Multidimensional vibration measurement system

Abstract

This system provides a multidimensional vibration measurement system that can simultaneously measure out-of-plane and in-plane vibrations of an object, i.e., multidimensional vibration phenomena, at multiple points by irradiating multiple measurement points on the measurement surface with de-division measurement light for each frequency component of the optical comb, obtained by de-division of the frequency components of each optical comb contained in the measurement light. [Solution] Multiple irradiation head units 14A, 14B for each measurement point are configured, each consisting of at least two single-point irradiation heads, which are used to irradiate a single measurement point from different directions using the decompressed measurement light for each decompressed frequency component, excluding adjacent frequency components of the decompressed measurement light, that is separated by the optical splitter / multiplexer optical system 3. These units irradiate the decompressed measurement light for each frequency component, excluding adjacent frequency components, that is separated by the optical comb at least 1 mode order away, by at least two single-point irradiation heads assigned by a connector unit 8 that functions as a measurement light transmission path selection means. The decompressed measurement reflected light, consisting of at least two frequency components for each measurement point, that is reflected at multiple measurement points on the measurement surface and returns via the at least two single-point irradiation heads is input to the optical splitter / multiplexer optical system 3.

Description

[Technical Field] 【0001】 This invention relates to a multidimensional vibration measurement system that uses light to measure multidimensional vibration information of a target object. [Background technology] 【0002】 To identify the cause of vibration and investigate vibration modes, it is necessary to measure the vibration distribution on the surface of the object being measured. For example, in the case of steady-state vibration, the vibration distribution on the surface can be measured by shifting the measurement location according to the vibration period. 【0003】 Laser Doppler vibrometers and similar devices, which use lasers, are widely available and in use as systems capable of non-contact, high-precision measurement of vibrations in objects ranging from small and lightweight to large. 【0004】 However, when you want to measure the distribution of transiently changing vibrations in real time, or when you don't know in advance what frequency components of vibrations are included, and you need vibration information from several points simultaneously, you will need a vibration measuring device that can measure vibration information from several points at the same time. 【0005】 Laser Doppler vibrometers can generally measure the amplitude of vibrations in a velocity range of about 10 m / s, but they cannot synchronously measure the vibration distribution at multiple points. Furthermore, they cannot obtain the height in a stationary state. 【0006】 The applicant has previously proposed a vibration measurement system and vibration measurement method that enables simultaneous measurement of vibration information at multiple measurement points on the surface of an object being measured by using an optical multiplexing head that separates the measurement light into frequency components and irradiates multiple measurement points on the surface of the object being measured, in a vibration meter that analyzes vibration information on the surface of an object being measured by detecting interference light between a coherent reference light and a measurement light, which have spectra with predetermined frequency intervals, and determining the phase difference between the reference light and the measurement light. (See, for example, Patent Documents 1-3.) 【0007】 Furthermore, without using a frequency shifter, the center frequency f0 (Hz) and frequency interval f m An optical comb is generated as a probe beam, with a center frequency f0 (Hz) and frequency interval f m +Δf m A multi-point vibration meter with a simplified system configuration has been proposed by generating an optical comb as a reference light (see, for example, Patent Document 4). 【0008】 Furthermore, a multi-point laser Doppler vibrometer has been proposed that uses an optical comb generator capable of generating a wideband optical comb with multiple modes using a single modulator (see, for example, Patent Document 5). 【0009】 Furthermore, systems have been proposed that can measure vibrations of an object in directions other than the optical axis (single axis) using multiple units (or multiple beams), in addition to measuring vibrations in a single axis (see, for example, Patent Documents 6 and 7). 【0010】 Furthermore, Polytec Corporation has commercialized three-dimensional optical units for laser Doppler vibrometers (LV-1800 / LV-1710 / LV-1720 / 1720A) for constructing a laser Doppler vibrometer system that detects vibrations occurring in three axes non-contact, as well as the LV-3800 three-dimensional optical unit from Ono Sokki Co., Ltd. [Prior art documents] [Patent Documents] 【0011】 [Patent Document 1] Patent No. 5336921 [Patent Document 2] Japanese Patent Publication No. 2010-203860 [Patent Document 3] Patent No. 5363231 [Patent Document 4] Patent No. 7276051 [Patent Document 5] Japanese Patent Publication No. 2022-47249 [Patent Document 6] Japanese Patent Application Publication No. 4-270934 [Patent Document 7] Japanese Patent Publication No. 2004-251804 [Overview of the Initiative] [Problems that the invention aims to solve] 【0012】 Conventional laser Doppler vibrometer systems, which use commercially available three-dimensional optical units to non-contactly detect vibrations occurring in three axes, have the problem of being costly and requiring a large system configuration because they require separate sensor heads and signal processing devices to perform three-dimensional vibration measurement at the same location (point). 【0013】 Furthermore, particularly in the sensor head section, it is necessary to use independent laser light sources with low coherence in the three axes so that laser interferometry can be performed independently of each other. 【0014】 Here, when light is incident perpendicularly on the surface of the object to be measured, the direction of the incident ray is called the out-of-plane direction, and the direction of the horizontal component perpendicular to the incident ray is called the in-plane direction. As shown in Figure 1, the component Vz parallel to the incident ray that vibrates in the out-of-plane direction (Z-axis direction) is called the out-of-plane vibration, and the horizontal component that vibrates in the in-plane direction (x-axis direction, y-axis direction) is called the in-plane vibration. 【0015】 The vibration measurement system and vibration measurement method disclosed in the above-mentioned Patent Documents 1-3, previously proposed by the applicant, can simultaneously measure out-of-plane vibrations at multiple measurement points on a measurement surface. Furthermore, as shown in the multi-point vibration measurement system 10 in Figure 2, by modularizing the input and output of the interference optical system 2 into optical fiber cables and transmitting reference light and measurement light, it is possible to use modularized optical elements with various functions, making system assembly and repair easier. In addition, by using a spatial optical system and optical fiber cables to make some functional element an optical integrated circuit, the system can be miniaturized. 【0016】 This multi-point vibration measurement system 10 includes the interference measurement light L output from the light source 1 S and the reference light L R input into the interference optical system 2, and an optical multiplexing / demultiplexing optical system 3 into which the measurement light L S from the light source 1 is input through the interference optical system 2. The frequency components of the optical comb included in the measurement light L S input through the interference optical system 2 are demultiplexed by the optical multiplexing / demultiplexing optical system 3 composed of the optical multiplexing / demultiplexing element 3A into, for example, n (n is an arbitrary positive integer) types of frequency components, and the demultiplexed measurement light L S for each demultiplexed frequency component of the measurement light L S1 , L S2 , ··· are output to the measurement light transmission paths of n channels CH1, CH2, ···, CHn, and are irradiated onto n measurement points S1, S2, ···, S n on the measurement surface 5 of the measurement object through the projection optical system 4. The measurement light L S1 , L S2 , ···, L Sn reflected by the measurement surface 5 of the measurement object and returning from the n measurement points S1, S2, ···, S n is the demultiplexed measurement reflected light L S for each demultiplexed frequency component of the optical comb of the measurement light L S1 ’, L S2 ’, ··· L Sn ’ is input into the measurement light transmission paths of the n channels CH1, CH2, ···, CHn through the projection optical system 4, and the demultiplexed measurement reflected light L S for each demultiplexed frequency component of the measurement light L S1 ’, L S2 ’, ··· L Sn ’ returned through the measurement light transmission paths of the n channels CH1, CH2, ···, CHn is multiplexed by the optical multiplexing / demultiplexing optical system 3 composed of the optical multiplexing / demultiplexing element 3A to obtain the measurement reflected light L S composed of the demultiplexed measurement reflected light L S1 ’, L S2 ’, ··· L Sn ’ for each demultiplexed frequency component of the measurement light L S ’. Then, the measurement reflected light L S ’ obtained by the optical multiplexing / demultiplexing optical system 3 is input into the interference optical system 2. 【0017】 The above light source 1 is a linearly polarized measurement light L S and reference light L R It consists of a first optical comb generator (COMB1) 1A and a second optical comb generator (COMB2) 1B that output a signal, each using a polarization-maintaining fiber (PMF). 12A , FB 12B It is connected to the interference optical system 2 via the first optical comb generator (COMB1) 1A and the second optical comb generator (COMB2) 1B, the above measurement light L S and reference light L R This generates two types of optical combs, each with periodically modulated intensity or phase, and with different modulation frequencies. A polarized (PZ) fiber capable of propagating only one polarization can also be used instead of a PMF. 【0018】 Here, PMF is an optical fiber cable that utilizes photoelastic effects and structural changes to create birefringence, where the effective refractive index differs in the longitudinal and transverse directions of the core, thereby improving the polarization plane maintenance characteristics of the transmitted light. 【0019】 The interference optical system 2 is connected to the first optical comb generator (COMB1) 1A via an optical fiber cable FB. 12A Measurement light L via S As the input is received, the optical fiber cable FB is sent from the second optical comb generator (COMB2) 1B. 12B Reference light L via R The following is entered. 【0020】 The above interference optical system 2 uses a PMF (Photon-Marked Fiber) with an optical fiber cable FB (Fiber Gauge). 2A1 FB 2A2 FB 2B1 FB 2B2 FB 2C Five optical couplers OC connected by A OC B OC C OC D OC E Consists of, Optical Coupler OC A Externally connected fiber optic cable FB 12AThe measurement light L is transmitted from the first optical comb generator (COMB1) 1A via the above-mentioned first optical comb generator (COMB1) 1A. S As soon as this is input, the optical coupler OC B Externally connected fiber optic cable FB 12B The reference light L is transmitted from the second optical comb generator (COMB2) 1B via the above-mentioned second optical comb generator (COMB2) 1B. R The following is entered. 【0021】 In this interference optical system 2, the optical coupler OC A It has two fiber optic cables FB 2A1 FB 2A2 Two optical couplers OC D OC E It is internally connected, and the optical coupler OCB has two optical fiber cables FB 2B1 FB 2B2 Two optical couplers OC C OC D They are internally connected, optical coupler OC E Fiber optic cable FB 2C via optical coupler OC C They are internally connected. 【0022】 Then, the measurement light L input to this interference optical system 2 S The above optical coupler OC E Optical fiber cable FB using PMF externally connected to it 23 The light is input to the optical optical system 3, which consists of the optical optical splitter / multiplexer element 3A, via the above-mentioned optical splitter / multiplexer element 3A. 【0023】 Here, in the optical multiplexing optical system 3 of this multipoint vibration measurement system 10, the above measurement light L S The optical demultiplexer / multiplexer 3A, which demultiplexes the frequency components of the optical comb contained in the optical comb into multiple demultiplexed measurement beams, is the measurement beam L S The frequency components contained in the optical comb are decomposed and measured by optical L for each mode order. S1 ,L S2 ,···,L Sn That is, the decompression measurement of the frequency component of the mode order 1 of the optical comb L S1 , optical comb mode order 2 frequency component decompression measurement optical L S2, the demultiplexed measurement light L of the frequency component of the mode order 3 of the optical comb S3 , ···, the demultiplexed measurement light L of the frequency component of the mode order n of the optical comb Sn is output to the measurement optical transmission paths of n channels CH1, CH2, ···, CHn corresponding to the mode order of the optical comb. 【0024】 And the above measurement light L S The demultiplexed measurement light L for each of the n types of demultiplexed frequency components that are demultiplexed into the frequency components for each mode order of the optical comb included in S1 , L S2 , ··· L Sn are n optical fiber cables FB using PMF as the measurement optical transmission paths of the above n channels CH1, CH2, ···, CHn 341 , FB 342 , FB 343 , ···, FB 34n are input to the n condenser optical systems 4 of the projection optical system 4 through A1 , 4 A2 , 4 A3 , ···, 4 An The demultiplexed measurement light L for each of the n types of frequency components S1 , L S2 , ··· L Sn is condensed by the above n condenser optical systems 4 A1 , 4 A2 , 4 A3 , ···, 4 An and is irradiated onto n measurement points S1, S2, ···, S on the measurement surface 5 of the measurement object through the quarter-wave plates 4 B1 , 4 B2 , 4 B3 , ···, 4 Bn . n That is, the projection optical system 4 connected to the optical multiplexer / demultiplexer element 3A of the optical multiplexer / demultiplexer optical system 3 through the measurement optical transmission paths of n channels CH1, CH2, ···, CHn, the condenser optical system 4 <00​​​​​​​​​​​​​​A3 ,···,4 An and 1 / 4 wave plate 4 B1 ,4 B2 ,4 B3 ,···,4 Bn n single-point irradiation heads 41, 42, 43, ..., 4 n It consists of. 【0026】 Then, n measurement points S1, S2, ..., S on the measurement surface 5 of the object to be measured. n The reflection is directed to the n single-point illumination heads 41, 42, 43, ..., 4 of the projection optical system 4. n From the above fiber optic cable FB 341 FB 342 FB 343 ,···,FB 34n That is, the above measurement light L returns via the measurement light transmission path of n channels CH1, CH2, ..., CHn. S Decompression measurement of reflected light L for each frequency component of an optical comb S1 ',L S2 ',···L Sn The signal is input to the optical splitter / multiplexer optical system 3, and is combined by the optical splitter / multiplexer element 3A of the optical splitter / multiplexer optical system 3, and n measurement points S1, S2, ..., S on the measurement surface 5. n The above measurement light L reflected by S Decompression measurement of reflected light L for each frequency component of an optical comb S1 ',L S2 ',··· L Sn ' consists of the measured reflected light L S As described above, the optical fiber cable FB is connected to the optical fiber element 3A of the optical fiber optical system 3. 23 That is, the optical coupler OC of the interference optical system 2 is transmitted via the measurement optical transmission path of n channels CH1, CH2, ..., CHn. E It will be entered into. 【0027】 Here, the above optical coupler OC E The n measurement points S1, S2, ..., S on the above measurement surface 5 are input to the system. n The above measurement light L reflected by S Decompression measurement of reflected light L for each frequency component of an optical comb S1 ',L S2',···L Sn ' consists of the measured reflected light L S ' is the above optical coupler OC E Measurement light L output from S Decompressed reflected light L for each frequency component S1 ',L S2 ',···L Sn 'The above n single-point irradiation heads 41, 42, 43, ..., 4 n 4 quarter-wave plate B1 ,4 B2 ,4 B3 ,···,4 Bn By passing through twice, the polarization of the measured reflected light LS' becomes perpendicular to the measured reflected light Ls, and the optical coupler OC E Since it is a polarized beam combiner / splitter (PBC / PBS, hereafter referred to as a PBC module when it is modularized to allow input / output via fiber), the n measurement points S1, S2, ..., S on the above measurement surface 5, where the polarization component is orthogonal to Ls, n The above measurement light L reflected by S Decompressed reflected light L for each frequency component S1 ',L S2 ',···L Sn ' consists of the measured reflected light L S ' is the above optical coupler OC E From fiber optic cable FB 2C via optical coupler OC C It will be entered into. 【0028】 In the interference optical system 2 described above, n measurement points S1, S2, ..., S on the measurement surface 5 are n The above measurement light L reflected by S Decompressed reflected light L for each frequency component S1 ',L S2 ',··· L Sn ' consists of the measured reflected light L S 'and the reference light L input from the above light source 1 R The interference light from the above optical coupler OC is used as the interference light for measurement. C The measurement light L input from the light source 1 is output from the light source 1. S and reference light L RThe interference light from the above optical coupler OC is used as the reference interference light. D Output from here. 【0029】 The interference light detection unit 6, which receives the measurement interference light and reference interference light obtained by the interference optical system 2 described above, is equipped with a measurement interference light detector 6A and a reference interference light detector 6B, both consisting of balanced photodetectors, and the optical coupler OC of the interference optical system 2 described above C Two externally connected fiber optic cables FB 26A1 FB 26A2 The above optical coupler OC is used via C The measurement interference light detector 6A, which receives the measurement interference light input from the above, detects the measurement interference light and outputs the measurement interference signal SS converted into an electrical signal, and the optical coupler C of the interference optical system 2 outputs the measurement interference signal SS, and the optical coupler C D Two externally connected fiber optic cables FB 26B1 FB 26B2 The above optical coupler OC is used via D The reference interference light received from the reference interference light detector 6B detects the reference interference light and converts it into an electrical signal S. R Outputs. 【0030】 In the balanced photodetectors used as the measurement interference photodetector 6A and the reference interference photodetector 6B, beats with frequencies corresponding to the frequency difference between the frequency components of the optical combs of the input measurement light and the reference light are combined into a single electrical signal and output. The frequency difference between the frequency components of each optical comb of the measurement light and the reference light, as described here, is sufficiently small compared to the interval between the frequency components of the optical combs, and is not separated by the optical multiplexer and optical demultiplexer described below. Furthermore, the bandwidth of the balanced photodetector is sufficiently small compared to the interval between the frequency components of the optical combs, and is sufficiently large to detect the frequency difference between the frequency components of each optical comb of the measurement light and the reference light. 【0031】 Furthermore, in the signal processing unit 7 of this multi-point vibration measurement system 10, the measurement interference signal S obtained by the interference light detection unit 6 is processed. S and reference interference signal S RBy performing a discrete Fourier transform (DFT) analysis (including the fast Fourier transform (FFT)) on the input measurement light and reference light, the phase difference of each beat corresponding to the frequency difference of each optical comb is calculated for the n measurement points S1, S2, ..., S on the measurement surface 5 of the object being measured. n The phase difference for each frequency component of the optical comb caused by the Doppler shift due to vibration is determined, and n measurement points S1, S2, ..., S on the measurement surface 5 of the object being measured are determined. n The vibration information is analyzed to measure the vibration distribution on the measurement surface 5. 【0032】 Furthermore, when measuring multi-point vibrations using multiple channels (Ch), the frequency components of the optical comb contained in the measurement light LS are decomposed and output to the n-channel measurement optical transmission path as decompressed measurement light L S1 ,L S2 ,···L Sn This refers to n measurement points S1, S2, ..., S on the measurement surface 5 of the object to be measured. n By being irradiated, n measurement points S1, S2, ..., S on the above measurement surface 5 are n It undergoes a Doppler shift due to vibrations, and as a result, the frequency is shifted by the vibrations. 【0033】 In this multi-point vibration measurement system 10, when the measurement light that has undergone a Doppler shift due to vibration at the measurement point returns to the optical comb interferometer, the optical comb interference effect compresses the frequency bandwidth from the optical region to the electrical signal region while maintaining the phase shift or instantaneous frequency fluctuation amount due to the vibration. 【0034】 Interference signals based on measurement light reflected from multiple measurement points on the measurement surface form a comb-like structure in the electrical signal bandwidth. When the amount of variation due to Doppler shift is large and extends into the region of adjacent frequency components in the electrical signal bandwidth, it can lead to errors in vibration measurement. When the Doppler shift is large, crosstalk between adjacent comb modes when the interference signal is heterodyne detected, i.e., electrical crosstalk, can cause the shifted portions to overlap in the electrical signal domain between adjacent frequencies. If the vibration amplitude due to the Doppler shift of the electrical signal obtained by heterodyne detection of the interference signal is large and the vibration frequency is also high, the frequency shift due to the Doppler shift becomes relatively large compared to the frequency spacing of the comb-like interference signal. If it extends into the region of adjacent frequency components, it can cause measurement errors. 【0035】 Furthermore, as in this multi-point vibration measurement system 10, by configuring the input and output of the interference optical system 2 with optical fiber cables and transmitting reference light and measurement light via optical fiber cables, it becomes possible to use modularized optical elements with various functions, making system assembly and repair easier. 23 The measurement light L input to the optical splitter / multiplexer element 3A of the optical splitter / multiplexer optical system 3 via the optical splitter / multiplexer optical system 3 S A problem arises when some of the light is reflected by the light splitter / multiplexer element 3A of the above-mentioned light splitter / multiplexer optical system 3 and returns to the interference optical system 2, mixing with the interference light necessary for multi-point vibration measurement, thus causing measurement errors. 【0036】 In optical splitter / multiplexer devices such as arrayed waveguide gratings (AWGs) and optical switches, the ideal scenario is that signal light of the intended frequency components is emitted from the output port. However, in reality, there is inter-channel crosstalk, i.e., leakage light from other channels. Inter-channel crosstalk is greatest from adjacent channels, at around -30 dB, while non-adjacent crosstalk from non-adjacent channels decreases. 【0037】 In this multi-point vibration measurement system 10, for example, when an arrayed waveguide grating is used for the optical multiplexing / demultiplexing element 3A of the optical multiplexing / demultiplexing optical system 3, the adjacent crosstalk is about -30 dB. Therefore, it is restricted to the flat part of the transmission filter of the frequency components and the vibration frequency (Doppler shift) near the center of the band as much as possible. 【0038】 For example, when an arrayed waveguide grating (AWG) is used for the optical multiplexing / demultiplexing element 3A of the optical multiplexing / demultiplexing optical system 3, it is small-sized and has high resolution, but the return loss (RL) is about 40 dB. This reflection occurs inside the optical multiplexing / demultiplexing element 3A and at the connection between the optical fiber cable and the optical multiplexing / demultiplexing element 3A of the optical multiplexing / demultiplexing optical system 3. Also, when the optical path from the interference optical system 2 to the optical multiplexing / demultiplexing element 3A of the optical multiplexing / demultiplexing optical system 3 is an optical fiber cable, the reflection from the connector of the optical fiber cable cannot be ignored. 【0039】 That is, as the optical multiplexing / demultiplexing element 3A, a triangular prism, a plurality of wavelength division multiplexing filters, a diffraction grating, etc. are used, but the problem was that the RL was small. 【0040】 On the other hand, the amount of reflected light returning from the measurement surface 5 to the optical multiplexing / demultiplexing element 3A of the optical multiplexing / demultiplexing optical system 3 depends on the properties and shape of the surface on the measurement surface 5 and greatly attenuates. 【0041】 Also, the insertion loss (IL) of the optical multiplexing / demultiplexing element 3A is about 6.5 dB for an AWG at intervals of 25 GHz, for example. When used reciprocally, the loss becomes about 13 dB, and the influence of RL becomes relatively large. 【0042】 Due to the RL inside the optical multiplexing / demultiplexing element 3A, it is difficult to distinguish the reflection of the measurement light (first optical comb) L from the measurement surface 5 when the reflection from the measurement surface 5 is not sufficiently large. S There was a problem that the vibration information calculated by the signal processing unit 7 would be incorrect in such a case. 【0043】 In such a case, there was a problem that the vibration information calculated by the signal processing unit 7 would be incorrect. 【0044】 In other words, a multi-point vibration measurement system using an optical comb includes an interference optical system into which the reference light and measurement light are input, an optical splitter / multiplexer element that separates the measurement light irradiated onto the measurement surface according to the frequency components of the optical comb, and the measurement light L separated by this optical splitter / multiplexer element. S Various optical elements, such as optical elements that emit demultiplexed measurement light for each frequency component of the optical comb contained within and return the reflected light (scattered light) from the measurement surface to the optical splitter / multiplexer element, are provided in the optical system that propagates the reference light and measurement light in space. However, unwanted reflective components are generated in these various optical elements and may mix with the interference light necessary for multi-point vibration measurement, potentially causing measurement errors. Furthermore, because optical splitting and multiplication are performed by a single optical splitter / multiplexer element, the signal-to-noise ratio (S / N) of the vibration measurement signal is poor, and crosstalk and signal S / N become major problems when measuring vibrations using multiple channels of measurement optical transmission lines. 【0045】 Furthermore, in multi-point vibration measurement systems using optical combs, since the vibration phase is measured with high precision by analyzing the interference signals of the reference light and the measurement light, the stability of the optical paths (lengths) of the two optical waves, the reference light and the measurement light, may affect the measured values, similar to general interferometric measurements. 【0046】 In other words, by making the optical path lengths of the two optical waves, the reference light and the measurement light, the system can be made robust to fluctuations in the light source. However, because the optical path arrangement differs for each vibration measurement channel, it is affected by environmental fluctuations. As it is a vibration measurement, the measurement of AC vibration components is the main focus, but changes in the optical path (internal fiber optical path length) due to temperature and vibration affect the measured values. 【0047】 Furthermore, in a multi-point vibration measurement system using an optical comb, various optical elements are provided in the optical system that propagates the reference light and measurement light in space. These elements include an interference optical system to which the reference light and measurement light are input, an optical splitter / multiplexer element that splits the measurement light irradiated onto the measurement surface according to the frequency components of the optical comb, and an optical element that irradiates the measurement light of the frequency components split by the optical splitter / multiplexer element onto the measurement surface and returns the reflected light (scattered light) from the measurement surface back to the optical splitter / multiplexer element. However, unwanted reflective components may be generated in these various optical elements and may mix with the interference light necessary for multi-point vibration measurement, potentially causing measurement errors. 【0048】 Therefore, the present invention was devised in view of the above-mentioned problems, and its objective is to provide a multidimensional vibration measurement system that can simultaneously measure out-of-plane and in-plane vibrations of an object, that is, multidimensional vibration phenomena, at multiple points by irradiating multiple measurement points on the measurement surface with de-division measurement light for each frequency component of the optical comb, obtained by de-division of the frequency components of each optical comb contained in the measurement light. 【0049】 Another object of the present invention is to solve the problem that, when measuring the multidimensional vibration phenomena of an object at multiple points simultaneously by irradiating multiple measurement points on a measurement surface with decomposed measurement light for each frequency component of the optical comb, the scattered light component of the decomposed measurement reflected light for each frequency component of the optical comb leaks into the measurement light transmission path of the adjacent channel, causing crosstalk between adjacent frequency components to be a cause of measurement errors, thereby enabling high-precision (high S / N) multidimensional vibration measurement at multiple points simultaneously. 【0050】 Another objective of the present invention is to eliminate measurement errors caused by unwanted reflection components from various optical elements, such as optical splitters and multiplexers, provided in the optical path through which the measurement light irradiated onto the measurement surface via the interference optical system, mixing with the interference light necessary for multi-point vibration measurement, thereby enabling high-precision, simultaneous multi-dimensional vibration measurement at multiple points. 【0051】 Furthermore, another object of the present invention is to enable high-precision multi-frequency vibration measurement without the risk of the stability of the optical path (length) of the two optical waves, the reference light and the measurement light, affecting the measurement value. 【0052】 Other objects of the present invention and specific advantages obtained by the present invention will become even clearer from the description of the embodiments described below. [Means for solving the problem] 【0053】 In this invention, multiple decompressed measurement lights, obtained by decompressing multiple wavelength (frequency) components contained in the measurement light, are simultaneously irradiated from at least two different directions at each measurement point of the object to be measured, thereby simultaneously measuring the multidimensional vibration phenomena of the object at multiple points. Furthermore, for the decompressed measurement lights irradiated simultaneously from at least two different directions at each measurement point, at least two frequency components other than the adjacent frequency components of the decompressed measurement light for each decompressed frequency component are assigned. 【0054】 In other words, the present invention relates to a multidimensional vibration measurement system, comprising: a light source that outputs coherent measurement light and reference light having a spectrum with multiple modes in the shape of an optical comb at predetermined frequency intervals; an interference optical system that receives the measurement light and reference light output from the light source, as well as measurement reflected light that is reflected back by the measurement surface of the object to be measured after being irradiated onto the measurement surface of the object to be measured, and outputs measurement interference light by interfering the reference light and the measurement reflected light; an optical demultiplexing and multiplication optical system that receives the measurement light output from the light source via the interference optical system, demultiplexes the frequency components of the optical comb contained in the measurement light, outputs demultiplexed measurement light for each demultiplexed frequency component to multiple channels of measurement optical transmission lines, receives the demultiplexed measurement reflected light for each demultiplexed frequency component that is reflected back by the measurement surface after being irradiated onto multiple measurement points on the measurement surface of the object to be measured via multiple channels of measurement optical transmission lines, and combines the demultiplexed measurement reflected light for each demultiplexed frequency component and inputs it to the interference optical system as measurement reflected light; and Multiple separatedThe optical system comprises: a plurality of single-point irradiation heads that receive demultiplexed measurement light via the plurality of channel measurement light transmission paths, assign and irradiate multiple measurement points on the measurement surface of an object to be measured with the demultiplexed measurement light, and input multiple demultiplexed measurement reflected light that is reflected back from the multiple measurement points on the measurement surface to the optical demultiplexing optical system via the plurality of channel measurement light transmission paths; a plurality of measurement light transmission paths consisting of a plurality of optical fiber cables that connect the optical demultiplexing optical system and the plurality of single-point irradiation heads; a measurement light transmission path selection means that selectively changes the connection relationship between the optical demultiplexing optical system and the plurality of single-point irradiation heads connected via the plurality of channel measurement light transmission paths; a measurement interference photodetector that receives measurement interference light obtained from the interference optical system and converts it into an electrical signal to obtain a measurement interference signal; and a signal processing unit that analyzes vibration information of the measurement surface based on the measurement interference signal obtained from the measurement interference photodetector, wherein the plurality of single-point irradiation heads divide the demultiplexed measurement light for each demultiplexed frequency component demultiplexed by the optical demultiplexing optical system into frequency components of the optical comb that are separated by a mode order of 1 or more, other than adjacent frequency components. The system is configured such that, based on the measurement interference signal obtained by the measurement light transmission path selection means, the signal processing unit obtains multidimensional vibration information of the measurement point by performing calculation processing on the interference signal for each measurement point, based on the measurement interference signal obtained by the measurement interference light detector, the signal processing unit is configured to obtain multidimensional vibration information of the measurement point by performing calculation processing on the interference signal for each measurement point, where the wave measurement light is irradiated from different directions to a single measurement point by the measurement light transmission path selection means, and the delimited measurement reflected light that is reflected at multiple measurement points on the measurement surface of the object to be measured and returns via the at least two single-point irradiation heads is input to the optical splitter / multiplexer optical system. The delimited measurement reflected light for each measurement point input from the multiple irradiation head units is combined in the optical splitter / multiplexer optical system and the resulting measurement reflected light is input to the interference system. 【0055】 In the multidimensional vibration measurement system according to the present invention, the measurement optical transmission path selection means can selectively change the connection relationship between the optical dispersive and multiplexing optical system and the plurality of single-point irradiation heads connected via the plurality of channel measurement optical transmission paths by channel blocking of the plurality of channels, thereby assigning at least two frequency components of the decompressed measurement light, other than adjacent frequency components, of the decompressed measurement light for each decompressed frequency component decompressed by the optical dispersive and multiplexing optical system to each measurement point. 【0056】 Furthermore, in the multidimensional vibration measurement system according to the present invention, the irradiation head unit may be configured such that the at least two single-point irradiation heads are arranged and fixed at an inclination angle to each other so that the optical axes of the decompressed measurement light intersect at one measurement point, and the decompressed measurement light of at least two frequency components assigned by the measurement light transmission path selection means is irradiated to one measurement point from different directions. 【0057】 Furthermore, in the multidimensional vibration measurement system according to the present invention, the irradiation head unit may be configured such that at least two single-point irradiation heads are arranged and fixed so as to output delimited measurement light with their optical axes parallel, and the delimited measurement light of at least two frequency components output from the at least two single-point irradiation heads assigned by the measurement light transmission path selection means is focused by a focusing optical system and irradiated onto a single measurement point from different directions. 【0058】 Furthermore, the multidimensional vibration measurement system according to the present invention may include a focusing optical system array in which the focusing optical systems of multiple irradiation head units are arranged in an array. 【0059】 Furthermore, in the multidimensional vibration measurement system according to the present invention, each of the plurality of irradiation head units consists of two single-point irradiation heads, and the signal processing unit is configured to obtain two-dimensional vibration information of in-plane vibration and out-of-plane vibration at multiple measurement points on the measurement surface of the object to be measured. 【0060】 Furthermore, in the multidimensional vibration measurement system according to the present invention, the plurality of irradiation head units consist of at least three single-point irradiation heads, and the signal processing unit is configured to obtain three-dimensional vibration information of in-plane and out-of-plane vibrations at multiple measurement points on the measurement surface of the object to be measured. 【0061】 Furthermore, in the multidimensional vibration measurement system according to the present invention, the optical splitter / multiplexer optical system may consist of an optical splitter / multiplexer element that receives measurement light output from the light source via the interference optical system, splits the frequency components of the optical comb contained in the measurement light, outputs the split measurement light for each split frequency component to multiple channels of measurement optical transmission lines, receives the split measurement light for each split frequency component that is reflected back by the measurement surface from multiple measurement points on the measurement surface of the object to be measured, inputs the split measurement reflected light for each split frequency component via multiple channels of measurement optical transmission lines, and combines the split measurement reflected light for each split frequency component to input the measurement reflected light to the interference optical system. 【0062】 In the multi-dimensional vibration measurement system according to the present invention, in the optical multiplexing / demultiplexing optical system, the measurement light output from the light source is input via the interference optical system, and a frequency component of an optical comb included in the measurement light is demultiplexed, and demultiplexed measurement light of one frequency component is output to a plurality of channels of measurement light transmission paths for each one-point irradiation head. The demultiplexed measurement light of one frequency component for each one-point irradiation head is irradiated to a plurality of measurement points on the measurement surface of the measurement object via the plurality of irradiation head units, and the demultiplexed measurement reflected light of one frequency component for each one-point irradiation head that is reflected back from the plurality of measurement points on the measurement surface is input via the plurality of channels of measurement light transmission paths. The optical multiplexing / demultiplexing optical system includes an optical demultiplexing element that multiplexes the demultiplexed measurement reflected light of one frequency component for each one-point irradiation head and inputs the multiplexed measurement reflected light as the measurement reflected light to the interference optical system, and a coupling optical system that is connected to the optical multiplexing / demultiplexing optical system via the plurality of channels of measurement light transmission paths. The demultiplexed measurement light of one frequency component for each one-point irradiation head demultiplexed by the optical demultiplexing element of the optical multiplexing / demultiplexing optical system is input via the plurality of channels of measurement light transmission paths, and outputs the demultiplexed measurement light of one frequency component for each one-point irradiation head that irradiates a plurality of measurement points on the measurement surface of the measurement object via the plurality of irradiation head units. The coupling optical system includes a plurality of coupling optical elements that input the demultiplexed measurement reflected light of one frequency component for each one-point irradiation head that is reflected from the plurality of measurement points on the measurement surface and returns via the plurality of irradiation head units to the optical multiplexing element of the optical multiplexing / demultiplexing optical system via the plurality of channels of measurement light transmission paths. 【0063】 In the multi-dimensional vibration measurement system according to the present invention, in the optical multiplexing / demultiplexing optical system, the optical demultiplexing element demultiplexes the frequency component of the optical comb from the measurement light input via one optical fiber cable from the interference optical system, and outputs the demultiplexed measurement light for each demultiplexed frequency component via a plurality of optical fiber cables. The optical multiplexing / demultiplexing optical system includes the optical multiplexing element that multiplexes the demultiplexed measurement reflected light for each demultiplexed frequency component input via a plurality of optical fiber cables and outputs the multiplexed measurement reflected light via one optical fiber cable. The coupling optical system can include the coupling optical element that aligns the optical axes of two light beams with orthogonal polarization directions output from two optical fiber cables. 【0064】 Furthermore, in the multidimensional vibration measurement system according to the present invention, each of the multiple single-point irradiation heads constituting the irradiation head unit incorporates a coupling optical element of the coupling optical system and is connected to the optical demultiplexing element and optical multiplexing element of the optical demultiplexing and multiplexing optical system via a pair of optical fiber cables consisting of an optical fiber cable through which the demultiplexing measurement light passes and an optical fiber cable through which the demultiplexing measurement reference light passes. 【0065】 Furthermore, in the multidimensional vibration measurement system according to the present invention, each of the plurality of irradiation head units is provided with at least one optical path length variation compensation optical system, and in the optical demultiplexing optical system, at least one frequency component of the demultiplexed measurement light obtained by demultiplexing the frequency components of the optical comb contained in the measurement light is assigned to each irradiation head unit as a demultiplexed measurement reference light for optical path length variation compensation, and the demultiplexed measurement reference light for optical path length variation compensation is input to at least one optical path length variation compensation optical system provided for each irradiation head unit via at least one optical path length variation compensation optical path among the plurality of measurement optical transmission paths, and the at least one channel from the optical path length variation compensation optical system The system can be configured to obtain a measurement reflected light by combining the decompressed measurement reference light of at least one frequency component, which returns via the optical path for compensating for optical path length fluctuations of the channel, with decompressed measurement reflected light of at least two frequency components for each measurement point, and then, based on the measurement interference signal obtained by the measurement interference photodetector, use the measurement result of the optical path length of the at least one channel for compensating for optical path length fluctuations using the decompressed measurement reference light for compensating for optical path length fluctuations of at least one frequency component to correct the fluctuation in the optical path length of each of the multiple channels of measurement optical transmission paths through which the decompressed measurement light and the decompressed measurement reflected light of at least two frequency components pass for each measurement point, for each irradiation head unit, and analyze multidimensional vibration information of the measurement surface. 【0066】 Furthermore, the multidimensional vibration measurement system according to the present invention includes a plurality of optical path length variation compensation optical systems provided for each of the plurality of single-point irradiation heads constituting the irradiation head unit, and uses a plurality of decompressed measurement lights from each decompressed frequency component obtained by decompressing the frequency component of the optical comb contained in the measurement light as a decompressed measurement reference light for optical path length variation compensation, and the signal processing unit is configured to correct the variation in each optical path length of the measurement optical transmission path for each of the plurality of single-point irradiation heads constituting the irradiation head unit and the optical decompression and multiplexing optical system. 【0067】 Furthermore, in the multidimensional vibration measurement system according to the present invention, the plurality of optical path length variation compensation optical systems can be configured such that, among the decompressed frequency components obtained by decompressing the frequency components of the optical comb contained in the measurement light by the optical decompression element of the optical decompression optical system, the decompressed measurement light of channels that were not output to the measurement optical transmission path among the decompressed frequency components is assigned as the decompressed measurement reference light for optical path length variation compensation by the measurement optical transmission path selection means. [Effects of the Invention] 【0068】 The multidimensional vibration measurement system according to the present invention is equipped with a measurement optical transmission path selection means that selectively changes the connection relationship between an optical splitter / multiplexer optical system connected via multiple channel measurement optical transmission paths and a plurality of single-point irradiation heads. The measurement optical transmission path selection means assigns to the plurality of single-point irradiation heads constituting the irradiation head unit the decompressed measurement light of frequency components that are at least 1 mode order away from adjacent frequency components of the optical comb, other than adjacent frequency components of the decompressed measurement light for each decompressed frequency component decompressed by the optical splitter / multiplexer optical system. The plurality of irradiation head units simultaneously irradiate each measurement point of the object to be measured with the decompressed measurement light for each decompressed frequency component from at least two different directions. This makes it possible to obtain decompressed measurement reflected light of at least two frequency components for each measurement point that is reflected back from multiple measurement points on the measurement surface. By processing interference signals for each measurement point where decompressed measurement light is irradiated from different directions to a single point on the measurement surface of the object to be measured, the multidimensional vibration phenomenon of the object to be measured can be measured simultaneously at multiple points. 【0069】 Furthermore, in the multidimensional vibration measurement system according to the present invention, by assigning decomposition measurement light of at least two frequency components other than adjacent frequency components of the decomposition measurement light for each frequency component to each measurement point, the coherence of the decomposition measurement light of at least two frequency components at each measurement point used for multidimensional vibration measurement can be reduced, and the problem that crosstalk between adjacent frequency components caused by the scattering light component of the decomposition measurement light of at least two frequency components leaking into the measurement light transmission path of adjacent channels can be avoided. 【0070】 Furthermore, the multidimensional vibration measurement system according to the present invention includes an optical demultiplexing and multiplexing optical system consisting of an optical demultiplexing element and an optical multiplexing element, and a coupled optical system consisting of a plurality of coupled optical elements, and the plurality of measurement optical transmission paths connecting the optical demultiplexing and multiplexing optical system and a plurality of single-point irradiation heads are provided as a first plurality of measurement optical transmission path through which demultiplexing measurement light of one frequency component passes for each single-point irradiation head, and a second plurality of measurement optical transmission paths through which demultiplexing measurement reflected light of one frequency component passes for each single-point irradiation head that is reflected back from a plurality of measurement points on the measurement surface of the object to be measured. In addition to separating the optical optical system and the interference optical system, the measurement light transmission path through which the measurement light and measurement reflected light passing through the optical optical system can be separated into a first measurement light transmission path through which the measurement light passing through the interference optical system and the optical optical system passes, and a second measurement light transmission path through which the measurement reflected light passing through the optical optical system and the interference optical system passes. This eliminates measurement errors caused by unwanted reflection components from optical demultiplexers provided in the optical path through which the measurement light irradiated onto the measurement surface via the interference optical system are mixed into the interference light necessary for multidimensional vibration measurement. 【0071】 Furthermore, the multidimensional vibration measurement system according to the present invention is equipped with a measurement optical transmission path selection means that selectively changes the connection relationship between the optical splitter / multiplexer optical system and the plurality of single-point irradiation heads connected via the plurality of measurement optical transmission paths of the plurality of channels. This allows the connection relationship between the optical splitter / multiplexer optical system and the plurality of single-point irradiation heads to be freely changed, enabling independent measurement arrangements for the plurality of irradiation head units. 【0072】 Furthermore, in the multidimensional vibration measurement system according to the present invention, since at least one optical path length variation compensation optical system is provided for each irradiation head unit, it is possible to correct variations in the optical path length of each of the multiple channels of measurement optical transmission paths through which at least two frequency components of delimited measurement light and delimited measurement reflected light pass for each irradiation head unit. This eliminates the influence on measurement values ​​due to changes in optical path length caused by temperature and vibration of the multiple channels of optical transmission paths, and enables high-precision multi-point vibration measurement without the risk of the stability of the optical paths (lengths) of the two optical waves, the reference light and the measurement light, affecting the measurement values. 【0073】 Furthermore, in the multidimensional vibration measurement system according to the present invention, by using the optical demultiplexing element of the optical wave splitting optical system to demultiplex the frequency components of the optical comb contained in the measurement light, and excluding the component with the maximum spectral intensity of the demultiplexed measurement light for each demultiplexed frequency component, the channel that was not output to the measurement optical transmission path among the demultiplexed frequency components is used as the demultiplexed measurement reference light for compensating for optical path length fluctuations. This makes it possible to achieve a channel arrangement configuration that is highly intense and highly efficient for vibration measurement using the demultiplexed measurement light irradiated onto the measurement surface. 【0074】 Therefore, according to the present invention, a multidimensional vibration measurement system can be provided that can perform high-precision (high S / N) simultaneous multi-point vibration measurement of at least two dimensions of an object by simultaneously irradiating each measurement point of the object with multiple delimited measurement lights obtained by demultiplexing multiple wavelength (frequency) components contained in the measurement light from at least two different directions. [Brief explanation of the drawing] 【0075】 [Figure 1] Figure 1 is a schematic diagram illustrating out-of-plane and in-plane vibrations. [Figure 2] Figure 2 is a schematic diagram showing the configuration of a multipoint vibration measurement system that includes an interference optical system, which is modularized using modularized optical elements with various functions such as polarizing beam splitters and polarizing beam combiners, with inputs and outputs configured to form optical fiber cables, and an optical multiplexing optical system consisting of optical multiplexing elements. [Figure 3] Figure 3 is a schematic diagram showing an example of the configuration of a multidimensional vibration measurement system to which the present invention is applied. [Figure 4] Figures 4(A) and 4(B) are perspective views showing examples of the configuration of an irradiation head unit in a multidimensional vibration measurement system. (A) shows an irradiation head unit consisting of three single-point irradiation heads, and (B) shows an irradiation head unit consisting of two single-point irradiation heads. [Figure 5] Figures 5(A) and (B) illustrate the Doppler effect in the electrical signal domain of the decomposed measurement light due to vibrations at multiple measurement points when multi-point vibration measurement is performed by irradiating multiple measurement points on the measurement surface with decomposed measurement light obtained by decomposing the measurement light into frequency components for each mode order of the optical comb in the above multi-point vibration measurement system. (A) shows the Doppler effect when the crosstalk between adjacent comb modes is large when the interference signal is heterodyne detected, the shift portion between adjacent frequencies overlaps in the electrical signal domain, and the electrical crosstalk between adjacent frequencies causes measurement errors. (B) shows the Doppler effect when Doppler shift detection can be performed without electrical crosstalk between adjacent frequencies being a problem due to decimation measurement. [Figure 6] Figure 6 is a schematic diagram showing another example of a multidimensional vibration measurement system to which the present invention is applied. [Figure 7] Figures 7(A) and 7(B) show examples of the configuration of a single-point irradiation head with a built-in coupled optical element provided in the irradiation head unit of the multidimensional vibration measurement system described above. (A) is a schematic diagram showing the configuration of the single-point irradiation head with a built-in coupled optical element, and (B) is a front view of a two-core capillary provided in the single-point irradiation head with a built-in coupled optical element. [Figure 8]Figures 8(A) and 8(B) show other configuration examples of the single-point illumination head with a built-in coupling optical element, where (A) is a schematic diagram showing the configuration of the single-point illumination head with a built-in coupling optical element, and (B) is a front view of the two-core capillary provided in the single-point illumination head with a built-in coupling optical element. [Figure 9] Figures 9(A) and (B) show examples of the configuration of the optical path length variation compensation optical system provided in the irradiation head unit of the multidimensional vibration measurement system described above. (A) is a schematic diagram showing the configuration of the optical path length variation compensation optical system, and (B) is a front view of the two-core capillary provided in the optical path length variation compensation optical system. [Figure 10] Figures 10(A), (B), and (C) are schematic diagrams showing various configuration examples of a single-point irradiation head unit incorporating an optical path length variation compensation optical system, which is provided in the irradiation head unit of the above-mentioned multidimensional vibration measurement system. [Figure 11] Figure 11 is a perspective view showing an example of a measurement arrangement using multiple irradiation head units in the multidimensional vibration measurement system described above. [Figure 12] Figures 12(A) and (B) are perspective views showing other configuration examples of the irradiation head unit in a multidimensional vibration measurement system, where (A) shows an irradiation head unit consisting of three single-point irradiation heads, and (B) shows an irradiation head unit with a built-in optical path length variation compensating optical system. [Figure 13] Figures 13(A), (B), and (C) illustrate an irradiation head unit with a multi-point irradiation arrangement with 120° in-plane distribution in a multidimensional vibration measurement system. (A) is a schematic diagram showing the demultiplexed measurement light irradiated to one measurement point on the measurement surface by the irradiation head unit. (B) is a schematic diagram showing a longitudinal cross-section of an irradiation head unit in which three single-point irradiation heads are evenly arranged at 120° in-plane. (C) is a schematic diagram showing the specular reflection component of the demultiplexed measurement light irradiated to one measurement point on the measurement surface by the above irradiation head unit, and the in-plane component of the demultiplexed measurement reflected light projected into the plane at sinθ. [Figure 14] Figure 14 is a schematic diagram showing a group of irradiation head units equipped with a focusing optical system array, which is an array of focusing optical systems of multiple irradiation head units. [Figure 15]Figures 15(A) and (B) illustrate the functions of the optical demultiplexer and optical multiplexer elements provided in the optical demultiplexer / multiplexer optical system in the multipoint vibration measurement system described above. Figure (A) shows the function of the optical demultiplexer element to separate the frequency components of the optical comb contained in the measurement light according to the mode order of the optical comb, and Figure (B) shows the function of the optical multiplexer element to combine the frequency components separated for each frequency component of the optical comb. [Figure 16] Figure 16 is a schematic diagram showing the optical comb spectrum used to explain the deselected measurement light that is assigned as a deselected measurement reference light for compensating for optical path length fluctuations to a plurality of optical path length fluctuation compensation optical systems built into a plurality of single-point irradiation head units in the multidimensional vibration measurement system according to the present invention. [Modes for carrying out the invention] 【0076】 Embodiments of the present invention will be described in detail below with reference to the drawings. Common components will be denoted by common reference numerals in the drawings. Furthermore, it goes without saying that the present invention is not limited to the following examples and can be modified as needed without departing from the spirit of the invention. 【0077】 Figure 3 is a schematic diagram showing an example of the configuration of a multidimensional vibration measurement system to which the present invention is applied. 【0078】 The multidimensional point vibration measurement system 100A shown in the schematic diagram of Figure 3 is an improved version of the multi-point vibration measurement system 10 shown in the schematic diagram of Figure 2, adapted for multidimensional vibration measurement. Components identical to those in the multi-point vibration measurement system 10 are denoted by the same reference numerals, and their detailed descriptions are omitted. 【0079】 In this multidimensional vibration measurement system 100A, the measurement light L S Multiple demultiplexed measurement light L is obtained by demultiplexing multiple wavelength (frequency) components contained in by the optical demultiplexing optical system 3. S1 ,L S2 ,···L SnMultiple irradiation head units 14A, 14B, each consisting of at least two single-point irradiation heads, simultaneously irradiate each measurement point of the object 5 from at least two different directions to simultaneously measure the multidimensional vibration phenomena of the object at multiple points. Furthermore, for the decompressed measurement light irradiated simultaneously from at least two different directions for each measurement point, decompressed measurement light of at least two frequency components other than the adjacent frequency components of the decompressed measurement light for each decompressed frequency component is assigned. 【0080】 In other words, this multidimensional vibration measurement system 100A has a spectrum with predetermined frequency intervals and coherent measurement light L S and reference light L R A light source 1 that outputs light, and measurement light L output from the light source 1. S and reference light L R As the input is received, the measurement light L is irradiated onto the measurement surface 5 of the object to be measured. S The measured reflected light L is reflected back by the above measuring surface 5. S ' is input, and the above reference light L R and the above measured reflected light L S An interference optical system 2 outputs interference light for measurement, and the measurement light L output from the light source 1. S The above interference optical system 2 is input, and the above measurement light L S The frequency components contained in the signal are decomposed, and n types of decomposed measurement light L are sent to multiple n channels (where n is an arbitrary positive integer) of measurement optical transmission lines 34, CH1, CH2, ..., CHn, for each decomposed frequency component. S1 ,L S2 ,···L Sn The output is generated, and the decompressed measurement light L for each of the above frequency components is irradiated onto multiple measurement points S1, S2, ... on the measurement surface 5 of the object to be measured. S1 ,L S2 ,···L Sn The decompressed measured reflected light L for each decompressed frequency component is reflected back by the above-mentioned measuring surface 5. S1 ',L S2 ',···L Sn The n channels CH1, CH2, ..., CHn are input via the measurement optical transmission path 34, and the decompressed reflected light L for each of the above decompressed frequency components is input as decompressed. S1 ',L S2',···L Sn ' is combined to obtain the above measured reflected light L S The optical splitting and multiplexing optical system 3 consists of an optical splitting and multiplexing element 3A that is input to the above interference optical system 2 as ', and the decompressed measurement light L for each of the above frequency components that has been decompressed by the optical splitting and multiplexing optical system 3 S1 ,L S2 ,···L Sn The above n channels CH1, CH2, ..., CHn are input via the measurement optical transmission path 34, and multiple measurement points S1, S2, ... on the measurement surface 5 of the object to be measured are assigned and illuminated with decompressed measurement light having at least two frequency components for each measurement point, and decompressed reflected measurement light L having at least two frequency components is reflected back from the multiple measurement points S1, S2, ... on the measurement surface 5 and returns for each measurement point. S1 ',L S2 ',···L Sn Multiple single-point irradiation heads 41, 42, ... input the above n channels CH1, CH2, ..., CHn to the above optical light splitter / multiplexer optical system 3 via the above n-channel optical light transmission path 34, and the measurement interference signal S obtained by the above interference optical system 2 is received and converted into an electrical signal. S A measuring interference light detector 6A obtains the reference interference signal S obtained by receiving the reference interference light obtained by the interference optical system 2 and converting it into an electrical signal. R An interference light detection unit 6, consisting of a reference interference light detector 6B, and a measurement interference signal S obtained by the interference light detection unit 6. S and reference interference signal S R The system includes a signal processing unit 7 that analyzes multidimensional vibration information at multiple measurement points S1, S2, ... on the measurement surface 5 based on the above-mentioned signal. 【0081】 The optical splitter / multiplexer element 3A that constitutes the optical splitter / multiplexer optical system 3 in this multipoint vibration measurement system 100A uses the above-mentioned measurement light L S The frequency components contained in are decomposed into decompressed frequency components for each mode order of the optical comb, and the decompressed measurement optical L of the frequency component of mode order 1 of the optical comb is obtained. S1 , optical comb mode order 2 frequency component decompression measurement optical L S2 , optical comb mode order 3 frequency component decompression measurement optical L S3 ..., the decompression measurement of the frequency components of the mode order n of the optical comb, optical L Snn optical fiber cables FB corresponding to the mode order of the optical comb 341 FB 342 FB 343 ,···,FB 34n The measurement optical transmission path 34, consisting of n channels CH1, CH2, ..., CHn, outputs the demultiplexed reflected light L of the optical comb, which is reflected back by the measurement surface 5, for each mode order. S1 ',L S2 ',···L Sn The above n channels CH1, CH2, ..., CHn are input via the measurement optical transmission path 34, and the decompressed reflected light L for each frequency component is input. S1 ',L S2 ',···L Sn ' is combined to obtain the above measured reflected light L S This is input to the above interference optical system 2 as '. 【0082】 Furthermore, in this multidimensional vibration measurement system 100A, the n optical fiber cables FB constitute the measurement optical transmission path 34 of the n channels CH1, CH2, ..., CHn derived from the optical multiplexing element 3A of the optical multiplexing optical system 3. 341 FB 342 FB 343 ,···,FB 34n It is detachably connected to the optical splitter / multiplexer 3A via a connector section 8 consisting of n cable connectors provided at each end. 【0083】 From the above optical demultiplexing optical system 3, the above n-channel measurement optical transmission path 34 transmits the demultiplexed measurement light L for each mode order of the optical comb. S1 ,L S2 ,···L Sn Multiple single-point irradiation heads 41, 42, ... to which the input is received are connected by n optical fiber cables FB that constitute the above-mentioned measurement optical transmission path 34. 341 FB 342 ,···,FB 34nSince the optical splitter 3A is detachably connected to the optical splitter 3A via a connector section 8 consisting of n cable connectors, the connection relationship with the optical splitter 3A can be selectively changed by attaching or detaching the cable connectors in the connector section 8. 【0084】 In other words, the connector section 8, consisting of the n cable connectors, connects to the optical splitter / multiplexer optical system 3 and comprises n optical fiber cables FB that constitute the n-channel measurement optical transmission path 34. 341 FB 342 ,···,FB 34n A detachable mechanism is provided at one end of each of the components, and functions as a measurement optical transmission path selection means that allows the connection relationship between the optical dispersive and multiplexing optical system 3, which is connected via the n-channel measurement optical transmission path 34, and the plurality of single-point illumination heads 41, 42, ... to be changed by selective channel blocking. The measurement optical transmission path selection means may or may not be selectable by the user. 【0085】 The above-mentioned multiple single-point irradiation heads 41, 42, ... irradiate a single measurement point from different directions using at least two single-point irradiation heads, each assigned to a plurality of measurement points S1, S2, ... on the measurement surface 5 of the object to be measured, with at least two frequency components of decompressed measurement light for each measurement point. The decompressed measurement reflected light, each with at least two frequency components for each measurement point, which is reflected by the plurality of measurement points S1, S2, ... on the measurement surface 5 and returns via the at least two single-point irradiation heads, is input to the optical decompression and multiplexing optical system 3. At the very least, each measurement point is configured with multiple irradiation head units consisting of two single-point irradiation heads. In this multidimensional vibration measurement system 100A, there is an irradiation head unit 14A consisting of three single-point irradiation heads 41, 43, and 45 that irradiate the first measurement point S1 on the measurement surface 5 with demultiplexed measurement light of three frequency components from three different directions, and an irradiation head unit 14B consisting of two single-point irradiation heads 47 and 49 that irradiate the second measurement point S2 on the measurement surface 5 with demultiplexed measurement light of two frequency components from two different directions. 【0086】 Figures 4(A) and 4(B) are perspective views showing examples of the configuration of the irradiation head unit provided in this multidimensional vibration measurement system 100A. (A) shows the irradiation head unit 14A consisting of three single-point irradiation heads 41, 43, and 45, and (B) shows the irradiation head unit 14B consisting of two single-point irradiation heads 47 and 49. 【0087】 The irradiation head unit 14A provided in this multidimensional vibration measurement system 100A is configured such that three single-point irradiation heads 41, 43, and 45 are arranged and fixed at an angle to each other so that the optical axes of the decompressed measurement light of three frequency components intersect at one measurement point S1, and the decompressed measurement light of the three frequency components is irradiated onto the one measurement point S1 from different directions. 【0088】 That is, as shown in Figure 4(A), the single-point irradiation head 41 constituting the irradiation head unit 14A emits a single-frequency demultiplexed measurement light L from a direction perpendicular to the measurement point S1 on the measurement surface 5, i.e., from the Z-axis direction, relative to the measurement surface 5 which is arranged in the XY plane including the X and Y axes. Z The single-point irradiation head 43 is positioned on the Z-axis to irradiate, and the single-point irradiation head 43 emits a single-frequency decompressed measurement light L from the direction of an inclination angle θx relative to the single-point irradiation head 41 in the XZ plane including the X and Z axes to the measurement point S1 on the measurement surface 5. Sx The XZ plane is positioned to irradiate the area, and furthermore, the single-point irradiation head 4 is positioned in the direction of an inclination angle θy with respect to the single-point irradiation head 41 in the YZ plane including the Y and Z axes, and the decompressed measurement light L of one frequency component is directed to the measurement point S1 on the measurement surface 5. Y It is positioned in the YZ plane so as to illuminate. 【0089】 This multidimensional vibration measurement system 100A is equipped with an irradiation head unit 14A consisting of the three single-point irradiation heads 41, 43, and 45, thereby providing a demultiplexed measurement light L of one frequency component from three different directions to the measurement point S1 on the measurement surface 5. X ,L Y ,L Z By irradiating the object to be measured, the demultiplexed measurement light L caused by the Doppler shift due to vibration at the measurement point S1 on the measurement surface 5 of the object to be measured is obtained. X ,LY ,L Z Vibration measurement can be performed by Doppler shift detection, which detects phase fluctuations for each step, and the signal processing unit 7 receives the measurement interference signal S obtained by the interference light detection unit 6. S and reference interference signal S R Based on this, by analyzing the three-dimensional vibration information at the measurement point S1 on the measurement surface 5, the decompressed measurement light L of each single-frequency component irradiated from three different directions onto the measurement point S1 on the measurement surface 5 is obtained. X ,L Y ,L Z Each incident angle and the above-mentioned demultiplexed measurement light L X ,L Y ,L Z By measuring vibrations using Doppler shift detection, each vibration quantity obtained at the above measurement point S1 can be simultaneously measured individually, decomposed into a three-dimensional measurement coordinate system (or target coordinate system). 【0090】 In other words, in the multidimensional vibration measurement system according to the present invention, each of the plurality of irradiation head units consists of at least three single-point irradiation heads, and the signal processing unit is configured to obtain three-dimensional vibration information of in-plane and out-of-plane vibrations at multiple measurement points on the measurement surface of the object to be measured. 【0091】 Furthermore, the irradiation head unit 14B provided in this multidimensional vibration measurement system 100A is configured such that two single-point irradiation heads 47 and 49 are arranged and fixed at an angle to each other so that the optical axes of the decompressed measurement light of two frequency components intersect at one measurement point S2, and the decompressed measurement light of the two frequency components is irradiated onto the one measurement point S2 from different directions. 【0092】 That is, as shown in Figure 4(B), the two single-point irradiation heads 47 and 49 constituting the irradiation head unit 14B, each tilted in opposite directions with respect to the Z axis at an inclination angle 2θx, emit two-frequency decompressed measurement light L from two directions onto the measurement point S2 on the measurement surface 5 positioned in the XY plane including the X and Y axes. Sa ,L Sb It is positioned in the XZ plane so as to illuminate. 【0093】 This multidimensional vibration measurement system 100A is equipped with an irradiation head unit 14B consisting of the two single-point irradiation heads 47 and 49, thereby providing a demultiplexed measurement light L of one frequency component from two different directions to the measurement point S2 on the measurement surface 5. Sa ,L Sb By irradiating the object to be measured, the demultiplexed measurement light L caused by the Doppler shift due to vibration at the measurement point S2 on the measurement surface 5 of the object to be measured is obtained. Sa ,L Sb Vibration measurement can be performed by Doppler shift detection, which detects phase fluctuations for each step, and the signal processing unit 7 receives the measurement interference signal S obtained by the interference light detection unit 6. S and reference interference signal S R Based on this, by analyzing the two-dimensional vibration information at the measurement point S2 on the measurement surface 5, the decompressed measurement light L of each single-frequency component irradiated from two different directions onto the measurement point S2 on the measurement surface 5 is obtained. Sa ,L Sb Each incident angle and the above-mentioned demultiplexed measurement light L Sa ,L Sb By measuring vibrations using Doppler shift detection, each vibration quantity obtained at the above measurement point S2 can be decomposed into a two-dimensional measurement coordinate system (or target coordinate system) and measured individually and simultaneously. 【0094】 In other words, in the multidimensional vibration measurement system according to the present invention, each of the plurality of irradiation head units consists of two single-point irradiation heads, and the signal processing unit can obtain two-dimensional vibration information of in-plane vibration and out-of-plane vibration at multiple measurement points on the measurement surface of the object to be measured. 【0095】 Therefore, in this multidimensional vibration measurement system 100A, the irradiation head unit 14A can acquire three-dimensional vibration information at measurement point S1 on the measurement surface 5, and the irradiation head unit 14B can acquire two-dimensional vibration information at measurement point S2 on the measurement surface 5, enabling multi-point multidimensional vibration measurement that simultaneously measures multidimensional vibration information at two measurement points S1 and S2. 【0096】 Here, a single measurement point that is illuminated by multiple measurement beams from different directions by the irradiation head units 14A and 14B can be treated as a single measurement point if it is in a nearby region exhibiting the same vibration. 【0097】 In this example, we have assumed that multidimensional vibration information is measured simultaneously at two measurement points S1 and S2. However, this multidimensional vibration measurement system 100A can perform multi-point multidimensional vibration measurement by equipping itself with three or more irradiation head units, each consisting of at least two single-point irradiation heads, thereby simultaneously measuring multidimensional vibration information at three or more measurement points S1, S2, ... 【0098】 In other words, in this multidimensional vibration measurement system 100A, the measurement light L output from the light source 1 is used. S Decompressed measurement light L obtained by decompressing multiple wavelength (frequency) components contained in S1 ,L S2 ,···L Sn Multiple irradiation head units receive the input, and the decompressed measurement light L for each of the above frequency components is generated. S1 ,L S2 ,···L Sn The object to be measured is simultaneously illuminated from at least two different directions at each measurement point, and the decompressed reflected light L, which is reflected back from multiple measurement points S1, S2, ... on the measurement surface 5, has at least two frequency components at each measurement point. S1 ',L S2 ',···L Sn This allows us to obtain and simultaneously measure the multidimensional vibration phenomena of the object being measured at multiple points. 【0099】 In this way, the decomposition measurement light L for each decomposition frequency component S1 ,L S2 ,···L SnIn the multidimensional vibration measurement system 100A, which measures the multidimensional vibration phenomena of an object simultaneously at multiple points by simultaneously irradiating each measurement point of the object from at least two different directions, the decompressed reflected light L of the optical comb, which has undergone Doppler shift, is measured for each frequency component at multiple measurement points S1, S2, ... on the measurement surface. S1 ',L S2 ',···L Sn Because the scattered light component of ' leaks into the measurement optical transmission path of the adjacent channel, resulting in crosstalk between adjacent frequency components, and due to the crosstalk of adjacent frequency components that have undergone a Doppler shift due to the vibration phenomenon in the opposite direction, there is a possibility that the shifted portions between adjacent frequency components will overlap in the domain of electrical signals, and crosstalk between adjacent frequency components will cause measurement errors, but the n optical fiber cables FB that constitute the n-channel measurement optical transmission path 34 connected to the optical dissociation and multiplexing optical system 3 341 FB 342 ,···,FB 34n Each end of the cable is equipped with a connector section 8 consisting of n cable connectors, which functions as a measurement optical transmission path selection means that allows the connection relationship between the optical splitter / multiplexer optical system 3 and the plurality of single-point illumination heads 41, 42, ... connected via the n-channel measurement optical transmission path 34 to be changed by selective channel switching. S1 ,L S2 ,···L Sn By assigning decompressed measurement light of at least two frequency components other than adjacent frequency components of the decompressed measurement light for each frequency component to each measurement point irradiated with the above frequency component, the coherence of the decompressed measurement light of at least two frequency components for each measurement point used for multidimensional vibration measurement can be reduced, thereby avoiding the problem that crosstalk between adjacent frequency components caused by scattered light components of the decompressed measurement light of at least two frequency components leaking into the measurement light transmission path of adjacent channels can cause measurement errors. 【0100】 In this multidimensional vibration measurement system 100A, the connector section 8, which consists of the n cable connectors, functions as a measurement optical transmission path selection means that allows the connection relationship between the optical dispersion and multiplexing optical system 3 and the plurality of single-point irradiation heads 41, 42, ... connected via the n-channel measurement optical transmission path 34 to be changed by selective channel exchange. 341 FB 342 ,···,FB 34n The connection relationship between the optical dispersive and multiplexing optical system 3, which is connected via an n-channel measurement optical transmission path 34, and the plurality of single-point illumination heads 41, 42, ... is changed by selective channel blocking, thereby altering the connection relationship between the n optical fiber cables FB. 341 FB 342 ,···,FB 34n The even-numbered channels of the n-channel measurement optical transmission path 34 are blocked, and the three FBs connected via the connector section 8 to the odd-numbered input / output ports P1, P3, and P5 of the optical splitter / multiplexer element 3A of the optical splitter / multiplexer optical system 3 are blocked. 341 FB 343 FB 345 The irradiation head unit 14A, consisting of three single-point irradiation heads 41, 43, and 45 from which the above was derived, decompresses the frequency component of the mode order 1 of the optical comb, measuring the optical light L S1 , optical comb mode order 3 frequency component decompression measurement optical L S3 ..., optical comb mode order 5 frequency component decompression measurement optical L S5 The light is directed onto the measurement point S1 on the measurement surface 5. 【0101】 In other words, in this multidimensional vibration measurement system 100A, the connector section 8, which consists of the n cable connectors that function as the measurement optical transmission path selection means, in the irradiation head unit 14A shown in Figure 4(A), the single-point irradiation head 41 emits a single-frequency decompressed measurement light L that is irradiated perpendicular to the measurement point S1 on the measurement surface 5, i.e., from the Z-axis direction. Z As a mode order 1, the demultiplexed measurement light L S1The single-point irradiation head 42 is assigned a single-frequency decompressed measurement light L that irradiates the measurement point S1 on the measurement surface 5 from the direction of the inclination angle θx with respect to the single-point irradiation head 41 in the XZ plane. X As a mode order 3, the decompressed measurement light L S3 The single-point irradiation head 43 is assigned a single-frequency decompressed measurement light L that irradiates the measurement point S1 on the measurement surface 5 from the direction of the inclination angle θy with respect to the single-point irradiation head 41 in the YZ plane. Y As a mode order 5, the decompressed measurement light L S5 It will be assigned. 【0102】 In this way, the decompressed measurement light L of the three frequency components is irradiated onto the measurement point S1 on the measurement surface 5. X ,L Y ,L Z The demultiplexing measurement light L is assigned as S1 ,L S3 ,L S5 This avoids the problem where the mode orders of the optical combs are far apart, resulting in low coherence, and crosstalk between adjacent frequency components caused by scattered light components leaking into the measurement optical transmission path of adjacent channels, which can lead to measurement errors. 【0103】 Furthermore, in this multidimensional vibration measurement system 100A, the connector section 8, which consists of the n cable connectors and functions as a measurement optical transmission path selection means, selectively blocks the connection relationship between the optical splitter / multiplexer optical system 3 and the plurality of single-point irradiation heads 41, 42, ... connected via the n-channel measurement optical transmission paths 34, thereby selectively blocking channels, and connecting two FBs via the connector section 8 to the odd-numbered input / output ports P7, P9 of the optical splitter / multiplexer element 3A of the optical splitter / multiplexer optical system 3. 345 FB 349 The irradiation head unit 14B, consisting of two single-point irradiation heads 47 and 49 from which the above was derived, provides a demultiplexed measurement light L of the optical comb with mode order 7. S7 , Mode order 9 demultiplexed measurement light L S9 The light is directed onto the measurement point S2 on the measurement surface 5. 【0104】 In other words, in this multidimensional vibration measurement system 100A, the irradiation head unit 14B shown in Figure 4(B) emits a single-frequency decompressed measurement light L from the single-point irradiation head 47 to the measurement point S2 on the measurement surface 5. X As a mode order 1, the demultiplexed measurement light L S5 The single-point irradiation head 49 is assigned a single-frequency decompressed measurement light L that irradiates the measurement point S2 on the measurement surface 5. Y As a mode order 6, the demultiplexed measurement light L S9 It will be assigned. 【0105】 Therefore, the two-frequency decompressed measurement light L irradiated onto the measurement point S2 on the measurement surface 5 is X ,L Y The demultiplexing measurement light L is assigned as S7 ,L S9 This avoids the problem where the mode orders of the optical combs are far apart, resulting in low coherence, and crosstalk between adjacent frequency components caused by scattered light components leaking into the measurement optical transmission path of adjacent channels, which can lead to measurement errors. 【0106】 Thus, in this multi-point vibration measurement system 100A, the connector section 8 provided in the measurement optical transmission path 34 of the n channels CH1, CH2, ..., CHn functions as a measurement optical transmission path selection means that thins out the channels between them by channel blocking in the measurement optical transmission path 34. This makes it possible to irradiate adjacent measurement points with demultiplexed measurement light of frequency components that are at least 1 mode order apart from the optical comb. When measuring vibration information of an object to be measured simultaneously at multiple points, if the Doppler shift is large, crosstalk between adjacent comb modes when the interference signal is heterodyne detected, i.e., electrical crosstalk, causes the shifted portions between adjacent frequencies to overlap in the domain of the electrical signal, and this electrical crosstalk between adjacent frequencies becomes a cause of measurement error. This solves the problem that electrical crosstalk between adjacent frequencies causes measurement errors, and enables high-precision (high S / N) multi-point simultaneous measurement by Doppler shift detection. 【0107】 Here, the irradiation head units 14A and 14B are configured such that at least two single-point irradiation heads are arranged and fixed at an inclination angle to each other so that the optical axes of multiple decompressed measurement beams intersect at one measurement point S1, and the decompressed measurement beams of at least two frequency components assigned to one measurement point S1 by the measurement light transmission path selection means are irradiated to the one measurement point S1 from different directions. However, in the multi-point vibration measurement system 100A, the irradiation head unit may be configured such that at least two single-point irradiation heads are arranged and fixed so that the decompressed measurement beams are output with their optical axes parallel, and the decompressed measurement beams of at least two frequency components output from the at least two single-point irradiation heads assigned by the measurement light transmission path selection means are focused by a focusing optical system and irradiated to one measurement point from different directions. 【0108】 Next, Figures 5(A) and (B) illustrate the Doppler effect in the electrical signal domain of the decomposed measurement light due to vibrations at multiple measurement points when multi-point vibration measurement is performed in the multi-point vibration measurement system 100A by irradiating multiple measurement points on the measurement surface 5 with decomposed measurement light for each decomposed frequency component obtained by decomposing the measurement light into frequency components for each mode order of the optical comb. (A) shows the Doppler effect when the crosstalk between adjacent comb modes is large when the interference signal is heterodyne detected, the shift portion between adjacent frequencies overlaps in the electrical signal domain, and the electrical crosstalk between adjacent frequencies causes measurement errors. (B) shows the Doppler effect when Doppler shift detection can be performed without electrical crosstalk between adjacent frequencies being a problem due to decimation measurement. 【0109】 In this multi-point vibration measurement system 100A, the decompressed frequency components output to the measurement optical transmission path of all channels CH1, CH2, CH3, ... are measured using decompressed optical light L S1 ,L S2 ,L S3 ,···L Sn When multi-point vibration measurement is performed using this method, the decompressed frequency components L are decompressed and reflected at measurement points S1, S2, S3, ... on the measurement surface 5 of the object being measured, and subjected to a Doppler shift. S1 ',L S2 ',LS3 ',···L Sn ' consists of the measured reflected light L S In the optical multiplexing element 3A of the optical multiplexing optical system 3, the demultiplexed frequency components input via the input / output ports P1, P2, ..., Pn are measured as demultiplexed reflected light L S1 ',L S2 ',L S3 ',···L Sn Since an optical multiplexing filter is applied to each input / output port of the optical multiplexing element 3A, as shown in Figure 5(A), when the Doppler shift is large, the crosstalk between adjacent comb modes when the interference signal is heterodyne detected, that is, the electrical crosstalk that falls within the bandwidth of the electrical filter characteristics F1, F2, ... shown by the dotted lines, causes the shifted portion between adjacent frequencies to overlap in the domain of the electrical signal, and this electrical crosstalk between adjacent frequencies becomes the cause of measurement errors. However, since the connector 8 functions as a measurement optical transmission path selection means that thins out the channels between the measurement optical transmission path 34 by channel blocking, as shown in Figure 5(B), even when the Doppler shift is large, When an interference signal is heterodyne detected, crosstalk between adjacent comb modes, i.e., electrical crosstalk, does not cause measurement errors because the shift portions between adjacent frequencies do not overlap in the domain of the electrical signal. By avoiding this electrical crosstalk between adjacent frequencies becoming a cause of measurement errors, the irradiation head units 14A and 14C can acquire three-dimensional vibration information at measurement point S1 on the measurement surface 5, and the irradiation head unit 14B can acquire two-dimensional vibration information at measurement point S2 on the measurement surface 5. Doppler shift detection enables multi-point multi-dimensional vibration measurement, where multi-dimensional vibration information at two measurement points S1 and S2 is measured simultaneously with high accuracy (high S / N). 【0110】 In other words, the decompressed measurement light L for each frequency component output to the measurement optical transmission path of all channels CH1, CH2, CH3, ... S1 ,L S2 ,L S3 ,···L Sn When multi-point vibration measurement is performed using this method, as shown in Figure 5(A), the delimited reflected light L S1Regarding the electrical filter characteristics F1 for vibration measurement using Doppler shift detection, the bandwidth and delimited reflected light L S2 For vibration measurement by Doppler shift detection, the Doppler-shifted decompressed reflected light L is within the bandwidth of the electrical filter characteristic F2. S1 ',L S2 Each electrical signal exists at a signal level equal to or greater than the judgment level TH, and the delimited measurement reflected light L S3 Regarding the electrical filter characteristics F3 for vibration measurement using Doppler shift detection, the bandwidth and delimited reflected light L S4 For vibration measurement by Doppler shift detection, the Doppler-shifted decompressed reflected light L is within the bandwidth of the electrical filter characteristic F4. S3 ' ,L S4 The two electrical signals ' exist at a signal level above the judgment level TH, and the delimited measurement reflected light L S6 Regarding ', the Doppler-shifted decompressed reflected light L is within the bandwidth of the electrical filter characteristic F6 for vibration measurement by Doppler shift detection. S5 ' ,L S6 ' ,L S7 The three electrical signals ' exist at a signal level above the judgment level TH, and furthermore, the delimited measurement reflected light L S7 Regarding the Doppler shift detection used for vibration measurement, the demultiplexed reflected light L, which has been Doppler shifted, falls within the bandwidth of the electrical filter characteristic F7. S6 ' ,L S7 The two electrical signals exist at signal levels above the judgment level TH, and electrical crosstalk between adjacent frequencies causes measurement errors. 【0111】 In this multi-point vibration measurement system 100A, the connector section 8 provided in the measurement optical transmission path 34 of the n channels CH1, CH2, ..., CHn functions as a measurement optical transmission path selection means that thins out the channels between them by channel blocking in the measurement optical transmission path 34, thereby decompressing the measurement light L for each mode order of the optical comb. S1 ,L S2 ,L S3 ,···L SnDecompression measurement optical L of an even-numbered mode order from an optical comb S2 ,L S4 ,L S6 ,···L Sn Demultiplying measurement light L of odd mode order from which the decimated portion is obtained. S1 ,L S3 ,L S5 ...that is, multi-point vibration measurement is performed using demultiplexed measurement light of frequency components separated by a mode order of 1 of the optical comb, so as shown in Figure 5(B), the demultiplexed measurement reflected light L S1 Regarding ', within the bandwidth of the electrical filter characteristic F1 for vibration measurement by Doppler shift detection, the demultiplexed reflected light L, which has been subjected to a Doppler shift due to vibration at the measurement point S1, is included. S1 Only the electrical signal of ' exists at a signal level of TH or higher, and the delimited measurement reflected light L S3 Regarding ', within the bandwidth of the electrical filter characteristic F3 for vibration measurement by Doppler shift detection, the demultiplexed reflected light L, which has been subjected to a Doppler shift due to vibration at the measurement point S3, is S3 Only the electrical signal of ' exists at a signal level of TH or higher, and similarly, the odd-numbered order demultiplexed reflected light L S5 ',L S7 Regarding ',..., the electrical filter characteristics F5, F7,... for vibration measurement by Doppler shift detection, within each band, the deselected reflected light L that has been affected by the Doppler shift due to vibration at measurement points S5, S7,... S5 ',L S7 Only the electrical signals of ',··· exist at a signal level above the judgment level TH, and even when the Doppler shift is large, the shift portion between adjacent frequencies does not overlap in the domain of the electrical signal due to crosstalk between adjacent comb modes when the interference signal is heterodyne detected, i.e., electrical crosstalk. This avoids the electrical crosstalk between adjacent frequencies becoming a cause of measurement errors, and by detecting the Doppler shift, it is possible to perform multi-point multi-dimensional vibration measurement, simultaneously measuring multi-dimensional vibration information at multiple measurement points S1, S2,··· on the measurement surface 5 with high accuracy (high S / N). 【0112】 Here, the connector section 8, which functions as the measurement optical transmission path selection means, consists of the n optical fiber cables FB that constitute the n-channel measurement optical transmission path 34 CH1, CH2, ..., CHn. 31 FB 32 FB 33 ,···,FB 3n It is sufficient that a detachable mechanism is provided at least one end of each of the n optical fiber cables FB, and the detachable mechanism provided at at least one end of each of the n optical fiber cables FB 31 FB 32 FB 33 ,···,FB 3n The connection is switched to connect the above-mentioned optical splitter / multiplexer optical system 3 and the above-mentioned multiple single-point irradiation heads 41, 42, ..., 4 via the above-mentioned n-channel optical transmission path 34 of CH1, CH2, ..., CHn. n The connection relationship can be freely changed by selective channel blocking. 【0113】 Next, Figure 6 is a schematic diagram showing another example of a multidimensional vibration measurement system to which the present invention is applied. 【0114】 The multi-point vibration measurement system 100B shown in the schematic diagram of Figure 6 utilizes the optical demultiplexing element 3A, which is provided in the optical demultiplexing optical system 3 of the multi-point vibration measurement system 100A shown in the schematic diagram of Figure 3, to perform the functions of an optical demultiplexing element and an optical multiplexing element separately, thereby outputting measurement light L from the light source 1 via the interference optical system 2. S Decompressed optical comb for each mode order Decompressed optical L S1 ,L S2 ,···L Sn An optical path that illuminates multiple measurement points S1, S2, ... on the measurement surface 5 of the object, and the demultiplexed reflected light L of the optical comb that is reflected back by the multiple measurement points S1, S2, ... on the measurement surface 5 for each mode order. S1 ',L S2 ',···L Sn By separating the optical path that combines the ' and inputs it into the interference optical system 2, the measurement light L irradiates the measurement surface 5 of the object. SThe system is designed so that unwanted reflection components generated in various optical elements provided in the optical system that propagates vibrations do not mix with the interference light necessary for multi-point vibration measurement. Components identical to those in the multi-point vibration measurement system 100A are given the same reference numerals, and their detailed descriptions are omitted. 【0115】 In other words, this multi-point vibration measurement system 100B uses measurement light L output from light source 1. S The above measurement light L is input via the interference optical system 120. S The frequency components contained in the optical comb are decomposed according to the mode order, and one frequency component is decomposed and measured for each point irradiation head. S1 ,L S2 ,······L Sn The optical demultiplexer 130A outputs as such, and the demultiplexer measurement light L of one frequency component for each of the above single-point irradiation heads S1 ,L S2 ,······L Sn The light is irradiated onto multiple measurement points S1, S2, ... on the measurement surface 5, and the reflected light L, which has one frequency component, is reflected back from each single-point irradiation head. S1 ',L S2 ',···L Sn ' is input, and for each of the above single-point irradiation heads, one frequency component is decompressed and reflected light L S1 ',L S2 ',··· L Sn ' is combined and the reflected light L is measured. S The optical optical system 130 comprises an optical multiplexing element 130B that is input to the above interference optical system 120. 【0116】 The optical demultiplexing and multiplexing optical system 130 is provided with a connector section 131 consisting of multiple cable connectors, each with two channels, connected to the output channel of the optical demultiplexing element 130A and the input channel of the optical multiplexing element 130B. 【0117】 Furthermore, this multi-point vibration measurement system 100B has n / 4 irradiation head units 1401,...,140 n / 4 Equipped with the above irradiation head unit 1401,...,140n / 4 Multiple single-point illumination heads 401, 402, ... which incorporate multiple coupled optical elements, are connected to multiple detachable cable connectors in the connector section 131 via multiple paired optical transmission paths 1341, 1342, ... thereby connecting to the output channel of the optical demultiplexer 130A and the input channel of the optical multiplexer 130B of the optical demultiplexer optical system 130. 【0118】 In this multidimensional vibration measurement system 100B, the irradiation head units 1401, ..., 140 n / 4 Each unit has four pairs of optical transmission paths, and consists of a single-point illumination head with three built-in coupled optical elements and an optical path length variation compensation optical system. 【0119】 In other words, the irradiation head unit 1401 has four paired optical transmission paths 1341, 1342, 1343, and 1344 derived from it, and consists of three single-point irradiation heads 401, 402, and 403 with built-in coupled optical elements and an optical path length variation compensating optical system 501. 【0120】 Also, the irradiation head unit 140 n / 4 This consists of four pairs of optical transmission lines 134 n-3 ,134 n-2 ,134 n-1 ,134 n This has been derived, and three single-point irradiation heads 40 n-3 ,40 n-2 ,40 n-1 and optical path length variation compensating optical system 50 n / 4 It consists of. 【0121】 Other irradiation head units, not shown in the illustration, have a similar configuration. 【0122】 In the above multidimensional vibration measurement system 100B, the above irradiation head unit irradiation head unit 1401, ... 140 n / 4 For example, the single-point irradiation heads 401, 402, ... which incorporate a coupled optical element and constitute the system, use a single-point irradiation head 40 with a coupled optical element built into a configuration as shown in Figures 7(A) and (B). 【0123】 Figures 7(A) and (B) show examples of the configuration of the single-point irradiation head 40A with a built-in coupled optical element used in the single-point irradiation heads 401, 402, 403, etc., which constitute the above-mentioned irradiation head units 1401, 1402, etc. (A) is a schematic diagram showing the configuration of the single-point irradiation head 40A with a built-in coupled optical element, and (B) is a front view of the two-core capillary 4C1 provided in the single-point irradiation head 40A with a built-in coupled optical element. 【0124】 This single-point illumination head 40A with a built-in coupling optical element consists of a two-core capillary 4C1 and a coupling optical element 4C2 that has optical properties to align the axes of the optical beams whose polarization directions are orthogonal, output from the tips of the two-core optical fibers inserted into the two-core capillary 4C1. A It is equipped with the above 2-core capillary 4C1 and the input side optical fiber cable FB 34 and the output side optical fiber cable FB 43 This is derived externally. 【0125】 The above-mentioned coupled optical unit 4C A The stress application section of the polarization-maintaining fiber inserted into the 2-core capillary 4C1 provided is arranged orthogonally, as shown in Figure 7(B). In this text, the optical module elements connected to all optical fibers are manufactured to a unified standard so that the direction of the stress application section becomes the plane of polarization. 【0126】 The input optical fiber cable FB is led out from the above 2-core capillary 4C1. 34 This is connected to the optical demultiplexing element 130A of the optical demultiplexing optical system 130, and is also connected to the output optical fiber cable FB that is led out from the 2-core capillary 4C1. 43 It is connected to the optical multiplexing element 130B of the optical multiplexing optical system 130, and the two optical fiber cables FB mentioned above. 34 FB 43 This constitutes a pair of optical transmission paths 134. 【0127】 Furthermore, in this single-point irradiation head 40A with a built-in coupling optical element, the optical fiber cable FB on the input side is connected from the optical demultiplexer 130A. 34 The above measurement light L is input via S The frequency component l S The above-mentioned coupled optical element 4C2 is input to the focusing optical system 4A. The frequency component l is focused by this focusing optical system 4A. S The light is irradiated onto the measurement surface 5 of the object to be measured via the quarter-wave plate 4B. The reflected light reflected from the measurement surface 5 passes through the quarter-wave plate 4B and contains the above frequency components l S This refers to the frequency components l of the polarization plane where the polarization directions are orthogonal. S It is returned to the above-mentioned focusing optical system 4A as '. 【0128】 The above frequency component l S This refers to the frequency components l of the polarization plane where the polarization directions are orthogonal. S ' is focused by the above-mentioned focusing optical system 4A and then combined with the above-mentioned coupling optical system 4C A The output side optical fiber cable FB is connected via the coupling optical element 4C2. 43 The input is to this output side of the optical fiber cable FB. 43 The signal is input to the optical multiplexing element 130B of the optical multiplexing optical system 130 via the above-mentioned signal. 【0129】 For example, a birefringent crystal can be used in the above-mentioned coupled optical element 4C2 to separate light rays using walk-off. 【0130】 Furthermore, the above-mentioned single-point irradiation heads 401, 402... which incorporate the coupled optical element, are equipped with a Wollaston prism 4C2, as shown in Figures 8(A) and (B), instead of the above-mentioned coupled optical element 4C2 using a birefringent crystal. b A single-point illumination head 40B with a built-in coupled optical element, which uses a coupled optical element 4C2' composed of the above, can also be used. 【0131】 Figures 8(A) and (B) show examples of the configuration of a single-point illumination head 40B with a built-in coupled optical element used in the above-mentioned single-point illumination heads 401, 402, ..., where (A) is a schematic diagram showing the configuration of the single-point illumination head 40B with a built-in coupled optical element, and (B) is a front view of the two-core capillary 4C1 provided in the single-point illumination head 40B with a built-in coupled optical element. 【0132】 This single-point illumination head 40B with a built-in coupling optical element consists of a two-core capillary 4C1 and a coupling optical element 4C2' which has optical properties that align the axes of the optical beams whose polarization directions are orthogonal, output from the tips of the two-core optical fibers inserted into the two-core capillary 4C1. B It is equipped with the above 2-core capillary 4C1 and the input side optical fiber cable FB 34 and the output side optical fiber cable FB 43 A pair of optical transmission lines 134 consisting of these elements is led out to the outside. 【0133】 The above-mentioned coupled optical unit 4C B The polarization-maintaining fibers inserted into the stress-applying section of the 2-core capillary 4C1 provided are arranged orthogonally, as shown in Figure 8(B). 【0134】 The above-mentioned coupled optical element 4C2' consists of two collimator lenses 4C a ,4C c Between Wollaston Prism 4C b It is made by arranging these elements. 【0135】 In this single-point illumination head 40B with a built-in coupling optical element, the optical fiber cable FB on the input side is also connected from the optical demultiplexer 130A. 34 The above measurement light L is input via S The frequency components of the optical comb S The above-mentioned coupled optical element 4C2' is input to the focusing optical system 4A, and the frequency component l is focused by this focusing optical system 4A. S The light is irradiated onto the measurement surface 5 of the object to be measured via the quarter-wave plate 4B. The reflected light reflected from the measurement surface 5 passes through the quarter-wave plate 4B and contains the above frequency components lS This refers to the frequency components l of the polarization plane where the polarization directions are orthogonal. S It is returned to the above-mentioned focusing optical system 4A as '. 【0136】 The above frequency component l S This refers to the frequency components l of the polarization plane where the polarization directions are orthogonal. S The light is focused by the focusing optical system 4A and transmitted via the coupling optical element 4C2 to the output side optical fiber cable FB. 43 The input is to this output side of the optical fiber cable FB. 43 The signal is input to the optical multiplexing element 130B of the optical multiplexing optical system 130 via the above-mentioned signal. 【0137】 In the above-mentioned single-point irradiation heads 40A and 40B with built-in coupling optical elements, as shown in Figure 7(B) and Figure 8(B), the polarization plane of the optical input from the fiber end faces Port1 and Port2 of the two-core capillary 4C1, which are arranged so that the stress application portion is orthogonal, to the coupling optical elements 4C2 and 4C2', is such that the optical axis becomes coaxial and is output in the same direction as the optical input in the direction of the stress application portion passes through the coupling optical elements 4C2 and 4C2'. S The frequency component l S The polarization plane is in the same direction as the stress application part of Port1 (input side optical fiber cable FB) 34 The input is taken from the above measurement surface 5, and the frequency component l reflected from it is obtained. S 'The polarization plane is in the same direction as the stress application part of Port2 (output side optical fiber cable FB) 43 It can receive light with ). 【0138】 Furthermore, in this multi-point vibration measurement system 100B, the above-mentioned irradiation head units 1401,...,140 n / 4 Optical path length variation compensation optical system 501,...,50 n / 4 For example, a path length variation compensating optical system 50 with a configuration such as those shown in Figures 9(A) and (B) is used. 【0139】 Figures 9(A) and (B) show examples of the configuration of the optical path length variation compensating optical system 50. (A) is a schematic diagram showing the configuration of the optical path length variation compensating optical system 50, and (B) is a front view of the 2-core capillary 4C1 provided in the optical path length variation compensating optical system 50. 【0140】 This optical path length variation compensation optical system 50 consists of a two-core capillary 4C1 and a coupling optical element 4C3 which has optical properties that align the axes of optical beams with orthogonal polarization directions output from the tips of two optical fibers inserted into the two-core capillary 4C1. C It is equipped with the above 2-core capillary 4C1 and the input side optical fiber cable FB 34R and the output side optical fiber cable FB 43R An optical path 34R for compensating for optical path length fluctuations, which is a pair of optical transmission paths consisting of these elements, is led out to the outside. 【0141】 The above-mentioned coupled optical unit 4C C The polarization-maintaining fibers inserted into the stress-applying section of the 2-core capillary 4C1 provided are arranged orthogonally, as shown in Figure 9(B). 【0142】 The coupling optical unit 4C is provided in the optical path length variation compensation optical system 50 described above. C The coupled optical unit 4C includes a coupled optical element 4C2 made of a birefringent crystal in the single-point irradiation head 40A with a built-in coupled optical element shown in Figures 7(A) and (B). A Also, the Wollaston prism 4C in the single-point illumination head 40B with a built-in coupled optical element shown in Figures 8(A) and (B). b Coupled optical unit 4C equipped with a coupled optical element 4C2' using B This is used. 【0143】 In other words, the optical path length variation compensation optical system 50 shown in Figures 9(A) and (B) is connected to the input optical fiber cable FB that constitutes the optical path length variation compensation optical path 34R from the optical demultiplexing element 130A of the optical demultiplexing optical system 130. 34R Decompression measurement reference light L SR The coupled optics unit 4C receives the input. C This combined optical unit 4C is equipped withC Decompression reference light L input via SR The light-gathering optical system 11 A The light is further focused into a quarter-wave plate 11 B via reflector 11 C It is designed to be illuminated. And the reflector 11 C Decompression measurement reference light L irradiated onto SR The above reflector 11 C The above quarter-wave plate 11 is reflected by the reflection. B The above-mentioned light-gathering optical system 11 A It is returned to the above decompression measurement reference light L SR This refers to the reflected light L, a demultiplexed measurement reference light whose polarization plane is orthogonal. SR ' is the above-mentioned light-gathering optical system 11 A The light is focused by the above-mentioned coupled optical unit 4C C The output optical fiber cable FB constitutes the optical path 43R for compensating for optical path length fluctuations. 43R The signal is input to the optical multiplexing element 130B of the optical multiplexing optical system 130 via the above-mentioned signal. 【0144】 Here, Figures 10(A), (B), and (C) show the irradiation head units 1401, ..., 140 in the multidimensional vibration measurement system 100B described above. n / 4 This is a schematic diagram showing various configuration examples of a single-point illumination head unit incorporating an optical path length variation compensation optical system. 【0145】 That is, irradiation head units 1401, ... 140 using the above-mentioned single-point irradiation head 40A with a built-in coupling optical element or the single-point irradiation head 40B with a built-in coupling optical element n / 4 In the multi-point vibration measurement system 100B, the single-point irradiation head nit, which incorporates a coupling optical element and an optical path length variation compensation optical system, provided in the above-mentioned irradiation head unit, can employ, for example, single-point irradiation head nits 144A, 144B, and 144C with various configuration examples as shown in the schematic diagrams (A), (B), and (C) of Figure 10. 【0146】 The single-point irradiation head 144A shown in the schematic diagram of Figure 10(A) incorporates the optical path length variation compensation optical system 111 along with the single-point irradiation head 44 with a built-in coupled optical element, which employs the single-point irradiation head 40A with a built-in coupled optical element shown in Figures 7(A) and (B), and the single-point irradiation head 40B with a built-in coupled optical element shown in Figures 8(A) and (B). The single-point irradiation head 44 with a built-in coupled optical element consists of a coupled optical unit 4C, a focusing optical system 4A, and a quarter-wave plate 4B, and the optical path length variation compensation optical system 111. 【0147】 The above optical path length variation compensation optical system 111 consists of a coupling optical unit 4C and a focusing optical system 11 A , 1 / 4 wavelength plate 11 B , reflector 11 C The coupled optical unit 4C comprises a coupled optical element 4C2 using a birefringent crystal in the single-point irradiation head 40A with a built-in coupled optical element shown in Figures 7(A) and (B). A Also, the Wollaston prism 4C in the single-point illumination head 40B with a built-in coupled optical element shown in Figures 8(A) and (B). b Coupled optical unit 4C equipped with a coupled optical element 4C2' using B The above quarter-wave plate 11 is used. B This may be a Faraday rotator, and also a focusing optical system 11 A If the output is collimated light, the reflector 11 C A retroreflector may be used for this purpose. 【0148】 Here, the above irradiation head units 1401,...,140 n / 4 The combined optical elements are built into single-point illumination heads 401, 402, ... and optical path length variation compensation optical systems 501, ..., 50 n / 4 Each coupled optical unit provided in the above irradiation head unit 1401, ..., 140 n / 4 Although it can also be an external coupling optical system, in this multi-point vibration measurement system 100B, the above-mentioned coupling optical element-integrated single-point illumination head 401, 402, ... and the optical path length variation compensation optical system 501, ... 50 n / 4By adopting a configuration that incorporates the function of a combined optical system, the configuration is simplified, and the above irradiation head units 1401,...,140 n / 4 This avoids the generation of unwanted reflected light from each end face of the optical fiber cables that constitute the pair of optical transmission paths 1341, 1342, ... connecting the optical demultiplexing element 130A and the optical multiplexing element 130B of the optical demultiplexing and multiplexing optical system 130. 【0149】 In other words, using elements such as PBC modules as external coupling optics complicates the optical system and presents problems such as reflections within the PBC module and extinction ratio of PM fibers. Furthermore, using PBC modules increases the number of components. Reflections from multiple lenses and fiber end faces within the PBC module also pose problems, but in this multi-point vibration measurement system 100B, the above-mentioned coupling optical element-integrated single-point illumination heads 401, 402, ... which have the function of a coupling optics system, and the optical path length variation compensation optics 501, ..., 50 n / 4 By incorporating this feature, it becomes unnecessary to use the aforementioned PBC module or other components separately, and a configuration with greater directional coupling loss from Port1 to Port2 can be achieved, thus resolving these problems. 【0150】 Furthermore, in the above-mentioned optical splitter / multiplexer optical system 130, the measurement light L is measured by the above-mentioned optical splitter / multiplexer element 130A. S Decompression measurement light L, decompressed for each frequency component of the optical comb S1 ,L S2 ,···,L Sn However, the demultiplexed measurement reflected light L is irradiated from three directions to each measurement point on the measurement surface 5 of the object to be measured via the above-mentioned single-point irradiation heads 401, 402, ... which have the above-mentioned coupling optical elements built into them, and is reflected back by the multiple measurement points S1, S2, ... on the measurement surface 5 of the object to be measured. S1 ',L S2 ',···L Sn 'Then, the measurement light L is measured by the above-mentioned optical splitter / multiplexer element 130A. S The frequency components of the optical comb are separated and assigned to the decompression measurement reference optical L SR4 ,L SR8,··· is the optical path 43R1,···,43R for compensating for optical path length fluctuations n / Through the optical path length variation compensation optical system 501, ... 50 n / 4 The delimited measurement reference reflected light L is reflected back after being reflected. SR4 ',L SR8 The light ',··· is input to the optical splitter / multiplexer element 130B, and the split-measurement reflected light L reflected at the measurement points S1, S2,··· on the measurement surface 5 is input to the optical splitter / multiplexer element 130B. S1 ',L S2 ',···L Sn Along with the above delimited measurement reference reflected light L SR4 ',L SR8 The ',··· are combined, and the demultiplexed measured reflected light L is reflected at the measurement points S1, S2,··· on the above measurement surface 5. S1 ',L S2 ',···L Sn 'and the above delimited measurement reference reflected light L SR4 ',L SR8 ',··· consisting of measured reflected light L S The above-mentioned optical multiplexer 130B inputs the interference optical system 120. 【0151】 In the above interference optical system 120, the measured reflected light L, which is combined by the optical multiplexing element 130B in the above optical splitting and multiplexing optical system 130, S 'and the reference light L input from the second optical comb generator (COMB2) 1B of the above light source 1 R The interference light with the light source is output as the interference light for measurement. In addition, the interference optical system 120 receives the measurement light L input from the first optical comb generator (COMB1) 1A of the light source 1. S And the reference light L input from the second optical comb generator (COMB2) 1B of the above light source 1 R The interference light from this source is output as reference interference light. 【0152】 In the interference light detection unit 6, which receives the measurement interference light and reference interference light obtained by the above-mentioned interference optical system 120, the measurement interference light detector 6A, which receives the measurement interference light, detects the measurement interference light and converts it into an electrical signal to obtain the measurement interference signal S. SThe reference interference signal S is output and, in addition, the reference interference light is detected by the interference light detector 6B which receives the reference interference light and converted into an electrical signal. R Outputs. 【0153】 Then, the signal processing unit 7 processes the measurement interference signal S obtained by the interference light detection unit 6. S and reference interference signal S R Regarding this, the phase of each frequency component of the optical comb is calculated using DFT analysis, and the above measurement interference signal S is obtained. S and reference interference signal S R Between the above measuring surface 5, n measuring points S1, S2, ..., S n By determining the phase difference for each frequency component of the optical comb caused by the Doppler shift due to vibration, the n measurement points S1, S2, ..., S on the measurement surface 5 are determined. n The vibration information, such as vibration velocity, distance traveled, and acceleration, is analyzed to measure the vibration distribution on the measurement surface 5. 【0154】 This multidimensional vibration measurement system 100B is equipped with an irradiation head unit 1401 consisting of the three integrated single-point irradiation heads 401, 402, and 403, thereby providing a single-frequency demultiplexed measurement light L from three different directions to the measurement point S1 on the measurement surface 5. S1 ,L S3 ,L S7 By irradiating the object to be measured, the demultiplexed measurement light L caused by the Doppler shift due to vibration at the measurement point S1 on the measurement surface 5 of the object to be measured is obtained. S1 ,L S3 ,L S7 Vibration measurement can be performed by Doppler shift detection to detect phase fluctuations, and in a signal processing unit 67 equipped with an interference light detection unit 6 and a signal processing unit 7, the measurement interference signal S obtained by the interference light detection unit 6 is used. S and reference interference signal S R Based on this, by analyzing the three-dimensional vibration information at the measurement point S1 on the measurement surface 5, the decompressed measurement light L of each single-frequency component irradiated from three different directions onto the measurement point S1 on the measurement surface 5 is obtained. S1 ,L S3 ,L S7Each incident angle and the above-mentioned demultiplexed measurement light L S1 ,L S3 ,L S7 By measuring vibrations using Doppler shift detection, each vibration quantity at the measurement point S1 obtained can be simultaneously measured individually and decomposed into a three-dimensional measurement coordinate system (or target coordinate system). Similarly, with other irradiation head units 1402,..., each vibration quantity at the measurement point S2,... on the measurement surface 5 can be simultaneously measured individually and decomposed into a three-dimensional measurement coordinate system (or target coordinate system) from the incident angles of decomposed measurement light of one frequency component, each irradiated from three different directions for each measurement point, and the vibration quantity at the measurement point S2,... obtained by measuring vibrations using Doppler shift detection with the decomposed measurement light. By using the information processing device 150, for example, by performing vibration analysis using SOLIDWORKS simulation, computer-aided design software developed by Dassault Systèmes, the vibration conditions on the measurement surface 5 can be accurately confirmed. 【0155】 In other words, in this multi-point vibration measurement system 100B, the three single-point irradiation heads of the irradiation head units 1401, 1402, ... irradiate each measurement point S1, S2, ... on the measurement surface 5 with demultiplexed measurement light of one frequency component from three different directions, and vibration measurement can be performed by detecting the phase variation for each demultiplexed measurement light caused by the Doppler shift due to vibration at the measurement points S1, S2, ... on the measurement surface 5 of the object to be measured. The signal processing unit 7 then processes the measurement interference signal S obtained by the interference light detection unit 6. S and reference interference signal S R Based on this, by analyzing the three-dimensional vibration information at measurement points S1, S2, ... on the measurement surface 5, it is possible to simultaneously measure each vibration quantity decomposed into a three-dimensional measurement coordinate system (or target coordinate system) from the incident angles of decomposed measurement light of one frequency component each, irradiated from three different directions to measurement points S1, S2, ... on the measurement surface 5, and the respective vibration quantities at measurement points S1, S2, ... obtained by vibration measurement by Doppler shift detection using the decomposed measurement light. 【0156】 Furthermore, the multi-point vibration measurement system 100B includes a connector section 131 that functions as a measurement optical transmission path selection means, which allows the connection relationship between the output channel of the optical demultiplexer 130A of the optical demultiplexer optical system 130, the input channel of the optical multiplexer 130B, and the single-point illumination heads 401, 402, etc., which are connected via the pair optical transmission paths 1341, 1342, ..., to be changed by selective channel switching. S1 ,L S2 ,······L Sn For each measurement point illuminated by the light, it is possible to assign decompressed measurement light for at least three frequency components other than the adjacent frequency components of the decompressed measurement light for each frequency component. This reduces the coherence of the decompressed measurement light for at least three frequency components at each measurement point used for multidimensional vibration measurement, and avoids the problem that crosstalk between adjacent frequency components, caused by scattered light components of the decompressed measurement light for the three frequency components leaking into the measurement light transmission path of adjacent channels, can cause measurement errors. 【0157】 Furthermore, in this multi-point vibration measurement system 100B, of the four paired optical transmission paths 1341, 1342, 1343, and 1344 derived from the irradiation head unit 1401, which consists of three single-point irradiation heads 405, 406, and 407 and an optical path length variation compensation optical system 501, the paired optical transmission path 1344 connected to the optical path length variation compensation optical system 501 is used as the optical path length variation compensation optical path 34R1, and the demultiplexed measurement reference optical light L for optical path length variation compensation SR4 As a demultiplexed measurement light L S4 Using this, the length of each compensating optical path, including the optical path 34R4 for compensating the optical path length variation, is measured, and based on the measurement results, the decompressed measurement light L for each of the three frequency components is irradiated from three directions to multiple measurement points S1 on the measurement surface 5 of the object to be measured via the three coupled optical element-integrated single-point irradiation heads 401, 402, and 403 of the irradiation head unit 1401. S1,L S2 ,L S3 Three optical fiber cables through which the light passes, and the reflected light L, which is reflected at multiple measurement points S1 on the measurement surface 5 and decompressed for each of the three frequency components, is transmitted via the three integrated single-point irradiation heads 401, 402, and 403 of the irradiation head unit 1401. S1 ',L S2 ', L S3 The signal processing unit 67 can correct for variations in the optical path length of each of the three pairs of optical transmission paths, which consist of three optical fiber cables through which the signal passes. Other irradiation head units 1401, 1402, ..., 140 n / 4 Similarly, for each of the four pairs of optical transmission paths derived from each, variations in the optical path length can be corrected on a per-illumination head unit basis. 【0158】 In other words, in this multi-point vibration measurement system 100B, the above irradiation head units 1401, ..., 140 n / 4 Since each optical path length variation compensation optical system 501, 502, ... is provided, each pair of optical transmission paths 1344, 1348, ... connected to the above optical path length variation compensation optical systems 501, 502, ... is designated as optical path length variation compensation optical paths 34R4, 34R8, ... and the measurement light L in the above optical splitter / multiplexer optical system 3 S The decompressed measurement light L is obtained by decompressing each of the n types of frequency components contained therein. S1 ,L S2 ,L S3 ,···L Sn Decompression measurement light L of each of the single frequency components S4 ,L S8 ...to demultiplexing measurement reference light L for optical path length variation compensation SR4 ,L SR8 Using the above optical path length variation compensation optical path 34R4, the compensation optical path lengths are measured, and based on the measurement results, a plurality of measurement points S1,...,S on the measurement surface 5 of the object to be measured are measured for each irradiation head unit. n / 4 For each measurement point, the above irradiation head unit 1401,...,140 n / 4Three optical fiber cables through which demultiplexed measurement light, each with three frequency components, is irradiated from three directions via the above measurement surface 5, and multiple measurement points S1,...,S n / 4 The above irradiation head units 1401,...,140 are reflected and n / 4 This allows for correction of variations in the optical path length of each of the three pairs of optical transmission paths, which consist of three optical fiber cables through which the demultiplexed measured reflected light for each of the three frequency components returning via the device passes. 【0159】 Therefore, in this multi-point vibration measurement system 100B, the irradiation head units 1401,...,140 n / 4 Each optical path length variation compensating optical system 501,...,50 n / 4 As a result of the provision of the above irradiation head units 1401, ..., 140 n / 4 This system can compensate for variations in the optical path length of multiple measurement optical transmission paths, each consisting of three pairs of optical transmission paths through which decompressed measurement light with three frequency components passes, and three pairs of optical transmission paths through which decompressed measurement reflected light passes. This eliminates the influence on measurement values ​​due to changes in optical path length caused by temperature and vibration in the multiple optical transmission paths, and enables high-precision multi-point vibration measurement without the risk of the stability of the optical paths (lengths) of the two optical waves, the reference light and the measurement light, affecting the measurement values. 【0160】 In this multi-point vibration measurement system 100B, the temperature of the various optical devices constituting the interference optical system 120 and the optical splitter / multiplexer optical system 130, which are located inside the housing 160, is controlled by a device temperature controller 162 powered by an external power supply unit 161, thereby maintaining a predetermined temperature state. This device temperature control function is not essential. 【0161】 Furthermore, in this multi-point vibration measurement system 100B, the measurement light L S The measurement light L output from the interference optical system 120, which is provided with the optical demultiplexing element 130A that demultiplexes multiple frequency components of the optical comb contained in the optical comb, S The optical path through which the light passes, and n / 4 measurement points S1,...,S on the measurement surface 5 of the object. n / 4The above-mentioned optical multiplexing element 130B is provided to combine the reflected light of the frequency components of the optical comb reflected by the optical comb, and the measured reflected light L S Since the optical path that inputs ' to the interference optical system 120 is separated, the measurement light L irradiated onto the measurement surface 5 via the interference optical system 120 is separated. S By eliminating measurement errors caused by unwanted reflective components from the optical demultiplexer 130A, which is installed in the optical path through which the light passes, mixing with the interference light necessary for multi-point vibration measurement, high-precision multi-point vibration measurement can be performed. 【0162】 Furthermore, in the above multidimensional vibration measurement system 100B, the above pair optical transmission paths 1341, 1342, ..., 134 n The output channel of the optical demultiplexer 130A and the input channel of the optical multiplexer 130B of the optical demultiplexer optical system 130 are connected via the above optical element-integrated single-point illumination heads 401, 402, 403, ..., 40 n Since it is equipped with a connector section 131 that functions as a means for selecting a measurement optical transmission path, allowing the connection relationship to be freely changed by selective channel exchange, the optical splitter / multiplexer optical system 130 is connected to the above-mentioned single-point irradiation heads 401, 402, ..., 40 n The connection relationship with the above multiple irradiation head units 1401, ..., 140 can be freely changed, n / 4 This allows for independent measurement configurations. 【0163】 Figure 11 shows the multiple irradiation head units 1401, ..., 140 in the multidimensional vibration measurement system 100B described above. n / 4 This is a perspective view showing an example of a measurement setup. 【0164】 In the example measurement setup shown in the perspective view of Figure 11, the multidimensional vibration measurement system 100B analyzes the vibration state of the vibrating body 150 placed on the surface plate 200, with the upper surface of the vibrating body 150 being the first measurement surface 150A, the bottom surface of the groove formed on the upper surface of the vibrating body 150 being the second measurement surface 150B, and the side surface of the vibrating body 150 being the third measurement surface 150C, and the reference point position on the surface plate 200 being the measurement point S1. Vibration measurements at the reference point position are performed by irradiation head unit 1401, vibration measurements at four measurement points S2, S3, S4, S5 on the first measurement surface 150A are performed by irradiation head units 1402, 1403, 1404, 1405, vibration measurements at two measurement points S6, S7 on the second measurement surface 150B are performed by irradiation head units 1406, 1407, and vibration measurements at three measurement points S8, S9, S on the third measurement surface 150C are performed. 10 Each vibration measurement in the irradiation head unit 1408, 1409, 140 10 To do so, 10 irradiation head units 1401, 1402, ..., 140 10 It is positioned there. 【0165】 Here, the above 10 irradiation head units 1401, 1402, ..., 140 10 The system employs an illumination head unit that includes a single optical path length variation compensation optical system 50 along with three single-point illumination heads 401, 402, and 403, which are arranged and fixed at mutually inclined angles to illuminate a single measurement with delimited measurement light of three frequency components from different directions. However, the illumination head unit 140A shown in the perspective view of Figure 12(A) or the illumination head unit 140B shown in the perspective view of Figure 12(B) can also be used. 【0166】 Figures 12(A) and (B) are perspective views showing other configuration examples of the irradiation head units 1401, 1402, ... in the multidimensional vibration measurement system 100B. (A) shows the irradiation head unit 140A, which consists of three single-point irradiation heads 401, 402, and 403 with built-in coupled optical elements. (B) shows the irradiation head unit 140B, which incorporates three single-point irradiation heads 401, 402, and 403 with built-in coupled optical elements and an optical path length variation compensating optical system 50. 【0167】 The irradiation head unit 140A in the perspective view shown in Figure 12(A) is configured such that the three single-point irradiation heads 401, 402, and 403, each containing a coupled optical element, have internal lenses arranged to output collimated light, and are fixed in place to output demultiplexed measurement light of three frequency components with parallel optical axes. The demultiplexed measurement light of the three frequency components output from the three single-point irradiation heads 401, 402, and 403 is focused by a focusing optical system 60 and irradiated onto a single measurement point from different directions. 【0168】 Furthermore, the irradiation head unit 140B in the example configuration shown in the perspective view of Figure 12(B) incorporates a single optical path length variation compensation optical system 50 along with three single-point irradiation heads 401, 402, and 403 with built-in coupled optical elements, which are arranged and fixed to output demultiplexed measurement light of three frequency components with their optical axes parallel. The demultiplexed measurement light of three frequency components output from the three single-point irradiation heads 401, 402, and 403 with built-in coupled optical elements is focused by a focusing optical system 60 and irradiated onto a single measurement point from different directions. 【0169】 Figures 13(A), (B), and (C) illustrate the illumination head unit 140 with a multi-point illumination arrangement that distributes light 120° in-plane in the multidimensional vibration measurement system 100B. (A) is a schematic diagram showing the demultiplexed measurement light irradiated onto one measurement point S1 on the measurement surface 5 by the illumination head unit 14C. (B) is a schematic diagram showing a longitudinal section of the illumination head unit 14C in which three single-point illumination heads 401, 403, and 405 with built-in coupled optical elements are evenly arranged at 120° in-plane. (C) is a schematic diagram showing the specular reflection components Va, Vb, Vc of the demultiplexed measurement light irradiated onto one measurement point S1 on the measurement surface 5 by the illumination head unit 14C, and the in-plane components Va', Vb', Vc' of the demultiplexed measurement reflected light projected into the plane at sinθ. 【0170】 As shown in Figure 13(B), the irradiation head unit 14C has the demultiplexed measurement light L with its optical axis parallel to the others. S1 ,L S3 ,L S5 The system is equipped with three single-point irradiation heads 401, 403, and 405 containing coupled optical elements, which are evenly arranged at 120° in-plane to output a demultiplexed measurement light L, as shown in Figure 13(A). S1 ,L S3 ,L S5 The system is configured to illuminate a single measurement point S1 from two different directions, each tilted by an angle θ with respect to the optical axis of the focusing optical system 60, by focusing the light with a focal length f. 【0171】 In the irradiation head unit 140C, which has three single-point irradiation heads 401, 403, and 405 with built-in coupled optical elements evenly arranged at 120° in-plane, the demultiplexed measurement light L is output from the three single-point irradiation heads 401, 403, and 405, focused by the focusing optical system 60, and irradiated onto one measurement point S1 on the measurement surface 5. S1 ,L S3 ,L S5 Since the specularly reflected light is not directly incident on other sensor heads, frequency crosstalk is less likely to occur. In addition, the decompressed measurement light L irradiated onto one measurement point S1 on the measurement surface 5 by the irradiation head unit 140C is less likely to occur.S1 ,L S3 ,L S5 The specular reflection components Va, Vb, and Vc, and the demultiplexed reflected light L projected into the plane at sinθ. S1 ',L S3 ',L S5 The in-plane components Va', Vb', Vc' of ' are deselected from the wave-deselected measurement light L, as shown in the schematic diagram of Figure 13 (C). S1 ,L S3 ,L S5 Since the specular reflection components Va, Vb, and Vc do not affect the other components, adjacent frequencies can also be measured. 【0172】 Furthermore, in the multidimensional vibration measurement system 100B equipped with this irradiation head unit 140C, the three single-point irradiation heads 41, 43, and 45 constituting the irradiation head unit 140C are evenly arranged at 120° in-plane. Therefore, when the signal processing unit 7 calculates the out-of-plane component Vz and the in-plane two-axis components Vx and Vy using vector calculations, the in-plane component cancels out with respect to the out-of-plane component or the out-of-plane component cancels out with respect to the in-plane component, and the out-of-plane component Vz is given by the following equation (1) Vz=1 / 3*(cosθ)*(Va+Vb+Vc) Formula (1) It can be calculated using the following equations (2) and (3). Vx = 1 / 2 * (cos30°) * (V'b - V'c) =1 / 2*cos30°*(sinθ)*(Vb-Vc) Equation (2) Vy=1 / 2*(V'a-sin30°*(V'b+V'c)) =1 / 2*(1 / sinθ)*(Va-1 / 2*(Vb+Vc)) Formula (3) This can be calculated using the following method. 【0173】 Figure 14 is a schematic diagram showing a group of irradiation head units equipped with a focusing optical system array 160, which is an array of focusing optical systems 601, 602, etc. of multiple irradiation head units 140A1, 140A2, etc. 【0174】 In other words, when using the above-mentioned irradiation head unit 140A or irradiation head unit 140B as multiple irradiation head units 1401, 1402, ... in the multidimensional vibration measurement system 100B, it is possible to use an irradiation head unit group equipped with a focusing optical system array 160 which is an array of focusing optical systems 601, 602, ... of multiple irradiation head units 140A1, 140A2, .... 【0175】 Therefore, the irradiation head unit in the multidimensional vibration measurement system according to the present invention may be configured such that at least two single-point irradiation heads are arranged and fixed to output delimited measurement light of at least two frequency components with their optical axes parallel, and the delimited measurement light of at least two frequency components output from the at least two single-point irradiation heads assigned by the measurement light transmission path selection means is focused by a focusing optical system and irradiated onto a single measurement point from different directions, and may also include a focusing optical system array in which the focusing optical systems of the plurality of irradiation head units are arranged in an array. 【0176】 Figures 15(A) and (B) illustrate the functions of the optical demultiplexer 130A and optical multiplexer 130B provided in the optical demultiplexer / multiplexer optical system 130 in the multipoint vibration measurement system 100B described above. Figure (A) shows the function of the optical demultiplexer to separate the frequency components of the optical comb contained in the measurement light according to the mode order of the optical comb, and Figure (B) shows the function of the optical multiplexer to combine the frequency components separated for each frequency component of the optical comb. 【0177】 In other words, in this multi-point vibration measurement system 100B, the optical demultiplexing element 130A provided in the optical demultiplexing optical system 130 receives the measurement light L output from the light source 1. S The light is amplified by the optical amplifier 145 and input via the interference optical system 120, and the frequency components contained in the measurement light LS are decomposed according to the mode order of the optical comb to obtain decomposed measurement light L with one frequency component for each point irradiation head. S1 ,L S2 ,···L SnThe output is as follows. In addition, the optical multiplexer 130B outputs the decompressed reflected light L of one frequency component for each single-point irradiation head that is reflected back from multiple measurement points S1, S2, ... on the measurement surface 5. S1 ',L S2 ',···L Sn ' is input, and for each of the above single-point irradiation heads, one frequency component is decompressed and measured reflected light L S1 ',L S2 ',···L Sn ' is combined and the reflected light L is measured. S This is input to the above interference optical system 120 as '. 【0178】 Here, in the multi-point vibration measurement system 100B described above, the irradiation head units 1401, ..., 140 n / 4 Each optical path length variation compensating optical system 501,...,50 n The above measurement light L is measured by the optical demultiplexing element 130A provided in the optical demultiplexing optical system 130 described above. S Decompressed optical measurement light L, obtained by decompressing the frequency components of the optical comb contained within. S1 ,L S2 ,···L Sn Excluding the component with the maximum spectral intensity, the decompressed frequency components of the channels that were not output to the measurement optical transmission path 34 for the n channels CH1, CH2, ..., CHn can be allocated by the measurement optical transmission path selection means as the decompressed measurement reference light for compensating for optical path length fluctuations. 【0179】 Figure 16 shows the irradiation head units 1401, ..., 140 in the multi-point vibration measurement system 100B described above. n / 4 Each of the following single-point illumination heads has three integrated coupling optical elements: 401, 402, 403, ..., 40 n-2 ,40 n-1 ,40 n Along with the built-in optical path length variation compensation optical system 501,...,50 n / 4 For optical path length variation compensation, use a demultiplexing measurement reference light L SR4 ,L SR8 This is a schematic diagram showing the optical comb spectrum used to explain the demultiplexed measurement light assigned as ,.... 【0180】 Furthermore, in the above multi-point vibration measurement system 100B, the above irradiation head units 1401,...,140 n / 4 Optical path length variation compensation optical system 501,...,50 n / 4 The above optical path length variation compensation optical systems 501,...,50 n / 4 Each pair of optical transmission paths connected to 1344,...,134 n Optical path 34R4,···,34 for compensating for optical path length variation n In the above optical splitter / multiplexing optical system 3, the measurement light L S The decompressed measurement light L is obtained by decompressing each of the n types of frequency components contained therein. S1 ,L S2 ,L S3 ,···L Sn Decompression measurement light L of each of the single frequency components S4 ,L S8 ...to demultiplexing measurement reference light L for optical path length variation compensation SR4 ,L SR8 Although used as such, the optical system 501, 50, and 50 used above for compensating for optical path length variation n / 4 In the detection channel for optical path length correction, stable and highly sensitive detection is possible, so as shown in Figure 16, channels in the wavelength regions AR1 and AR2 with low optical comb spectral intensity can be used. The optical demultiplexing element 130A of the optical demultiplexing optical system 130 separates the frequency components of the optical comb contained in the measurement light, and the demultiplexed measurement light with low spectral intensity among the demultiplexed measurement light for each frequency component, i.e., the demultiplexed measurement light of the frequency component with a high mode order of the optical comb, is used as the demultiplexed measurement reference light for optical path length variation compensation. The wavelength region AR3 with a high optical comb spectral intensity and a low mode order of the optical comb is used as the measurement channel for vibration measurement, and the demultiplexed measurement light of the frequency component with a low mode order of the optical comb in the wavelength region AR3 with a high optical comb spectral intensity is assigned as the demultiplexed measurement light to irradiate the measurement surface 5. This makes it possible to achieve a channel arrangement configuration that is highly intense and highly efficient for vibration measurement using the demultiplexed measurement light irradiated onto the measurement surface 5. 【0181】 Furthermore, in the signal processing unit 7, by differentially detecting the vibration detection signal from the demultiplexed measurement light irradiated onto the measurement surface 5 and the detection signal from the demultiplexed measurement reference light for optical path length correction, which enables stable and highly sensitive detection, static fluctuations, i.e., fluctuations in the optical length of the waveguide path due to temperature fluctuations and strain fluctuations, can be reduced, making it possible to measure vibrations in the low-frequency range. [Explanation of Symbols] 【0182】 1 light source, 1A, 1B optical comb generator, 2 interference optical system, 3 optical demultiplexing / combining optical system, 3A optical demultiplexing / combining element, 41,42,43,...,4 n Single-point illumination head, 4 projection optics, 4 A1 ,4 A2 ,4 A3 ,···,4 An ,4A, 11 A ,601,602,···Collecting optical system, 4 B1 ,4 B2 ,4 B3 ,···,4 Bn 1 / 4 wavelength plate, 4C, 4C A ,4C B Coupled optical unit, 4C12 core capillary, 4C2, 4C2' coupled optical element, 4C a ,4C c Collimator lens, 4C b Wollaston prism, 4C B Combined optics unit, 5 150A, 150B, 150C measuring surfaces, 6 Interferometric light detection unit, 6A Interferometric light detector for measurement, 6B Interferometric light detector for reference, 7 Signal processing unit, 11 B ,4B 1 / 4 wavelength plate, 11 C Reflector, 14A,14B,14C,140A1,140A2,...,140 n / 4 ,140A,140B Irradiation head unit, 401,402,403,···,40 n-2 ,40 n-1 ,40 n ,40A,40B,44 Combined optical element built-in single-point irradiation head, 50,501,···,50 n / 4Optical path length variation compensation optical system, 67 Signal processing unit, 100A, 100B Multipoint vibration measurement system, 111 Optical path length variation compensation optical system, 130 Optical demultiplexing optical system, 130A Optical demultiplexing element, 130B Optical multiplexing element, 134, 1341, 1342, ... Paired optical transmission line, 144A, 144B, 144C Single-point illumination head unit, 160 Focusing optical system array, 145 Optical amplifier, 150 Information processing device, 160 Enclosure, 161 Power supply unit, 162 Device temperature controller, FB 12A FB 12B FB 2A1 FB 2A2 FB 2B1 FB 2B2 FB 2C FB 23 FB 34 FB 43 FB 341 FB 342 ,···,FB 26A1 FB 26A2 FB 26B1 FB 26B2 Fiber optic cable, OC A OC B OC C OC D OC E Optical coupler, L S Measuring light, L S1 ,L S2 ,L S3 ,···L Sn ,L X ,L Y ,L Z ,L Sa ,L Sb Demultiplexed measurement light, L S1 ',L S2 ',···L Sn ' Demultiplexed measurement reflected light, L S ' Measured reflected light, L SR , L SR4 ,L SR8 ,... Demultiplexed measurement reference light, L SR ', L SR4 ',L SR8 ' ,... Demultiplexed measurement reference reflected light, L R Reference light, S S Interference signal for measurement, S R Reference interference signals: S1, S2, ..., Sn Measurement point

Claims

[Claim 1] A light source that outputs coherent measurement light and reference light, having a spectrum with multiple modes in the shape of an optical comb at predetermined frequency intervals, An interference optical system receives measurement light and reference light output from the above light source, as well as measurement reflected light that is returned when the measurement light irradiated onto the measurement surface of the object to be measured is reflected by the measurement surface, and outputs measurement interference light by interfering the above reference light and the above measurement reflected light. The optical optical splitter and multiplexer optical system receives the measurement light output from the above light source via the above interference optical system, decompresses the frequency components of the optical comb contained in the measurement light, and outputs the decompressed measurement light for each decompressed frequency component to multiple channels of measurement optical transmission lines, and the decompressed measurement light for each decompressed frequency component that is reflected back by the measurement surface after being irradiated onto multiple measurement points on the measurement surface of the object to be measured receives the decompressed measurement reflected light for each decompressed frequency component via multiple channels of measurement optical transmission lines, and combines the decompressed measurement reflected light for each decompressed frequency component and inputs it to the above interference optical system as the measurement reflected light, Multiple delimited measurement light beams, delimited by the above-mentioned optical splitter / multiplexer optical system, are input via the above-mentioned multi-channel measurement light transmission path. These delimited measurement light beams are assigned to and irradiated at multiple measurement points on the measurement surface of the object to be measured. Multiple delimited measurement reflected light beams, reflected back from the multiple measurement points on the measurement surface, are input to the above-mentioned optical splitter / multiplexer optical system via the above-mentioned multi-channel measurement light transmission path. The above-mentioned optical splitter and multiplexer optical system and the above-mentioned multiple optical fiber cables connecting the multiple single-point irradiation heads comprise the above-mentioned multi-channel measurement optical transmission path, A measurement optical transmission path selection means for selectively changing the connection relationship between the optical dispersion and multiplexing optical system and the multiple single-point irradiation heads connected via the above-mentioned multi-channel measurement optical transmission path, A measuring interference photodetector that receives the measuring interference light obtained by the above interference optical system and converts it into an electrical signal to obtain a measuring interference signal, A signal processing unit analyzes the vibration information of the measurement surface based on the interference signal obtained by the above-mentioned interference photodetector. Equipped with, The above-mentioned plurality of single-point irradiation heads constitute a plurality of irradiation head units for each measurement point, each consisting of at least two single-point irradiation heads assigned by the measurement light transmission path selection means to irradiate a single measurement point from different directions with decompressed measurement light of frequency components of the optical comb that are separated by the optical splitter / multiplexer optical system, excluding adjacent frequency components, at a mode order of 1 or more. The decompressed measurement reflected light for each measurement point, which is reflected at multiple measurement points on the measurement surface and returns via the at least two single-point irradiation heads, is input to the optical splitter / multiplexer optical system. The decompressed measurement reflected light from each of the above multiple irradiation head units is input to the above multiple measurement points, and the resulting measurement reflected light is input to the above interference optical system by combining the decompressed measurement reflected light in the above optical decompression and multiplexing optical system. A multidimensional vibration measurement system configured such that, for each measurement point, the decompressed measurement reflected light input from the above-mentioned multiple irradiation head units is combined by the above-mentioned optical decompression and multiplexing optical system, and the resulting measured reflected light is input to the above-mentioned interference optical system. Based on the measurement interference signal obtained by the above-mentioned measurement interference light detector, the above-mentioned signal processing unit is configured to obtain multidimensional vibration information of the measurement point by performing calculation processing on the interference signal for each measurement point where the decompressed measurement light is irradiated from different directions to a single point on the measurement surface of the object to be measured. [Claim 2] The multidimensional vibration measurement system according to claim 1, characterized in that the measurement optical transmission path selection means selectively changes the connection relationship between the optical dispersive and multiplexing optical system and the plurality of single-point irradiation heads connected via the plurality of channel measurement optical transmission paths by channel blocking of the plurality of channels, and assigns at least two frequency components of the decompressed measurement light, other than adjacent frequency components, of the decompressed measurement light for each decompressed frequency component decompressed by the optical dispersive and multiplexing optical system to each measurement point. [Claim 3] The multidimensional vibration measurement system according to claim 2, characterized in that the irradiation head unit is configured such that the at least two single-point irradiation heads are arranged and fixed at an inclination angle to each other so that the optical axes of the decompressed measurement light intersect at one measurement point, and the decompressed measurement light of at least two frequency components assigned by the measurement light transmission path selection means is irradiated at one measurement point from different directions. [Claim 4] The multidimensional vibration measurement system according to claim 2, characterized in that the irradiation head unit is configured such that at least two single-point irradiation heads are arranged and fixed to output delimited measurement light with their optical axes parallel, and the delimited measurement light of at least two frequency components output from the at least two single-point irradiation heads assigned by the measurement light transmission path selection means is focused by a focusing optical system and irradiated onto a single measurement point from different directions. [Claim 5] The multidimensional vibration measurement system according to claim 4, characterized by comprising a focusing optical system array in which the focusing optical systems of multiple irradiation head units are arranged in an array. [Claim 6] The multidimensional vibration measurement system according to claim 2, characterized in that each of the above-mentioned multiple irradiation head units consists of two single-point irradiation heads, and the signal processing unit is configured to obtain two-dimensional vibration information of in-plane vibration and out-of-plane vibration at multiple measurement points on the measurement surface of the object to be measured. [Claim 7] The multidimensional vibration measurement system according to claim 2, characterized in that the above-mentioned plurality of irradiation head units consist of at least three single-point irradiation heads, and the signal processing unit is configured to obtain three-dimensional vibration information of in-plane vibration and out-of-plane vibration at a plurality of measurement points on the measurement surface of the object to be measured. [Claim 8] The optical splitter / multiplexer optical system is characterized by comprising an optical splitter / multiplexer element that receives measurement light output from the light source via the interference optical system, splits the frequency components of the optical comb contained in the measurement light, outputs the split measurement light for each split frequency component to multiple channels of measurement light transmission lines, receives the split measurement light for each split frequency component that is reflected back by the measurement surface from multiple measurement points on the measurement surface of the object to be measured via multiple channels of measurement light transmission lines, and combines the split measurement light for each split frequency component to input the measurement reflected light to the interference optical system. [Claim 9] The above optical demultiplexing and multiplexing optical system comprises: an optical demultiplexing element that receives measurement light output from the above light source via the above interference optical system, demultiplexes the frequency components of the optical comb contained in the measurement light, and outputs demultiplexed measurement light with one frequency component for each single-point irradiation head to multiple channels of measurement light transmission paths; and an optical multiplexing element that receives demultiplexed measurement light with one frequency component for each single-point irradiation head that is irradiated to multiple measurement points on the measurement surface of the object to be measured via the above multiple irradiation head units, and receives demultiplexed measurement reflected light with one frequency component for each single-point irradiation head that is reflected back from the multiple measurement points on the measurement surface via multiple channels of measurement light transmission paths, and combines the demultiplexed measurement reflected light with one frequency component for each single-point irradiation head and inputs it to the above interference optical system as the measurement reflected light. A multi-point vibration measurement system according to any one of claims 1 to 7, comprising a coupling optical system consisting of a plurality of coupling optical elements, which are connected to the optical splitter / multiplexer optical system via the plurality of measurement optical transmission paths described above, to which delimited measurement light of one frequency component is input via the plurality of measurement optical transmission paths for each of the single-point irradiation heads that are delimited by the optical splitter element of the optical splitter / multiplexer optical system, to which delimited measurement light of one frequency component is input via the plurality of measurement optical transmission paths, to which delimited measurement light of one frequency component is output for each of the single-point irradiation heads that are irradiated to a plurality of measurement points on the measurement surface of an object to be measured via the plurality of irradiation head units, and to which delimited measurement reflected light of one frequency component is input to the optical multiplexer element of the optical splitter / multiplexer optical system via the plurality of measurement optical transmission paths. [Claim 10] The above optical demultiplexing optical system includes an optical demultiplexing element that demultiplexes the frequency components of an optical comb into the measurement light input from the above interference optical system via a single optical fiber cable and outputs demultiplexed measurement light for each demultiplexed frequency component via multiple optical fiber cables, and an optical multiplexing element that combines the demultiplexed measurement reflected light for each demultiplexed frequency component input via multiple optical fiber cables and outputs it via a single optical fiber cable. The multidimensional vibration measurement system according to claim 9, characterized in that the coupling optical system comprises the coupling optical element that aligns the optical axes of two optical beams whose polarization directions are orthogonal and output from two optical fiber cables. [Claim 11] The multidimensional vibration measurement system according to claim 9, characterized in that each of the multiple single-point irradiation heads constituting the above irradiation head unit incorporates a coupling optical element of the above coupling optical system, and is connected to the optical demultiplexing element and optical multiplexing element of the optical demultiplexing and multiplexing optical system via a pair of optical fiber cables consisting of an optical fiber cable through which the demultiplexing measurement light passes and an optical fiber cable through which the demultiplexing measurement reference light passes. [Claim 12] Each of the above-mentioned multiple irradiation head units is provided with at least one optical path length variation compensation optical system. In the above optical wave splitting and multiplexing optical system, at least one frequency component of the decompressed measurement light obtained by decompressing the frequency components of the optical comb contained in the measurement light is assigned to each irradiation head unit as a decompressed measurement reference light for compensating for optical path length variation. The multidimensional vibration measurement system according to any one of claims 1 to 7, characterized in that the decompressed measurement reference light for compensating optical path length fluctuations is input to at least one optical path length fluctuation compensation optical system provided for each irradiation head unit via at least one optical path length fluctuation compensation optical path among the plurality of channel measurement optical transmission paths, and a measurement reflected light is obtained by combining the decompressed measurement reference light of at least one frequency component and decompressed measurement reflected light of at least two frequency components for each measurement point, which is returned from the optical path length fluctuation compensation optical system via the at least one optical path length fluctuation compensation optical path, and the signal processing unit is configured to analyze multidimensional vibration information of the measurement surface by correcting the fluctuations in each optical path length of the plurality of channel measurement optical transmission paths through which the decompressed measurement light and decompressed measurement reflected light of at least two frequency components pass, based on the measurement interference signal obtained by the measurement interference photodetector. [Claim 13] The above irradiation head unit is equipped with multiple optical path length variation compensation optical systems, each of which is provided for each of the multiple single-point irradiation heads, Multiple decompressed measurement beams, obtained by decompressing the frequency components of the optical comb contained in the above measurement beam, are used as decompressed measurement reference beams for compensating for optical path length variations. The multidimensional vibration measurement system according to claim 12, characterized in that the signal processing unit is configured to correct for variations in the optical path length of each of the multiple single-point irradiation heads constituting the irradiation head unit and the optical splitter / multiplexer optical system, for each single-point irradiation head. [Claim 14] The multidimensional vibration measurement system according to claim 13, wherein the multiple optical path length variation compensation optical systems described above are characterized in that the decompressed measurement light of channels that were not output to the measurement optical transmission path among the decompressed frequency components, excluding the component whose spectral intensity of the decompressed measurement light is maximum among the decompressed frequency components obtained by decompressing the frequency components of the optical comb contained in the measurement light using the optical decompression element of the optical decompression optical system, is assigned by the measurement optical transmission path selection means as a decompressed measurement reference light for optical path length variation compensation.

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