light from the frequency comb light source, with a detection channel for returning measuring light.
- an unbalanced two-beam interferometer is understood in particular to be an interferometer for generating a reference light beam and an object light beam in the manner described above, in which there is an average optical path difference Xm different from zero.
- the measurement arrangement also includes at least one rastered detector for recording holograms and having a computer or computer system for highly dynamic control of the frequency comb light source and synchronization of the hologram recording with respect to the controllable frequency comb light source and numerical hologram reconstruction algorithms.
- this is the detector already described above, which is arranged in particular in the areal hologram detection area HDB at the output of the interferometer.
- the measuring arrangement in this preferred embodiment comprises means for at least approximate determination of the distance and the speed of an object to be measured and an interface for data transfer.
- a planar hologram detection area HDB in which at least one at least in spectral Partial areas spectrally integrally detecting, rasterized detector is arranged, and
- the frequency comb light source may be a femtosecond frequency comb laser system, a microresonator frequency comb laser, a microresonator frequency comb laser system, or a frequency comb light source based on a Fabry-Perot cavity powered by a superluminescent diode be.
- the use of the last-mentioned frequency comb light source for frequency comb interferometry has already been described by I. Härder, G. Leuchs, K. Mantel and J. Schwider in the article: "Adaptive frequency comb illumination for interferometry", in the journal Applied Optics 50, no. 25, pages 4942-4956 (201 1).
- At least one measurement for determining the distance and the speed - or a multiple measurement of the distance also by means of time measurement performed suitable for determining the speed of an object to be measured, which at least with a component of its movement in the direction of propagation of the Measuring light moves, performed.
- the size of the distance and the speed is therefore at least approximately present as information in measuring real-time and is provided for the measuring method for shape detection by means of optical cutting.
- the spatial pulse spacing Y1 (optical delay length) of the emitted short pulses of a pulse train of the frequency comb light source is determined by predetermined change of the optical path length of at least one integrated cavity or cavity assigned to the frequency comb light source on the basis of the information provided in measurement real time changed to speed and distance of the object.
- the cavity affects the frequency comb light in its frequency comb distance.
- optical path length of this cavity is changed in the form of a long scan-either reduced or enlarged, so that the ordinal number q of object-sensing short pulses is kept constant for at least the recording time delta_t_Hol of a hologram.
- the ordinal number q results from the quotient of optical path length Lopt, calculated from the position of zero optical path difference at the interferometer in the object beam path up to a probed object point OP, and the spatial pulse distance Y1.
- the atomic number q is kept constant by virtue of the fact that the first derivative over the time of the spatial pulse spacing, which results from the delay length of the frequency comb-forming cavity, is at least approximately equal to a value of the 2 / q-value. times (ie 2 divided by q) of the component of the velocity of the object in the direction of movement or the difference in speed between the holographic recording device and the object.
- the phase in the hologram should change by at least a part of the same by less than 2 pi.
- the optical path length Lopt always exceeds the spatial pulse distance Y1.
- At least one hologram is recorded by means of a screened detector and a numerical reconstruction of the same is carried out, whereby at least one sectional plane or a sectional area is calculated by the object being probed.
- the cut surface can also be curved. Due to the multiplication effect given here by the FC light source (frequency comb light source) with the ordinal number q, the cavity only has to be shortened or lengthened by a fraction of the optical path difference, which is given by the object position, per unit of time. The higher the atomic number q for a given velocity v and the object distance, the slower, but also the more precise, eg in the single-digit nanometer range or sub-nanometer range, the optical path of the integrated or associated cavity must be adjusted.
- Such an object-controlled controlled frequency comb light source may also be referred to as an adaptive Jojo frequency comb light source.
- the measurement of the moving or vibrating object to determine the required absolute object distance - at least one object point - can be done with double-frequency comb laser technology or with optical time of flight measurement technique.
- the spatial pulse spacing Y1 can be made small relative to the wave-optical depth of field D in the detection channel of the holographic measuring arrangement. This can be done in order to achieve a simultaneous detection of the object in a plurality of comparatively closely adjacent (Y1 / 2) sectional planes (multi-sectioning), if the detection time for a hologram is made sufficiently small.
- the respective current simple optical delay length L1 of the cavity is determined.
- the recording period delta_t_Hol for a hologram the movement time duration delta_t_depth for the passage of the wave-optical depth of field D of the holographic detection by the moving object should not be significantly exceeded in order to achieve a sufficiently large modulation possible in the entire hologram, the wave-optical depth of field D through the effective numerical aperture and the centroid wavelength of the detecting radiation is given.
- At least two frequency comb light sources each with one controlled by the distance and the speed measurement optical length of the cavity can be used, each of which determines only one of the current spatial pulse spacing Y1 at a time, and in each case a short-pulse frequency comb light source with the active variable cavity, the object optically in at least one sectional plane E or a weakly curved surface touches, so that the object is alternately, but always holographically detected by at least partially by one of the two frequency comb light sources and the rasterized detector and so at least two, id R.
- a variety of holograms are recorded sequentially.
- At least one short scan for varying the optical length of the frequency comb generating cavity can also be carried out, resulting in an at least approximately staircase-like progression of the optical path length of the cavity over time.
- the cutting plane E or a curved cut surface thus moves slightly over the object. Successive short scans can thus screen the object in depth.
- a scan of the reference mirror between one or more hologram recordings can be performed to have a further degree of freedom for matching the optical paths in the holographic interferometer. This may be done to pre-determined to capture another depth range of the object in a temporally ongoing scan.
- a highly dynamic fine control can be performed, especially when the reference mirror, wherein the reference mirror is located directly on a piezo actuator, is made very small in a focused beam path. This means that even the smallest vibrations in the measuring system can be almost completely compensated. For this purpose, however, suitable reference signals are required, which will not be further elaborated here.
- point-wise measuring high-speed photodetectors can be acted upon by at least a part of the hologram formed by means of an object. This serves to obtain a control signal for fine regulation of the optical path length of the cavity with the aim of "freezing" a hologram on the screened detector in the time of hologram detection.
- high-speed image recordings of the holograms formed by means of an object can preferably each take place. This makes sense if regulation of the optical path length of the cavity does not take place perfectly or if unexpected vibrations or shocks occur.
- the coherence length Ic is at least approximately 200 pm.
- the spatially highly coherent light beam emerging from the frequency comb laser 1a which is intended to have plane wave fronts in the wave-optical model, is widened by a mirror widening optics 2 and impinges on the beam splitter 3 of a Michelson interferometer, forming a reference beam and an object beam become.
- the portion of the incident light beam passing through the beam splitter 3 is reflected in the reference arm R by a paraboloid of revolution 4 at time j whose focal point F is on the heavy beam SWT of the lies on the paraboloid of revolution 4 incident light beam.
- the focus point F thus represents the origin of a spherical wave, in this case the reference spherical wave, for the focused light beam.
- the beam reflected at the beam splitter 3 strikes the object 5, which here should have a control geometry in the form of a rotationally symmetric cone.
- an object point OP_k is shown here, a spherical wave Kk emitted by light scattering.
- the circular arc section KBA from the focal point F into the object space O, on which at least approximately also the object point OP_k lies, makes it clear that the radii of curvature of the reference spherical wave and the object spherical wave k are at least approximately equal, so that the case of the Fourier holography is very is well approximated.
- a part of the reference spherical wave is reflected at the beam splitter 3 in the direction of the rastered detector 6.
- Part of the object spherical wave Kk also passes the beam splitter 3 in the direction of the rastered detector 6.
- a Fourier hologram kj is formed from the object point OP_k.
- the paraboloid of revolution 4 now undergoes a scan to the left, wherein the scan step should be 50 micrometers, so that the optical path difference delta_Xm changes by 100 micrometers. It is clear that in the hologram the optical retardation is usually not a constant.
- the focal point Fj + 1, where j + 1 defines the time, is at the time tj + 1 on the dashed arc.
- the slightly deeper object points in the area Bj + 1 can form holograms, since the difference of optical path difference in the area Bj + 1 to simple delay length Y1 here is made smaller than the coherence length Ic of 200 microns.
- the Fourier case is given for the region near the cone apex. For example, the addressed depth range ATB can be scanned over time t by registering holograms.
- FIG. 2 relates to the detection of an object having a control geometry in the form of a rotationally symmetric cone with a height extension of approximately 200 mm with a base surface diameter of 30 mm made of a metallic material which is half matt, ie also at least somewhat light-scattering. by means of a holographic arrangement.
- the object is located in the vicinity of this holographic arrangement.
- the task is to carry out a measurement of the circular deviation with a measurement uncertainty of 50 microns at height intervals of 25 mm on the conical surface.
- the coherence length Ic is 50 ⁇ .
- the spatially highly coherent light beam emerging from the frequency comb laser 1b and intended to have plane wavefronts here in the wave-optical model is enlarged in its cross-section by a mirror expansion optics 2 and impinges on the beam splitter 3 of a Michelson interferometer, a reference beam and a reference beam Object bundles are formed.
- the portion of the incident light beam passing through the beam splitter 3 is reflected in the reference arm R by a paraboloid of revolution 4 whose focal point F on the heavy beam SWT of incident on the paraboloid of revolution light beam is located.
- the focus point F thus represents the origin of a spherical wave, in this case the reference spherical wave, for the focused light beam.
- the beam reflected at the beam splitter 3 strikes the object 5, which here is to have a control geometry in the form of a rotationally symmetric cone. Represented here is an object point OP_k shown, which emits a spherical wave Kk by light scattering.
- the circular arc section KBA from the focal point F into the object space O, on which at least approximately the object point OP_k lies, makes it clear that the radii of curvature of the reference spherical wave and the object spherical wave k are at least approximately the same, so that the case of the Fourier Holography at the apex is quite well approximated.
- a part of the reference spherical wave is reflected at the beam splitter 3 in the direction of the rastered detector 6.
- Part of the object spherical wave Kk also passes the beam splitter 3 in the direction of the rastered detector 6.
- a Fourier hologram FH_kj is formed on the rastered detector 6 from the object point OP_k.
- the rasterized detector used for this purpose should have a camera chip with a diagonal of 90 mm (medium format camera) and a camera pixel pitch of less than 10 micrometres, in order to achieve a lateral resolution of 0.1 mm in the process, the object points located in the detected measuring field can be evaluated by means of associated holograms. Again, the digital reconstruction of the registered holograms a demanding for the expert, but in the knowledge of the hologram reconstruction algorithm and the state of computer technology quite solvable Task dar.
- FIG. 3 shows, by means of a holographic arrangement, the localization and also 3D detection of a component to be removed, for example, in a nuclear power plant in the event of an accident by means of robots and 3D sensors without any availability of reliable a-priori information via the 3D sensor. Scene around the component as well as its current 3D shape.
- the object 51 in this case a severely destroyed, long-extended power plant component, is not located in the immediate vicinity of the holographic arrangement, but at a distance of the order of one meter.
- the task is to carry out an investigation with regard to the destruction of this component, whereby it should also be measured in comparatively wells with a comparatively large aspect ratio.
- the current 3D shape can be determined with a measurement uncertainty of 0.1 millimeters in all three spatial coordinates. There is virtually no secure a-priori information about the object to the current state.
- a first frequency comb laser 1.1 and a second frequency comb laser 1.2 are arranged, each having a delay length Y1 of 300 mm and a delay length Y2 of 333.3 mm.
- the centroid wavelength here is 840 nm in each case and the coherence length Ic is in each case 50 ⁇ m.
- the spatially highly coherent light beam emerging from the first frequency comb laser 1.1 at a time t1 which is made possible by an opened micro diaphragm 11.1, has plane wavefronts here and is enlarged in its cross section by a mirror expansion optics 2.
- the downstream micro-aperture 11.2 is closed.
- the frequency comb light of the first frequency comb laser 1.1 impinges on the beam splitter 3 of a Michelson interferometer, forming a reference beam and an object beam.
- the portion of the incident light beam which passes through the beam splitter 3 is detected in the reference arm R by a spherical mirror 41 whose focal point F lies on the heavy beam SWT of the spherical mirror 41 on the incident light beam.
- the focal point F thus represents the origin of a spherical wave, here the reference spherical wave, for the focused light beam.
- the bundle reflected at the beam splitter 3 strikes the object 51.
- an object point OP_k Represented here.
- the case of Fourier holography is not very well approximated here. Therefore, if the spatial situation permits, the distance to the object 51 should, for obvious reasons, be reduced in the further investigation.
- a part of the reference spherical wave is reflected at the beam splitter 3 in the direction of the rastered detector 6.
- a part of the object spherical wave passes through the beam splitter 3 in the direction of the rastered detector 6.
- an H_kj is formed from the object point OP_k. Due to the coherence length Ic of approximately 50 microns, only a smaller part of the object points of the object 51 form holograms on the rasterized detector 6.
- the rastered detector 6 used should have a camera chip with a diagonal of 85 mm and a camera pixel pitch of less than 10 micrometres, in order to reliably achieve a lateral resolution of 0.1 mm and thereby detect those detected Field of view also external object points holographically evaluate.
- FIG. 4 shows the situation when the coherence length is approximately 30 millimeters in each case and the scanning step size at the spherical mirror 41, here by 10 millimeters, is selected. Then, this scene can be described with about 100 holograms, the achievable depth resolution is now in the order of 10 millimeters, but the high lateral resolution of at least 0.1 millimeters remains. Depending on need, knowledge about damage to the object (51), the measurement process can be focused on individual details.
- FIG. 5 shows a holographic arrangement for measuring objects with dimensions in the single-digit millimeter range.
- the Frequenzkamm- laser with a ring-shaped microresonator 7.1 in the single-mode fiber 7.1 Frequenzkamm- light with the centroid wavelength Lambda_S of 840 nm and a shorter coherence length than 100 ⁇ leaves after passing the end of the single-mode fiber 7.1 and forms after the Exit a spherical wave.
- the delay length Y1 between two successive pulses is 400 ⁇ .
- the light impinges on a coupling-beam splitter 31 and is collimated at the collimator 81, where subsequently at the beam splitter 3 of a Michelson interferometer Reference bundle arises.
- This reference beam reaches the spherical mirror 4 which focuses the bundle into its focal point F4, which at the same time also represents the focal point of the collimator 81.
- a collimated beam which passes as a reference beam after passing the coupling-beam splitter 31 on the camera 6, where it forms the reference wave for a hologram.
- the object 5 has an extension in the single-digit millimeter range.
- the resulting spherical waves are detected by the collimator after passing through the beam splitter 3 and reach the camera 6 after wavefront formation via the coupling-beam splitter 31, where a Fourier hologram is formed, since a multiplicity of object points are at least approximately in the vicinity the focal plane of the collimator is located.
- the spherical mirror 4 is moved in each case in a fraction of the delay length Y1 between two successive pulses by means of a scanner, not shown here, to holographically scan the object in depth.
- 3 steps are carried out by one-eighth of the centroid wavelength Lambda_S by means of a piezoelectric actuator, not shown here, and a hologram is recorded in each setting position in order to be able to use the phase-shift method in the known manner.
- the image of the object 5 in this case the intensity, is reconstructed numerically by means of digital computer technology in the manner well known to the person skilled in the art.
- the image information is provided numerically in layers and assembled into an overall image of the object 5.
- FIG. 6 shows a holographic arrangement for measuring objects with dimensions in the sub-millimeter range. That of a frequency comb laser 101 Frequency comb light with the centroid wavelength Lambda_S of 840 nm and a coherence length less than 20 ⁇ m leaving the monomode fiber 7.1 after passing through it leaves the end of the monomode fiber 7.1 with ring-shaped microresonator in the monomode fiber 7.1 and forms a spherical wave after emerging. The delay length Y1 between two consecutive pulses in air is 100 pm.
- a subordinate focusing system 82 maps the end of the single-mode fiber 7.1 into the focal point F82.
- the focused in focus point F82 spherical wave reaches the beam splitter 3 of a Linnik interferometer, where a reference beam is formed.
- This reference beam reaches a scannable mirror lens 41 whose focal point at least approximately coincides with the focal point F82 and thus collimates the beam, which subsequently passes the beam splitter 3 in the direction of an afocal transfer stage 85 and camera 6, where it passes through the transfer stage forms the reference bundle in a hologram.
- the light which is reflected at the beam splitter 3 and collimated by means of high-aperture microscope objective 801, forms the object beam, which forms many spherical waves at the light-scattering object points of the object 55.
- the microscopically small object 55 has an extension in the sub-millimeter range and is located with a plurality of its object points in, in the immediate vicinity or in the immediate vicinity of the focal plane of the microscope objective 801.
- the resulting spherical waves become again from the microscope objective 801 after passing through the beam splitter 3 detected, collimated and arrive via the beam splitter 3 in transmission via the afocal transfer stage 85 to the camera 6, where these spherical waves generate the hologram together with the reference beam.
- the mirror lens 41 is moved in each case in a fraction of the delay length Y1 between two successive pulses by means of a scanner, not shown here, to holographically scan the object 55 in depth.
- 3 steps of one eighth of the centroid wavelength Lambda_S will not be made by one here Piezo plate shown performed and in each position a hologram is recorded in order to apply the phase shift method in the known manner.
- the image of the microscopically small object 55 in this case the intensity, is numerically reconstructed numerically by means of digital computer technology in a manner which is well known to the person skilled in the art.
- the image information is provided numerically in layers and assembled into an overall image of the object 55.
- FIG. 7 shows a very simple holographic arrangement for measuring objects with dimensions in the single-digit or two-digit millimeter range.
- the delay length Y1 between two consecutive pulses in air is 400 pm.
- the light passes onto a beam splitter 3.
- the transmitted there light passes as a reference light for the hologram formation on the camera 6.
- the light reflected at the beam splitter 3 passes as an object bundle via a rotatable mirror staircase consisting of the plane mirrors 32a and 32b, with the fulcrum RP on the object 5, which is at least approximately in the focal plane of a microscope objective 801.
- the spherical waves produced by light scattering on the object 5 are detected by the microscope objective 801 and form in the rear focal plane of the microscope objective 801, where the camera 6 is arranged, the hologram H with the reference light.
- the rotatable mirrored staircase consisting of the plane mirrors 32a and 32b, shown in two different rotational positions, each corresponding to a different optical path difference.
- the rotatable mirror staircase is arranged in the reference beam path. By means of a rotatable mirror staircase, the optical path difference in the measuring process is varied by at least one delay length Y1.
- the optical path difference to the phase position is set by means of a piezoelectric actuator, not shown here, which is associated with the plane mirror 32a in steps of well one eighth of the centroid wavelength in each rotational position of the mirror staircase at least three times, each one hologram is recorded.
- a set of 4 holograms with different phases is generated for the phase evaluation in order to be able to use the phase-shift method in the known manner.
- the image of the object 5 is reconstructed numerically in the manner well-known to the skilled person by means of digital computer technology by providing the image information numerically in layers and composing it into an overall image of the object 5.
- FIG. 8 shows a holographic arrangement for measuring objects with a Schwarzschild objective 84, which is dispersion-free as a mirror objective, whereby the dispersion effects in the holographic arrangement can be kept very low overall. Again, this involves the detection of an object 5 with dimensions in the single-digit millimeter range.
- the coming of a frequency comb laser 102 light with frequency comb characteristic with a delay length of the short pulses Y1 of 500 pm and a coherence length of less than 30 ⁇ reaches a beam splitter 3, where the reference beam is formed in transmission and on the roof edge arrangement, which consists of the plane mirrors 33 and 34, and the Einkoppelstrahlteiler 31 in transmission to the Camera 6 arrives.
- the roof edge arrangement with the plane mirrors 33 and 34 serves by displacement in the direction shown to produce the change in the optical path difference in the holographic arrangement in the order of the delay length Y1.
- the beam reflected at the beam splitter 3 passes to the object 5, which is located at least approximately in the focal plane of a Schwarzschild objective 84.
- the spherical waves produced on the object 5 by light scattering are detected by the Schwarzschild objective 84 and, after passing through the beam splitter 3 in reflection with the reference light, form the hologram H on the camera 6.
- a piezoelectric actuator (not shown here) associated with the plane mirror 34 is used the required phase position, so that in the manner already described a hologram stack is generated, which is used for the numerical reconstruction of the intensity of the image.
- the image information is provided numerically in layers and assembled into an overall image of the object 5.
- FIG. 9 shows a holographic arrangement in a Linnik configuration for measuring objects with a particularly high lateral resolution.
- the frequency comb light with the centroid wavelength Lambda_S of 840 nm going from one frequency comb laser 101 with an annular microresonator into the single mode fiber 7.1 and a coherence length less than 20 m passes through a Y-coupler 7.2 and enters the single-mode fiber 7.3A.
- the spherical wave emerging at the end of the single-mode fiber 7.3A passes the beam splitter 3 partially in transmission and reaches the mirror lens 41, where an at least approximately plane wave or a wave with a large radius of curvature is formed from the spherical wave, which now reflects the beam splitter 3 in reflection in the direction of an afocal transfer stage 85 with the diaphragm 36 passes, where this on the downstream Camera 6 represents the reference wave for the hologram H.
- the frequency comb light coupled into the single-mode fiber 7.3B receives a reflection at the beam splitter 3 and passes via the microscope objective 81 as a plane wave B also on the object 55, where a spatially high-frequency interference fringe pattern IFM arises.
- the object 5 is located at least approximately in the focal plane of the microscope objective 81.
- the interference fringe pattern IFM can be changed in its phase by at least 360 ° by a stretcher 42 in a predetermined manner.
- the spherical waves produced on the object 55 are detected by the microscope objective 81, pass through the afocal imaging stage 85 onto the camera 6, where a hologram H is formed with the reference light.
- a scan is performed, which can change the optical path difference by at least the size of the delay length Y1.
- a piezo plate (not shown here) on the mirror lens 41 also allows a phase position in the size of 90 ° - steps to use the phase-shifting method can.
- the light from the single-mode fiber 7.3B is not permitted as a reference light by the shadowing effect of the diaphragm 36, so that there is only a single reference wave in the arrangement, which comes from the single-mode fiber 7.3A and is collimated via the mirror lens 41.
- hologram stacks are recorded in a plurality of phase positions of the interference fringe pattern IFM and serve the skilled person in a well-known manner for the numerical reconstruction of the image of the object 55, here the intensity, by means of digital computing.
- the image information is numerically also provided in layers and assembled into an overall image of the object 5.
- the term light is always synonymous with electromagnetic radiation from Terahertz, across the infrared to the deep UV spectrum used.
- a not shown here dual-frequency comb measuring system with time base for determining the distance and the speed of the object to be measured 51 is arranged, which provides the information about distance and the speed of the Passing measuring system in real-time measurement by means of an interface, not shown here.
- the coherence length Ic is at least approximately 1200 ym.
- the spatially highly coherent light beam emerging from the frequency comb laser 1c and intended to have plane wavefronts here is widened by a mirror widening optics (not shown here) and impinges on the beam splitter 3 of a Michelson interferometer, a reference beam and an object bundle being formed.
- the reflected at the beam splitter 3 portion of the incident light beam is reflected in the reference arm R of a mirror 4a.
- a part of the light beam is transmitted at the beam splitter 3 in the direction of the rastered detector 6.
- the beam passing through the beam splitter 3 impinges on the object 51, which is to represent space-moving space junk in space with a maximum lateral extent of 2 m here.
- a spherical wave Kk is created, which also propagates with a part of its wavefront in the direction of the interferometer.
- a part of the object spherical wave Kk passes after collecting and reflecting by means of large-level detection optics 100 and not shown here wave shaping the beam splitter 3 by reflection in the direction of the rasterized detector 6.
- the diameter of the focusing main mirror in the large-mirror detection optics 100th This is 2 m and the focal length of the same is 10 m.
- On the Rasterized detector 6 forms from the object point OP a Fourier hologram H1 at time t1.
- the cavity 1 d of the frequency comb laser 1 c is permanently scanned on the basis of the information of distance and velocity of the moving object, which are available in real-time measurement.
- the optical delay length of 2L11 at time t1 has changed to that of 2L12 at time t2.
- the spatial pulse spacing Y1 1 or Y12 results respectively from 2L11 and 2L12.
- a short scan is performed in order to be able to touch another part of the object 51 in another sectional plane E2 for shape recognition thereof.
- a Fourier hologram H2 is detected in a time interval delta_t_Hol2, which contains the time t2.
- the section plane E on the moving object in the depth fine shifted here in the single-digit millimeter range, in order to additionally scan the object in its movement in its object depth in order to obtain its shape by optical multiple optical cutting.
- the cavity After taking in a third hologram H3, in a time interval delta_t_Hol3 containing time t3, the cavity becomes 1d in the time period reset delta t_R, so that at time t4 a new hologram H4 can be recorded.
- the ordinal number q is reduced by the meanwhile approximation of the object 51, here reduced by the value 16 with respect to the time t1.
- the object 51 has thus approximated by 16 delay lengths Y1 (ie spatial pulse intervals) of the holographic measuring device.
- the cavity 1 d of the frequency comb laser 1 c is controlled on the basis of the extremely precise information available in real-time measuring distance and the speed of the object 51 in a control system.
- the holograms on the screened detector 6 can thus be regarded as "frozen", at least in the period of their detection Part of the same changes by less than 2 Pi and thus the hologram is digitally evaluated.
- the phase in the hologram can be kept constant even for the best control quality only for a single atomic number.
- the phases of other cutting planes e.g. the section plane E_q-1 or E_q + 1 belonging to the ordinal number q-1 or q + 1 also slightly displaces when changing the optical path length of the cavity.
- time delta_t_Hol all cutting planes-except those belonging to q-can be rendered "invisible" in the detected hologram by time averaging, since the phase change in the time interval of the detection can exceed clearly more than 2 pi in all other cutting planes.
- the mirror 4a is associated with an extremely fast scanner, not shown here, to be able to readjust the optical path difference in the holographic interferometer highly dynamically, if this is not exactly possible or not fast enough by means of cavity 1d. This gives the possibility of additional intervention in the holographic measuring device in order to be able to keep the phase in the hologram during the hologram detection time delta_t_Hol sufficiently constant by means of rastered detector 6 or to be able to change it in a desired manner.
- the computer-based control system for highly complex and highly dynamic control of the frequency comb laser 1c with the cavity 1d and the control systems for synchronizing the recording of holograms by means of rasterized detector 6 are not shown here.
- the holographic arrangement according to FIG. 10 can be used for objects 51 having the following features: distance of the object 51: 10 km, relative velocity v thereof with component in the direction of the measurement light: 100 m per second, lateral object extent: 2 m.
- the biide integration time in the exemplary embodiment, with sufficiently good control is in the single-digit millisecond range.
- the scan frequency of the cavity 1 d in this embodiment is a few hertz up to a few 10 Hz, so that this "reset" several times per second (yo-yo effect).
- FIG. 11 shows the temporal relationships for the delay lengths (spatial pulse intervals) Y1j.
- the facts are presented for the ordinal number q and for the ordinal number q-16 for two long scans, each with the duration delta_t_LS.
- the duration delta_t_LS In a long scan with the duration delta_t_LS, several short scans with the duration delta_t_KS each take place, which alone apply to the depth scanning of the object 51 for shape detection.
- the recording time for one Hologram by means of rastered detector 6 is delta_t_Hol.
- FIG. 12 relates to the detection of a light-scattering object 52 made of a metallic material by means of a holographic arrangement.
- the task is to perform a measurement of the shape deviation. It is known that the object 52 has no major deviations from the desired geometry.
- the spatially highly coherent light beam emerging from the fiber 7-R passes as a reference beam onto the screened detector 6.
- the spatially highly coherent object light beam emerging from the fiber 7-0 passes via an off-axis mirror 8, which slightly focuses the light at the location of a small aperture of an off-axis mirror 10, as a result of which in the bundle cross-section again significantly enlarged on the object 52, where it is also scattered back.
- the maximum lateral extent of the aperture in the off-axis mirror 10 is about 40% of the lateral extent of the off-axis mirror 10, which has a maximum lateral extent of 120 mm. The comparatively large breakdown is needed to produce a well-collimated light beam for probing the object 52 at a greater distance.
- the light returning from the object 52 is focused by the off-axis mirror 10 and impinges on the rasterized detector 6, where it forms with the reference beam a Fourier hologram which is detected.
- the optical arrangement shown in FIG. 12 can also form the basis for the detailed design of the optical arrangement according to FIG.
- the digital reconstruction of the registered holograms for FIG. 13 shows the mechanical oscillation of the object 52 in the form of the oscillation path s and FIG. 14 the optical path length Y1j for compensating for this oscillation the time that is generated by control using the information about the current displacement of the object 52 in real-time measurement.
- the recording of the hologram takes place.
- delta_t_KS the short scan for depth scanning of the object 52 takes place.
- the duration delta_tR serves to return the cavity to its initial position.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Computing Systems (AREA)
- Theoretical Computer Science (AREA)
- Holo Graphy (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE112011105124.7T DE112011105124A5 (de) | 2011-04-04 | 2011-12-23 | Verfahren und Anordnung zur Kurz-Kohärenz-Holografie |
GB1319268.7A GB2505106B (en) | 2011-04-04 | 2011-12-23 | Method and arrangement for short coherence holography |
US14/110,100 US9175954B2 (en) | 2011-04-04 | 2011-12-23 | Method and arrangement for short coherence holography |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102011016660A DE102011016660B4 (de) | 2011-04-04 | 2011-04-04 | Verfahren und Anordnung zur Kurz-Kohärenz-Holografie |
DE102011016660.2 | 2011-04-04 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2012136238A1 true WO2012136238A1 (de) | 2012-10-11 |
Family
ID=45476451
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2011/006546 WO2012136238A1 (de) | 2011-04-04 | 2011-12-23 | Verfahren und anordnung zur kurz-kohärenz-holografie |
Country Status (4)
Country | Link |
---|---|
US (1) | US9175954B2 (de) |
DE (2) | DE102011016660B4 (de) |
GB (1) | GB2505106B (de) |
WO (1) | WO2012136238A1 (de) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10281877B2 (en) * | 2014-11-27 | 2019-05-07 | Shimadzu Corporation | Digital holography device and digital hologram generation method |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9513164B2 (en) * | 2013-03-15 | 2016-12-06 | Honeywell International Inc. | Stand-off spectrometry systems and methods |
CN105700321B (zh) * | 2016-04-18 | 2018-02-16 | 中国工程物理研究院激光聚变研究中心 | 基于重建像强度方差的数字全息图在焦重建距离判断方法 |
USD928987S1 (en) | 2019-02-21 | 2021-08-24 | Labyrinth Technologies, Llc | Municipal infrastructure pole |
US20200096179A1 (en) | 2016-07-29 | 2020-03-26 | Labyrinth Technologies, Llc | Localization systems and methods |
US11204156B2 (en) | 2016-07-29 | 2021-12-21 | Labyrinth Technologies, Llc | Systems and methods for aggregating edge signals in a mesh network |
DE102018207081A1 (de) * | 2018-05-07 | 2019-11-07 | Carl Zeiss Smt Gmbh | Prüfvorrichtung und Verfahren zum Prüfen der Oberflächenform eines optischen Elements |
USD957039S1 (en) | 2020-01-13 | 2022-07-05 | Labyrinth Technologies, Llc | Enclosure with extension |
CN111901044B (zh) * | 2019-11-28 | 2021-11-02 | 阳光学院 | 一种单光束相干光通信装置 |
CA3214736A1 (en) * | 2021-04-26 | 2022-11-03 | Philip ZYLSTRA | Vehicle damage detection system and method |
US20230019064A1 (en) * | 2021-07-14 | 2023-01-19 | Vmware, Inc. | Methods and systems for resolving dependencies of a data center model |
CN114001654B (zh) * | 2021-11-01 | 2024-03-26 | 北京卫星制造厂有限公司 | 工件端面位姿评价方法 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20010045513A1 (en) * | 2000-02-18 | 2001-11-29 | Ricoh Company, Ltd. | Interference detecting apparatus and tomography apparatus |
EP1870030A1 (de) * | 2006-06-23 | 2007-12-26 | OPTOPOL Technology Spolka z o.o. | Gerät und Verfahren für die optische Kohärenztomographie in der Frequenzdomäne |
WO2010092533A1 (en) * | 2009-02-13 | 2010-08-19 | Ecole Polytechnique Federale De Lausanne (Epfl) | Method and apparatus for 3d object shape and surface topology measurements by contour depth extraction acquired in a single shot |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6760134B1 (en) * | 2003-03-20 | 2004-07-06 | The United States Of America As Represented By The Secretary Of The Army | Multicolor electronic holography and 3D image projection system |
US7672342B2 (en) * | 2005-05-24 | 2010-03-02 | MAX-PLANCK-Gesellschaft zur Förderung der Wissenschaften e.V. | Method and radiation source for generating pulsed coherent radiation |
US8706083B2 (en) | 2009-01-07 | 2014-04-22 | Eckey Corporation | Bluetooth authentication system and method |
-
2011
- 2011-04-04 DE DE102011016660A patent/DE102011016660B4/de not_active Expired - Fee Related
- 2011-12-23 WO PCT/EP2011/006546 patent/WO2012136238A1/de active Application Filing
- 2011-12-23 US US14/110,100 patent/US9175954B2/en not_active Expired - Fee Related
- 2011-12-23 GB GB1319268.7A patent/GB2505106B/en not_active Expired - Fee Related
- 2011-12-23 DE DE112011105124.7T patent/DE112011105124A5/de not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20010045513A1 (en) * | 2000-02-18 | 2001-11-29 | Ricoh Company, Ltd. | Interference detecting apparatus and tomography apparatus |
EP1870030A1 (de) * | 2006-06-23 | 2007-12-26 | OPTOPOL Technology Spolka z o.o. | Gerät und Verfahren für die optische Kohärenztomographie in der Frequenzdomäne |
WO2010092533A1 (en) * | 2009-02-13 | 2010-08-19 | Ecole Polytechnique Federale De Lausanne (Epfl) | Method and apparatus for 3d object shape and surface topology measurements by contour depth extraction acquired in a single shot |
Non-Patent Citations (14)
Title |
---|
1. HARDER; G. LEUCHS; K. MANTEL; J. SCHWIDER: "Adaptive frequency comb illumination for interferometry", FACHZEITSCHRIFT APPLIED OPTICS, vol. 50, no. 25, 2011, pages 4942 - 4956, XP001569111, DOI: doi:10.1364/AO.50.004942 |
AUTOREN CHRISTOPH WAGNER; SÖNKE SEEBACHER; WOLFGANG OSTEN; WERNER JÜPTNER: "Digital recording and numerical reconstruction of lensless Fourier-Hologramms in optical metrology", APPLIED OPTICS, vol. 38, no. 22, 1 August 1999 (1999-08-01), pages 4812 - 4820 |
CAOJIN YUAN; HONGCHEN ZHAI; XIAOLEI WANG; LAN WU: "Lensless digital holography with short coherence light source for three-dimensional surface contouring of reflecting micro objects", OPTICS COMMUNICATIONS, vol. 270, 2007, pages 176 - 179, XP005814307, DOI: doi:10.1016/j.optcom.2006.09.016 |
CHEN H ET AL: "TWO-DIMENSIONAL IMAGING THROUGH DIFFUSING MEDIA USING 150-FS GATED ELECTRONIC HOLOGRAPHY TECHNIQUES", OPTICS LETTERS, OSA, OPTICAL SOCIETY OF AMERICA, WASHINGTON, DC, US, vol. 16, no. 7, 1 April 1991 (1991-04-01), pages 487 - 489, XP000179779, ISSN: 0146-9592 * |
FU Y ET AL: "Dual-wavelength image-plane digital holography for dynamic measurement", OPTICS AND LASERS IN ENGINEERING, ELSEVIER, AMSTERDAM, NL, vol. 47, no. 5, 1 May 2009 (2009-05-01), pages 552 - 557, XP025994815, ISSN: 0143-8166, [retrieved on 20081120], DOI: 10.1016/J.OPTLASENG.2008.10.002 * |
HOTATE K ET AL: "SELECTIVE EXTRACTION OF A TWO-DIMENSIONAL OPTICAL IMAGE BY SYNTHESIS OF THE COHERENCE FUNCTION", OPTICS LETTERS, OSA, OPTICAL SOCIETY OF AMERICA, WASHINGTON, DC, US, vol. 17, no. 21, 1 November 1992 (1992-11-01), pages 1529 - 1531, XP000310755, ISSN: 0146-9592 * |
J. SCHWIDER: "Coarse frequency comb interferometry", PROCEEDINGS OF SPIE, vol. 7063, 1 January 2008 (2008-01-01), pages 706304 - 706304-15, XP055023235, ISSN: 0277-786X, DOI: 10.1117/12.793221 * |
KLAUS KÖRNER ET AL: "Short temporal coherence digital holography with a femtosecond frequency comb laser for multi-level optical sectioning", OPTICS EXPRESS, vol. 20, no. 7, 26 March 2012 (2012-03-26), pages 7237, XP055023243, ISSN: 1094-4087, DOI: 10.1364/OE.20.007237 * |
KOUKOURAKIS N ET AL: "New concepts for depth resolved holographic imaging based on spectrally tunable diode lasers", LASERS AND ELECTRO-OPTICS, 2009 AND 2009 CONFERENCE ON QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE. CLEO/QELS 2009. CONFERENCE ON, IEEE, PISCATAWAY, NJ, USA, 2 June 2009 (2009-06-02), pages 1 - 2, XP031521046, ISBN: 978-1-55752-869-8 * |
LINGFENG YU ET AL: "Multi-wavelength digital holographic tomography based on spectral interferometry", PROCEEDINGS OF THE SPIE, SPIE, BELLINGHAM, VA, US, vol. 7184, 26 January 2009 (2009-01-26), pages 71840P - 1, XP007913131, ISSN: 0277-786X, DOI: 10.1117/12.808328 * |
LLUIS MARTINEZ-LEÖN; GIANCARLO PEDRINI; WOLFGANG OSTEN: "Applications of short-coherence digital holography in microscopy", APPLIED OPTICS, vol. 44, no. 19, 1 July 2005 (2005-07-01), pages 3977 - 3984, XP055023232, DOI: doi:10.1364/AO.44.003977 |
P. DEL'HAYE; A. SCHLIESSER; O. ARCIZET; T. WILKEN; R. HOLZWARTH; T. J. KIPPENBERG: "Optical frequency comb generation from a monolithic microresonator", NATURE, vol. 450, 27 December 2007 (2007-12-27), pages 20 |
T. BAJRASZEWSKI ET AL: "Fourier domain optical coherence tomography using optical frequency comb", PROCEEDINGS OF SPIE, vol. 6429, 1 January 2007 (2007-01-01), pages 64291F - 64291F-8, XP055023234, ISSN: 0277-786X, DOI: 10.1117/12.703600 * |
T. NOMURA ET AL: "Profilometry and Reflectmetry Using Low-Coherent Digital Holography", DIGITAL HOLOGRAPHY AND THREE-DIMENSIONAL IMAGING, OSA, 1 January 2010 (2010-01-01), pages JMA25_1 - JMA25_3, XP055023231 * |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10281877B2 (en) * | 2014-11-27 | 2019-05-07 | Shimadzu Corporation | Digital holography device and digital hologram generation method |
Also Published As
Publication number | Publication date |
---|---|
GB2505106A (en) | 2014-02-19 |
US9175954B2 (en) | 2015-11-03 |
DE112011105124A5 (de) | 2014-02-06 |
GB201319268D0 (en) | 2013-12-18 |
US20140022553A1 (en) | 2014-01-23 |
GB2505106B (en) | 2015-09-30 |
DE102011016660B4 (de) | 2012-10-25 |
DE102011016660A1 (de) | 2012-10-04 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2012136238A1 (de) | Verfahren und anordnung zur kurz-kohärenz-holografie | |
EP2843360B1 (de) | Robustes One-Shot-Interferometer und OCT- Verfahren, insbesondere zur Materialmessung und auch Tumorzellen-Erkennung | |
DE102008062879B4 (de) | Verfahren und Anordnung zur skalierbaren Interferometrie | |
EP2526373B1 (de) | Verfahren und anordnung zur robusten interferometrie | |
EP1984770B1 (de) | Verfahren und anordnung zur schnellen und robusten, chromatisch-konfokalen 3d-messtechnik | |
EP1846923B1 (de) | Verfahren und anordnung zur konfokalen, chromatischen, interferometrischen, spektroskopischen abtastung für optische mehrlagen-datenspeicher | |
EP1805477B1 (de) | Interferometrisches verfahren und anordnung | |
EP1962049B1 (de) | System und Verfahren zur optischen Kohärenztomographie | |
DE102008020902B4 (de) | Anordnung und Verfahren zur konfokalen, spektralen Zweistrahl-Interferometrie | |
EP1962052B1 (de) | System und Verfahren zur optischen Kohärenztomographie | |
EP2592462B1 (de) | Verfahren und Anordnung zur Autofokussierung eines Mikroskops | |
EP2699970B1 (de) | Verfahren zur optischen tomographie | |
DE102005006724A1 (de) | Verfahren und Anordung zur konfokalen Spektral-Interferometrie, insbesondere auch zur optischen Kohärenz-Tomografie (OCT)und/oder optischen Kohärenz-Mikroskopie (OCM)von biologischen und technischen Objekten | |
EP2267403A2 (de) | System und Verfahren zur optischen Kohärenztomographie | |
EP2339329A2 (de) | System und Verfahren zur optischen Kohärenztomographie | |
DE102010046907B4 (de) | Robustes One-Shot-Interferometer und Verfahren , insbesondere auch als Scout-Sensor zur multi-sensoriellen Materialmessung oder Tumorzellen-Erkennung | |
DE102010006239B3 (de) | Verfahren und Anordnung zur robusten Interferometrie | |
DE102012016318B4 (de) | Anordnung für ein linsenloses, holografisches Inline-Auflichtmikroskop | |
DE102005042733B3 (de) | Verfahren und Anordnung zur Spektral-Interferometrie mit chromatischer Tiefenaufspaltung, insbesondere auch Mirau-Interferometer | |
DE102010044826B4 (de) | Detektor sowie Meßvorrichtung und Verfahren zur Bestimmung der Dicke einer Probe | |
DE10321887A1 (de) | Robuster optischer Sensor und Verfahren zur Hochgeschwindigkeits-Detektion | |
DE10321886A1 (de) | Robuster interferometrischer Sensor und Verfahren zur Objektabtastung | |
DE102010056122B3 (de) | Verfahren zur robusten, insbesondere weitskaligen Interferometrie | |
WO2024129857A1 (en) | Optical imaging apparatus | |
KR20240108376A (ko) | 관찰 장치 및 관찰 방법 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 11807869 Country of ref document: EP Kind code of ref document: A1 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 14110100 Country of ref document: US Ref document number: 112011105124 Country of ref document: DE Ref document number: 1120111051247 Country of ref document: DE |
|
ENP | Entry into the national phase |
Ref document number: 1319268 Country of ref document: GB Kind code of ref document: A Free format text: PCT FILING DATE = 20111223 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1319268.7 Country of ref document: GB |
|
REG | Reference to national code |
Ref country code: DE Ref legal event code: R225 Ref document number: 112011105124 Country of ref document: DE Effective date: 20140206 |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 11807869 Country of ref document: EP Kind code of ref document: A1 |