JP2009236774A - Three dimensional ranging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small and high precision three dimensional ranging device which can ensure scanning angle of 180 degrees. <P>SOLUTION: This ranging device includes: scanning mechanism which rotates a deflecting mirror 9 obliquely-positioned to level surface around its perpendicular axial center P1; light projector 3 for emitting measured light along light axis L1 located around the axial center and slanted by a certain degree of θ to the axial center; a light collection optical system 6 for collecting reflections to the measured light emitted from the light projector and deviation-reflected by the deflecting mirror 9; a single light-receiving section 5 for detecting the collected reflections; a drive controller which drives the light projector so that one measured light may be emitted at different timing from each mutually-different position along circumferential direction of the axial center P1; and a distance calculating section which calculates angle of the measuring object from scanning angle of the measured light emitted from the scanning mechanism, while calculating distance to the above measuring object from delay time of the reflection to the measured light scanned from the light projector towards measuring target space by the scanning mechanism. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a three-dimensional distance measuring apparatus that measures a distance to a measurement object by three-dimensionally scanning a measurement object space in order to acquire a three-dimensional shape of the measurement object.

  As shown in FIG. 10, a distance measuring device that modulates the measurement light output from the laser light source LD and irradiates the object R, and detects the reflected light from the object R with a light receiving element PD to measure the distance. In this case, two types of modulation methods for measuring light, an AM (amplitude modulation) method and a TOF (Time of Flight) method, have been put into practical use.

In the AM method, as shown in FIGS. 10A and 10, the measurement light modulated with a sine wave and the reflected light are photoelectrically converted, and a phase difference Δφ between these signals is calculated, This is a method for calculating the distance from the phase difference Δφ, and the TOF method photoelectrically converts the measurement light modulated in a pulse shape and its reflected light as shown in FIGS. In this method, the distance is calculated from the delay time Δt between signals. Here, L is the distance to the object R, C is the speed of light, f is the modulation frequency, Δφ is the phase difference, and Δt is the delay time.
(Equation 1) L = Δφ · C / (4π · f)
(Expression 2) L = Δt · C / 2

  As a two-dimensional distance measuring device employing the detection principle shown in FIG. 10, for example, as shown in FIG. 11, a first deflection mirror that rotates measurement light output from the light projecting unit 3 around the axis P <b> 1 by the motor 11. By deflecting by 9a and rotating and scanning on a plane orthogonal to the axis P1, the reflected light from the object R to be measured is deflected by the second deflecting mirror 9b and detected by the light receiving unit 5, so that The inventors of the present application have proposed a two-dimensional distance measuring device including a signal processing circuit 90 for calculating a distance (Japanese Patent Application No. 2006-253833).

  This type of two-dimensional distance measuring device is mainly used for visual sensors of robots and automatic guided vehicles, door opening / closing sensors, monitoring sensors for detecting the presence or absence of intruders in the monitoring area, and for dangerous devices. It is used as a safety sensor that detects the approach of objects and objects and stops the machine safely.

  Furthermore, it is also used when recognizing the shape of a car or a person. For example, in an ETC system, it is used as a sensor that discriminates the vehicle type and counts the number of passing cars. It is used as a monitoring sensor that detects the condition and the flow of people.

  However, when used in a robot vision device or an area sensor for the safety of dangerous machines, the detection area is a two-dimensional plane, so objects and obstacles that exist in the vertical direction from the scanning surface of the measurement light can be detected. It cannot be detected. In particular, when used for environment recognition of a robot or the like, it is important to obtain data of a wide field angle area having an appropriate width in the vertical direction, and it is desired to scan the area with as uniform density as possible.

  Therefore, in Patent Document 1, as shown in FIG. 12, the optical signal emitted from the light source 3 is incident on the mirror 13a of the galvanometer scanner 14a, and the second galvanometer scanner is further transmitted from the mirror 13a of the galvanometer scanner 14a. There has been proposed a three-dimensional distance measuring device that irradiates a space where a detection target is present via a mirror 13b of 14b.

  In Patent Document 2, as shown in FIG. 13, a two-dimensional distance measuring device 102 as shown in FIG. 12 is rotationally driven around a second axis P2 obliquely intersecting the first axis P1, and the first axis A three-dimensional unit comprising a second rotation mechanism 20 that changes the roll angle and pitch angle of the core P1, a first rotation mechanism that rotates around the first axis P1, and a rotation control means that controls the rotation of the second rotation mechanism. A distance measuring device 200 has been proposed.

  In the three-dimensional distance measuring device, a plane formed by measurement light rotated and scanned around the first axis by a simple mechanism is inclined around the second axis, and the roll angle and pitch angle of the first axis Therefore, it becomes possible to scan three-dimensionally with a constant scanning density in a predetermined range along the second axis by using the scanning two-dimensional distance measuring device.

11 to 13 use the codes of each patent document as they are, and are not related to each other even if they overlap with the codes used in the embodiments of the present invention described below.
JP 2001-147269 A Japanese Patent No. 4059911

  However, distance measuring devices are generally designed to increase the light sensitivity of the light receiving axis in order to increase the detection sensitivity. In a distance measuring device for high sensitivity and long distance measurement, the scanning mirror has the size of the light beam of the light receiving axis. Increase proportionally.

  Therefore, in the technique described in Patent Document 1, in principle, the scanning angle is limited to 180 degrees, and even when the scanning angle is increased within that range, a correspondingly large mirror is required, and the entire apparatus is There is a problem that it becomes difficult to control the mirror with high accuracy as well as the size. In particular, when mounting on a robot that requires a field of view in the lateral direction, a scanning angle of 180 degrees or more is required, and this method is difficult to adopt.

  Moreover, in the technique described in Patent Document 2, since large parts such as a motor and a crank mechanism constituting the second rotation mechanism are arranged outside the apparatus main body, not only a safety cover that covers the entire apparatus is required. There is a problem that the entire apparatus becomes large and cannot be easily mounted on a personal robot or the like.

  In view of the above-described problems, an object of the present invention is to provide a small and highly accurate three-dimensional distance measuring device while ensuring a scanning angle of 180 degrees or more.

  In order to achieve this object, a first characteristic configuration of the three-dimensional distance measuring device according to the present invention includes a deflecting mirror inclined with respect to a reference plane, as described in claim 1 of the document of the claims. A scanning mechanism that rotates around an axis perpendicular to the reference plane through the deflection mirror, and a measuring beam that is arranged at a position spaced from the axis and inclined at a predetermined angle with respect to the axis. A light projecting unit that emits light, a condensing optical system that condenses the reflected light from the object to be measured among the measurement light that is emitted from the light projecting unit and deflected and reflected by the deflecting mirror, and the condensing optical system A single light receiving unit that detects the condensed reflected light and a drive that drives the light projecting unit so that one measurement light is emitted from different positions along the circumferential direction of the axis at different timings. Measurement from the light projecting unit by the control unit and the scanning mechanism. The distance to the object to be measured is calculated from the delay time or phase difference of the reflected light with respect to the measuring light scanned toward the target space, and the object to be measured is calculated from the scanning angle of the measuring light emitted from the scanning mechanism. It is in the point provided with the distance calculation part which calculates an angle.

  According to the above configuration, since the measurement light emitted from the light projecting unit enters the deflection mirror along the optical axis inclined by a predetermined angle with respect to the axis, it is deflected and reflected by the deflection mirror rotated by the scanning mechanism. The measurement light is scanned on a plane inclined with respect to the reference plane.

  When the deflection mirror is positioned at a certain scanning angle, the tilt angle between the measurement light deflected and emitted toward the measurement target space and the reference plane can be calculated geometrically, so that the reflected light from the object to be measured with respect to the measurement light If the distance is calculated based on the above, the angle and distance with respect to the object to be measured can be obtained.

  Then, the light projecting unit is driven by the drive control unit so that one measurement light is emitted from different positions along the circumferential direction of the shaft center at different timings, thereby along the circumferential direction of the shaft center. The scanning surfaces of the respective measurement beams emitted from different positions are scanned on planes that are inclined with respect to the reference plane and inclined at different angles.

  As shown in FIG. 4, for example, when the measurement light emitted from the light projecting unit is irradiated on the deflection mirror so as to intersect the axis, the angle between the optical axis of the measurement light and the axis is θ Then, the trajectory of each measurement light irradiated on the peripheral surface of the virtual cylinder having the radius L with the axis at the center draws a Lissajous shape with a shake width of ± L · tan θ.

  If the distance is calculated based on the reflected light from the object to be measured with respect to each measurement light, the three-dimensional distance to the object to be measured existing in the measurement target space can be calculated.

  According to such a light projecting unit, since it can be extremely small and accurately arranged in the casing, a small and highly accurate three-dimensional distance measuring device can be constructed.

  In the second feature configuration, as described in claim 2, in addition to the first feature configuration described above, the deflection mirror deflects the measurement light emitted from the light projecting unit toward the measurement target space. A single deflecting mirror that reflects and deflects and reflects reflected light from the object to be measured toward the light receiving unit, and the condensing optical system and the light receiving unit are disposed on the axis. The plurality of light projecting units are arranged around the light receiving unit.

  According to the above-described configuration, the deflection mirror that guides the measurement light to the space to be measured and the mirror that guides the reflected light from the object to be measured to the light receiving unit are combined to reduce the size of the apparatus along the axial direction. Will be able to.

  In the third feature configuration, as described in claim 3, in addition to the first feature configuration described above, the deflection mirror deflects and reflects the measurement light emitted from the light projecting unit toward the measurement target space. And a second deflecting mirror that deflects and reflects reflected light from the object to be measured toward the light receiving unit, and the light receiving unit sandwiches the deflection mirror and the light projecting unit. It is in the point arrange | positioned in the position which opposes.

  According to the configuration described above, even when stray light is generated in which part of the measurement light irradiated to the measurement target space by the first deflection mirror is reflected from the optical window of the apparatus, the stray light is transmitted to the second deflection mirror. Since the incidence is suppressed, it is possible to suppress erroneous detection due to stray light and to improve the reliability of the apparatus.

  In the fourth feature configuration, in addition to any one of the first to third feature configurations described above, the condensing optical system includes a light receiving lens that focuses reflected light. And a light guide member that guides reflected light from the in-focus position by the light receiving lens to the light receiving portion.

  Since the measurement light emitted from the light projecting unit is incident on the deflection mirror along the optical axis inclined by a predetermined angle with respect to the axis, the reflected light with respect to the measurement light deflected and reflected toward the light receiving unit by the deflection mirror is reflected. The optical axis is also inclined with respect to the axis. Therefore, by providing a light guide member that guides the reflected light from the focus position of the reflected light by the light receiving lens to the light receiving unit, the reflected light can be appropriately detected by the light receiving unit.

  Note that when the reflected light inclined with respect to the axial center is detected by the light receiving unit having a large light receiving area without providing the light guide member, the response of the light receiving unit to the reflected light is lowered, and the measurement is performed with high accuracy. Although the distance cannot be obtained, a light receiving element having a narrow light receiving area and excellent response can be used by providing the light guide member, and highly accurate distance measurement is possible.

  The fifth feature configuration is the measurement light emitted from the light projecting portion in addition to any of the first to fourth feature configurations described above, as described in claim 5. Are arranged so as to intersect the axis on the deflection mirror.

  According to the above-described configuration, the center of the scanning surface of each measurement light emitted from different positions along the circumferential direction of the axis intersects at the center point of the reference plane and is on a plane inclined at different angles. Therefore, the angle with respect to the object to be measured can be easily calculated.

  The sixth feature configuration is the measurement light emitted from the light projecting unit in addition to any of the first to fourth feature configurations described above, as described in claim 6. The optical axes are arranged on the deflection mirror so as to intersect on the near side or the far side with respect to the point where the axes intersect.

  According to the configuration described above, the vertical width of the Lissajous shape is reduced or enlarged. If the optical axis of the measurement light is arranged on the deflection mirror so that it intersects in front of the point where the axes intersect, the fluctuation width decreases but the resolution increases. By adopting such a configuration, the apparatus can be configured compactly even when a large light receiving optical system is used to increase sensitivity. Further, if the optical axis of the measurement light is arranged on the deflection mirror so that it intersects behind the point where the axis intersects, the resolution is lowered but the fluctuation width is increased and the detection range is widened.

  In the seventh feature configuration, as described in claim 7, in addition to any of the first to sixth feature configurations described above, the light projecting portions may be arranged along the circumferential direction of the axis. A plurality of them are arranged at different positions, and the drive control unit selects one of the plurality of light projecting units in synchronization with one scanning of the deflection mirror and sequentially drives it.

  By driving one of the plurality of light projecting units in synchronization with one scanning of the deflecting mirror by the drive control unit, each light projecting unit without erroneously detecting measurement light from other light projecting units Thus, the object to be measured can be reliably detected with respect to the measurement light from the.

  In the eighth feature configuration, in addition to any one of the first to sixth feature configurations described above, the light projecting unit may be a rotating body that rotates about the axis. The driving control unit is configured to rotate the rotating body by a predetermined angle in synchronization with one scanning of the deflection mirror.

  According to the above-described configuration, it is possible to perform the same three-dimensional distance measurement as in the case where a plurality of light projecting units are arranged at different positions along the circumferential direction of the axis while being a single light projecting unit. An inexpensive three-dimensional distance measuring device can be configured by reducing the number of parts of the expensive light projecting unit.

  As described above, according to the present invention, it is possible to provide a small and highly accurate three-dimensional distance measuring device while ensuring a scanning angle of 180 degrees or more.

Hereinafter, a three-dimensional distance measuring device according to the present invention will be described.
As shown in FIG. 1, the three-dimensional distance measuring device 1 is a horizontal plane parallel to the bottom surface of the casing 2 in a cylindrical casing 2 in which a cylindrical optical window 2 a having a constant vertical width is arranged around the circumference. The scanning mirror 4 that rotates the deflection mirror 8 inclined at an angle of 45 degrees with respect to the reference plane and rotates around the axis P1 passing through the deflection mirror 9 and perpendicular to the reference plane is positioned away from the axis P1. A plurality of light projecting units 3 that are arranged and emit measurement light along an optical axis L1 inclined by a predetermined angle θ with respect to the axis P1, and are emitted from each light projecting unit 3 and deflected and reflected by the deflecting mirror 9. Of the measurement light, the condensing optical system 6 that condenses the reflected light from the object to be measured, the single light receiving unit 5 that detects the reflected light collected by the condensing optical system 6, and the three-dimensional measurement. A signal processing board 90 for driving the distance device 1 to calculate the distance and angle with respect to the object to be measured. Eteiru.

  The deflecting mirror 9 deflects and reflects the measurement light emitted from the light projecting unit 3 toward the measurement target space and deflects and reflects the reflected light from the object to be measured toward the light receiving unit 5.

  The condensing optical system 6 and the light receiving unit 5 are disposed on the axis P <b> 1, and the plurality of light projecting units 3 are disposed around the light receiving unit 5.

  A plurality of light projecting units 3 may be arranged at different positions, and here, eight light projecting units 3 are arranged at equal intervals along the circumferential direction of the axis P1. Each light projecting unit 3 includes light sources 31a to 38a made of semiconductor lasers or LEDs, and lenses 31b to 38b that form light beams output from the light sources 31a to 38a into parallel light.

  Each light projecting unit 3 is arranged such that the optical axes L11 to L18 of the measurement light output from the respective light sources 31a to 38a are inclined at an angle θ with respect to the axis P1, and the optical axes L11 to L11 of the measurement light L18 is arranged on the deflection mirror 9 so as to intersect the axis P1.

  The scanning mechanism 4 includes a motor 11 supported at the bottom of the casing 2, a support portion 8 that is driven to rotate around the axis P <b> 1 by the motor 11, and a deflection mirror 9 that is fixed to the inclined upper surface of the support portion 8. Yes.

  A slit plate 15a having a plurality of optical slits formed in the circumferential direction is installed on the peripheral portion of the support portion 8, and a photo interrupter 15b is disposed on the rotation path of the slit plate 15a. A scanning angle detector 15 for detecting the rotational scanning angle is configured.

  When the deflecting mirror 9 is rotated about the axis P1 by the scanning mechanism 4, the measurement light emitted from each light projecting unit 3 is emitted from the optical window 2a toward the measurement target space. For example, the measurement light emitted from the light source 31a is changed and reflected by the deflecting mirror 9 and irradiated toward the measurement target space along the optical axis L11, and the measuring light emitted from the light source 35a is changed and reflected by the deflecting mirror 9. Then, it is irradiated toward the measurement object space along the optical axis L15.

  As shown in FIG. 5, the signal processing board 90 has a drive control unit that drives the light projecting unit 3 so that one measurement beam is emitted from different positions along the circumferential direction of the axis P1 at different timings. 93 and the measurement light emitted from the scanning mechanism 4 while calculating the distance from the delay time of the reflected light to the measurement light scanned from the light projecting unit 3 toward the measurement target space by the scanning mechanism 4. A distance calculation unit 95 is provided for calculating the angle of the object to be measured from the scanning angle.

  Based on the pulse signal input from the scanning angle detection unit 15, the drive control unit 93 rotates the position of each of the light sources 31a to 38a every time the deflection mirror 9 rotates around one axis of the scanning mechanism 4, that is, around the axis P1. Either one is lit.

  Specifically, as shown in FIG. 2A, the light source 31a is driven in the first cycle, the light source 32a is driven in the next cycle, and then the light sources 33a to 38a are rotated clockwise in the cycle unit. Drive sequentially.

The drive signals output to the light projecting units 3 by the drive control unit 93 are input to the drive circuits 31c to 38c that drive the light sources 31a to 38a, respectively. The drive circuits 31c to 38c drive the light sources 31a to 38a in sine waves. AM modulation or pulse driving at a predetermined frequency. In the case of AM modulation, the distance to the object to be measured is calculated by (Equation 1), and in the case of pulse driving, the distance to the object to be measured is calculated by (Equation 2). In the present embodiment, the latter is adopted.
(Equation 1) L = Δφ · C / (4π · f)
(Expression 2) L = Δt · C / 2

  For example, as shown in FIGS. 1 and 4A, the measurement light emitted from the light source 31a is incident on the deflecting mirror 9 along the optical axis L11 inclined by a predetermined angle θ with respect to the axis P1, so that scanning is performed. The measurement light deflected and reflected by the deflecting mirror 9 rotated by the mechanism 4 is scanned on the plane PL11 inclined with respect to the reference plane PL.

  Further, since the measurement light emitted from the light source 35a enters the deflection mirror 9 along the optical axis L15 inclined by a predetermined angle θ with respect to the axis P1, it is deflected and reflected by the deflection mirror 9 rotated by the scanning mechanism 4. The measurement light is scanned on the plane PL15 inclined with respect to the reference plane PL.

  When the deflection mirror 9 is positioned at a certain scanning angle, the inclination angle between the measurement light deflected and reflected toward the measurement object space and the reference plane can be calculated geometrically, so that the measurement light is reflected from the object to be measured. If the distance is calculated based on the light, the angle and distance to the object to be measured can be obtained.

  Then, the light projecting unit 3 is driven by the drive control unit 93 so that one measurement light is emitted from different positions along the circumferential direction of the axis P1 at different timings, so that the circumference of the axis P1 is increased. The scanning planes of the respective measurement beams emitted from different positions along the direction are scanned on planes that are inclined with respect to the reference plane PL and inclined at different angles. FIG. 4A shows the scanning planes PL11 and PL35 of the measurement light emitted from the light source 31a and the light source 35a.

  As shown in FIGS. 4A and 4B, for example, when the measurement light emitted from each light projecting unit is irradiated on the deflection mirror 9 so as to intersect the axis P1, the light of the measurement light Assuming that the angle formed between the axis L and the axis P is θ, the trajectory of each measurement light irradiated on the peripheral surface of the virtual cylinder 20 having the radius L centered on the axis P1 has a fluctuation width of ± L · tan θ. Draw a Lissajous shape. In the present embodiment, since eight light projecting units 3 are installed at equal intervals around the axis P1, the phases of adjacent trajectories are shifted by 45 degrees.

  If the distance is calculated based on the reflected light from the measurement object with respect to each measurement light, the three-dimensional distance to the measurement object existing in the measurement target space can be calculated.

  As shown in FIG. 3, the condensing optical system 6 includes a light receiving lens 6a for focusing the reflected light, and a light guide member 6b for guiding the reflected light from the focus position by the light receiving lens 6a to the light receiving unit 5.

  The light guide member 6b can be formed of an inverted cone cone prism or an optical fiber array that guides the reflected light focused by the light receiving lens 6a to the light receiving window of the light receiving unit 5 having a diameter of about 1 mm. The optical fiber array is made up of a plurality of optical fibers having a distal end side arranged in a cylindrical end region and the other end side arranged in a proximal end side, and the diameter is gradually narrowed from the distal end side to the proximal end side. Has been.

  When the reflected light from the object to be measured corresponding to the measurement light emitted from the light source is focused by the light receiving lens 6a, a light image I is formed on the end surface of the light guide member 6b. The light that forms the optical image I is guided to the light receiving unit 5 by the light guide member 6b, so that the reflected light is detected with high sensitivity.

  As shown in FIGS. 2A and 2B, when the reflected light with respect to the measurement light emitted from the respective light sources 31a to 38a is focused by the light receiving lens 6a, the surface of the end portion of the light guide member 6b is The optical images I31 to I38 are formed. The light forming each of the optical images I31 to I38 is guided to the light receiving unit 5.

  As shown in FIG. 5, on the signal processing board 90, a motor control circuit 94 for driving the motor 11 incorporated in the scanning mechanism 4 and drive circuits 31c to 38c for driving the light emitting elements 31a to 38a as light sources respectively. And an amplification circuit 5c that amplifies a reflected signal corresponding to reflected light photoelectrically converted by a light receiving element 5a such as an avalanche photodiode provided in the light receiving unit 5, and a pulse signal input from the scanning angle detecting unit 15. A drive control unit 93 that drives one of the drive circuits 31c to 38c by switching every scanning cycle, an AD conversion unit 91 that AD converts the reflection signal, and a reflection signal from the rise of the drive signal for each of the drive circuits 31c to 38c A delay time calculation unit 92 for calculating a delay time until the rising edge of the signal, a distance to the object to be measured based on the delay time, and scanning And a system control unit 95 which functions as a distance calculation unit that calculates an angle of the measurement object from the scan angle of the measurement light emitted from the structure 4.

  The system control unit 95 incorporates a microcomputer. When the power is turned on, the system control unit 95 drives the scanning mechanism 4 via the motor control circuit 94 to rotate and scan, and when the motor starts up, scanning is performed based on the pulse signal input from the scanning angle detection unit 51. Each time the mechanism 4 makes one revolution, the drive circuits 31c to 38c are sequentially driven.

  The slit interval of the slit plate 15a constituting the scanning angle detector 15 is formed so as to be different from the others at a preset reference position of the rotating body, and the system controller 95 is based on the waveform of the pulse signal. The rotation angle of the scanning mechanism 4 from the reference position is calculated by grasping the reference position and counting the number of pulses from the reference position.

  The system control unit 95 calculates the distance to the measurement object corresponding to the rotation angle of the scanning mechanism 4 based on the delay time input from the delay time calculation unit 92, and the rotation angle of the scanning mechanism 4 at that time Then, the inclination angle of the measurement light with respect to the reference plane is determined from the arrangement of the light projecting unit 3, that is, the relative angle between the light projecting unit from which the measurement light is emitted and the rotation angle and the angle between the optical axis L and the axis P1 of the light projecting unit. The three-dimensional direction and distance where the measurement object is located are obtained by calculation.

  Although the TOF type three-dimensional distance measuring device has been described above, the mechanism for detecting the three-dimensional direction in which the measurement object is located is the same even in the AM type three-dimensional distance measuring device. In the case of the AM method, in place of the delay time calculation unit 92, a phase difference calculation unit for obtaining the phase difference between the measurement light and the reflected light is provided.

Hereinafter, another embodiment of the present invention will be described.
In the above-described embodiment, the example in which the eight light projecting units 3 are arranged at equal intervals around the axis P1 has been described. However, the number of the light projecting units 3 is not limited to eight, but is an arbitrary number. May be arranged. Moreover, it does not restrict | limit to what each light projection part is arrange | positioned at equal intervals.

  Furthermore, although the case where the angles formed by the optical axis L and the axis P1 of the measurement light emitted from each light projecting unit are all the same has been described, they may be arranged to have different angles. . When the angle formed by the optical axis L of the measurement light emitted from the light projecting unit and the axis P1 increases, the resolution in the direction along the optical axis P1 decreases. However, the detection range increases, and light decreases when the angle decreases. The detection range in the direction along the axis P1 is narrowed, but the resolution is increased.

  For example, when the eight light projecting units 3 are arranged around the axis P1, as shown in FIG. 2, the angle θ1 formed by the optical axis of the odd-numbered light projecting unit 3 and the axis P1, and The angle θ2 formed by the optical axis of the even-numbered light projecting unit 3 and the axis P1 is measured using the odd-numbered light projecting unit 3 as θ1> θ2, or the even-numbered light projecting unit 3 is used. A switch for switching whether or not to measure may be provided, and the measurement may be switched between measurement that places importance on high resolution and measurement that places importance on a wide detection range. Furthermore, it is also possible to switch so as to perform wide-range and high-resolution measurement using all the light projecting units by the changeover switch.

  In addition, a posture switching mechanism for switching the angle θ formed between the optical axis of each light projecting unit 3 and the axis P1 is provided so as to switch between measurement focusing on high resolution and measurement focusing on a wide detection range. It may be configured.

  For example, the light projecting unit is supported on the upper part of the casing so that the light projecting unit can swing on a plane including the axis P1 and the optical axis L, and the spring is biased in a direction in which the angle θ decreases. An attitude switching mechanism including a cam member that presses in the direction in which the angle θ increases is configured to switch the angle of the optical axis of the measurement light emitted from the light projecting unit by driving the cam member. it can.

  In addition, the light projecting unit is fixed to the upper part of the casing, and an optical member such as a deflecting mirror or a prism for switching the optical axis is disposed on the optical path of the measurement light emitted from the light projecting unit so that the position of the optical member can be changed. An actuator for changing the position of the member may be provided.

  Although the case where the drive control unit 93 sequentially switches the light projecting units to be driven in synchronization with one rotation of the scanning mechanism 4 has been described, the switching timing of the light projecting units may be synchronized with two rotations of the scanning mechanism 4. It may be switched at an arbitrary timing during one rotation. That is, the drive control unit 93 only needs to drive the light projecting unit so that one measurement light is emitted from different positions along the circumferential direction of the axis at different timings.

  Further, the light projecting unit is composed of a single light projecting unit supported by a rotating body that rotates around the axis, and the drive control unit rotates the rotating body by a predetermined angle in synchronization with one scanning of the deflection mirror. You may comprise so that it may drive.

  Specifically, as shown in FIG. 6, the single light projecting unit 3 is fixed to the rotating member 12 such that the optical axis L of the measuring light is inclined with respect to the axis P <b> 1 by the angle θ, and the rotating member 12. The motor 13 is configured to be rotatable.

  In this case, the motor 13 is rotationally driven by the drive control unit 93 so that one measurement light is emitted from different positions along the circumferential direction of the axis P1 at different timings, and the light projecting unit is driven. .

  Needless to say, in order to calculate the angle of the measurement light with respect to the reference plane, it is necessary to provide a position detection mechanism that detects the rotational position of the light projecting unit 3 that rotates about the axis P1 by the motor 13. .

  The projector 3 may be configured to be driven while the motor 13 is stopped, or the projector 3 may be driven simultaneously while the motor 13 is being driven. Since the light projecting unit 3 can be arranged at an arbitrary position around the axis P1, the Lissajous shape is drawn with a fine pitch, and more accurate measurement is possible.

  In FIG. 6, the two light projecting portions may be arranged on the rotating member 12 with the axis P <b> 1 interposed therebetween so that the angle θ between the optical axis of each light projecting portion and the shaft center P <b> 1 is different. For example, by providing a switch for switching which of the respective light projecting units is used, it is possible to switch between measurement that places importance on high resolution and measurement that places importance on a wide detection range.

  In the above-described embodiment, the configuration in which the light projecting unit 3 is arranged so that the optical axis L of the measurement light emitted from the light projecting unit 3 intersects the axis P1 on the deflection mirror 9 has been described. 7, the angle θ formed by the optical axis L of the measurement light emitted from the light projecting unit 3 and the optical axis P <b> 1 is kept constant, and the light projecting unit 3 emits the measurement light emitted from the light projecting unit 3. These optical axes L may be arranged so as to intersect on the near side or the far side from the point where the axis P1 intersects on the deflection mirror 9. According to such a configuration, the vertical width of the Lissajous shape described with reference to FIG. 4B is reduced or enlarged.

  When the optical axis L of the measurement light emitted from the light projecting unit 3 intersects the axis P1 on the deflection mirror 9, the locus of the optical axis L is on the inclined plane PL10 as shown in FIG. If the optical axis L of the measurement light is arranged on the deflection mirror 9 so as to intersect with the front side of the point where the axes intersect, the locus of the optical axis L is as shown in FIG. Since it rotates on the inclined plane PL10, the deflection width in the direction of the axis P1 decreases, but the resolution increases. By adopting such a configuration, the apparatus can be configured compactly even when a large light receiving optical system is used to increase sensitivity.

  Further, when the optical axis of the measurement light is arranged on the deflection mirror so that it intersects behind the point where the axes intersect, the locus of the optical axis L is on the inclined plane PL10 as shown in FIG. However, although the resolution is reduced, the amplitude in the direction of the axis P1 is increased and the detection range is expanded.

  Further, as shown in FIG. 9, the deflection mirror 9 receives the reflected light from the object to be measured and the first deflection mirror 9a that deflects and reflects the measurement light emitted from the light projecting unit 3 toward the measurement target space. It comprises a second deflection mirror 9b that deflects and reflects toward the section 5, and includes a motor 11 that rotationally drives a rotating body 4a incorporating the deflection mirror 9 about the axis P1. The three-dimensional distance measuring device 1 may be configured so as to be disposed at a position facing the light projecting unit 3 with being sandwiched.

  According to the above-described configuration, even when stray light is generated such that part of the measurement light irradiated to the measurement target space by the first deflection mirror 9a is reflected from the optical window 2a of the apparatus 1, the stray light is Since the incident on the second deflecting mirror 9b is suppressed, it is possible to suppress erroneous detection due to stray light and to improve the reliability of the apparatus.

  Furthermore, the three-dimensional distance measuring device according to the present invention can be configured by appropriately combining the above-described embodiments within a range not inconsistent with the present invention.

  Any of the above-described embodiments is an example of the present invention, and the specific configuration of each part of the three-dimensional distance measuring device, such as the shape, configuration, material used, and circuit configuration for signal processing, is according to the present invention. Needless to say, the design can be changed as appropriate within the range where the effects are exhibited.

Schematic explanatory diagram of a three-dimensional distance measuring device according to the present invention. Explanatory drawing of the principal part of the three-dimensional distance measuring device according to the present invention Explanatory drawing of the principal part of the three-dimensional distance measuring device according to the present invention (A) is explanatory drawing of the locus | trajectory of measuring light, (b) is explanatory drawing of the Lissajous shape which the locus | trajectory of each measuring light produces Block diagram of a signal processing circuit of a three-dimensional distance measuring device according to the present invention. Schematic explanatory diagram of a three-dimensional distance measuring device showing another embodiment of the present invention Schematic explanatory diagram of a three-dimensional distance measuring device showing another embodiment of the present invention The state in which the tilt angle of the plane of the measurement light to be scanned differs depending on the position at which the optical axis of the measurement light emitted from the light projecting unit is incident on the deflection mirror, and (a) shows the measurement light incident on the optical axis. (B) is an explanatory diagram when measurement light is incident before the optical axis, and (c) is an explanatory diagram when measurement light is incident on the back side of the optical axis. Schematic explanatory diagram of a three-dimensional distance measuring device showing another embodiment of the present invention (A) is a principle explanatory diagram of an AM type distance measuring device, (b) is a principle explanatory diagram of a TOF type distance measuring device. Illustration of a conventional two-dimensional distance measuring device Explanatory drawing of a conventional three-dimensional distance measuring device Explanatory drawing of a conventional three-dimensional distance measuring device

Explanation of symbols

1: three-dimensional distance measuring device 2: casing 2a: optical window 3: projectors 31a to 38a: light source (light emitting element)
4: Scanning mechanism 5: Light receiving unit 6: Condensing optical system 6a: Light receiving lens 6b: Light guide member 9: Deflection mirror 11: Motors L, L11, L2: Optical axis P1: Axis center

Claims (8)

  A scanning mechanism that rotates the deflection mirror that is inclined with respect to a reference plane around an axis that passes through the deflection mirror and is perpendicular to the reference plane; and a position that is spaced from the axis and that is disposed with respect to the axis Of the measuring light emitted from the light projecting unit and deflected and reflected by the deflection mirror, the reflected light from the object to be measured is collected from the light projecting unit that emits the measuring light along an optical axis inclined at a predetermined angle. A condensing optical system, a single light receiving unit for detecting reflected light collected by the condensing optical system, and a single measurement light emitted from different positions along the circumferential direction of the axis at different timings The measured object from the delay time or the phase difference of the reflected light with respect to the measurement light scanned from the light projecting unit toward the measurement target space by the scanning mechanism. And calculate the distance to Serial to have three-dimensional distance measuring apparatus comprising a distance calculation unit that calculates an angle of the object to be measured from a scanning angle of the measurement light emitted from the scanning mechanism.   The deflecting mirror deflects and reflects the measurement light emitted from the light projecting unit toward the measurement target space, and deflects and reflects the reflected light from the object to be measured toward the light receiving unit. The three-dimensional distance measuring device according to claim 1, wherein the condensing optical system and the light receiving unit are arranged on the axis, and the plurality of light projecting units are arranged around the light receiving unit. apparatus.   A first deflection mirror that deflects and reflects the measurement light emitted from the light projecting unit toward the measurement target space, and a second that deflects and reflects the reflected light from the object to be measured toward the light receiving unit. The three-dimensional distance measuring device according to claim 1, further comprising a deflection mirror, wherein the light receiving unit is disposed at a position facing the light projecting unit across the deflection mirror.   The said condensing optical system is provided with the light-receiving lens which focuses reflected light, and the light guide member which guides reflected light to the said light-receiving part from the focus position by the said light-receiving lens. 3D ranging device.   5. The three-dimensional image according to claim 1, wherein the light projecting unit is arranged such that an optical axis of measurement light emitted from the light projecting unit intersects the axis on the deflection mirror. Distance measuring device.   The light projecting unit is disposed so that the optical axes of measurement light emitted from the light projecting unit intersect on the near side or the far side of the deflection mirror from the point where the axis intersects. The three-dimensional distance measuring device according to any one of 1 to 4.   A plurality of the light projecting units are arranged at different positions along the circumferential direction of the axis, and the drive control unit is one of the plurality of light projecting units in synchronization with one scan of the deflection mirror. The three-dimensional distance measuring device according to any one of claims 1 to 6, wherein the three-dimensional distance measuring device is selected and sequentially driven.   The light projecting unit includes a single light projecting unit supported by a rotating body that rotates about the axis, and the drive control unit is configured to predetermine the rotating body in synchronization with one scanning of the deflection mirror. The three-dimensional distance measuring device according to any one of claims 1 to 6, wherein the three-dimensional distance measuring device is angularly driven.

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