JP3353365B2 - Displacement and displacement velocity measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring a displacement distribution and a displacement speed accompanying deformation or movement of an object.

[0002]

2. Description of the Related Art Displacement distribution due to deformation or movement of a rough object or movement of a group of particles is determined by identifying a specific point or particle before and after the deformation or movement without processing the object to be measured. Is difficult, and it is difficult to apply ordinary measurement methods. Therefore, images reflecting local features of the structure of the object to be measured are taken before and after the deformation or movement, and the spatial correlation of these two images (one image is matched with the spatial movement by the two images) Degree) and a displacement distribution are known.

[0003] A typical example of this method is obtained when a transmitted light or a reflected light of an object irradiated with laser light and having an irregular structure on a microscopic scale of about the wavelength of the irradiated light is imaged by a lens. There is a speckle double exposure method in which a speckle pattern is superimposed and imaged before and after deformation or movement. FIG. 8 shows the measurement of the amount of displacement by the speckle double exposure method. First, the measured object 710 is irradiated with laser light emitted from the laser light source 150, and images before and after the deformation of the measured object 710 are double-exposed on the same film by the camera 900 (see FIG. 8A). Next, each part of the imaged negative (hereinafter referred to as a specklegram) 910 is irradiated with a thin laser beam emitted from the laser light source 160, and the ground glass placed on the focal plane of the convex lens 930 via the convex lens 930. An image is formed on the plate 950 (see FIG. 8B). In the frosted glass 950, Young fringes at equal intervals in parallel representing speckle movement are generated, and the following formula (1) holds for the Young fringe spacing.

| Ma _T | = λ ₀ f / d (1) where, m: imaging magnification a _T : in-plane displacement of the object, λ ₀ : laser beam wavelength emitted from the laser light source 150 f: focal point of the convex lens Distance d: Young fringe interval Accordingly, the Young fringe interval is measured while changing the incident position of the laser beam on the specklegram in FIG. 8B, and the measured object is calculated by equation (1). The displacement | a _T | at each point is measured.

[0005] Further, in obtaining the displacement | a _T | from the double exposure speckle image obtained in FIG.
A method of mathematically examining image correlation without using an optical device as in (b) is also known. One example of this method is the joint transform correlation method. In the joint transform correlation method, first, a Fourier transform for performing variable transformation from a spatial coordinate value to a spatial frequency value is performed on an image obtained by superimposing a reference image and an image after displacement, and then a power spectrum related to the spatial frequency is obtained. . Next, a Fourier transform for transforming the variable of the power spectrum from a spatial frequency to a spatial coordinate is performed to obtain a spatial correlation function of the two images, and a displacement amount is obtained on condition that the correlation value is large. This procedure is represented by the following equation.

Assuming that the two-dimensional image of the measured object before deformation or movement is g (x, y), the deformed or moved two-dimensional image displaced by the value a in the positive direction of x is a local image. Since the deformation is almost negligible, it can be expressed as g (x−a, y). Therefore, an image o (x, y) obtained by superimposing these two two-dimensional images can be expressed by the following equation (2).

O (x, y) = g (x, y) + g (x−a, y) (2) First, the superimposed image o (x, y) is Fourier-transformed.

F [o (x, y)] = G (u, v) + G (u, v) exp (jua) (3) where F [o (x, y)]: o ( x (y) Fourier transform result G (u, v): g (x, y) Fourier transform result (u, v): spatial frequency coordinate Next, power spectrum | F [o on spatial frequency coordinate
(X, y)] | ² .

| F [o (x, y)] | ² = 2 | G (u, v) | ² + G (u, v) G ^* (u, v) exp (jua) + G ^* (u, v) G (u, v) exp (-jua) (4) Next, assuming that this power spectrum is Fourier-transformed and the conversion result is i (x ′, y ′), the following equation (5) is established.

I (x ′, y ′) = 2g (x ′, y ′) ★ g (x ′, y ′) + g (x ′, y ′) ★ g (x′−a, y ′) + g ( x ′, y ′) ★ g (x ′ + a, y ′) (5) where ★: indicates the correlation operation of the function before and after this i (x ′, y ′) is (x ′, y ′) y ′) = (0,0), (a, 0), (− a, 0)... (6) Since the peaks are found, the displacement | a | Can be.

In the above-described displacement measurement, the absolute value of the average displacement speed can be measured by double-exposing the image at a fixed time interval.

On the other hand, for speed measurement, a speckle correlation method has been put to practical use in which speckle images are individually taken at regular time intervals and the speed is obtained from the correlation between these two images. As a method of directly measuring the velocity, there is a two-beam laser Doppler velocimeter that measures the Doppler shift of scattered light by a moving object using the Doppler effect.

[0013]

Since the conventional displacement and displacement velocity measuring apparatus measures the displacement and displacement velocity of the object to be measured as described above, it is apparent from equations (1) and (6). Thus, although the displacement amount, that is, the absolute value of the displacement and the absolute value of the displacement speed could be known, there was a problem that the direction of the displacement could not be directly known from the measurement result. That is, the direction of displacement is
The determination must be made in consideration of the physical situation, and if the direction of the displacement cannot be estimated before the measurement, there is a problem that the displacement as a vector and the displacement speed cannot be measured.

Further, in the conventional speckle correlation method, the image processing is performed individually after image processing of the captured image data, so that a relatively long time is required for the entire processing. The two-beam laser Doppler velocimeter uses a phase-locked loop for scattered light detection. At present, however, there is a limit to the time for phase locking, and measurement cannot be performed with good S / N when speed fluctuations are involved. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. Even when the direction of displacement cannot be estimated before measurement, the displacement amount and displacement speed including the direction of displacement can be measured at high speed. It is an object of the present invention to provide a device capable of performing such operations.

The displacement and displacement velocity measuring device of the present invention comprises:
A spatially uniform first quantity and a two-dimensional optical image reflecting characteristics of the object to be measured generated by irradiating the object with (a) a laser light source and (b) laser light emitted from the laser light source. A deflection means for selectively applying a second amount of deflection;
A two-dimensional optical image at a first time with a deviation of
An imaging device that records an image obtained by superimposing a two-dimensional optical image at a second time after the second amount of deviation is applied, and (d) a joint conversion correlation between the optical image recorded in the imaging device. An arithmetic unit for performing an operation, wherein an absolute value of a difference between the first amount of deviation and the second amount of deviation is calculated between a first time and a second time. The displacement of the measured object is set to be larger than the absolute value of the displacement amount of the measured object, and the displacement generated between the first time and the second time of the measured object, the first time and the second An average displacement speed between the second time and the second time is obtained. Here, the two-dimensional light image may be characterized in that it is a speckle pattern obtained by one of reflected light and transmitted light from the object irradiated with the laser light.

The deflection means of the apparatus is characterized in that it is optically deflected, receives light carrying information reflecting the characteristics of the object to be measured, and receives a linearly polarized light component having a substantially specific polarization direction. A polarization plate that emits only polarization light, a polarization plane rotation element that receives linearly polarized light that has arrived through the polarization plate, and selectively performs one of non-rotation of the polarization direction and rotation of 90 °, and a polarization plane rotation element. A polarization plane rotation controller for setting one of the operation modes of rotation non-execution and 90 ° rotation execution, and receives linearly polarized light through the polarization plane rotation element,
A birefringent plate that changes the optical path depending on the polarization direction. A reflective element disposed in an optical path of an optical system for obtaining a two-dimensional optical image reflecting characteristics of the measured object; a reflective element controller for changing a spatial direction or a position of a reflective surface of the reflective element; A light transmitting element having a refractive index higher than that of air disposed in an optical path of an optical system for obtaining a two-dimensional optical image reflecting the characteristics of the measured object, and a light receiving surface of the light transmitting element And a light transmission element controller that changes the position in the spatial direction or in a direction substantially perpendicular to the optical path of the light transmission element. Further, the imaging device may include an imaging device that moves in a direction parallel to the imaging surface of the two-dimensional optical image reflecting the characteristics of the measured object, and a translation controller that changes a spatial direction of the imaging device. .

The deflection means of this device is characterized in that it is electrically deflected, receives light carrying information reflecting the characteristics of the object to be measured, and emits electrons by a photoelectric effect. A surface, an accelerating electrode for accelerating the electrons in a first direction, an electron lens for forming an image of the electrons accelerated by the accelerating electrode, a phosphor screen for displaying an image formed by the electron lens, and an electron lens. A deflecting electrode pair disposed between the phosphor screen and a direction perpendicular to the first direction to generate an electric field; a variable voltage source for controlling the intensity of the electric field between the deflecting electrode pair; A closed container that houses at least a photoelectric surface, an acceleration electrode, an electron lens, a fluorescent screen, and a pair of deflection electrodes, and has a substantially vacuum storage space, for making the flight path of electrons substantially vacuum. Or
Receives light carrying information that reflects the characteristics of the device under test,
A photoelectric surface that emits electrons by a photoelectric effect, and
An accelerating electrode that accelerates in the direction of, an electron lens that forms electrons accelerated by the accelerating electrode, a phosphor screen that displays an image formed by the electron lens, and a space between the electron lens and the phosphor screen. A deflection coil for generating a magnetic field in a direction perpendicular to the first direction, a variable current source for controlling the strength of the magnetic field, and at least a photocathode for making a flight path of electrons from the photocathode to the phosphor screen substantially vacuum. , An accelerating electrode, an electron lens, and a fluorescent screen, and a closed container whose storage space is substantially vacuum.

Further, the deflection means of the device is characterized in that the deflection is performed in an electronic circuit, and a memory for storing the two-dimensional image data picked up by the imaging device, and a storage for each pixel of the imaging device. In generating the memory address, the first
And a second address generation mode for selectively performing a second address generation mode for performing the second deviation and a second address generation mode for performing the second deviation. An adder for adding pixel data and pixel data at a corresponding address in the two-dimensional image data input from the imaging device, wherein the first time is stored when the image data captured at the first time is stored. Using the address generation mode and storing each pixel data in the memory without performing addition with the data already stored at the corresponding address in the memory, and storing the image data captured at the second time Sometimes, the second address generation mode is used, and each pixel data is added with the data already stored at the corresponding address in the memory,
By using the added value, image data obtained by superimposing the two-dimensional image at the first time and the secondary development at the second time may be obtained.

The calculating means of this apparatus is a digital computer, and digitizes the superimposed image picked up by the image pickup apparatus, and then performs a joint conversion correlation operation. Further, a first Fourier transform lens for performing Fourier transform on a captured image of the imaging device, a first imaging device of the first Fourier transform lens, and a Fourier transform of an image formed by the first imaging device. A second Fourier transform lens, and a second imaging device of the second Fourier transform lens, and may be characterized by performing an optical joint transform correlation operation.

[0021]

According to the structure of the present invention, when capturing a two-dimensional image at the first time and a two-dimensional image at the second time reflecting the characteristics of the measured object, the two-dimensional image at the second time is captured. Is imaged by applying a known amount of deviation whose absolute value is set to be larger than the absolute value of the displacement amount of the measured object between the first time and the second time. A calculation of a joint conversion correlation is performed on the superimposed images, the correlation between the two images is checked, and a position where the correlation value reaches a peak is obtained. The displacement amount and the direction of the displacement are measured by correcting the above-described known displacement amount from the peak position. Further, the absolute value of the displacement speed is calculated by dividing the measured displacement amount by the time difference between the first time and the second time, and the speed as a vector is determined in accordance with the direction of the measured displacement. .

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of the embodiments of the present invention, the principle of the method used in the displacement and displacement velocity measuring apparatus of the present invention will be described. This method is an improvement of the joint conversion correlation method described above, and simultaneously measures the amount of displacement and the direction of displacement.

Assuming that the two-dimensional image of the measured object before deformation or movement is g (x, y), the deformed or moved two-dimensional image displaced by the value a in the positive direction of x is a local image. Since the deformation is almost negligible, it can be expressed as g (x−a, y). An image obtained by further displacing the deformed or moved two-dimensional image in the positive direction of x by a known deviation amount b is represented as g (x-ab, y). Therefore, an image o (x, y) obtained by superimposing this image and two two-dimensional images before deformation or before movement can be expressed by the following equation (7).

O (x, y) = g (x, y) + g (x-ab, y) (7) where | a | <b.

First, the superimposed image o (x, y) is subjected to Fourier transform.

F [o (x, y)] = G (u, v) + G (u, v) exp (ju (a + b)) (8) where F [o (x, y)] : Fourier transform result of o (x, y) G (u, v): Fourier transform result of g (x, y) (u, v): spatial frequency coordinate Next, power spectrum | F [ o
(X, y)] | ² .

| F [o (x, y)] | ² = 2 | G (u, v) | ² + G (u, v) G ^* (u, v) exp (ju (a + b)) + G ^* (u , V) G (u, v) exp (−ju (a + b)) (9) Next, when this power spectrum is Fourier-transformed and the conversion result is i (x ′, y ′), the following equation is obtained. (10)
Holds.

I (x ′, y ′) = 2g (x ′, y ′) g (x ′, y ′) + g (x ′, y ′) ★ g (x′−ab, y ′) + G (x ′, y ′) ★ g (x ′ + a + b, y ′) (10) where: ★: Correlation operation of functions before and after This i (x ′, y ′) is expressed by (x ', Y') = (0, 0), (a + b, 0), (-ab, 0) (12). In the conventional superimposed image in which b = 0, the sign of the displacement a cannot be determined from the peak position, but | a | <b in the above joint conversion correlation calculation. The second peak position always appears on the positive side of x. Therefore, by subtracting the value b from the peak position coordinate value appearing on the positive side of x,
It can be determined including the positive and negative of the value of the displacement a. Furthermore, the velocity as a vector can be obtained by dividing the measured displacement a by the time difference between the first time and the second time. Note that the calculation can be similarly performed even when the target to which the known deviation b is applied is a two-dimensional image at the first time.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.

(First Embodiment) FIG. 1 is a configuration diagram of a displacement and displacement velocity measuring apparatus according to a first embodiment of the present invention. This apparatus includes a laser light source 100 for generating a laser beam for irradiating the object 700, and an imaging lens system 200 for forming a two-dimensional image reflecting the characteristics of the object 700 generated as a result of the laser beam irradiation. A deflector 300 for giving a fixed spatial deviation to the formed two-dimensional image, a CCD camera 400 for capturing a two-dimensional image via the deflector 300, and a CC
TV set 51 for monitoring a captured image of D camera 400
0, an image processing device 520 for digitizing and recording the image captured by the CCD camera 400, executing a joint conversion correlation operation on the digitized image data, and determining the displacement and the displacement speed of the measured object 700 from the operation result. And a computer 530 to be determined.

Here, the laser light source 100 is Ne-He
A laser 101, a convex lens 102 for spatially expanding the laser light emitted by the laser 101, a slit 103 for restricting the spatial spread of the laser light and transmitting the laser light, Body 7
And a convex lens 104 for generating a beam to irradiate 00. In addition, the imaging lens system 200 includes a convex lens 20 disposed at a distance f ₁ on the optical path from the measured object 700.
1 (focal length = f ₁ ) and a pinhole slit 202 located at a distance f ₁ on the optical path from the convex lens 201
And the distance f on the optical path from this pinhole slit 202
Convex lens 203 arranged at position ₂ (focal length = f ₂ )
Consists of Also, the deflector 300 is a 90 ° twisted TN type liquid crystal panel 302 which is a polarization plane rotating element disposed at a distance f ₂ on the optical path from the convex lens 203.
A polarizing plate 301 that transmits a specific polarization component disposed between the convex lens 203 and the TN type liquid crystal panel 302;
It comprises a birefringent plate 303 of 1 cm thick calcite and a driving device 304 for a TN type liquid crystal panel. The polarizing plate 30
1 passes through the TN type liquid crystal panel 302 without rotation of the polarization plane and becomes ordinary light of the birefringent plate 303, passes through the polarizing plate 301, and passes through the TN type liquid crystal panel 3.
The polarized light that has been transmitted by rotating the polarization plane by 90 ° in 02 is arranged to be extraordinary light of the birefringent plate 303.

The beam emitted from the laser light source 100 is incident on the object 700 to be measured, and the transmitted light is transmitted to the imaging lens system 20.
Only the specific polarization component is selectively transmitted by the polarizing plate 301 via 0, and is imaged on the TN type liquid crystal panel 302 which is a polarization plane rotation element. First, the laser light source 100 is turned on at a first time in a pulsed manner. At this time, the driving device 304 is set to the “ON” state, and the polarization plane is incident on the birefringent plate 303 without rotating as shown in FIG.
In this case, since the incident light is ordinary light for the birefringent plate 303, the incident light passes through the birefringent plate 303 without spatial deviation. In this state, an image is written to the CCD camera 400.
Next, at a second time, the laser light source 100 is turned on in a pulsed manner. At this time, the driving device 304 is set to the “OFF” state, and the polarization plane of the incident light is set to 90 ° by the TN type liquid crystal panel.
It is rotated and made incident on the birefringent plate 303. In this case, the incident light becomes extraordinary light with respect to the birefringent plate 303, and is emitted from the birefringent plate 303 after being subjected to a certain spatial deviation. Since this spatial deviation amount is proportional to the thickness of the birefringent plate 303, it can be set with high accuracy. In this apparatus, since calcite having a thickness of 1 cm is used as the birefringent plate 303, the amount of deviation is about 1 mm. The image thus displaced is superimposed on the image written at the first time and written to the CCD camera 400. here,
Double writing for superimposing two images may be performed by operating an electronic shutter or a mechanical shutter twice.

The superimposed image written in the CCD camera 400 is taken into the image processing device 520, digitized and recorded. Using the computer 530, Fourier transform is performed on the digitized image data to obtain a power spectrum in spatial frequency coordinates. Using the computer 530 again, a Fourier transform is performed on the power spectrum at this spatial frequency coordinate to obtain an autocorrelation function. Calculate the value of this autocorrelation function at each spatial coordinate,
Find the coordinate value of a positive value that becomes a peak other than the origin. The displacement intentionally applied is subtracted from the coordinate values thus obtained, and the displacement of the measured object between the first time and the second time is calculated including the direction of the displacement. The displacement speed is calculated by dividing the displacement thus obtained by the time difference between the first time and the second time. The displacement acceleration can be calculated by repeatedly measuring the displacement of the object to be measured.

(Second Embodiment) The apparatus of this embodiment has the same configuration as that of the first embodiment except for the configuration of the deflector 300. FIG. 3A shows the configuration of the deflector 300 according to the second embodiment. This deflector 300 is the same as the convex lens 20 shown in FIG.
Rotatable reflective element 31 for reflecting light emitted from 3
1 and a reflective element controller 312 composed of a piezo element for controlling the direction of the reflective surface of the reflective element 311. The light reflected by the reflective element 311 is reflected on the imaging surface of the CCD camera 400 shown in FIG. It is arranged to form an image.
The direction of the reflecting surface of the reflecting element 311 at the first time;
By changing the direction of the reflecting surface of the reflecting element 311 at the second time by the reflection direction controller, a constant spatial deviation can be obtained by a two-dimensional image at the first time and a two-dimensional image at the second time. And the relative application is realized. In the device of this embodiment, except for the operation of the deflector 300, the first
The operation is performed in exactly the same manner as in the example, and the displacement and the displacement speed are measured. Note that the displacement may be given by changing the spatial position of the reflection element 311.

(Third Embodiment) The apparatus of this embodiment is configured in the same manner as the first embodiment except for the configuration of the deflector 300. FIG. 3B shows the configuration of the deflector 300 according to the third embodiment. This deflector 300 is the same as the convex lens 20 shown in FIG.
A rotatable transmission element 321 having a refractive index different from that of air for refracting light emitted from the light transmission element 3 and a light reception direction controller 322 composed of a piezo element for controlling the direction of the light receiving surface of the transmission element 321. The light transmitted through the transmission element 321 is arranged so as to form an image on the imaging surface of the CCD camera 400 shown in FIG. By changing the optical path by changing the direction of the light receiving surface of the transmission element 321 at the first time and the direction of the light receiving surface of the transmission element 321 at the second time by the light receiving direction controller, a certain spatial deviation is obtained. It is realized that the position is relatively assigned between the two-dimensional image at the first time and the two-dimensional image at the second time. The apparatus of this embodiment operates exactly the same as the first embodiment except for the operation of the deflector 300, and measures the displacement and the displacement speed.
The light transmitting element 321 in a direction substantially perpendicular to the optical path
May be changed to change the position.

(Fourth Embodiment) The apparatus of this embodiment has the same configuration as that of the first embodiment except for the configuration of the deflector 300. FIG. 3C shows the configuration of the deflector 300 according to the fourth embodiment. The deflector 300 is a parallel movement controller 332 made of a piezo element that spatially changes the position of the imaging element 450. The light emitted from the convex lens 203 shown in FIG. 1 forms an image on the image sensor 450,
32, the spatial position of the image sensor 450 at the first time and the spatial position of the image sensor 450 at the second time are changed in parallel to the imaging surface, so that a certain spatial deviation is obtained. The relative application is realized between the two-dimensional image at the first time and the two-dimensional image at the second time. The apparatus of this embodiment operates exactly the same as the first embodiment except for the operation of the deflector 300, and measures the displacement and the displacement speed.

(Fifth Embodiment) The apparatus of this embodiment is configured in the same manner as the first embodiment except for the configuration of the deflector 300. FIG. 4A shows the configuration of the deflector 300 according to the fifth embodiment. This deflector 300 is provided with a convex lens 203 shown in FIG.
A photocathode 341 arranged at an imaging position of light emitted from
An accelerating electrode 342 for accelerating electrons emitted from the photocathode 341 in a certain direction, an electron lens 343 for converging the accelerated electrons, and a fluorescent screen 344 for forming an electron image.
A deflection electrode pair 345 for generating an electric field between the electron lens 343 and the phosphor screen 344 in a direction perpendicular to the electron acceleration direction;
Variable voltage source 3 for controlling electric field strength between deflection electrode pair 345
65 and a closed container 349 for making the flight path of electrons from the photoelectric surface 341 to the fluorescent surface 344 substantially vacuum. The CCD camera shown in FIG. 1 writes an image formed on the phosphor screen 344.

At the first time, the voltage applied by the variable voltage source 346 between the pair of deflection electrodes 345 is set to 0, and the electrons travel straight without generating an electric field. At the second time, the deflection electrode pair 34
A voltage for generating an electric field that gives a certain spatial deviation to the image formed on the phosphor screen 344 during the period 5 is applied. In this way, it is possible to implement a constant spatial deviation relatively between the two-dimensional image at the first time and the two-dimensional image at the second time. In the device of this embodiment, except for the operation of the deflector 300, the first
The operation is performed in exactly the same manner as in the example, and the displacement and the displacement speed are measured. In the device of this embodiment, deviation can be given at a higher speed than in the devices of the first to fourth embodiments.

(Sixth Embodiment) The apparatus of this embodiment has the same configuration as that of the first embodiment except for the configuration of the deflector 300. FIG. 4B shows the configuration of the deflector 300 according to the sixth embodiment. This deflector 300 is provided with a convex lens 203 shown in FIG.
A photocathode 341 arranged at an imaging position of light emitted from
An accelerating electrode 342 for accelerating electrons emitted from the photocathode 341 in a certain direction, an electron lens 343 for converging the accelerated electrons, and a fluorescent screen 344 for forming an electron image.
A deflection coil 347 that generates a magnetic field between the electron lens 343 and the phosphor screen 344 in a direction perpendicular to the electron acceleration direction;
A variable current source 348 for controlling the magnetic field strength;
And a hermetically sealed container 349 for making the flight path of the electrons from the to the fluorescent screen 344 substantially vacuum. The CCD camera shown in FIG. 1 writes an image formed on the phosphor screen 344.

At the first time, the current supplied from the variable current source 348 to the deflection coil 347 is set to 0, and the electrons travel straight without generating a magnetic field. At the second time, a current is supplied to the deflection coil 347 to generate a magnetic field that gives a certain spatial deviation to the image formed on the fluorescent screen 344. In this way, it is possible to implement a constant spatial deviation relatively between the two-dimensional image at the first time and the two-dimensional image at the second time. In the device of this embodiment, except for the operation of the deflector 300, the first
The operation is performed in exactly the same manner as in the example, and the displacement and the displacement speed are measured. In the device of this embodiment, similarly to the device of the fifth embodiment, the deviation can be given at a higher speed than in the devices of the first to fourth embodiments.

(Seventh Embodiment) FIG. 5 is a block diagram of a displacement and displacement velocity measuring device according to a seventh embodiment of the present invention. This apparatus includes a laser light source 100 for generating a laser beam for irradiating the object 700, and an imaging lens system 200 for forming a two-dimensional image reflecting the characteristics of the object 700 generated as a result of the laser beam irradiation. A CCD camera 400 that captures a formed two-dimensional image; a TV set 510 that monitors an image captured by the CCD camera 400;
The image processing device 520 digitizes the captured image of 0, gives a deviation, and superimposes the two images, executes the joint conversion correlation operation on the digitized image data, and calculates the displacement of the measured object 700 based on the operation result. And a calculator 530 for calculating the displacement speed.

Here, the laser light source 100 and the imaging lens system 200 are configured in the same manner as in the first embodiment. A convex lens 230 at a distance of the distance f ₂ of the optical path, the imaging surface of the CCD camera 400 is disposed. As shown in FIG. 6, the image processing device 520 includes a readout control circuit 521 for image data of the CCD camera 400 and a CCD camera 40.
A for digitizing the pixel data signal read from 0
/ D converter 522 and memory 52 for storing pixel data
3, an address generator 524 for generating an access address of the memory 523, and an adder for adding the data value stored in the memory address designated by the address generator 524 to the pixel data value read from the CCD camera 400. 525 and a computer interface 526 for transferring the addition result to the computer 530.

From the image picked up at the first time, each pixel data is sequentially read from the CCD camera 400 in accordance with the instruction of the read control circuit 521 and stored in the memory 523. The image captured at the second time is also read by the read control circuit 5.
The pixel data is read from the CCD camera 400 according to the instruction of 21 and input to the adder 525. At the same time, a memory address corresponding to a position where a certain spatial deviation is given to the pixel position is generated by the address generator 524, and the data stored in the corresponding address position of the memory is added to the adder 5
25. The result of this addition is pixel data of an image obtained by superimposing an image obtained by giving a spatial deviation to the image taken at the first time and an image taken at the second time. 530.
Reading of pixel data from the CCD camera 400,
By sequentially performing the superposition and the transfer to the computer 530, the computer 530 inputs each pixel data of the superimposed image. Thereafter, the computer 530 performs the joint conversion correlation operation as described in the first embodiment, obtains the coordinate value at which the correlation value becomes a peak, and then calculates the displacement and the displacement speed.

In this apparatus, the deviation is given by using the address generator 524. When the image data is read from the CCD camera 400, the deviation is given by adjusting the horizontal or vertical pulse for reading. Is also good. Also, C
Instead of a CD camera, an image dissector or a vidicon may be used to adjust the bias applied to the scan electrode or scan coil during reading.

(Eighth Embodiment) FIG. 7 is a block diagram of a displacement and displacement velocity measuring apparatus according to an eighth embodiment of the present invention. This apparatus includes a laser light source 100 for generating a laser beam for irradiating the object 700, and an imaging lens system 200 for forming a two-dimensional image reflecting the characteristics of the object 700 generated as a result of the laser beam irradiation. , A deflector 300 for giving a fixed spatial deviation to the formed two-dimensional image, a spatial light modulator 410 for writing a two-dimensional image via the deflector 300, and an image on the spatial light modulator 410 Fourier transformer 610 for performing Fourier transform on the formed image, spatial light modulator 420 for forming an image of the Fourier transform result, and optical Fourier transformer 620 for performing Fourier transform on the image formed on spatial light modulator 420
And a CCD camera 40 for imaging the result of the Fourier transform.
0, an image processing device 520 for digitizing and recording the image captured by the CCD camera 400, and a calculator 530 for obtaining the displacement and the displacement speed of the measured object 700 from the digitized image data.

Here, the laser light source 100, the imaging lens system 200, and the deflector 300 have the same configuration as in the first embodiment. The optical Fourier transformer 610 includes a laser light source 611 that emits readout light of an image formed on the spatial light modulator 410, a half mirror 612 that irradiates the readout light onto an image forming surface of the spatial light modulator 410, And a conversion lens 613. Also, the optical Fourier transformer 62
0 denotes a laser light source 621 that emits readout light of an image formed on the spatial light modulator 420, a half mirror 622 that irradiates the readout light to the image forming surface of the spatial light modulator 410, and a Fourier transform lens 623. Become.

As in the first embodiment, the laser light source 100,
The imaging lens system 200 and the deflector 300 operate, and the superimposed image is written on the spatial light modulator 410. Next, the image written in the spatial light modulator 410 is read out and Fourier transformed by the optical Fourier transformer 610, and the resulting power spectrum image in the spatial frequency coordinate is formed in the spatial light modulator 420. The image is written to the spatial light modulator 420. Next, the image written in the spatial light modulator 420 is read out and Fourier-transformed by the optical Fourier transformer 620, and the resulting correlation function image in spatial coordinates is formed on the imaging surface of the CCD camera 400. Then, the data is written to the CCD camera 400. The image written in the CCD camera 400 is
This is the result of the joint conversion correlation operation already completed.

The image of the result of the joint conversion operation is stored in the CCD camera 4
00 and digitized by the image processing device 520, and the digital image data is used by the computer 530.
Then, the displacement value and the direction of the displacement of the measured object are obtained by subtracting the deviation value intentionally given from the coordinate value at which the correlation value becomes a peak. The displacement speed is calculated by dividing the displacement thus obtained by the time difference between the first time and the second time. In addition,
The displacement acceleration can be calculated by repeatedly measuring the displacement of the object to be measured, similarly to the first embodiment.
Since this apparatus optically executes Fourier transform for each point, which is a joint transform correlation operation, the operation speed and thus the measurement speed are significantly higher than those in the first to seventh embodiments. In addition, if the center-of-gravity position detection element PSD is used instead of the CCD camera 400, there is no need to perform scanning detection, so that higher speed can be achieved. Note that the second embodiment related to the first embodiment
Modifications of the deflector 300 as in the sixth to sixth embodiments are also possible in this embodiment.

[0049]

As described above in detail, according to the displacement and displacement velocity measuring apparatus of the present invention, the two-dimensional image at the first time and the two-dimensional image at the second time reflecting the characteristics of the object to be measured. When capturing an image, a known amount whose absolute value is set to be larger than the absolute value of the displacement amount of the measured object between the first time and the second time in the two-dimensional image at the second time Therefore, the superimposed image is subjected to the calculation of the joint conversion correlation, the correlation between the two images is checked, and the position where the correlation value becomes a peak is obtained. By correcting the known amount of deviation, the amount of displacement and the direction of the displacement can be measured at high speed. Further, the absolute value of the displacement speed is calculated by dividing the measured displacement amount by the time difference between the first time and the second time, and the speed as a vector is increased at a high speed together with the direction of the measured displacement. Can be determined.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a displacement and displacement velocity measuring device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of an operation of a deflection unit of the displacement and displacement velocity measuring device according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of a deflection unit of a displacement and displacement velocity measuring device according to second to fourth embodiments of the present invention.

FIG. 4 is a configuration diagram of a deflection unit of a displacement and displacement velocity measuring device according to fifth and sixth embodiments of the present invention.

FIG. 5 is a configuration diagram of a displacement and displacement velocity measuring device according to a seventh embodiment of the present invention.

FIG. 6 is a configuration diagram of a displacement / image superposition unit of a displacement and displacement velocity measuring device according to a seventh embodiment of the present invention.

FIG. 7 is a configuration diagram of a displacement and displacement velocity measuring device according to an eighth embodiment of the present invention.

FIG. 8 is an explanatory diagram of a conventional speckle double exposure method.

[Explanation of symbols]

100 laser light source 200 imaging lens system 300
Deflector, 400: CCD camera, 510: TV monitor,
520: Image processing device, 530: Computer, 610, 62
0: optical Fourier transformer, 700: object to be measured.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-204312 (JP, A) JP-A-60-31677 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 11/00-11/30 102 G01P 1/00-3/80 G02B 26/00-26/08

Claims (6)

(57) [Claims] 1. A spatially uniform first amount in a laser light source and a two-dimensional optical image reflecting characteristics of the object to be measured generated by irradiating the object with laser light emitted from the laser light source. And a deviation means for selectively applying a second amount of deviation, and the second means at a first time at which the first amount of deviation is applied.
An imaging device that records an image obtained by superimposing a two-dimensional optical image and the two-dimensional optical image at the second time at which the second amount of deflection has been performed, and an optical image recorded in the imaging device And a computing device that performs a joint transform correlation operation on the first time and the second time, wherein the absolute value of the difference between the first amount of deviation and the second amount of deviation is equal to the first time and The absolute value of the displacement amount of the measured object between the second time and the second time is set to be larger than the absolute value of the displacement amount of the measured object.
A displacement generated between the second time and the second time, and an average displacement speed between the first time and the second time. 2. The apparatus according to claim 1, wherein the two-dimensional light image is a speckle pattern obtained by one of reflected light and transmitted light from an object irradiated with the laser light. Displacement velocity measuring device. 3. The displacement and displacement velocity measurement device according to claim 1, wherein performing the first amount of deflection is substantially the same as not performing the deflection. 4. The polarizing means receives light carrying information reflecting characteristics of the measured object, and emits only a linearly polarized light component having a substantially specific polarization direction. A polarization plane rotation element that receives linearly polarized light that has arrived and selectively performs one of non-rotation and non-rotation of the polarization direction, and one of non-rotation and non-rotation of the polarization plane rotation element. A polarization plane rotation controller for setting one of the operation modes, and a birefringent plate for receiving linearly polarized light via the polarization plane rotation element and changing an optical path according to a polarization direction. The displacement and displacement velocity measuring device according to claim 1. 5. The displacement and displacement velocity according to claim 1, wherein the arithmetic unit is a digital computer, and performs a joint conversion correlation operation after digitizing the superimposed image captured by the imaging device. measuring device. 6. A first Fourier transform lens for Fourier transforming the superimposed image, a first imaging device of the first Fourier transform lens, and the first imaging device. Of the Fourier transform of the image formed by
The displacement and displacement velocity measurement according to claim 1, comprising: a Fourier transform lens of (1), and a second imaging device of the second Fourier transform lens, and optically performing a joint transform correlation operation. apparatus.