JP4401989B2 - 3D image information acquisition system - Google Patents

Description

  The present invention acquires three-dimensional image information of a measurement object by irradiating the measurement object with a plurality of laser beams emitted from different positions and receiving the reflected light of each laser beam reflected by the measurement object. This is a three-dimensional image information acquisition system, which is suitable for a technical field such as a machine vision system (industrial image inspection apparatus) or a laser radar that knows the state of a measurement object from information of a laser beam returned to the measurement object. It relates to a system that can be used.

In recent years, in the automation of work in industrial robots and machine tools, it has been desired to perform accurate work using the three-dimensional position information of a target object.
Various methods are known for acquiring three-dimensional position information of an object.
In a system equipped with a plurality of cameras, position information of an object is acquired using a captured image, and in a system using a plurality of distance sensors, distance information of the object is acquired from the distance sensor. Further, in a system in which a camera and a distance sensor are combined, a captured image of the object and distance information are acquired, and three-dimensional position information of the object is acquired.
Further, it is desired to acquire three-dimensional position information of an object as a military or security laser radar or as a Mars exploration robot.

For example, in a system equipped with a plurality of cameras, a method is known in which a three-dimensional image of an object is acquired from captured images of the object captured from different directions by the plurality of cameras. (Non-Patent Document 1).
Also, the laser beam is reflected on a polygon mirror or galvanometer mirror, scanned two-dimensionally on the object, and the laser beam reflected from the object is received to know the position information of the object, separately from this. There is known a method of acquiring three-dimensional position information of an object together with distance information obtained by using a triangulation method or a pulse echo method (Non-Patent Document 2).
Further, a method is known in which laser light is slit-projected on an object and the three-dimensional shape of the object is known using the deformation state of the slit-shaped laser light projected on the object (Non-patent Document 3). ).

1998 Supplementary Budget Dynamic Content Market Environment Improvement Project, “3D Model Data Collection Device for Non-stopped Objects by Simultaneous Shooting with Multiple Cameras”, May 6, 2004 Search, Internet, <URL: http // www.dcaj .org / bigbang / mmca / works / 04 / 04_050.html> Sekimoto Kiyohide et al., “Development of 3D Laser Radar”, Ishikawajima Harima Technique, Vol. 43, No. 4, July 2003, May 6, 2004, Internet, <URL: http: // www .ihi.co.jp / ihi / technology / gihou / image / 43-4-2.pdf> "3D Modeling Display Technology", Osaka Prefectural Industrial Technology Research Institute, May 6, 2004 search, Internet, <http://www.tri.pref.osaka.jp/group/sense/oldfile/3d/3d3 .htm>

  In Non-Patent Document 1, it is possible to measure a three-dimensional position of a subject based on a plurality of photographed images as needed, acquire a three-dimensional image of the subject, and create a virtual three-dimensional image. In addition, it is possible to create a three-dimensional image of a human body shape using the human body shape as a measurement object. However, simply measuring the 3D position of a subject based on a captured image captured by a camera cannot measure the 3D position of the object surface for an object having a uniform surface without a pattern. is there.

  Further, in Non-Patent Document 2, when acquiring three-dimensional position information with a desired resolution, a laser having a large light beam is used when a polygon mirror or a galvano mirror is rotated and reflected to narrow down the light beam of the laser beam and scanned on the object. There is a limit to acquiring three-dimensional position information by rotating a large polygon mirror or galvanometer mirror that reflects light at high speed. In Non-Patent Document 2, laser light emitted from one laser emitter is received by one camera. For example, depending on the angle of the surface of the object (the shape of the object), such as when the surface of the object has a high reflectivity with respect to the emitted laser, the laser light reflected by the surface of the object may enter the camera. It may not be incident. Non-Patent Document 2 has a problem that three-dimensional position information cannot be acquired for the surface of such an object.

  In Non-Patent Document 3, a three-dimensional shape can be obtained, but in order to obtain distance information of an object and obtain three-dimensional position information, a reference point for obtaining distance information in advance on the object. There is a problem that it must be set and is difficult to automate. In addition, there is a limit to acquiring the three-dimensional position information by scanning the slit-shaped laser light projected on the object at high speed. Further, in Non-Patent Document 3, the deformation state of the slit-shaped laser light projected on the object is photographed with one camera. In Non-Patent Document 3, similarly to Non-Patent Document 2, laser light reflected on the surface of the object does not enter the camera depending on the reflectance of the surface of the object or the angle of the surface of the object (the shape of the object). In some cases, there is a problem that the three-dimensional position information cannot be obtained for the surface of such an object.

  The present invention has been made to solve the above-described conventional problems, and obtains high-precision three-dimensional image information of a measurement object at high speed irrespective of the surface reflectance and surface shape of the measurement object. A possible three-dimensional image information acquisition system is provided.

In order to achieve the above object, the present invention irradiates a measurement object with a plurality of laser beams emitted from different positions, and receives the reflected light of each laser beam reflected by the measurement object. Is a three-dimensional image information acquisition system for acquiring three-dimensional image information, and simultaneously irradiates laser light, which is time-modulated in accordance with an amplitude modulation signal, from different directions toward the same range of an object to be measured, at different positions. A plurality of arranged laser beam emitting units, a plurality of photoelectric converters that receive a plurality of laser beams reflected by the measurement object, and output electrical signals corresponding to the received plurality of laser beams, respectively; An element having a plurality of micromirrors arranged on a plane provided corresponding to each converter, and a micromirror selected from these micromirrors. By controlling the reflecting surface of-to be in a predetermined direction and turning it on, a plurality of laser beams from the measurement object reflected by the micro mirror in the on state are respectively received by the light receiving surfaces of the corresponding photoelectric converters. For each of a plurality of laser beams received by the light receiving surface of each photoelectric converter, with respect to each of the micromirror array spatial modulation elements arranged at different positions and the electric signals output from the respective photoelectric converters. Each laser beam is obtained by using an electrical signal component identifying unit for identifying a signal component, information on the emission position of each laser beam, and information on the arrangement position of the micromirrors in the ON state in each micromirror array spatial modulation element. For each of the electric signal components corresponding to the position information calculation unit for obtaining the three-dimensional position information of the measurement object, and the electric signal corresponding to each laser beam Provided is a three-dimensional image information acquisition system having a three-dimensional image information creation unit that creates three-dimensional image information of the measurement object based on three-dimensional position information of the plurality of measurement objects obtained for each of the minutes To do.

  Each of the plurality of laser beams emitted simultaneously from the plurality of laser beam emitting units is time-modulated by the amplitude modulation signal and further time-modulated by an encoded modulation signal that can be identified for each laser beam, Preferably, the electrical signal component identification unit identifies electrical signal components corresponding to each of a plurality of laser beams using information of a coded modulation signal included in the electrical signal.

  Further, the micromirror array spatial modulation element is configured such that the micromirrors in the ON state occupy 50% or more of all the micromirrors, the micromirror control patterns are sequentially switched, and the laser light spatially modulated according to the control patterns is generated. It is preferable to guide to the light receiving surface of the photoelectric converter. At this time, the control patterns that are sequentially switched are preferably control patterns that are orthogonal to each other.

  According to the three-dimensional image information acquisition system of the present invention, the three-dimensional image information of the measurement object can be acquired with high accuracy and high speed regardless of the surface reflectance and the surface shape of the measurement object.

  Hereinafter, the three-dimensional image information acquisition system of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.

FIG. 1 is an external view of a three-dimensional image information acquisition system (hereinafter referred to as a system) 10 which is an embodiment of the three-dimensional image information acquisition system of the present invention.
The system 10 irradiates the measurement object S with laser light emitted from different positions, and receives the reflected light of each laser light reflected by the measurement object S from each of a plurality of photoelectric converters arranged at different positions. This is a system that acquires three-dimensional image information from the three-dimensional position information of the surface of the measurement target T acquired by receiving light on the surface and the reflectance on the surface of the measurement target T.

The system 10 includes a plurality (n pieces) of three-dimensional cameras D (D ₁ , D ₂ ,... D _n ) that can acquire three-dimensional image information that are arranged at different predetermined arrangement positions. The measurement object S is measured using a control device 14 that controls the operation of the three-dimensional camera D (e.g., emission of laser light) and an electrical signal including three-dimensional image information output from the plurality of three-dimensional cameras D. And a computer 16 that acquires three-dimensional image information of the surface of the target region T. Each of the three-dimensional cameras D _{1 to} D _n irradiates the measurement target T with laser light, receives reflected light from the measurement target S, and detects the surface of the measurement target S from the received electrical signal. An electrical signal corresponding to the three-dimensional position information and reflectance information is output.

Each of the cameras D _{1 to} D _n includes a laser light emitting unit 20 that emits laser light, and an optical unit 30 that receives the reflected light of the laser light reflected from the surface of the measurement target T and converts it into an electrical signal. And a data processing unit 50 for processing the laser light received by the optical unit 30 and converting the laser light into digital data of an electrical signal. Each camera D ₁ to D _n are arranged at predetermined positions different from each, all laser light emitted from each of the camera D ₁ to D _n, illuminates substantially the same range of the measuring object S Surface As described above, the orientations of the laser light emission holes 11 of the respective cameras D _{1 to} D _n are adjusted. In addition, each of the cameras D _{1 to} D _n has the same light receiving surface (see FIG. 4) of the photoelectric converter 38 (described later) of the optical unit 30 of each camera D _{1 to} D _{n as} the surface of the measuring object S. The direction and zoom of the finder 12 are adjusted so that the reflected light of each laser beam reflected by the measurement target region T is received.

FIG. 2 is a diagram illustrating laser beams received by the cameras D _{1 to} D _n . The reception of reflected light from the point P in the measurement target region T of the measurement target S in each of the cameras D _{1 to} D _n will be described with reference to FIG. For example, the camera D ₁ receives the reflected light of the laser light traveling on the reflected light path R ₁ from the point P toward the camera D ₁ . The point P is a point in the measurement target region T, and all of the laser beams emitted from the cameras D _{1 to} D _n are irradiated. The laser beams emitted from the respective laser beams travel on emission optical paths L _{1 to} L _n shown in FIG. 2 to reach the point P, and are reflected in various directions at the point P. Camera D ₁ is receiving all the components of the reflected light of each laser beam propagating the reflected light path R _1. That is, the camera D ₁ receives laser light (reflected light) of n paths represented by L ₁ R ₁ , L ₂ R ₁ , L ₃ R ₁ ... L _n R _1. . Each of the cameras D _{2 to} D _n similarly receives laser light of n paths. That is, a total of n × n paths of laser light are received by all n cameras for one point in the measurement target region. Thus, in the three-dimensional image information acquisition system of the present invention, each measurement unit region in the measurement target region T (specifically, a region corresponding to one micromirror of a micromirror array spatial modulation element 34 to be described later). In addition, information on the reflected light of n × n laser beams can be obtained.

For example, the camera D ₁ is received, the reflected light of the laser beam of n path (path), each light intensity are different. This is due to the reflectance and inclination of the surface of the measuring object S. For example, in the example shown in FIG. 2, the laser beam L ₂ emitted from the camera D ₂ reaches the point P at an incident angle substantially perpendicular to the surface of the measurement object at the point P, and the incident angle of the path L ₂ through the path R1 of substantially symmetrical reflection angle to reach the camera D _1. The intensity of the reflected light received by the camera D ₁ through such a path L ₂ R ₁ is relatively high. In contrast, laser light Ln from the camera D _n reaches the point P through the measurement object surface substantially parallel to the path L _n of the point P portion, not significantly different (symmetric to the incident angle of the path L _n ) The camera reaches the camera D ₁ through the reflection angle path R ₁ . The intensity of the reflected light received by the camera D ₁ through such a path L _n R ₁ is relatively weak. Conversely, for example, the surface of the measuring object S only from a laser light source disposed at the position of the camera D _n irradiated, only the light receiving unit disposed in the position of the camera D ₁ to the reflected light, measured With respect to the point P of the object S, only information on the reflected light of the relatively weak laser beam can be obtained. From such information of reflected light of a relatively weak laser beam, it is possible to acquire only three-dimensional position information with a strong noise component (poor S / N ratio) and low accuracy. In the three-dimensional image information acquisition system of the present invention, the measurement object is measured by irradiating the measurement object having an unspecified reflectance and an unspecified surface shape from a plurality of different positions. It is possible to irradiate high-intensity laser light on any part of the target region. And the light-receiving surface of reflected light is arrange | positioned in several different positions, respectively, and the laser beam reflected at every angle is received from every part of the measurement object area | region in a measurement object, respectively. With such a configuration, the three-dimensional image information acquisition system of the present invention can apply high-intensity laser light to any part in a measurement target region with respect to a measurement target having an unspecified reflectance and an unspecified surface shape. It is possible to acquire information of reflected light.

FIG. 3 is a schematic block diagram illustrating the control device 14 of the system 10. The control device 14 is connected to the cameras D _{1 to} D _n via the measurement data bus 49 and the control data bus 56, respectively. The control device 14 controls various signals (oscillation frequency control signal, phase) that control the measurement operation of each camera D _{1 to} D _n (specifically, the laser light emission unit 20, the optical unit 30, and the data processing unit 50 of each camera). A control signal, a control pattern signal, a PN encoded modulation signal, a clock signal, etc.) are generated and supplied to a predetermined unit of each camera. The control device 14 includes an oscillator 41, a power splitter 42, an amplifier 43, a phase shifter 44, an amplifier 45, a power splitter 46, an RF splitter 48, a measurement data bus 49, a system controller 51, and a control data bus 56.

  The oscillator 41 is a part that oscillates a signal at the oscillation frequency set by the oscillation frequency control signal. The oscillated signal is used as an RF modulation signal for time-modulating the laser light. For example, it oscillates at a frequency in the microwave to millimeter wave band of 50 MHz to 10 GHz.

The power splitter 42 is a part that separates the signal oscillated by the oscillator 41. One of the separated signals is supplied to the power splitter 46 via the amplifier 43. The power splitter 46 distributes the signal oscillated by the oscillator 41 to the laser light irradiation units 20 of the cameras D _{1 to} D _n via the measurement data bus 49. Signals distributed to the cameras D _{1 to} D _n are used as RF modulation signals. The other signal is supplied to the transporter 44.
The phase shifter 44 passes the RF modulation signal without phase shifting, and shifts the phase by 90 degrees according to the phase control signal to generate a phase shift modulation signal. These signals (RF modulation signal or phase shift modulation signal) are sent to the RF splitter 48 via the amplifier 45. The RF splitter 48 distributes these signals (RF modulation signal or phase shift modulation signal) to the data processing units 50 of the cameras D _{1 to} D _n via the measurement data bus 49.

The system controller 51 is a part that generates various control signals based on instructions from the computer 14. Of the various control signals generated by the system controller 51, the control pattern signal and the PN coded modulation signal are sent to the cameras D _{1 to} D _n via the control data bus 56, respectively.

FIG. 4 is a diagram illustrating the cameras D _{1 to} D _n . The cameras D _{1 to} D _n have the same configuration, and FIG. 4 shows the camera D ₁ as a representative. Later, it is described as a representative camera D _1.
The camera D ₁ includes a laser light emitting unit 20, an optical unit 30, and a data processing unit 50. The laser beam emitting unit 20 is connected to the measurement data bus 49 and the control data bus 56 of the control device 14.

  The laser light emitting unit 20 is a part that emits laser light, and includes a laser diode 22, a laser driver 24 that drives the laser diode 22, and an optical lens 28 that adjusts the laser light emitted from the laser diode 22. An amplitude modulation signal is sent from the control device 14 to the laser driver via the measurement data bus 49, and laser light is emitted from the laser diode in accordance with the amplitude modulation signal. The amplitude modulation signal (hereinafter referred to as RF modulation signal) is used for time-modulating the light intensity of the laser light emitted from the laser diode 24.

  The optical unit 30 is a part that receives laser light that has been reflected and arrived at the surface of the measurement target region T of the measurement target S. As shown in FIG. 4, the bandpass filter 31 sequentially from the upstream side of the optical path of the laser light. An optical lens 32, a prism 33, a micromirror array spatial modulation element (hereinafter referred to as a spatial modulation element) 34, an optical lens 36, a mirror 37, and a photoelectric converter 38 are disposed. The spatial modulation element 34 is connected to the micromirror controller 35.

The bandpass filter 31 is a narrowband filter that transmits light in the wavelength band of the laser light and blocks light in the other wavelength bands, blocks unnecessary external light, and reflects light from the measurement target T. Improve the signal-to-noise ratio.
The prism 33 is a portion that is used together with the spatial modulation element 34 described later and transmits or totally reflects the laser beam reflected by the micromirror of the spatial modulation element 34 on the oblique surface 33a. Specifically, in the prism 33, only the laser light reflected by the micromirror having the reflecting surface in a predetermined direction (the micromirror in the ON state) among the micromirrors of the spatial modulation element 34 is skewed. The laser beam that is transmitted through the surface 33a and reflected by a micromirror whose reflection surface does not face in a predetermined direction (a micromirror in the OFF state) is disposed so as to be totally reflected by the oblique surface 33a.

  The spatial modulation element 34 is a plurality of micromirrors arranged on a plane, for example, an element having a rectangular mirror with a side of 12 μm, and a reflection surface of a micromirror selected from these micromirrors is set in a predetermined direction. By being controlled to ON state, the laser light arriving from the measuring object T reflected by the micromirror in the ON state is arranged to be guided to the light receiving surface of the photoelectric converter 38.

FIG. 5 is a diagram for explaining the reflection of laser light in the micromirrors in the ON state and the OFF state. In FIG. 5, a description is given using 4 × 4 micromirror arrays.
The laser light reflected by the reflecting surface of the micromirror A in the ON state is guided to the photoelectric converter 38 through the lens 36, and the laser light reflected by the reflecting surface of the micromirror B in the OFF state is connected to the photoelectric converter 38. Reflects in different directions. Thus, the laser beam reflected by the micromirror in the ON state is received by the photoelectric converter 38. As described above, the photoelectric converter 38 of the camera D ₁ has the laser light of n paths represented by L ₁ R ₁ , L ₂ R ₁ , L ₃ R ₁ ... L _n R _1. (Reflected light) is received. Each micromirror of the spatial modulation element 34 receives information on the reflected light of the laser beam passing through the n paths reflected by each measurement unit region corresponding to each micromirror in the measurement target region T. It is sent to the light receiving surface of the converter 38. In the system 10, n cameras are arranged. As described above, the entire system 10 passes n × n paths for each measurement unit area corresponding to each micromirror in the measurement target area T. Information on the reflected light of the laser light is obtained.

Examples of the spatial modulation element 34 include a digital micromirror device (trademark) manufactured by Texas Instruments. In the digital micromirror device, for example, an SRAM (Static Ram) is provided below the arrangement surface of 1024 × 768 micromirrors, and each micromirror is oriented in a predetermined direction using electrostatic attraction generated using the SRAM. It is an element that rotates (+12 degrees or minus 12 degrees).
The spatial modulation element 34 is connected to a micromirror controller 35 for switching the state of each micromirror to the ON state / OFF state. Under the control of the micromirror controller 35, more than half of all the micromirrors are sequentially switched to different control patterns of the micromirrors that are turned on.

  The control pattern of the micromirror of the spatial modulation element 34 is sequentially switched to a different pattern so that the laser light is spatially modulated, and this spatially modulated laser light is guided to the light receiving surface of the photoelectric converter 38. . The control pattern of the micromirror is preferably a control pattern that is orthogonal to each other, where the ON state of the micromirror is 1 and the OFF state is -1. For example, it is preferably generated using a Hadamard matrix.

More specifically, the control pattern is a pattern of arrangement of micromirrors in which the spatial modulation element 34 is turned on. This control pattern is a pattern created by using a tensor product between each row of the Hadamard matrix. is there.
FIG. 6A is a diagram for explaining an example of the control pattern of the spatial modulation elements 34 of the 64 (= 8 × 8) micromirror arrays as viewed from the reflective surface side of the micromirrors.
The micromirrors are arranged in a rectangular shape with 8 rows in the vertical direction and 8 rows in the horizontal direction. In FIG. 6A, the gray micromirror indicates the ON state, and the white micromirror indicates the OFF state.
Such a control pattern is a control pattern in which the micromirrors in the ON state occupy 50% or more of all the micromirrors. The control pattern is controlled by a control pattern signal created by a control circuit unit 50 described later.

  As shown in FIG. 6B, among the 8-by-8 Hadamard matrix in which the matrix elements are 1 or -1, the combinations of the matrix elements in each row are in order from the top, 0th order, first order, second order, . . . . . , 7th order is a one-dimensional control pattern in the horizontal direction. On the other hand, as shown in FIG. 6C, among the 8-by-8 Hadamard matrix, a set of matrix elements in each row is assigned in order from the top, 0th order, first order, second order,. . . . . , 7th order and a vertical one-dimensional control pattern. Then, a desired order pattern is selected from the horizontal one-dimensional control pattern shown in FIG. 6B, and a desired order pattern is selected from the vertical one-dimensional control pattern shown in FIG. 6C.

In FIG. 6A, the horizontal one-dimensional control pattern is selected as the fourth order, and the vertical one-dimensional control pattern is selected as the sixth order.
On the other hand, the values (1 or −1) of the horizontal one-dimensional control pattern and the vertical one-dimensional control pattern at the vertical and horizontal positions of the micromirror to be controlled in the spatial modulation element 34 are respectively referred to. When the product of the vertical value and the horizontal value is 1, the micromirror to be controlled is set to the ON state, and when the product is −1, the micromirror is set to the OFF state. For example, the value of the one-dimensional control pattern in the horizontal direction of the micromirror M located at the position of 3 rows and 5 columns is -1, the value of the one-dimensional control pattern in the vertical direction is -1, and the product is 1. . For this reason, the micromirror M is set to the ON state. Thus, a control pattern signal of a control pattern in which the number of micromirrors in the ON state is 50% or more of the total number of micromirrors is created.
In this case, the control pattern of the micromirror can be created in 64 ways (= 8 × 8) by combining the horizontal one-dimensional control pattern and the vertical one-dimensional control pattern, and these 64 different control patterns are sequentially generated. A control pattern signal is created to switch.
Thus, the control pattern is generated by a tensor product between selected rows of the Hadamard matrix.

Note that the laser light reflected by the spatial modulation element 34 can be sequentially received by turning on the 64 micromirrors one by one and turning the others off. However, since the laser light reflected and received by one micromirror is weak, an electric signal generated by the weak laser light is easily buried in noise by processing such as amplification and detection performed as post-processing. However, as described above, by using the control pattern in which the micromirrors in the ON state occupy more than half of all the micromirrors, there is an effect that it is less likely to be buried in noise in post-processing amplification or detection. .
As described above, the spatial modulation element 34 reflects the laser light coming from the measurement object T while sequentially switching to different control patterns.

The optical lens 36 is configured to form an image of laser light on the light receiving surface of the photoelectric converter 38 via the mirror 37.
The photoelectric converter 38 is a part that converts received laser light into an electrical signal. Devices such as a photomultiplier tube and an avalanche photodiode are provided, and electrical signals are output from the devices. Note that the above devices differ depending on the laser light used. For example, an avalanche photodiode is used for laser light in the near infrared (800 to 1200 μm), and an avalanche photodiode or photoelectron is used for laser light in the visible band (400 μm to 800 μm). A multiplier tube is preferably used.

  The photoelectric converter 38 is an image sensor that receives a light receiving surface such as a CCD (Charged Coupled Device) image sensor divided into regions, accumulates signals for each region, and sequentially outputs the accumulated signals. Absent. As will be described later, since the RF modulation signal used for time modulation of the laser light is 50 MHz to 10 GHz, a CCD image pickup device that sequentially outputs accumulated signals responds quickly to signals modulated at such high frequencies. This is because it cannot be driven.

  The electrical signal output from the photoelectric converter 38 is sent to the data processing unit 50. The data processing unit 50 mixes the electric signal output from the photoelectric converter 38 using the same signal as the RF modulation signal supplied to the laser driver 24 as a reference signal (hereinafter referred to as a local signal), and performs RF modulation. The signal component of the laser light time-modulated with the signal is extracted as an intermediate frequency signal (IF signal) and sent to the computer 14 as an intermediate frequency digital signal. The data processing unit 50 includes a mixer 47, a low-pass filter 52, an A / D converter 54, and amplifiers 55 and 56.

  The RF modulation signal or phase shift modulation signal distributed from the RF splitter 48 of the control device 14 is transmitted to the mixer 47 via the measurement data bus 49 of the control device 14. The mixer 47 uses the RF modulation signal or the phase shift modulation signal as a local signal, and multiplies (mixes) the electric signal output from the photoelectric converter 38 and amplified through the amplifier 56, and performs RF modulation upon emission. This is a part that outputs an intermediate frequency signal (IF signal) having information of laser light time-modulated by the signal and a signal including higher-order components. The detection of the electric signal is performed by a known method. The RF modulation signal generates at least two signals having slightly different frequencies, and these signals are used as local signals. In addition, in the RF modulation signal of each frequency, the phase shifter 44 of the control device 14 generates a local signal that does not shift the phase of the RF modulation signal and a local signal that shifts the phase of the RF modulation signal by 90 degrees. The mixer 47 performs mixing (multiplication) of these local signals and the synthesized electric signal.

The low-pass filter 52 filters the signal including the intermediate frequency signal (IF signal) output from the mixer 47 and the high-order component to remove the high-order component, and includes only the signal information of the time-modulated laser beam. This is the part that makes the intermediate frequency signal. The intermediate frequency signal is amplified by the amplifier 53, converted to an intermediate frequency digital signal by the A / D converter 54, and supplied to the computer 14. Such an intermediate frequency digital signal is output from each of the cameras D _{1 to} D _n .

As shown in FIG. 7, the computer 14 includes a CPU 60, a memory 62, and a ROM (not shown), and a data processor 64 is functionally configured by executing computer software. The computer 14 is connected to the display 16.
The CPU 60 instructs the control circuit unit 50 of the control device 14 to generate various signals for controlling the driving of each unit of the camera D (emission of laser light, driving of the micromirror, etc.), and data to be described later. This is a part that substantially performs the calculation of each process of the processing unit 64.

The data processing unit 64 is based on each of the intermediate frequency digital signals transmitted from the cameras D _{1 to} D _n , and for each intermediate frequency digital signal acquired for each camera, the three-dimensional position information of the measurement target T and the measurement target The reflectance of the surface of the measuring object T is calculated, and the measurement target region T of the measuring object S is calculated based on the three-dimensional position information of the measuring object T for each camera and the reflectance of the surface of the measuring object T. This is a part for creating and outputting three-dimensional image information. The data processing unit 64 includes a signal conversion unit 66, a distance information calculation unit 68, a three-dimensional position information calculation unit 70, a reflectance calculation unit 72, a weighting coefficient setting unit 74, and a three-dimensional image information generation unit 76. Have
The signal converter 66 is a part that converts the intermediate frequency digital signal using the control pattern signal and the PN encoded modulation signal for each of the intermediate frequency digital signals transmitted from the cameras D _{1 to} D _n . Thereby, for each of the intermediate frequency digital signals transmitted from the cameras D _{1 to} D _n , one measurement unit region in the measurement target region T (region corresponding to one micromirror of the micromirror array spatial modulation element 34). Each measurement unit region signal component is further divided into measurement unit region signal components, and each measurement unit region signal component is further divided into laser light signal components for each of n reflected laser light beams reflected by each measurement unit region. Then, a weighting coefficient is set according to the signal intensity in each laser light signal component. Since the control pattern signal is a signal created by the system controller 51 of the control device 14 in accordance with an instruction from the computer 14, the control pattern signal is known, and signal conversion is performed using this control pattern signal.

  The control pattern signal is a signal that realizes a control pattern created by using a tensor product between the components of each row of the Hadamard matrix as shown in FIGS. For this reason, the signal converter 66 uses the known control pattern signal to perform Hadamard inverse transform from the intermediate frequency digital signal obtained by each control pattern and reflect the laser light reflected by each micromirror. Information (measurement unit region signal component) can be obtained. The signal conversion processing using Hadamard inverse transformation has already been filed by the present applicant (see Japanese Patent Application No. 2001-188301).

Since each row of the Hadamard matrix has orthogonality (the inner product of each row is 0), the synthesis matrix representing the control pattern obtained by the tensor product of the components of each row of the Hadamard matrix is also between the synthesis matrices. Maintain orthogonality. The Hadamard inverse transformation process is an inverse transformation process using the inverse matrix of the synthesis matrix. This inverse transformation uses the synthesis matrix except for the normalization factor because the synthesis matrix has orthogonality. The same processing content as the Hadamard transformation performed. Thereby, the information (measurement unit region signal component) of the laser beam reflected by each micromirror of each of the spatial modulation elements 34 for each camera can be easily decomposed using the Hadamard transform process.
Since the control pattern is represented by a composite matrix obtained by a tensor product between the row components of the Hadamard matrix, the control patterns are orthogonal to each other. In the present invention, the control pattern is generated by the composite matrix. It is not necessary and is not particularly limited as long as it can be decomposed into laser beam information reflected for each micromirror.
Incidentally, obtained by Hadamard inverse transform for each camera, information of the laser beam reflected on each micro mirror (measurement unit domain signal component), the laser beam (n emitted from each camera D ₁ to D _n Laser beams) are superimposed on each other. For this reason, as shown below, an intermediate frequency digital signal (laser light signal) corresponding to each laser light is utilized by utilizing the autocorrelation and orthogonality of the PN coded modulation signal used for time modulation when the laser light is emitted. Component). The autocorrelation and orthogonality of the PN encoded modulation signal will be described later.

As described above, the laser light emission units 20 from the cameras D _{1 to} D _n simultaneously emit laser light toward the measurement target region S of the measurement target S. At this time, the PN encoded modulation signal is transmitted. Using this, time modulation is performed by controlling on / off of laser light emission.
FIG. 8 is a diagram illustrating an example of a PN encoded modulation signal. In FIG. 8, one period of the PN encoded modulation signal is shown.
The PN encoded modulation signal is a signal having a value of 0 or 1, and the value of the correlation function becomes 0 or -1 / n (n is the length of a sequence code described later) by shifting by a certain time interval.
For example, the PN encoded modulation signal can be converted into a signal using encoded sequence data created as follows.
The order k = 5, the length of the code sequence n = 31, the coefficients h ₁ = 1, h ₂ = 1, h ₃ = 0, h ₄ = 1, h ₅ = 1, and the initial values a ₀ = 1, a _{When 1} = 1, a ₂ = 0, a ₃ = 1, and a ₄ = 0, the PN sequence code C = {a _k } (k is a natural number) is uniquely expressed by the recursion formula shown in the following formula (1). Can be sought.

Further, a reference encoded sequence signal is generated using the sequence code C = {a ₀ , a ₁ , a ₂ ,..., A _n−1 }, and the sequence code C is further converted into q1 bits, bits An encoded sequence signal is generated using a sequence code T _q1 · c that is bit-shifted in the direction (T _q1 is an operator that bit-shifts q1 bits in the bit direction). Here, the sequence code T _q1 · C is {a _q1 , a _{q1 + 1} , a _{q1 + 2} ,..., A _{q1 + N−1} }. Further, a coded sequence signal is generated using a sequence code T _q2 · C obtained by shifting the sequence code C by q2 bits (eg, q2 = 2 × q1) and bit-shifting in the bit direction.
Since the sequence codes C, T _q1 · C and T _q2 · C used to generate the encoded sequence signal have characteristics that are orthogonal to each other, the generated encoded sequence signals also have a property to be orthogonal to each other.

More specifically, a sequence code having a length n is C = {b ₀ , b ₁ , b ₂ ,..., B _n-1 }, and a sequence code in which the operator T _{q is applied} to the sequence code C. C ′ = T _q · C, that is, C ′ = {b _q , b _{q + 1} , b _{q + 2} ,..., B _{q + n−1} }, between the sequence codes C and C ′ The cross-correlation function R _{cc ′} (q) is defined as the following formula (2). Here, N _A is a number in which the term a _i and the term b _{q + i in} the sequence code coincide with each other (i is an integer between 0 and n−1), and N _D is the term a _i and the term b _q in the sequence code. _{+ i} is the number of mismatches. The sum of N _A and N _D is the sequence code length n (N _A + N _D = n). Here, i and q + i are considered as mod (n).

In the above PN sequence code, the result of adding two sequence codes for each term by mod (2) has a property of becoming a PN sequence code obtained by cyclically shifting the original PN sequence code, and the value of the PN sequence code is 0. Since the number is one less than the number where the value is 1, N _A −N _D = −1. Accordingly, the values shown in the following formulas (3) and (4) in the PN sequence code are shown.

From the above equation (3), when the bit shift amount is 0, that is, q = 0 (mod (n)), the value of R _{cc ′} (q) is 1 as shown in equation (3), and has autocorrelation. On the other hand, when the bit shift amount is not 0, that is, q ≠ 0 (mod (n)), R _{cc ′} (q) is − (1 / n) as shown in Expression (4). Here, by increasing the sequence code length n, the value of R _{cc ′} (q) (q ≠ 0) approaches zero.
That is, it can be said that the sequence codes C and C ′ have autocorrelation and orthogonality.
A PN coded sequence signal is a time series signal with such PN sequence code values of 0 and 1. Therefore, the PN coded modulation signals also have autocorrelation and orthogonality with each other. Therefore, when the correlation function between the C ₁ signal and the C _{2 to} C ₅ signals in FIG. 6 is obtained, the value becomes 0.

The signal conversion unit 66 uses the correlation function of the PN encoded modulation signal generated by the control circuit unit 50 for the signal time-modulated with the PN encoded modulation signal included in the intermediate frequency digital signal. It is possible to identify which laser beam signal information is included, and to decompose and extract the signal information (laser beam signal component) for each laser beam.
In this way, the signal conversion unit 66 performs the reflection position of each micromirror from the intermediate frequency digital signal by Hadamard inverse transformation and decomposition (coding identification conversion) using the autocorrelation and orthogonality of the PN coded modulation signal. Signal information of time modulation of each laser beam in can be acquired.
Note that the time modulation by the PN encoded modulation signal is performed at a frequency of 100 KHz to 10 MHz, which is lower than the frequency of the laser light time modulation by the RF modulation signal (50 MHz to 10 GHz).
In this way, the signal conversion unit 66 acquires time-modulated signal information of each of the n laser beams at the reflection position of each micromirror for each of the n cameras. That is, for one measurement unit region (corresponding to one micromirror) on the surface of the measurement object S, time-modulated signal information (electric signal) of n × n laser beams is obtained.

The distance information calculation unit 68 acquires phase shift information of each laser beam signal corresponding to a plurality of RF modulation signals having different frequencies, and from this, the change in the phase shift amount relative to the frequency of the RF modulation signal (relative phase change). (Quantity) is obtained, and distance information of the measuring object T is obtained using this relative phase change amount.
Specifically, the distance from the laser diode 22 of the laser beam emitting unit 20 of the main body 12 to the measurement object T and the distance from the reflection point on the surface of the measurement object T to the lens 32 are represented by ρ and RF modulation. When the wavelength of the signal is λ, the frequency of the RF modulation signal is f, the speed of light is c, and the phase shift of each laser light signal with respect to the RF modulation signal is θ, the distance ρ is expressed by the following equation (5) as follows: It can be expressed as equation (6).

That is, the distance ρ of the measurement target T is calculated using the equation (6) by obtaining the ratio of the phase shift amount of each laser beam signal with respect to the frequency of the RF modulation signal.
The distance ρ is the distance from the laser diode 22 to the optical lens 36 via the reflection point on the surface of the measuring object T, but it is sufficient to know this distance ρ. Since the distance of the optical path from the optical lens 32 to the light receiving surface of the photoelectric converter 38 and the distance of the transmission line leading to the mixer 47 are known, it can be corrected to a correct value using a predetermined correction equation or the like. it can.
Specifically, the distance information calculation unit 68 acquires the signal information for each laser beam at the reflection position of each micromirror calculated by the signal conversion unit 66. This signal information is r · cos (θ) (where r is the reflectance on the surface of the object to be measured and θ is the amount of phase shift) when the phase shift of the RF modulation signal that is the reference signal that enters the mixer 47 is 0. Since r · sin (θ) is obtained when the RF modulation signal is phase-shifted by 90 degrees, the distance information calculation unit 68 calculates the phase shift amount θ using these signals.

The three-dimensional position information calculation unit 70 uses the distance ρ calculated by the distance information calculation unit 68 and further uses the position information of the micromirror in the ON state to determine the position of the measurement target T reflected by the laser light. This is a part to be obtained as three-dimensional position information.
Specifically, as shown in FIG. 9A, an XYZ orthogonal coordinate system is defined with the center of the optical lens 32 as the origin O, and the emission position of the laser diode 22 corresponding to each piece of laser beam information is defined as a point Q (position coordinate). (Refer to (a, b, c)), the reflection position of the measuring object T is a point P (position coordinates (x, y, z)), and the spatial modulation element 34 to which the laser beam reflected at the point P is directed It is assumed that the position of the micromirror is R (position coordinates (−x ₀ , −y ₀ , −z ₀ )). At this time, as shown in FIG. 9B, the distance PO can be expressed as PO = m × RO using the magnification m of the lens 32 and the distance RO. Note that z ₀ of the position R of the micromirror is set as a dimension unique to the apparatus.
On the other hand, the distance ρ can be expressed by the following formula (7). Moreover, since the position x, y, z of the point P can be expressed by the following formula (8), the magnification m can be expressed by the following formula (9) using the formula (7) and the formula (8). .

The three-dimensional position information calculation unit 70 follows the above equation (9), the distance ρ, the emission position of the laser diode 22 (position coordinates (a, b, c)), the position of the micromirror in the ON state (position coordinates (− x ₀ , −y ₀ , −z ₀ )) is used to calculate the magnification m, and further, the three-dimensional position information (position coordinates (x, y, z) of the reflection position of the measuring object T is calculated using equation (8). )). In this manner, three-dimensional position information is acquired for each of the time modulation signal information of n × n laser beams for each measurement target region.

The reflectance calculation unit 72 calculates the reflectance on the surface of the measurement target T.
As described in the distance information calculation unit 68, the signal conversion unit 66 calculates the signal information of each laser beam at the reflection position of each micromirror, and supplies this to the reflectance calculation unit 72. For this signal, the signal information obtained when the phase shift of the RF modulation signal that is the reference signal that enters the mixer 47 is set to 0 is r · cos (θ) as described above, and the RF modulation signal is phase-shifted by 90 degrees. The signal information obtained at this time is r · sin (θ). The reflectance calculator 72 calculates the reflectance r from the values of these two signal information.

  By irradiating the measurement target T with the laser light in this way, the distance between the system 10 and the measurement target T and the reflectance r on the surface of the measurement target T can be obtained. The reflectance in the three-dimensional space on the surface can be obtained as image information. In this way, the reflectance calculation unit 72 acquires the reflectance information for each of the time-modulated signal information of n × n laser beams for each measurement target region.

  The weighting coefficient setting unit 74 sets a weighting coefficient for each signal information according to the signal information (electric signal) of time modulation of n × n laser beams acquired for one measurement unit region. As described above, the intensity of reflected light of a plurality of laser beams received by one camera from the same point P on the surface of the measuring object S is different for each of the n laser beams. The intensity of the reflected light of the plurality of laser beams from the same point P is different in each of the n cameras. The signal information (electric signal) of time modulation of n × n laser beams acquired for one measurement unit region is a signal corresponding to the intensity of such reflected light, and the signal intensity is also different. Naturally, when the signal strength is low, the noise component is high (the S / N ratio is low), and even if distance information and reflectance information described later are calculated using such a signal, only information with low accuracy can be obtained. Can not. The weighting coefficient setting unit 74 is provided for each signal in accordance with the intensity of each of the time-modulated signal information (electric signals) of the n × n laser beams according to the intensity of the reflected light from one measurement unit region. Weighting coefficients for weighting calculated distance information and reflectance information described later are set in advance. The set weighting coefficient is sent to the three-dimensional image information generation unit 76 and is used to create three-dimensional image information.

  The three-dimensional image information generation unit 76 uses the weighting coefficient set by the weighting coefficient setting unit 74 and is calculated based on the signal information of time modulation of n × n laser beams for each measurement target region. Each of the three-dimensional position information and the reflectance information is weighted, and an average value is calculated using the weighted n × n pieces of the three-dimensional position information and the reflectance information. By weighting and averaging (determining the centroid value) in this way, highly accurate three-dimensional position information in which the value calculated based on the strong reflected light is dominant for each measurement unit region, and Reflectance information is obtained. The three-dimensional image information generation unit 76 generates high-precision three-dimensional image information of the measurement target T using the high-accuracy three-dimensional position information and reflectance information obtained in this way. The generated three-dimensional image information is sent to the display 16 and displayed as an image. In the three-dimensional image information acquisition system of the present invention, as described above, for each measurement unit region, a weighting coefficient corresponding to the signal intensity is set for each of the signal information of time modulation of n × n laser beams, The three-dimensional position information and the reflectance information are each weighted and averaged to obtain highly accurate three-dimensional position information and reflectance information related to the creation of the three-dimensional image information. In the three-dimensional image information acquisition system of the present invention, three-dimensional position information and reflectance information are obtained using a value obtained by integrating time-modulated signal information of n × n laser beams without using a weighting coefficient. Also good. Even in such a case, three-dimensional position information and reflectance information having a high S / N ratio, in which the component of the time-modulated signal of the laser light having a high reflection intensity is dominant, can be obtained. In order to obtain more accurate three-dimensional image information, it is preferable to average each of the n × n pieces of time-modulated signal information of the laser beams by weighting (determining a centroid value).

The system 10 is configured as described above. Next, the operation of the system 10 will be described.
10A to 10D are timing charts of various trigger signals generated when the system 10 is driven.

First, the system controller 51 of the control device 14 generates an image trigger signal (see FIG. 10A) that starts capturing a three-dimensional image of the measurement target T in each camera in response to an instruction from the computer 14. Is done.
Next, the system controller 51 generates a frame trigger signal so that the spatial modulation element 34 of each camera is controlled with a predetermined control pattern. The frame trigger signal is a trigger signal for switching the control pattern of the spatial modulation element 34, and as described above, the trigger signal for sequentially switching the control pattern in which the arrangement of the micromirrors in the ON state is controlled to a predetermined pattern. It is.

As shown in FIG. 10B, a frame trigger signal for sequentially switching to each mode of mode 1, mode 2,... Is generated. In each mode, a predetermined control pattern signal (not shown) is generated and supplied to the micromirror controller 35.
When the frame trigger signal is generated, a plurality of laser beams are emitted from a plurality of cameras at the same time. Therefore, in the light reception by the photoelectric converter 38, it must be possible to identify which camera the laser beam is received from. Therefore, in order to time-modulate each laser beam with a PN encoded modulation signal (ON / OFF of laser beam emission), the system controller 51 generates a different PN encoded modulation signal for each laser beam, and each camera Supplied to each laser driver.
In other words, the intensity of the laser light emitted from each camera is time-modulated and further time-modulated by ON / OFF of the emission of the laser light by the PN encoded modulation signal. The frequency f is 50 MHz to 10 GHz, the output ON / OFF switching frequency by the PN encoded modulation signal is 100 KHz to 10 MHz, and the frequency range of time modulation is greatly different from each other.

  Further, the system controller 51 generates a phase trigger signal for driving the phase shifter 44 (see FIG. 10C). By generating the phase trigger signal, a phase control signal is generated so as to generate two local signals with a phase shift amount of 0 (no phase shift) and a phase shift amount of 90 degrees with respect to the RF modulation signal of frequency f. .

  In this manner, an RF modulation signal having the frequency f in mode 1 is generated, and the laser light time-modulated is emitted from the laser light emission unit 20 of each camera. The laser light reflected from the surface of the measurement target T enters the optical unit 30 and is guided to the spatial modulation element 34 via the prism 33. Since the micromirror of the spatial modulation element 34 is controlled by a predetermined control pattern, only the laser light reflected by the micromirror in the ON state is guided to the photoelectric converter 38 and received. The laser light having time-modulated signal information is converted into an electric signal by the photoelectric converter 38, amplified by the amplifier 48, and supplied to the mixer 47.

On the other hand, in the phase shifter 44, the RF modulation signal separated by the power splitter 42 is sequentially controlled to a phase shift amount 0 (no phase shift) and a phase shift amount 90 degrees to generate local signals. It is supplied to the mixer 47.
In the mixer 47, the electric signal supplied from the amplifier 48 is mixed (multiplied) with each of the two local signals to generate a signal composed of the IF signal and higher-order components. The IF signal includes time-modulated signal information of frequency f and time-modulated signal information based on a PN-coded modulated signal.
Further, a high-order component is removed from the generated signal by the low-pass filter 52, and an IF signal composed of time-modulated signal information of the frequency f and time-modulated signal information based on the PN encoded modulation signal is generated.
In this way, the signal is taken into the A / D converter 54 via the amplifier 53, sequentially sampled according to the sampling clock signal (see FIG. 10D), converted into an intermediate frequency digital signal, and supplied to the computer 14.

  Thus, when the emission and reception of the laser beam in mode 1 are completed, the mode is sequentially switched to modes 2, 3,..., Signal processing is sequentially performed by the control circuit unit 50, and the computer 14 is supplied.

For example, the intensity amplitude A _i (t) of the time-modulated laser beam emitted from the laser diode 22 of the i-th (i = 1 to n natural number) camera Di is determined by the following equation (10) (p _i (T) is a time-modulated component based on a PN encoded modulation signal), and local signals A ₀ (t) and A ₉₀ (t) supplied to the mixer 47 of each camera are defined by the following equation (11), and the measurement target When the amplitude of the electrical signal of the laser beam received by one camera is determined by the following equation (12) by being reflected by the surface of the object T and further reflected by the micro mirror in the ON state, the IF signal is expressed by the following equation ( 13). High-order components in the IF signal are removed by using a low-pass filter 52 and A / D converted to generate an intermediate frequency digital signal.

The intermediate frequency digital signal supplied to the computer 14 in this way is sequentially recorded in the memory 62 for each mode.
In the signal conversion unit 66, Hadamard inverse conversion and coding identification conversion are performed using the intermediate frequency digital signal of each mode.
Since the control pattern of the ON state of the micromirror determined for each mode uses a pattern using a tensor product between each row of the Hadamard matrix, the intermediate frequency digital signal obtained for each control pattern of each mode is used. It decomposes into an intermediate frequency digital signal for each micromirror. This decomposition is performed using Hadamard inverse transformation.

Furthermore, since the PN encoded sequence signal used for laser light time modulation has autocorrelation and orthogonality, the PN encoded sequence signal used for time modulation and the intermediate frequency digital signal subjected to Hadamard inverse transformation are used. By calculating the correlation function between them, coding discrimination conversion for decomposing the intermediate frequency digital signal is performed for each laser beam. That, 1/2 · r _i · cos in equation (13) (θ _i) and _{1/2 · r i · sin (θ} i) is obtained. These values are supplied to the distance information calculation unit 68 and the reflectance calculation unit 72.

In the distance information calculation unit 68 calculates an angle theta _i from the value of 1/2 was determined r _i · cos _{(θ i)} and _{1/2 · r i · sin (θ} i). The angle θ _i is the phase shift amount of the electrical signal output from the photoelectric converter 38 with respect to the RF modulation signal.
By substituting this phase shift amount into the above-described equation (6), the distance ρ of the measuring object T is obtained. This distance ρ is obtained for each laser beam and for each micromirror of the spatial modulation element 34. In the three-dimensional position information calculation unit 70, the three-dimensional position coordinates (x, y) of the surface of the measuring object T reflected by the laser beam using the distance ρ obtained by the distance information calculation unit 68 and the position information of the micromirror. , Z) is obtained using the above-described equations (8) and (9).

Further, the reflectance calculating section 72, supplied from the signal converting section _{66 1/2 · r i · cos (} θ i), the reflectivity r using the value of _{1/2 · r i · sin} (θ i) _i is required.
In this way, the three-dimensional position information and the reflectance obtained by the three-dimensional position information calculation unit 70 and the reflectance calculation unit 72 are supplied to the display 16 and a three-dimensional image of the measurement target T is displayed.

As described above, according to the present invention, the three-dimensional position of the measurement target T irradiated to the laser light using the time-modulated phase shift information and the position information of each micromirror in the laser light incident on the spatial modulation element 34 of the laser light. Information can be acquired at high speed. Furthermore, since the reflectance on the surface of the measuring object T can be obtained, it can be used as image information, and the three-dimensional image information can be acquired at high speed using this image information and the three-dimensional shape.
The reflectance r _i represents the reflectance of the surface of the measurement target T. For example, if the laser light is visible laser light of the three primary colors of red, green, and blue, the reflection on the surface of the measurement target T in the three primary colors. The rate can be determined. That is, the color information of the surface of the measurement target T can be acquired, and a three-dimensional color image of the measurement target T can be acquired.

  As described above, the system 10 irradiates the laser beam from a plurality of different positions, and arranges the light receiving surfaces of the reflected light at the plurality of different positions, thereby providing an unspecified reflectance and an unspecified surface. Information on the reflected light of high-intensity laser light can be acquired for any part in the measurement target region with respect to the shape measurement target object. In the three-dimensional image information acquisition system of the present invention, the laser light is time-modulated with a coded modulation signal that can be identified, and even if laser light is irradiated simultaneously from a plurality of positions, the laser is used using this coded modulation signal. Each light (the reflected light) can be identified. With such a configuration, the three-dimensional image information acquisition system of the present invention acquires information on the reflected light of high-intensity laser light for any part in the measurement target area without moving the laser light irradiation unit itself. It is possible to acquire highly accurate three-dimensional image information in a short time (at high speed).

  The three-dimensional image information acquisition system of the present invention has been described in detail above. However, the present invention is not limited to the above embodiment, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.

1 is an external view of a three-dimensional image information acquisition system according to an embodiment of the three-dimensional image information acquisition system of the present invention. In the three-dimensional image information acquiring system shown in FIG. 1, a diagram each camera D ₁ to D _n will be described laser light received. It is a schematic block diagram explaining the control apparatus of the three-dimensional image information acquisition system shown in FIG. In view for camera D ₁ to D _n of the three-dimensional image information acquiring system will be described as shown in FIG. 1 is a schematic block diagram showing a representative Camera D _1. It is a figure explaining reflection of the laser beam in the ON state and OFF state of the micromirror used in the three-dimensional image information acquisition system shown in FIG. (A)-(c) is a figure explaining the control pattern of the micromirror used in the three-dimensional image information acquisition system shown in FIG. It is a block diagram which shows the structure of the computer of the three-dimensional image information acquisition system shown in FIG. It is a figure which shows an example of the PN encoding modulation | alteration signal produced | generated in the three-dimensional image information acquisition system shown in FIG. (A) And (b) is explanatory drawing explaining the method of calculating | requiring three-dimensional position information in the three-dimensional image information acquisition system shown in FIG. (A)-(d) is a timing chart of the various trigger signals produced | generated in the three-dimensional image information acquisition system shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Three-dimensional image information acquisition system 14 Control apparatus 16 Computer 20 Laser beam emission unit 22 Laser diode 24 Laser driver 28 Optical lens 30 Optical unit 31 Band pass filter 32 Optical lens 33 Prism 34 Micro mirror array spatial modulation element 35 Micro mirror control 36 Optical lens 37 Mirror 38 Photoelectric converter 41 Oscillator 42 Power splitter 43 Amplifier 44 Phase shifter 45 Amplifier 46 Power splitter 47 Mixer 48 RF splitter 49 Measurement data bus 50 Data processing unit 51 System controller 54 A / D converter 60 CPU60
62 memory 64 data processing unit 66 signal conversion unit 68 distance information calculation unit 70 three-dimensional position information calculation unit 72 reflectance calculation unit 74 weighting coefficient setting unit 76 three-dimensional image information generation unit

Claims (7)

Three-dimensional image information for acquiring three-dimensional image information of a measurement object by irradiating the measurement object with a plurality of laser beams emitted from different positions and receiving the reflected light of each laser beam reflected by the measurement object An acquisition system,
A plurality of laser beam emitting units arranged at different positions, which simultaneously irradiate laser beams that have been time-modulated according to amplitude-modulated signals, from different directions toward the same range of the measurement object;
A plurality of photoelectric converters that receive a plurality of laser beams reflected by the measurement object and output electrical signals corresponding to the received laser beams;
An element having a plurality of micromirrors arranged on a plane provided corresponding to each photoelectric converter, and the reflective surface of the micromirror selected from these micromirrors is controlled in a predetermined direction. By turning them on, the laser beams reflected from the micromirrors in the ON state are guided to the respective light receiving surfaces of the corresponding photoelectric converters and are arranged at different positions. A mirror array spatial modulation element;
For each electrical signal output from each photoelectric converter, an electrical signal component identification unit that identifies electrical signal components corresponding to each of a plurality of laser beams received by the light receiving surface of each photoelectric converter;
Using the information on the emission position of each laser beam and the information on the arrangement position of the micromirrors in the ON state in each micromirror array spatial modulation element, for each electrical signal component corresponding to each laser beam, the measurement object A position information calculation unit for obtaining the three-dimensional position information of
A three-dimensional image information creating unit that creates three-dimensional image information of the measurement object based on the three-dimensional position information of the plurality of measurement objects obtained for each electrical signal component corresponding to each laser beam; 3D image information acquisition system. A weighting coefficient setting unit that sets a larger weighting coefficient for each electric signal component as the intensity of each electric signal component identified in the electric signal component identification unit is larger;
The three-dimensional image information creation unit weights each of the three-dimensional position information of the plurality of measurement objects obtained for each electric signal component corresponding to each laser beam using the weighting coefficient, and The three-dimensional image information acquisition system according to claim 1, wherein three-dimensional image information of an object is created. A distance information calculation unit that calculates distance information from the emission position of each laser beam to the measurement object using the amplitude modulation signal,
The three-dimensional image information acquisition system according to claim 1, wherein the position information calculation unit obtains three-dimensional position information of the measurement object by further using the distance information. Each of the plurality of laser beams emitted simultaneously from the plurality of laser beam emitting units is time-modulated by the amplitude modulation signal and further time-modulated by an encoded modulation signal that can be identified for each laser beam,
The electrical signal component identifying unit can use the information coded modulation signal included in the electrical signal, according to one of claims 1 to 3 for identifying an electrical signal components corresponding to the plurality of laser beams 3D image information acquisition system. In the micromirror array spatial modulation element, the micromirrors in the ON state occupy 50% or more of all the micromirrors, the micromirror control patterns are sequentially switched, and the laser light spatially modulated in accordance with the control patterns is converted into the photoelectrical light. The three-dimensional image information acquisition system according to any one of claims 1 to 4, wherein the three-dimensional image information acquisition system is guided to a light receiving surface of a converter. The three-dimensional image information acquisition system according to claim 5 , wherein the control patterns that are sequentially switched are control patterns that are orthogonal to each other. A reflectance calculation unit that calculates the reflectance at the surface of the measurement object from each of the electrical signal components identified by the electrical signal component identification unit;
  The said three-dimensional image information preparation part weights each of the said some reflectance using the said weighting coefficient, and produces the three-dimensional image information of the said measurement target object in any one of Claim 2 thru | or 6. 3D image information acquisition system.

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