JP2006258464A - Three-dimensional image information acquisition system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine three-dimensional location information and reflectivity of an object to be measured and acquire three-dimensional images at high speed on the basis of the information through the use of both two-dimensional location information of each micromirror of spatial modulation elements of a micromirror array and phase shift information of temporal modulation of optical intensity of a laser beam incident onto the spatial modulation elements of the micromirror array. <P>SOLUTION: The system for acquiring three-dimensional location information of an object to be measured by irradiating a laser beam to the object to be measured and receiving reflected light from the object to be measured is provided with a plurality of light reception surfaces for receiving a laser beam reflected at the object to be measured and comprises a photoelectric converter for converting information of the laser beam received at each light reception surface into an electric signal and outputting it; a spatial modulation element of the micromirror array for controlling the reflecting surface of a selected micromirror in a prescribed direction into an ON state for every one of a plurality of partial regions and guiding reflected light of a laser beam reflected at the micromirror in an ON state from the object to be measured to different light reception surfaces; and a data processing part for determining three-dimensional location information of the object to be measured through the use of both phase shift information of each electric signal and location information of the micromirror in an ON state in reach partial region. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a three-dimensional image information acquisition apparatus that acquires three-dimensional image information of a measurement object by irradiating the measurement object with laser light and receiving reflected light from the measurement object. The present invention relates to an apparatus that can be suitably used in a technical field such as (industrial image inspection apparatus) or a laser radar that knows the state of a measurement object from information of a laser beam returned upon hitting the measurement object.

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 of acquiring a three-dimensional image of an object from captured images of the object captured from different directions with a plurality of cameras is known (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 the said nonpatent literature 1, a three-dimensional image can be acquired based on a some picked-up image as needed, and a virtual three-dimensional image can be created. 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, when acquiring a three-dimensional image, it is necessary for a system user to separately define a reference point for aligning captured images captured by a plurality of cameras, which is difficult to automate.
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 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. Must be set and difficult to automate.

  Therefore, the present invention is an apparatus for automatically acquiring three-dimensional image information of a measurement object by irradiating the measurement object with laser light and receiving reflected light from the measurement object, An object of the present invention is to provide a three-dimensional image information acquisition apparatus that acquires a three-dimensional image at high speed using different methods.

  In order to achieve the above object, the present invention provides a three-dimensional image information acquisition device that acquires three-dimensional image information of a measurement object by irradiating the measurement object with laser light and receiving reflected light from the measurement object. A laser light emitting unit for time-modulating the light intensity of the laser light in accordance with an amplitude modulation signal and irradiating the measurement object; and a plurality of light receiving surfaces for receiving the laser light reflected by the measurement object. Laser light received between the measurement object and each light receiving surface of the photoelectric converter, which converts the information of the laser light received by the surface into an electrical signal for each light receiving surface and outputs the electrical signal An element having a laser light reflecting surface provided on a road and having a plurality of micromirrors arranged on a plane, each of the laser light reflecting surfaces being a plurality of partial regions each having a predetermined number of micromirrors arranged Divided into Thus, for each partial region, the reflection surface of the laser beam reflected from the measurement object reflected by the micromirror in the ON state is controlled by turning on the reflecting surface of the selected micromirror in a predetermined direction. And a phase difference information for the amplitude modulation signal in the electrical signal for each light receiving surface output from each of the photoelectric converters and the micromirror array spatial modulation element that leads to the different light receiving surfaces for each partial region. Data processing for obtaining three-dimensional position information of an object to be measured by obtaining each electric signal and using phase shift information for each electric signal and position information of the micromirrors in the ON state of each partial region And a three-dimensional image information acquisition device.

  The three-dimensional image information acquisition apparatus of the present invention includes coding modulation means for time-modulating each electric signal for each light receiving surface with a coded modulation signal that can be identified for each electric signal, and the data processing unit Uses the information of the encoded modulation signal included in the electrical signal to identify a light receiving surface that has received the reflected light of the laser light converted into the electrical signal, and reflects the laser light on the light receiving surface. Preferably, a partial area of the laser light reflecting surface that guides light is specified, and the three-dimensional position information is obtained using position information of the micromirror in the ON state of the specified partial area. The plurality of light receiving surfaces are preferably arranged on the same plane.

Also, the electrical signal output for each light receiving surface of the photoelectric converter is mixed using a signal having the same frequency as the amplitude modulation signal as a reference signal, and the laser light time-modulated with the amplitude modulation signal Having an intermediate frequency signal generating means for extracting a signal component as an intermediate frequency signal;
The data processing unit uses the intermediate frequency signal to acquire phase shift information for the amplitude modulation signal, and uses the phase shift information and the position information of the micromirrors in the ON state for each partial region. It is preferable to obtain the three-dimensional position information of the measurement object.

  Prior to the mixing process in the intermediate frequency signal generating means, the intermediate frequency signal generating means comprises the electric signal synthesizing means for synthesizing a plurality of electric signals output for each light receiving surface of the photoelectric converter. It is preferable that the combined electric signal generated in the electric signal combining means is mixed using a signal having the same frequency as the amplitude modulation signal as a reference signal.

  Further, the intermediate frequency signal generation means takes out the intermediate frequency signal by using the amplitude modulation signal and a phase shift modulation signal obtained by phase shifting the amplitude modulation signal by a predetermined amount as a reference signal, and the data processing unit It is preferable to obtain reflectance information on the surface of the measurement object together with the phase shift information from the signal, and use the reflectance information and the three-dimensional position information as three-dimensional image information.

  In addition, the data processing unit uses the phase shift information and the position information of the micromirrors in the ON state, and information on the emission position of the laser beam in the laser beam emission unit, and the three-dimensional position information of the measurement object. Is preferably obtained.

  The laser beam emitting unit time-modulates the laser beam using a plurality of amplitude modulation signals having different frequencies, and the data processing unit performs the phase shift information in the electrical signal for each amplitude modulation signal having a different frequency. It is preferable to obtain distance information between the three-dimensional image information acquisition device and the measurement object using the plurality of pieces of phase shift information.

  Further, the data processing unit determines the position of the measurement object in the direction orthogonal to the arrival direction of the laser light to the three-dimensional image information acquisition device from the obtained distance information and the position information of the micromirror in the ON state. It is preferable to seek information.

  Further, the laser beam emitting unit emits a plurality of laser beams having different wavelengths, and obtains color image information of the measurement object by obtaining information on the reflectance of the surface of the measurement object for each of the laser beams. It is preferable to obtain.

  In the micromirror array spatial modulation element, the micromirror control pattern is sequentially switched for each partial region, and the micromirrors in the ON state occupy 50% or more of all the micromirrors. It is preferable to guide the modulated laser light to each light receiving surface of the photoelectric converter. The control patterns that are sequentially switched are preferably control patterns that are orthogonal to each other.

  In the present invention, the measurement object is measured using the two-dimensional position information of each micromirror of the micromirror array spatial modulation element and the phase shift information in the time modulation of the light intensity of the laser light incident on the micromirror array spatial modulation element. By obtaining the three-dimensional position information and the reflectance of the object, the three-dimensional image information of the measurement object can be acquired at high speed from these information. Further, by using visible laser beams of the three primary colors of red, green and blue, the reflectance for each laser can be obtained, and the three-dimensional image information possessed by the color information can be acquired at high speed.

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

FIG. 1 is an external view of a three-dimensional image information acquisition apparatus (hereinafter referred to as an apparatus) 10 which is an embodiment of the three-dimensional image information acquisition apparatus of the present invention.
The apparatus 10 measures the three-dimensional position information of the measurement object acquired by receiving the reflected light from the measurement object among the laser beams irradiated to the measurement object existing within the measurement object region T, and the measurement. This is an apparatus for acquiring three-dimensional image information based on the reflectance on the surface of an object. The three-dimensional image information acquisition apparatus 10 emits laser light to irradiate the measurement target in the measurement target region T, and receives the laser light reflected from the surface of the measurement target in the measurement target region T.

The apparatus 10 irradiates a measurement target in the measurement target region T with a laser beam and receives a reflected light from the measurement target, and outputs a three-dimensional image of the measurement target in the measurement target region T. It has a main body 12 that outputs a signal including information, and a computer 14 that acquires three-dimensional image information of the measurement object using the signal output from the main body 12.
The computer 14 performs data processing using a signal output from the main body unit 12 and is also a control unit that controls driving of each unit of the main body unit 12 and driving timing.

FIG. 2 is a block diagram illustrating a device configuration of the main body 12.
The main body 12 includes a laser beam emitting unit 20, an optical unit 30, a radar circuit unit 40, and a control circuit unit 50. The control circuit unit 50 is connected to the computer 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 to the laser driver from a radar circuit unit described later, and laser light is emitted from the laser diode in accordance with the amplitude modulation signal. An amplitude modulation signal (hereinafter referred to as an RF modulation signal) is a signal having a frequency (50 MHz to 10 GHz), for example, and is used for temporally 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 object in the measurement target region T. As shown in FIG. 2, in order from the upstream side of the optical path of the laser light, a bandpass filter 31, 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 arranged. The spatial modulation element 34 is connected to the micromirror controller 35.

The band pass filter 31 is a narrow band 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 reflected light from the measurement object. 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 beam that has been reflected from the micromirror in the ON state and has arrived from the measurement object is guided to the light receiving surface of the photoelectric converter 38.

FIG. 3 is a diagram for explaining the reflection of laser light in the micromirrors in the ON state and the OFF state. In FIG. 3, 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 light receiving surface 39 of the photoelectric converter 38 via the lens 36, and the laser light reflected by the reflecting surface of the micromirror B in the OFF state is photoelectrically converted. Reflects in a different direction from the transducer 38. Thus, the laser beam reflected by the micromirror in the ON state is received by the photoelectric converter 38.

The optical lens 36 is configured to form an image of laser light on the light receiving surface 39 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, and is configured by arranging four photoelectric conversion devices 38 a to 38 d such as a photomultiplier tube and an avalanche photodiode. Each of the photoelectric conversion devices 38a to 38d includes light receiving surfaces 39a to 39d, and outputs an electrical signal corresponding to light incident on each light receiving surface. Note that the number of the devices provided in the photoelectric converter 38 is not limited to four, and may be four or more or four or less.

  In the optical unit 30, the entire mirror surface 29 of the spatial modulation element 34 on which a plurality of micromirrors are arranged on a plane is the entire reflected light of the laser light from the measurement target region T (reflected light from the measurement target). It is configured to receive light. In addition, the entire light receiving surface 39 (light receiving surfaces 39a to 39d) of the photoelectric conversion device 38 receives light reflected from the entire mirror surface 29 of the spatial modulation element 34. That is, the size of the entire image formed by the reflected light from the measurement target region T corresponds to the size of the entire mirror surface 29 of the spatial modulation element 34. Further, the overall size of the image formed by the reflected light from the entire mirror surface 29 corresponds to the overall size of the light receiving surface 39 (light receiving surfaces 39a to 39d) of the photoelectric conversion device 38. FIG. 4 is a schematic diagram for explaining the correspondence between the reflected light from the measurement target region T and the mirror surface 29 of the spatial modulation element 34, and the correspondence between the reflected light from the mirror surface 29 and the light receiving surface 39 of the photoelectric conversion device 38. It is.

  As shown in FIG. 4, the entire mirror surface 29 of the spatial modulation element 34 is divided into four partial mirror regions 29a to 29d each having a plurality of mirror surfaces arranged. In the spatial modulation element, the angle of each mirror is controlled by a micromirror controller 35 to be described later in a different pattern for each of the partial mirror regions 29a to 29d. The laser light reflected in the measurement target region T is shaped and reflected by the optical lens 32 and the prism 33 and enters the entire mirror surface 29 of the spatial modulation element 34. Reflected light from different partial measurement areas Ta to Td in the measurement target area T is incident on the partial mirror areas 29a to 29d, respectively. The laser beams reflected by the respective ON-state mirrors of the respective partial mirror regions 29a to 29d are reflected by the mirror 37 through the prism 33, and are incident on the light receiving surfaces 39a to 39d of the photoelectric conversion devices 38a to 38d, respectively. To do. In the optical unit 30, as described above, each of the laser beams reflected by the partial mirror regions 29a to 29d (specifically, reflected by the mirrors in the ON state) of the mirror surface 29 of the spatial modulation element 34 is photoelectrically converted. The light is incident on different light receiving surfaces 39a to 39d of the devices 38a to 38d, respectively.

  According to the three-dimensional image acquisition apparatus of the present invention, as described above, the laser light reflected by the micromirrors in the ON state is separately received for each light receiving surface of the plurality of photoelectric conversion devices, and the received laser light is received. The electric signal according to is output. And by processing each output electric signal individually, three-dimensional image information can be acquired in a short time. 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 of a CCD (Charged Coupled Device) image sensor or the like by dividing it 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.

Here, the spatial modulation element 34 will be described in more detail. 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. The micromirror controller 35 controls the direction of the reflecting surface of each of the plurality of micromirrors for each of the partial mirror regions 29a to 29d. Under the control of the micromirror controller 35, for each partial mirror region 29a to 29d, different control patterns of micromirrors in which more than half of all micromirrors (all micromirrors in each partial region) are in the ON state are sequentially applied. Can be switched. The control pattern of the micromirror is preferably a control pattern having orthogonality to each of the partial mirror regions 29a to 29d, where the micromirror ON state is 1 and the OFF state is -1. For example, it is preferably generated using a Hadamard matrix.

More specifically, the control pattern for each of the partial mirror regions 29a to 29d is a micromirror arrangement pattern in which the spatial modulation element 34 is turned on. This control pattern is a tensor product between each row of the Hadamard matrix. This is a pattern created using. Each of the partial mirror regions 29a to 29d is controlled by the same control pattern. Hereinafter, one partial mirror region 29a among the plurality of partial mirror regions 29a to 29d will be described, and a control pattern in the plurality of partial mirror regions will be described. FIG. 5A is a diagram for explaining an example of a control pattern viewed from the reflective surface side of the micromirror with respect to the partial mirror region 29a in which 64 (= 8 × 8) micromirrors are arranged. . In the example shown in FIG. 5A, for example, 256 (64 × 4) micromirrors are arranged on the entire mirror surface 29 of the spatial modulation element 34, which includes a plurality of partial mirror regions 29a to 29d. It becomes. In one partial mirror region 29a, the micromirrors are arranged in a rectangular shape with 8 rows in the vertical direction and 8 rows in the horizontal direction. In FIG. 5A, 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. 5B, 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 to the 0th order, the first order, the second order, . . . . . , 7th order is a one-dimensional control pattern in the horizontal direction. On the other hand, as shown in FIG. 5C, 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 pattern of a desired order is selected from the one-dimensional control pattern in the horizontal direction shown in FIG. 5B, and a pattern of the desired order is selected from the one-dimensional control pattern in the vertical direction shown in FIG.

In FIG. 5A, 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. .
In this way, the spatial modulation element 34 reflects the laser light coming from the measurement target region while sequentially switching to different control patterns in each of the partial mirror regions 29a to 29d.

The radar circuit unit 40 supplies an RF modulation signal to the laser driver 24 of the laser light emission unit 20 and also uses an RF amplitude modulator, which will be described later, to modulate an electrical signal output from each of the photoelectric converters 38a to 38d. A PN encoded modulation signal is supplied, and each electric signal is modulated by the PN encoded modulation signal. Then, the electrical signals output from each of the photoelectric converters 38a to 38d are mixed 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), This is a part for extracting the signal component of the laser light time-modulated with the RF modulation signal as an intermediate frequency signal (IF signal).
Specifically, the radar circuit unit 40 corresponds to the oscillator 41, the power splitter 42, the amplifier 43, the phase shifter 44, the amplifier 45, the RF combiner 46, the mixer 47, the amplifier 48, and the photoelectric converters 38a to 38d described above. RF amplitude modulators 49a to 49d connected to each other.

  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 oscillation frequency is a plurality of frequencies, for example, two frequencies, and the laser light is time-modulated with these two frequencies. The reason why the laser light is time-modulated with a plurality of frequencies is to obtain the absolute distance from the apparatus 10 to the measurement object, as will be described later, by time-modulating the laser light with different frequencies.

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 laser driver 24 via the amplifier 43 and used as an RF modulation signal. The other signal is supplied to the transporter 44.
The phase shifter 44 passes the RF modulation signal without phase shifting and generates a phase shift modulation signal by shifting the phase by 90 degrees in accordance with the phase control signal. 47 is a part to be sent. The mixer 47 will be described later.

  Each of the RF amplitude modulators 49a to 49d is connected to each of the photoelectric conversion devices 38a to 38d described above, and an electric signal output from each of the photoelectric conversion devices 38a to 38d is input thereto. The RF amplitude modulators 49a to 49d are supplied with PN encoded modulation signals, which will be described later, and the electrical signals output from the photoelectric conversion devices 38a to 38d are time-modulated with the PN encoded modulation signals. The RF combiner 46 combines each of the modulated electric signals that are time-modulated by the RF amplitude modulators 49a to 49d and outputs the combined electric signals. A combined modulated electric signal obtained by combining a plurality of modulated electric signals in the RF combiner 46 is sent to an amplifier 48. The amplifier 48 amplifies the combined modulation signal and sends it to the mixer 47.

  The mixer 47 uses the supplied RF modulation signal or phase shift modulation signal as a local signal, and multiplies (mixes) the above-described combined modulation signal with the electric signal amplified by the amplifier 48 to generate a modulated electric signal (PN encoding). This is a part that outputs an intermediate frequency signal (IF signal) having information of an electric signal (time-modulated with a modulation 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. Further, in the RF modulation signal of each frequency, a local signal in which the phase of the RF modulation signal is not shifted by the phase shifter 44 and a local signal in which the phase of the RF modulation signal is shifted by 90 degrees are generated. And electrical signal mixing (multiplication).

The control circuit unit 50 generates various control signals (oscillation frequency control signal, phase control signal, control pattern signal, PN encoded modulation signal) for controlling the driving of the laser light emitting unit 20, the optical unit 30, and the radar circuit unit 40. In addition, the signal is supplied to a predetermined unit and a signal output from the radar circuit unit 40 is processed.
The control circuit unit 50 includes a system controller 51, a low-pass filter 52, and an A / D converter 54.

The system controller 51 is a part that generates various control signals based on instructions from the computer 14.
The low-pass filter 52 filters the signal including the intermediate frequency signal (IF signal) output from the radar circuit unit 40 and the high-order component to remove the high-order component, and generates a modulated electric signal (PN encoded modulation signal). This is a portion to be an intermediate frequency signal including only information of a time-modulated electric signal). The intermediate frequency signal is converted into an intermediate frequency digital signal by the A / D converter 54 and supplied to the computer 14.

As shown in FIG. 6, the computer 14 has a CPU 60, a memory 62, and a ROM (not shown), and a data processing unit 64 is functionally configured by executing computer software. The computer 14 is connected to the display 16.
The CPU 60 is a part that instructs the control circuit unit 50 to generate various signals for driving and controlling each unit of the main body unit 12 and substantially performs operations of each process of the data processing unit 64 described later.

The data processing unit 64 is a part that calculates the three-dimensional position information of the measurement object constituting the three-dimensional image and the reflectance of the surface of the measurement object from the intermediate frequency digital signal. 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, and a reflectance calculation unit 72.
The signal converter 66 is a part that converts the intermediate frequency digital signal by using the control pattern signal and the PN coded modulation signal.
Since the control pattern signal is a signal created by the control circuit unit 50 in accordance with an instruction from the computer 14, the control pattern signal is known and is converted using this control pattern signal.

  As described above, the control pattern signal is supplied to each of the partial mirror regions 29a to 29d of the spatial modulation element 34, and the tensor between the components of each row of the Hadamard matrix as shown in FIGS. It is a signal that realizes a control pattern created by using a product. For this reason, the signal conversion unit 66 performs Hadamard inverse transform from the intermediate frequency digital signal obtained by each control pattern for each partial mirror region by using a known control pattern signal, and each partial mirror region The information of the laser beam reflected by each micromirror 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).

In the control pattern supplied to one partial mirror region, each row of the Hadamard matrix has orthogonality (the inner product of each row is 0), and thus is obtained by a tensor product between the components of each row of the Hadamard matrix. The synthesis matrix representing the control pattern also maintains orthogonality between the synthesis matrices. 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 of the laser beam reflected by each micromirror can be easily decomposed | disassembled for every partial mirror area | region using the process of Hadamard transformation.
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 information of laser light reflected for each micromirror.

  As described above, the reflected light from the mirrors corresponding to the partial mirror regions 29a to 29d of the spatial modulation element 34 is incident on the light receiving surfaces 39a to 39d of the photoelectric conversion devices 38a to 38d, respectively. From each of the photoelectric conversion devices 38a to 38d, the electrical signals output according to the laser light incident on the respective light receiving surfaces are reflected by the micromirrors in the partial mirror regions by performing Hadamard inverse transformation. Information of the laser beam can be easily decomposed.

  In addition, after the information of the laser beam which each partial mirror area | region 29a-29d of the spatial modulation element 34 calculated | required by Hadamard inversion received (reflected) is converted into an electrical signal in each photoelectric conversion device 38a-38d Are combined in the RF combiner 46 and sent to the signal converter 66. For this reason, the electrical signals sent to the signal conversion unit 66 are superimposed on the electrical signals output from the photoelectric conversion devices 38a to 38d (information on the laser beams received by the partial mirror regions 29a to 29d, respectively). For this reason, as shown below, each photoelectric conversion device 38a-38 is utilized using the autocorrelation and orthogonality of the PN encoding modulation signal used for the time modulation of the electric signal output from each photoelectric conversion device 38a-38d. It is decomposed into an intermediate frequency digital signal corresponding to 38d (that is, the partial mirror regions 29a to 29d).

As described above, the electric signals output from the photoelectric conversion devices 38a to 38d are time-modulated by the four RF amplitude modulators 49a to 49d using the PN encoded modulation signals, respectively. .
FIG. 7 is a diagram illustrating an example of a PN encoded modulation signal. In FIG. 7, one period of the PN coded 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.

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. In the RF amplitude modulation periods 49a to 49d, which RF amplitude modulator contains the signal information subjected to amplitude modulation, that is, in which partial mirror region of the partial mirror regions 29a to 29d of the spatial modulation element 34 It is possible to identify whether the electric signal corresponds to the incident and reflected laser light, and to decompose and extract the signal information for each partial mirror region.
In this way, the signal converter 66 performs the Hadamard inverse transform and the decomposition (encoding identification conversion) using the autocorrelation and orthogonality of the PN encoded modulation signal, from the intermediate frequency digital signal, to each partial mirror region. It is possible to acquire signal information of time modulation of laser light at the reflection position of each micromirror.
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).

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 phase shift amount of each laser beam 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 measurement 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. Since the phase shift amount θ is acquired for each of at least two frequencies of the RF modulation signal, the sensitivity (dθ / df) of the phase shift information is obtained by calculating the differential of the phase shift amount with respect to this frequency.

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. 8A, 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 is set to a point Q (position coordinates (a, b, c)). And the position of the micromirror in the ON state of the spatial modulation element 34 to which the laser beam reflected by the point P is directed to the point P (position coordinates (x, y, z)). Let R be (position coordinates (−x ₀ , −y ₀ , −z ₀ )). At this time, as shown in FIG. 8B, 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). )). Thus, the three-dimensional position information on the surface of the measuring object T is supplied to the display 16 and the three-dimensional shape of the measuring object T is displayed.

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 for each frequency of the RF modulation signal, and supplies this to the reflectance calculation unit 72. The 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 apparatus 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. The acquired image information of the measuring object T is sent to the display 16 and displayed as a three-dimensional image together with the three-dimensional shape of the measuring object T sent earlier.

The apparatus 10 is configured as described above. Next, the operation of the device 10 will be described.
9A to 9D are timing charts of various trigger signals generated when the device 10 is driven.

First, in response to an instruction from the computer 14, the control circuit unit 50 generates an image trigger signal (see FIG. 9A) that starts capturing a three-dimensional image of the measurement target T.
Next, the system controller 51 generates a frame trigger signal so that the spatial modulation element 34 controls the micromirror 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. 9B, 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, the laser light is reflected by the measurement object, received by each of the plurality of photoelectric converters 38a to 38d via the spatial modulation element 34, and converted into an electrical signal. The electrical signals from the photoelectric converters 38 a to 38 d are combined and sent to the signal converter 66. It is necessary to be able to identify the light receiving surface of which photoelectric converter has received the signal component of the combined electric signal (synthetic modulation electric signal). For this reason, in order to time-modulate the electrical signals output from the photoelectric converters 38a to 38d with the PN encoded modulation signals, the system controller 51 generates different PN encoded modulation signals for the photoelectric converters 38a to 38d. It is generated and supplied to the RF amplitude modulators 49a to 49d corresponding to the photoelectric converters 38a to 38d, respectively.
As described above, the time modulation by the PN coded 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), and each time modulation. The frequency ranges are greatly different from each other.

  Further, the system controller 51 generates a phase trigger signal for driving the phase shifter 44 (see FIG. 9C). 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 way, an RF modulation signal having the frequency f in mode 1 is generated, and the laser light that is time-modulated is emitted from the laser light emission unit 20. 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. For each partial mirror region of the spatial modulation element 34, the micromirror is controlled with a predetermined control pattern, and only the laser light reflected by the micromirrors in the ON state for each partial mirror region corresponds to each partial mirror region. Is incident on the photoelectric converter 38 (the light receiving surface 39). In each of the photoelectric converters 38a to 38d, the light incident on each of the light receiving surfaces 39a to 39d is converted into an electric signal, and this electric signal is converted into a supplied PN encoded modulation signal in each of the RF amplitude modulators 49a to 49d. Accordingly, the signals are modulated, amplified by the amplifiers 48 a to 48 d, 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. 9D), converted into an intermediate frequency digital signal, and supplied to the computer 14.

For example, a laser beam having a frequency f is reflected on the surface of the measuring object T, further reflected by the micromirror in the ON state, and received by the light receiving surface 39 of the i-th (i = 1 to 4 natural number) photoelectric converter 38. Then, the amplitude of the electric signal output from the i-th photoelectric converter 38 is determined by the following equation (10) (p _i (t) is a time modulation component by a PN encoded modulation signal, and θ _i is a photoelectric When the local signals A ₀ (t) and A ₉₀ (t) supplied to the mixer 47 are defined by the following formula (11), the phase shift amount of the electrical signal output from the converter 38 with respect to the RF modulation signal is determined. The IF signal is expressed by the following equation (12). 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 thus supplied to the computer 14 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 (12) (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 amount of phase shift of the electrical signal output from each of the photoelectric converters 38a to 38d 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 reflected laser beam received by each photoelectric converter 38 and for each micromirror in the partial mirror region corresponding to each photoelectric converter 38. 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, in the present invention, the three-dimensional position information of the measurement object T irradiated to the laser light is obtained by using the time modulation phase shift information in the laser light incident on the spatial light modulator 34 and the position information of each micromirror. It can be acquired at high speed. In the present invention, the electrical signals output from the photoelectric conversion devices 38a to 38d are combined by the RF combiner 46, and then the local signal (the signal that does not shift the phase of the RF modulation signal and the phase of the RF modulation signal) is mixed by the mixer 47. And an intermediate frequency signal (IF signal) having information of a modulated electric signal (electric signal time-modulated with a PN-coded modulated signal) and a signal including higher-order components. Output.

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 reflectivity r _i represents the reflectivity of the surface of the measurement target T. For example, if visible laser beams of the three primary colors of red, green, and blue are used as the laser light source, 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.
Thus, since the apparatus 10 uses the spatial modulation element 34, it is not necessary to rotate a large polygon mirror or galvanometer mirror that reflects the laser light at a high speed as in the prior art, and the optical lens 32 shown in FIG. A thing with a large diameter can be used. Thereby, the condensing capability of the laser beam is also increased, and thus a three-dimensional image can be acquired in a short time using a low-power laser beam from a distant measurement object.

  The three-dimensional image information acquisition apparatus 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.

It is an external view of the three-dimensional image information acquisition apparatus of one Embodiment of the three-dimensional image information acquisition apparatus of this invention. It is a block diagram which shows the apparatus structure of the main-body part of the three-dimensional image information acquisition apparatus shown in FIG. 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 apparatus shown in FIG. In the three-dimensional image information acquisition apparatus shown in FIG. 1, the correspondence between the reflected light from the measurement target region T and the mirror surface of the spatial modulation element, and the correspondence between the reflected light from the mirror surface and the light receiving surface of the photoelectric conversion device It is a figure explaining. (A)-(c) is a figure explaining the control pattern of the micromirror used in the three-dimensional image information acquisition apparatus shown in FIG. It is a block diagram which shows the structure of the computer of the three-dimensional image information acquisition apparatus shown in FIG. It is a figure which shows an example of the PN encoding modulation signal produced | generated in the three-dimensional image information acquisition apparatus 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 apparatus shown in FIG. (A)-(d) is a timing chart of the various trigger signals produced | generated with the three-dimensional image information acquisition apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 3D-type image information acquisition device 12 Main part 14 Computer 20 Laser light emission unit 22 Laser diode 24 Laser driver 28 Optical lens 30 Optical unit 31 Band pass filter 32 Optical lens 33 Prism 34 Micromirror array spatial modulation element 35 Micromirror control 36 Optical lens 37 Mirror 38 Photoelectric converter 39 Light receiving surface 40 Radar circuit unit 41 Oscillator 42 Power splitter 43 Amplifier 44 Phase shifter 45 Amplifier 46 RF combiner 47 Mixer 48 Amplifier 49 RF amplitude modulator 50 Control circuit unit 51 System controller 52 Low-pass filter 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

Claims (6)

A three-dimensional image information acquisition device for acquiring three-dimensional image information of a measurement object by irradiating the measurement object with laser light and receiving reflected light from the measurement object,
A laser beam emitting unit that time-modulates the light intensity of the laser beam according to the amplitude modulation signal and irradiates the measurement object;
A photoelectric converter that includes a plurality of light receiving surfaces that receive the laser light reflected by the measurement object, converts the information of the laser light received by each light receiving surface into an electrical signal for each light receiving surface, and
An element having a laser light reflecting surface provided on the optical path of laser light between the measurement object and each light receiving surface of the photoelectric converter, and configured by arranging a plurality of micromirrors on a plane; The laser light reflecting surface is divided into a plurality of partial regions each having a predetermined number of micromirrors arranged, and the reflective surface of the selected micromirror is controlled in a predetermined direction for each partial region. A micromirror array spatial modulation element for guiding the reflected light of the laser beam from the measurement object reflected by the micromirror in the ON state to the light receiving surface that is different for each partial region,
The phase shift information with respect to the amplitude modulation signal in the electric signal for each light receiving surface output from each of the photoelectric converters is acquired for each electric signal, and the phase shift information for each electric signal and each partial region A three-dimensional image information acquisition apparatus comprising: a data processing unit that obtains three-dimensional position information of a measurement object using position information of each of the micromirrors in the ON state. Each of the electrical signals for each light-receiving surface comprises a coding modulation means for time-modulating each of the electrical signals with a coded modulation signal that can be identified for each electrical signal,
The data processing unit uses the information of the encoded modulation signal included in the electrical signal to identify a light receiving surface that has received the reflected light of the laser light converted to the electrical signal, and The partial area of the laser light reflecting surface that guides the reflected light of the laser light is specified, and the three-dimensional position information is obtained using position information of the micromirror in the ON state of the specified partial area. 3D image information acquisition apparatus.   The three-dimensional image information acquisition apparatus according to claim 1, wherein the plurality of light receiving surfaces are arranged on the same plane. The electrical signal output for each light receiving surface of the photoelectric converter is mixed using the amplitude modulation signal as a reference signal, and the signal component of the laser light time-modulated by the amplitude modulation signal is used as an intermediate frequency signal. An intermediate frequency signal generating means for extracting,
The data processing unit uses the intermediate frequency signal to acquire phase shift information for the amplitude modulation signal, and uses the phase shift information and the position information of the micromirrors in the ON state for each partial region. The three-dimensional image information acquisition apparatus according to claim 1, wherein the three-dimensional position information of the measurement object is obtained. Prior to the mixing process in the intermediate frequency signal generating means, comprising an electric signal synthesizing means for synthesizing a plurality of electric signals output for each light receiving surface of the photoelectric converter,
5. The three-dimensional image information acquisition apparatus according to claim 4, wherein the intermediate frequency signal generation unit mixes the combined electric signal generated by the electric signal combining unit using a signal having the same frequency as that of the amplitude modulation signal as a reference signal. The intermediate frequency signal generation means takes out the intermediate frequency signal using the amplitude modulation signal and a phase shift modulation signal obtained by phase shifting the amplitude modulation signal by a predetermined amount as a reference signal,
The data processing unit obtains information on the reflectance at the surface of the measurement object together with the phase shift information from the intermediate frequency signal, and uses the reflectance information and the three-dimensional position information as three-dimensional image information. Item 6. The three-dimensional image information acquisition device according to Item 4 or 5.

Images