JP2019158598A - Distance measurement apparatus - Google Patents

Abstract

To provide a distance measurement apparatus capable of having a sufficient SN ratio and downsizing the apparatus.SOLUTION: A distance measurement apparatus comprises: a light projection section 10 which includes a light source 11 for emitting emission light and an emission light deflection element 12 having an emission light reflection member for variably deflecting a direction of the emission light; and each of a plurality of light reception sections 20 which is arranged separately from the light projection section in a direction perpendicular to an optical axis of the light projection section, and includes a reflection light deflection element 21 having a reflection light reflection member for variably deflecting a direction of reflection light which is the emission light reflected by an object and a light receiving element 22 for receiving the reflection light deflected by the reflection light deflection element.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a distance measuring device that measures a distance to an object.

  The optical distance measuring device, for example, measures the distance to the object by scanning the laser beam in the object region, that is, measures the distance.

  As such a distance measuring device, for example, Patent Document 1 discloses an optical distance measuring device in which a drive unit that swings and drives a light reflecting surface of an optical scanning device includes at least one of a phase difference changing unit and an amplitude changing unit. Has been.

JP 2011-053137 A

  Laser light scatters when irradiated on an object. For this reason, the intensity of the laser beam received by the distance measuring device decreases as the object moves away from the distance measuring device. Therefore, in order to perform distance measurement of an object located far from the distance measuring device, it is desired to receive more light reflected from the object.

  However, when more light is received, the amount of light that receives noise such as background light also increases. Here, the signal ratio (SN ratio) of the distance measuring device varies with the size of the aperture of the light receiving system. Specifically, the S / N ratio increases as the aperture of the light receiving system increases. However, when the aperture of the light receiving system is increased, one of the problems is that the apparatus becomes larger.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a distance measuring device that has a sufficient S / N ratio and can be downsized.

  The distance measuring device according to claim 1 of the present application includes a light projecting unit including a light source that emits outgoing light, and an outgoing light deflecting element that includes an outgoing light reflecting member that variably deflects the direction of the outgoing light, A reflected light deflecting element having a reflected light reflecting member that is arranged away from the light projecting unit in a direction perpendicular to the optical axis of the light projecting unit and variably deflects the direction of the reflected light reflected by the object. And a plurality of light receiving portions each including a light receiving element that receives the reflected light deflected by the reflected light deflecting element.

1 is a block diagram illustrating a configuration of a distance measuring device according to Embodiment 1. FIG. It is explanatory drawing explaining the operation principle of the light projection system of the distance measuring device which concerns on Example 1. FIG. FIG. 6 is an explanatory diagram illustrating an operation principle of a light receiving system of the distance measuring apparatus according to the first embodiment. It is a conceptual diagram which shows the example of arrangement | positioning of the light projection part of FIG. 1, and a light-receiving part. FIG. 10 is a conceptual diagram illustrating an arrangement example of a light projecting unit and a light receiving unit of a distance measuring apparatus according to a second embodiment. FIG. 10 is a conceptual diagram illustrating an arrangement example of a light projecting unit and a light receiving unit of a distance measuring apparatus according to a third embodiment. FIG. 10 is a process flow diagram in which a distance measuring unit of a distance measuring apparatus according to a fourth embodiment selects a light receiving unit. FIG. 10 is a process flow diagram in which a distance measuring unit of a distance measuring apparatus according to a fifth embodiment selects a light receiving unit. FIG. 10 is a process flow diagram in which a distance measuring unit of a distance measuring apparatus according to a sixth embodiment selects a light receiving unit. FIG. 10 is a process flow diagram in which a distance measuring unit of a distance measuring apparatus according to a seventh embodiment selects a light receiving unit. It is a conceptual diagram which shows the example of arrangement | positioning of the light projection part of the ranging device which concerns on Example 8, and a light-receiving part. It is a conceptual diagram which shows the light reception signal which the light-receiving part of FIG. 11 produced | generated. It is a conceptual diagram which shows the signal which synthesize | combined the light reception signal of FIG. It is a conceptual diagram which shows the example of correction | amendment of the light reception signal which the light-receiving part of FIG. 11 produced | generated. It is a conceptual diagram which shows the signal which synthesize | combined the light reception signal of FIG. It is a conceptual diagram which shows the other example of correction | amendment of the light reception signal which the light-receiving part of FIG. 11 produced | generated.

  FIG. 1 shows a distance measuring device 100 according to the present embodiment.

  The light projecting unit 10 is a light emitting device that emits outgoing light. The light source 11 of the light projecting unit 10 is, for example, a laser element that can emit pulsed light as emitted light.

  The outgoing light deflection element 12 has an outgoing light reflecting member including a light reflecting surface (not shown). The outgoing light deflection element 12 can reflect the pulsed light on the light reflecting surface and emit the scanning light toward a predetermined region to be scanned (hereinafter referred to as a scanning target region). In other words, the outgoing light deflection element 12 can deflect the direction of outgoing light variably. The scanning light reflected by the object existing in the scanning target area returns to the distance measuring device 100 as reflected light. The outgoing light deflection element 12 may be a MEMS (Micro Electro Mechanical System) mirror device, a polygon mirror, or the like.

  The light receiving unit 20 is a light receiving device that receives reflected light and generates a light reception signal. The distance measuring device 100 includes a plurality of light receiving units 20 having the same configuration. The reflected light deflecting element 21 as the reflected light deflecting element of the light receiving unit 20 has a reflected light reflecting member including a light reflecting surface (not shown), and the reflected light is transmitted to the light receiving element 22 by the light reflecting surface. It can be reflected toward. In other words, the reflected light deflecting element 21 can variably deflect the direction of the reflected light. The reflected light deflecting element 21 may be a MEMS mirror device, a polygon mirror, or the like.

  The light receiving element 22 is a photodetector that can receive reflected light and generate a received light signal that is an electrical signal. As the light receiving element 22, for example, an avalanche photodiode (APD) or the like can be employed.

  The control unit 30 controls the pulsed light emitted from the light source 11 and controls the angles of the light reflecting surfaces of the outgoing light deflection element 12 and the reflected light deflection element 21.

  The light source control unit 31 performs light emission control of the light source 11. Specifically, for example, the light emission is controlled with reference to a table (not shown) that defines the light emission timing so that the light source 11 emits pulsed light.

  The mirror control unit 32 controls the angle of inclination of the light reflecting surfaces of the outgoing light deflection element 12 and the reflected light deflection element 21. Specifically, the mirror control unit 32 controls the outgoing light deflection element 12 so that the scanning target region is scanned by the pulsed light emitted from the light source 11 and reflected by a light reflecting surface (not shown). To do. Further, the mirror control unit 32 reflects the reflected light deflecting element so that the direction of the light reflecting surface of the outgoing light reflecting member of the outgoing light deflecting element 12 and the direction of the light reflecting surface of the reflected light reflecting member of the reflected light deflecting element 21 are linked. 21 is controlled.

  A distance measuring unit 40 as a distance measuring unit calculates the distance between the distance measuring device 100 and an object in the scanning target area. The distance between the distance measuring device 100 and the object in the scanning target area is calculated based on the light reception signal generated by the light receiving unit 20, and for example, a time-of-flight method is used.

  Specifically, the distance measuring unit 40 includes a plurality of light receiving units 20 as reflected light by the emission time of one pulsed light emitted from the light source 11 and the one pulsed light reflected by an object in the scanning target region. The light reception time detected in each of the above is acquired. Then, based on the time difference between the emission time and the light reception time, the length of the optical path from when the one pulsed light is emitted from the light source 11 and received by the light receiving unit 20 is calculated. Based on this, the distance between the distance measuring device 100 and the object is calculated.

  FIG. 2 is a conceptual diagram showing the operation of the light projecting system of the distance measuring device 100. In FIG. 2, the emitted light EL emitted from the light source 11 enters the emitted light deflection element 12. The outgoing light deflection element 12 reflects the incident outgoing light EL toward the scanning target region R.

  Specifically, the outgoing light deflection element 12 reflects the light beam toward the scanning target region R in such a manner that the movable portion MR is swung and scanned. As a result, the irradiation direction of the outgoing light EL reflected by the outgoing light deflection element 12 changes. Specifically, the emitted light EL is reflected by the emitted light deflecting element 12 so that a Lissajous locus is drawn on a virtual surface VS that is a virtual surface in the reflection direction of the emitted light EL. The distance measuring device 100 measures the object OB existing in the scanning target region R. Note that the virtual surface VS does not exist. Further, the trajectory drawn on the virtual surface VS may not be the Lissajous trajectory. The trajectory drawn on the virtual plane VS may be a trajectory by raster scanning, for example.

  FIG. 3 is a conceptual diagram showing the operation of the light receiving system of the distance measuring device 100. In FIG. 3, when the object OB exists in the scanning target region R, the reflected light RL reflected from the object OB enters the reflected light deflection element 21 and enters the light receiving element 22. The light receiving element 22 converts the incident reflected light RL into an electrical signal and supplies it to the distance measuring unit 40. The distance measuring unit 40 measures the distance to the object OB based on the time when the light beam is emitted and the time when the light beam is received.

  FIG. 4 shows an arrangement example of the light projecting unit 10 and the light receiving unit 20. As shown in FIG. 4, each of the light receiving units 20 is disposed away from the light projecting unit 10 in the direction perpendicular to the optical axis FX of the light projecting unit 10. Specifically, the pair of light receiving units 20 are arranged at positions symmetrical with respect to the optical axis FX of the light projecting unit 10 as a central axis. The pair of light receiving units 20 are provided at three different locations.

  Each of the light receiving units 20 is arranged on a circular arc AR of a circle centered on a predetermined point P1 on the optical axis FX of the light projecting unit 10. Each of the light receiving units 20 is disposed at a position where the lengths of the lines L1 to L6 connecting the point P1 in the predetermined area RA on the optical axis FX of the light projecting unit 10 and each light receiving unit 20 are equal. .

An angle formed by the line L1 and the optical axis FX at the point P1 on the optical axis FX of the light projecting unit 10 is defined as an angle θ1. An angle formed by the line L2 and the optical axis FX at the point P1 on the optical axis FX of the light projecting unit 10 is defined as an angle θ2. The angle formed by the line L3 and the optical axis FX at the point P1 on the optical axis FX of the light projecting unit 10 is defined as an angle θ3. In other words, the angle θ1 is a point that is farthest from the light receiving unit 20 from the light projecting unit 10. A line L1 connecting P1 is an angle formed with the optical axis FX of the light projecting unit 10. The angle θ2 is an angle formed by the line L2 connecting the light receiving unit 20 closer to the light projecting unit 10 than the light receiving unit 20 of the line L1 and the point P1 with the optical axis FX of the light projecting unit 10. The angle θ3 is an angle formed by the line L3 connecting the light receiving unit 20 closer to the light projecting unit 10 than the light receiving unit 20 of the line L2 and the point P1 with the optical axis FX of the light projecting unit 10.

  The angle θ1 is larger than the angle θ2 and the angle θ3. Further, the angle θ2 is larger than the angle θ3. Accordingly, the angles θ1, θ2, and θ3 formed by the lines L1, L2, and L3 and the optical axis FX of the light projecting unit 10 increase as the distance between the light receiving unit 20 and the light projecting unit 10 increases.

  Since the light receiving units 20 are arranged so that the distances from the predetermined points P1 on the optical axis FX of the light projecting unit 10 to the respective light receiving units 20 are constant, the distances from the predetermined points P1 to the respective light receiving units 20 are set. Time of flight, that is, the time from when the emitted light EL is emitted from the light projecting unit 10 to when each of the light receiving units 20 receives the reflected light RL can be made constant.

  As described above, according to the distance measuring apparatus of the present embodiment, the plurality of light receiving units 20 are arranged apart from the light projecting unit 10 in the direction perpendicular to the optical axis FX of the light projecting unit 10, and the plurality of light receiving units 20. Each includes a reflected light deflection element 21 and a light receiving element 22 that receives the reflected light RL. That is, by configuring the light receiving system of the distance measuring device 100 with the plurality of light receiving units 20, it is possible to make the opening of each light receiving unit 20 smaller than when the light receiving system is configured with one light receiving unit 20. Therefore, each light receiving unit 20 can be made small, and the distance measuring device 100 can be downsized.

  In addition, the distance measuring device 100 performs distance measurement based on the light reception signals generated by the individual light receiving units 20, and as a result, even if the apertures of the individual light receiving units 20 are small, as a result, The light receiving system can have a high aperture. Therefore, the distance measuring device 100 has a sufficient S / N ratio and can be downsized.

  In the present embodiment, the light projecting unit 10 has been described as including the light source 11 and the outgoing light deflecting element 12, but the light projecting unit 10 may include the light receiving element 22. Thus, when the light projection part 10 is comprised, it is good to provide the beam splitter which divides | segments the emitted light EL and the reflected light RL.

  A distance measuring apparatus 100 according to a second embodiment will be described. The distance measuring device 100 according to the second embodiment differs from the distance measuring device 100 according to the first embodiment in the arrangement position of the light receiving unit 20 with respect to the light projecting unit 10. In addition, about the structure same as Example 1, description is abbreviate | omitted by attaching | subjecting the same code | symbol to the same location, and it is the same hereafter.

  FIG. 5 shows an arrangement example of the light projecting unit 10 and the light receiving unit 20 of the distance measuring device 100 according to the present embodiment. As shown in FIG. 5, lines L2 and L5 connecting the light receiving unit 20 and the point P1 intersect at a point P1 in a predetermined region RA on the optical axis FX of the light projecting unit 10. Lines L3 and L4 connecting the light receiving unit 20 and the point P2 are on the optical axis FX in the region RB located in the direction approaching the light projecting unit 10 from the predetermined region RA on the optical axis FX of the light projecting unit 10. Intersect at point P2. Furthermore, lines L1 and L6 connecting the light receiving unit 20 and the point P3 are the optical axes FX in the region RC located in a direction farther from the light projecting unit 10 than the predetermined region RA on the optical axis FX of the light projecting unit 10. Intersect at the upper point P3.

  That is, the distance measuring device 100 has one light receiving unit group G1 including two light receiving units 20 where the lines L2 and L5 intersect the optical axis FX of the light projecting unit 10 at a point P1 in the region RA. The distance measuring device 100 has one light receiving unit group G2 including two light receiving units 20 where the lines L3 and L4 intersect the optical axis FX of the light projecting unit 10 at a point P2 in the region RB. Further, the distance measuring device 100 has one light receiving unit group G3 including two light receiving units 20 whose lines L1 and L6 intersect the optical axis FX of the light projecting unit 10 at a point P3 in the region RC.

  As described above, the regions RA, RB, and RC where the lines connecting the optical axis FX of the light projecting unit 10, the light receiving unit 20, and the predetermined point intersect each depend on the distance of the light receiving unit 20 from the light projecting unit 10. Is different. That is, the distance measuring device 100 includes three light receiving unit groups G1, G2, and G3.

  For this reason, when the object OB is present near the point P1 on the optical axis FX of the light projecting unit 10, distance measurement is performed based on the received light reception generated by the two light receiving units 20 included in the light receiving unit group G1. Can do. Similarly, when the object OB exists near the point P2 on the optical axis FX, distance measurement can be performed based on the light reception signals generated by the two light receiving units 20 included in the light receiving unit group G2. Further, when the object OB is present near the point P3 on the optical axis FX, distance measurement can be performed based on the light reception signals generated by the two light receiving units 20 included in the light receiving unit group G3.

  Therefore, according to the distance measuring device 100 according to the present embodiment, when the object OB exists in the vicinity of the point P1, the point P2, or the point P3 on the optical axis FX of the light projecting unit 10, the light receiving unit The time of flight of the reflected light RL received by the groups G1, G2, G3 can be made constant. For this reason, it is possible to align the peak positions of the received light signals generated in the light receiving units 20 included in any of the light receiving unit groups G1, G2, and G3. Therefore, it is possible to improve the distance measurement accuracy of the distance measuring apparatus 100.

  A distance measuring apparatus 100 according to a third embodiment will be described. The distance measuring device 100 according to the third embodiment differs from the distance measuring device 100 according to the first or second embodiment in the arrangement position of the light receiving unit 20 with respect to the light projecting unit 10.

  FIG. 6 shows an arrangement example of the light projecting unit 10 and the light receiving unit 20 of the distance measuring device 100 according to the present embodiment. In FIG. 6, the plurality of light receiving units 20 are arranged in a row along a direction perpendicular to the optical axis FX of the light projecting unit 10.

  The pair of light receiving units 20 is arranged so that the optical axes RX2 and RX5 of the light receiving unit 20 intersect in a predetermined region RA on the optical axis FX of the light projecting unit 10. The pair of light receiving units 20 is arranged so that the optical axes RX3 and RX4 of the light receiving unit 20 intersect in a predetermined region RB on the optical axis FX of the light projecting unit 10. The pair of light receiving units 20 are arranged so that the optical axes RX1 and RX6 of the light receiving unit 20 intersect in a predetermined region RC on the optical axis FX of the light projecting unit 10.

  In each of the plurality of light receiving units 20, the optical axes RX3, RX4 or RX1, RX6 of the plurality of light receiving units 20 intersect with each other in a region RB or RC different from the predetermined region RA on the optical axis FX of the light projecting unit 10. Are arranged as follows. Specifically, in the direction perpendicular to the optical axis FX of the light projecting unit 10, the optical axis of the light receiving unit 20 farther from the light projecting unit 10 intersects on the optical axis FX of the light projecting unit 10 farther from the light projecting unit 10. In this way, the respective light receiving portions 20 are arranged.

  That is, the distance measuring device 100 has one light receiving unit group G1 including two light receiving units 20 in which the respective optical axes RX2 and RX5 intersect the optical axis FX of the light projecting unit 10 at a point P1 in the region RA. In addition, the distance measuring device 100 has one light receiving unit group G2 including two light receiving units 20 in which the respective optical axes RX3 and RX4 intersect the optical axis FX of the light projecting unit 10 at a point P2 in the region RB. Further, the distance measuring device 100 has one light receiving unit group G3 including two light receiving units 20 in which each of the optical axes RX1 and RX6 intersects the optical axis FX of the light projecting unit 10 at a point P3 in the region RC. Thus, the optical axis of the light receiving unit 20 that is farther from the light projecting unit 10 intersects on the optical axis FX of the light projecting unit 10 that is farther from the light projecting unit 10.

  Further, the optical axes RX1 to RX6 extending in the vertical direction from the light receiving surface 20a of each light receiving unit 20 and the optical axis FX of the light projecting unit 10 are arranged to have an acute angle. The angle formed by the optical axes RX1 to RX6 extending in the vertical direction from the light receiving surface 20a of each light receiving unit 20 and the optical axis FX of the light projecting unit 10 decreases as the distance from the light projecting unit 10 increases.

  As described above, the plurality of light receiving units 20 are arranged in a line along the direction perpendicular to the optical axis FX of the light projecting unit 10. Therefore, according to the distance measuring device 100 according to the present embodiment, the space for arranging the plurality of light receiving units 20 can be reduced, and the size of the device can be reduced.

  Further, the angle formed by the optical axes RX1 to RX6 extending in the vertical direction from the light receiving surface 20a of the light receiving unit 20 and the optical axis FX of the light projecting unit 10 decreases as the distance from the light projecting unit 10 increases. That is, the light receiving surface 20a of the light receiving unit 20 corresponding to each light receiving unit group G1 to G3 is inclined and arranged so that the optical axis RX intersects at a predetermined position on the optical axis FX of the light projecting unit 10. The amount of reflected light RL to be received can be increased without increasing the angle of the light reflecting surface of the light deflection element 21. Therefore, the intensity of the reflected light RL received by the distance measuring device 100 can be increased without being limited to the maximum angle of the light reflecting surface of the reflective light deflecting element 21 that can be designed, and the SN ratio can be increased.

  A distance measuring apparatus 100 according to a fourth embodiment will be described. The distance measuring device 100 according to the fourth embodiment is different from the distance measuring device 100 according to the first to third embodiments in processing of the distance measuring unit 40. Specifically, the distance measuring unit 40 selects a plurality of light receiving units 20 in different modes according to the light receiving state of the reflected light RL of the light receiving unit 20 and performs distance measurement.

  FIG. 7 shows a processing flow in which the distance measuring unit 40 selects the light receiving unit 20.

  As shown in FIG. 7, when the distance measurement unit 40 receives the light reception signal from the light reception unit 20, the distance measurement unit 40 determines whether or not the amount of background light included in the light reception signal exceeds a predetermined reference value (step S101). .

  When the distance measurement unit 40 determines that the background light included in the light reception signal does not exceed a predetermined reference value (step S101: N), the light reception signal generated by the light reception unit 20 is used as a light reception signal for distance measurement. Select (step S102).

  When the distance measurement unit 40 determines that the amount of background light included in the light reception signal exceeds a predetermined reference value (step S101: Y), the light reception signal that uses the light reception signal generated by the light reception unit 20 for distance measurement. Exclude from (Step S103).

  The distance measuring unit 40 determines whether the selection of the received light signals generated by all the light receiving units 20 has been completed (step S104).

  If the distance measuring unit 40 determines in step S104 that the selection of the received light signal has not been completed (step S104: N), it returns to the determination in step S101.

  If it is determined in step S104 that the selection of the received light signal has been completed (step S104: Y), the distance measuring unit 40 measures the distance using the received light signal selected in step S102 (step S105).

  As described above, the distance measurement unit 40 selects and measures the light reception signal according to the amount of noise of the light reception signal generated by each light reception unit 20. Therefore, according to the distance measuring device 100 according to the present embodiment, it is possible to reduce the noise amount of the received light signal, that is, to increase the SN ratio, in the process of distance measurement by the distance measuring unit 40. As a result, the ranging accuracy of the ranging device 100 can be increased.

  A distance measuring apparatus 100 according to a fifth embodiment will be described. The distance measuring device 100 according to the fifth embodiment is different from the distance measuring device 100 according to the fourth embodiment in processing of the distance measuring unit 40. Specifically, the distance measuring unit 40 includes a plurality of light receiving units 20 according to the time from when the emitted light EL is emitted until each light receiving unit 20 receives the reflected light RL (hereinafter referred to as measurement time). Ranging in different ways.

  FIG. 8 shows a processing flow in which the distance measuring unit 40 of the distance measuring apparatus 100 according to the fifth embodiment selects the light receiving unit 20. As shown in FIG. 8, when the distance measuring unit 40 receives the light reception signal from the light receiving unit 20, the distance measuring unit 40 determines whether the measurement time exceeds a predetermined time (step S201).

  When the distance measurement unit 40 determines that the measurement time does not exceed a predetermined time (step S201: N), the distance measurement unit 40 selects the light reception signal generated by the light reception unit 20 as a light reception signal used for distance measurement (step S202). ).

  When the distance measurement unit 40 determines that the measurement time exceeds a predetermined time (step S201: Y), the distance measurement unit 40 excludes the light reception signal generated by the light reception unit 20 from the light reception signal used for distance measurement (step S203). .

  The distance measuring unit 40 determines whether selection of the received light signals generated by all the light receiving units 20 is completed (step S204).

  When the distance measuring unit 40 determines that the selection of the received light signal is not completed in the determination in step S204 (step S204: N), the distance measurement unit 40 returns to the determination in step S201.

  If it is determined in step S204 that the selection of the received light signal has been completed (step S204: Y), the distance measuring unit 40 measures the distance using the received light signal selected in step S202 (step S205).

  As described above, the distance measuring unit 40 selects the light reception signal generated by the light receiving unit 20 according to the measurement time, and measures the distance to the object OB. That is, the distance measurement unit 40 selects a light reception signal used for the distance measurement process according to the distance to the object OB.

  Therefore, according to the distance measuring apparatus 100 according to the present embodiment, it is possible to perform distance measurement using a light reception signal having a close time of flight. As a result, it is possible to improve the distance measurement accuracy of the distance measuring apparatus 100.

  A distance measuring apparatus 100 according to Example 6 will be described. The distance measuring device 100 according to the sixth embodiment is different from the distance measuring device 100 according to the fifth embodiment in processing of the distance measuring unit 40. Specifically, the distance measuring unit 40 weights the light reception signals measured by each of the plurality of light receiving units 20 according to the measurement time, and measures the distance to the object OB.

  FIG. 9 shows a processing flow in which the distance measuring unit 40 of the distance measuring apparatus 100 according to the sixth embodiment selects the light receiving unit 20. As shown in FIG. 9, when the distance measuring unit 40 receives a light reception signal from the light receiving unit 20, the distance measuring unit 40 determines whether the measurement time exceeds a predetermined time (step S301).

  When the distance measuring unit 40 determines that the measurement time does not exceed a predetermined time (step S301: N), the distance measuring unit 40 weights the light reception signal generated by the light receiving unit 20 (step S302).

  The distance measuring unit 40 determines whether weighting is completed for the light reception signals generated by all the light receiving units 20 (step S303).

  If the distance measuring unit 40 determines in step S303 that weighting of the received light signal has not been completed (step S303: N), it returns to the determination in step S301.

  When the distance measuring unit 40 determines in step S303 that weighting of the light reception signal is completed (step S303: Y), the distance measurement unit 40 measures the distance using the plurality of weighted light reception signals (step S304). Here, the weighting means that for a light reception signal whose measurement time is shorter than the specified time, the ratio of using the light reception signal for the distance measurement process is reduced, or for a light reception signal whose measurement time is shorter than the specified time. For example, correction is made to the received light signal whose measurement time is short so as to approach the measurement time exceeding the specified time.

  In the determination in step S301, when the distance measurement unit 40 determines that the measurement time exceeds a predetermined time (step S301: N), the distance measurement unit 40 performs the process in step S303.

  As described above, the distance measuring device 100 performs weighting by weighting the received light signal whose measurement time is shorter than the specified time. Therefore, according to the distance measuring apparatus 100 according to the present embodiment, it is possible to perform distance measurement in consideration of data reliability, and therefore it is possible to perform distance measurement with high accuracy.

  A distance measuring apparatus 100 according to Example 7 will be described. The distance measuring device 100 according to the seventh embodiment is different from the distance measuring device 100 according to the sixth embodiment in processing of the distance measuring unit 40. Specifically, the distance measuring unit 40 increases the number of light receiving units 20 to be selected as the measurement time increases. In the present embodiment, the distance measuring device 100 will be described as having six light receiving units 20.

  FIG. 10 illustrates a processing flow in which the distance measuring unit 40 of the distance measuring apparatus 100 according to the seventh embodiment selects the light receiving unit 20. As illustrated in FIG. 10, when the distance measurement unit 40 receives a light reception signal from the light reception unit 20, the distance measurement unit 40 determines whether or not the measurement time exceeds a predetermined first specified time (step S401).

  When the distance measurement unit 40 determines that the measurement time exceeds a predetermined first predetermined time (step S401: Y), the distance measurement unit 40 selects all the light reception signals among the light reception signals generated by the six light reception units 20 ( Step S402). The distance measuring unit 40 measures the distance using the light reception signal selected in step S402 (step S403).

  When the distance measurement unit 40 determines that the measurement time does not exceed the first predetermined time (step S401: N), does the distance measurement unit 40 exceed the second predetermined time that is shorter than the first predetermined time? It is determined whether or not (step S404).

  When the distance measurement unit 40 determines that the measurement time exceeds a predetermined second predetermined time (step S404: Y), the measurement time is relatively short among the light reception signals generated by the six light reception units 20. Two light reception signals are selected (step S405). The distance measuring unit 40 measures the distance using the received light signal selected in step S405 (step S403).

  When the distance measuring unit 40 determines that the measurement time does not exceed the predetermined second specified time (step S404: N), the measurement time exceeds the third specified time that is shorter than the second specified time. Whether or not (step S406).

  When the distance measurement unit 40 determines that the measurement time exceeds a predetermined third predetermined time (step S405: Y), the measurement time 2 is relatively short among the light reception signals generated by the six light reception units 20. Two light reception signals are selected (step S407). The distance measuring unit 40 measures the distance using the received light signal selected in step S407 (step S403).

  When the distance measurement unit 40 determines that the measurement time does not exceed the predetermined third predetermined time (step S405: N), the measurement time is relatively short among the light reception signals generated by the six light reception units 20. One light reception signal is selected (step S408). The distance measuring unit 40 measures the distance using the received light signal selected in step S408 (step S403).

  As described above, the distance measuring unit 40 selects a light reception signal used for distance measurement according to the measurement time. That is, when the measurement time is long, since the distance from the distance measuring device 100 to the object OB is long, the difference in the measurement time of each light receiving unit 20 becomes short. Therefore, distance measurement can be performed with high signal intensity by performing distance measurement using the light reception signals of all the light receiving units 20 included in the distance measuring device 100.

  Further, in the measurement time shorter than the first specified time and longer than the second specified time, the difference in the measurement time of each light receiving unit 20 affects the distance measurement. Therefore, the distance measurement unit 40 can improve the accuracy of distance measurement by performing distance measurement using a light reception signal having a relatively short measurement time.

  As described above, the distance measurement unit 40 selects the light receiving unit 20 used for distance measurement according to the measurement time, and performs distance measurement using a light reception signal with less error. Therefore, the distance measuring device 100 can perform distance measurement with high accuracy. In the present invention, the selection of the received light signal is not limited to the above embodiment. For example, a light reception signal that is selected when the measurement time exceeds the first specified time, a light reception signal that is selected when the measurement time exceeds the second specified time, or a light reception signal that is selected when the measurement time exceeds the third specified time. The number of received light signals and the number of received light signals that are selected when the measurement time does not exceed the third specified time may be arbitrarily determined on the condition that the number of received light signals decreases in order.

  A distance measuring apparatus 100 according to an eighth embodiment will be described. The distance measuring device 100 according to the eighth embodiment is different from the distance measuring device 100 according to the first to seventh embodiments in the distance measuring process performed by the distance measuring unit 40.

  The distance measuring unit 40 measures the distance by using each of the received light signals generated by the plurality of light receiving units 20 according to the emission angle of the emitted light EL in a different manner.

  FIG. 11 shows an arrangement example of the light projecting unit 10 and the light receiving unit 20 of the distance measuring device 100 according to the present embodiment. As shown in FIG. 11, the light projecting unit 10 is disposed on the central axis CX. The light receiving units 20A to 20D are arranged in a row in the direction perpendicular to the central axis CX. Specifically, a pair of light receiving portions 20A and 20D are arranged at positions symmetrical with respect to the central axis CX. In addition, a pair of light receiving portions 20B and 20C is disposed between the pair of light receiving portions 20A and 20D at positions symmetrical with respect to the central axis CX.

  The light projecting unit 10 emits outgoing light EL at an angle θE with respect to the central axis CX. The outgoing light EL reflected by the object OB enters each of the light receiving units 20A to 20D as reflected light RL.

  Here, the distance from the distance measuring device 100 to the object OB is a distance Z. In the figure, the distances from the light receiving units 20A to 20D to the object OB are different. Specifically, the distance from the light receiving units 20A to 20D to the object OB becomes longer in the order of the light receiving unit 20A, the light receiving unit 20B, the light receiving unit 20C, and the light receiving unit 20D.

  FIG. 12 shows a light reception signal A generated by the light receiving unit 20A, a light reception signal B generated by the light receiving unit 20B, a light reception signal C generated by the light receiving unit 20C, and a light reception signal D generated by the light receiving unit 20D. In FIG. 12, the position of the peak PK of the light reception signals A to D varies depending on the distance from the light receiving units 20A to 20D to the object OB. Further, the intensity of the peak PK of each of the received light signals A to D is weak and slightly higher than the noise N.

  FIG. 13 shows a combined signal generated by adding the received light signals A to D of FIG. As shown in FIG. 13, when all the light reception signals A to D are added and synthesized, the peak PK of each light reception signal A to D is buried in noise N, and it is difficult to determine the position of the peak PK. Further, the positions of the peaks PK of the respective received light signals A to D are shifted, and it is difficult to accurately measure the object OB.

  The distance measurement unit 40 corrects each of the light reception signals A to D generated by the plurality of light reception units 20A to 20D according to the emission angle of the emission light EL, and measures the distance. Specifically, the distance measuring unit 40 indicates the distance Z between the measuring device 100 and the object OB with respect to the emission angle θE of the outgoing light deflection element 12, and the correction amount of the measurement time from the reference time for each light receiving unit 20. It has a table that stores the values.

  For example, as shown in Table 1, when the distance from the distance measuring device 100 to the object OB is Z1 at the emission angle θE1, the correction amount from the reference time for one light receiving unit 20 is ΔTA1 seconds. The correction amount from the reference time for the other light receiving units 20 under the same conditions is ΔTB1 second. As described above, the distance measuring unit 40 has a table that stores a value indicating the correction amount from the reference time according to the installation position of each light receiving unit 20.

  FIG. 14 shows a correction example of the received light signals A to D generated by the light receiving units 20A to 20D. In FIG. 14, the distance measuring unit 40 superimposes the light reception signals A to D according to the correction amount from the reference time for each light reception signal A to D with reference to the table of Table 1. Thereby, the distance measurement unit 40 performs distance measurement based on the signal having the maximum signal intensity of the reflected light RL from the object OB included in the superimposed light reception signal.

  Specifically, the distance measuring unit 40 corrects the received light signal A to a position where the correction amount ΔTA1 from the reference time is advanced. The distance measuring unit 40 corrects the received light signal B to a position where the correction amount ΔTB1 from the reference time is advanced. The distance measuring unit 40 corrects the received light signal C to a position where the correction amount ΔTC1 from the reference time is advanced. The distance measuring unit 40 corrects the received light signal D to a position where the correction amount ΔTD1 from the reference time is advanced.

  FIG. 15 shows a combined signal generated by adding the received light signals A to D of FIG. As shown in FIG. 15, when all the corrected received light signals A to D are added and synthesized, the intensity of the peak PK of the synthesized signal becomes larger than the noise at a predetermined position. Therefore, it becomes easy to determine the peak PK. Further, since the positions of the peaks PK of the respective light receiving signals A to D coincide with each other, it is possible to accurately measure the object OB.

  As described above, the distance measurement unit 40 can reduce the amount of noise with respect to the reflected light RL by increasing the signal intensity of the reflected light RL from the object OB by aligning the received light signals. Therefore, according to the distance measuring apparatus of the present embodiment, distance measurement can be performed with high accuracy. The table in Table 1 is not limited to the above, and a value indicating a correction amount of time from the reference time corresponding to each light receiving unit 20 from the reference time measured by the light receiving unit 20 serving as a reference is stored. Also good.

  FIG. 16 shows another correction example of the light reception signals A to D. In FIG. 16, the distance measuring unit 40 uses the light reception signal A as a reference time, and corrects the time from the reference time for the light reception signals B to D. Specifically, the distance measuring unit 40 corrects the light reception signal B to a position where the correction amount ΔTB2 from the reference time is advanced. The distance measuring unit 40 corrects the received light signal C to a position where the correction amount ΔTC2 from the reference time is advanced. The distance measuring unit 40 corrects the received light signal D to a position where the correction amount ΔTD2 from the reference time is advanced.

  Even if the light reception signals A to D are corrected in this way, the peak positions of the light reception signals A to D can be made uniform, and the distance measuring device 100 can perform distance measurement with high accuracy.

DESCRIPTION OF SYMBOLS 100 Distance measuring device 10 Light projection part 11 Light source 12 Output light deflection element 20 Light reception part 21 Reflection light deflection element 22 Light reception element 40 Distance measurement part FX Optical axis RX1-RX6 of a light projection part Optical axis of a light reception part

Claims (9)

A light projecting unit including a light source that emits outgoing light and an outgoing light deflecting element having an outgoing light reflecting member that variably deflects the direction of the outgoing light;
Reflecting members each having a reflected light reflecting member that is spaced apart from the light projecting unit in a direction perpendicular to the optical axis of the light projecting unit and that variably deflects the direction of the reflected light reflected by the object from the emitted light A plurality of light receiving portions each including a light deflecting element and a light receiving element that receives the reflected light deflected by the reflected light deflecting element;
A distance measuring device comprising:   2. The distance measuring device according to claim 1, wherein each of the light receiving units is arranged so that each of the optical axes of the plurality of light receiving units intersects in a predetermined region on the optical axis of the light projecting unit. apparatus.   Each of the light receiving units is arranged such that an angle formed by the optical axis of the light receiving unit and the optical axis of the light projecting unit increases as the distance from the light projecting unit of the light receiving unit increases. The distance measuring device according to claim 2.   The each of the light receiving units is arranged such that each of the optical axes of the plurality of light receiving units intersects with a region different from a predetermined region on the optical axis of the light projecting unit. 3. The distance measuring device according to 3.   5. The region where the optical axis of the light projecting unit and the optical axis of the light receiving unit intersect depends on a distance of the light receiving unit from the light projecting unit. 6. The distance measuring device described in 1.   6. The measurement according to claim 2, wherein an optical axis of the light receiving unit farther from the light projecting unit intersects on an optical axis of the light projecting unit farther from the light projecting unit. Distance device. One light receiving unit group including the plurality of light receiving units, each optical axis intersecting the optical axis of the light projecting unit in one region;
The other light receiving unit group including the plurality of light receiving units, each of which has an optical axis intersecting with the optical axis of the light projecting unit in another region, according to any one of claims 2 to 6. The described distance measuring device.   8. The measurement according to claim 1, wherein each of the light receiving parts is arranged on a circular arc centered on a predetermined point on the optical axis of the light projecting part. 9. Distance device.   9. The distance measuring device according to claim 1, wherein the reflected light reflecting member of each of the light receiving portions swings in conjunction with the outgoing light reflecting member of the light projecting portion. apparatus.