JP7148249B2 - rangefinder - Google Patents

Description

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

An optical rangefinder, for example, scans a target area with a laser beam to measure the distance to the target, that is, measures the distance.

As such a rangefinder, for example, Japanese Patent Laid-Open No. 2002-200001 discloses an optical rangefinder in which a drive section for driving the light reflection surface of an optical scanning device to oscillate includes at least one of a phase difference changer and an amplitude changer. It is

JP 2011-053137 A

Laser light scatters when it hits an object. For this reason, the intensity of the laser beam received by the distance measuring device becomes weaker as the object becomes farther from the distance measuring device. Therefore, in order to measure the distance of an object located far from the distance measuring device, it is desirable 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 changes with the size of the aperture of the light receiving system. Specifically, the SN ratio increases as the aperture of the light receiving system increases. However, one of the problems is that if the aperture of the light-receiving system is increased, the size of the device increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a distance measuring apparatus which has a sufficient SN ratio and which can be miniaturized.

A distance measuring apparatus according to claim 1 of the present application comprises: a light source for emitting emitted light; A reflected light deflecting element having a reflected light reflecting member arranged apart from the light projecting part in a direction perpendicular to the optical axis of the light projecting part and variably deflecting the direction of the reflected light of the emitted light reflected by an object. and a plurality of light receiving units each including a light receiving element for receiving the reflected light deflected by the reflected light deflection element.

1 is a block diagram showing the configuration of a distance measuring device according to Example 1; FIG. FIG. 4 is an explanatory diagram illustrating the principle of operation of the projection system of the rangefinder according to the first embodiment; FIG. 4 is an explanatory diagram for explaining the principle of operation of the light receiving system of the distance measuring device according to the first embodiment; FIG. 2 is a conceptual diagram showing an arrangement example of a light projecting section and a light receiving section in FIG. 1; FIG. 11 is a conceptual diagram showing an example of arrangement of a light projecting unit and a light receiving unit of a distance measuring device according to a second embodiment; FIG. 11 is a conceptual diagram showing an example of arrangement of a light projecting unit and a light receiving unit of a distance measuring device according to Example 3; FIG. 11 is a processing flow diagram for selecting a light receiving unit by the distance measuring unit of the range finder according to the fourth embodiment; FIG. 11 is a processing flow diagram for selecting a light receiving unit by the distance measuring unit of the range finder according to the fifth embodiment; FIG. 12 is a processing flow diagram for selecting a light receiving unit by the distance measuring unit of the range finder according to the sixth embodiment; FIG. 20 is a processing flow diagram for selecting a light receiving unit by the distance measuring unit of the range finder according to the seventh embodiment; FIG. 11 is a conceptual diagram showing an example of arrangement of a light projecting unit and a light receiving unit of a distance measuring device according to Example 8; FIG. 12 is a conceptual diagram showing a light receiving signal generated by the light receiving unit of FIG. 11; FIG. 13 is a conceptual diagram showing a signal obtained by synthesizing the received light signals of FIG. 12; FIG. 12 is a conceptual diagram showing an example of correction of the received light signal generated by the light receiving unit of FIG. 11; FIG. 15 is a conceptual diagram showing a signal obtained by synthesizing the received light signals of FIG. 14; FIG. 12 is a conceptual diagram showing another correction example of the received light signal generated by the light receiving unit of FIG. 11;

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

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

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

The light-receiving unit 20 is a light-receiving device that receives reflected light and generates a light-receiving signal. The distance measuring device 100 has a plurality of light receiving units 20 having the same configuration. A reflected light deflecting element 21 as a reflected light deflecting element of the light receiving section 20 has a reflected light reflecting member including a light reflecting surface (not shown). It can be reflected towards. In other words, the reflected light deflection element 21 can variably deflect the direction of the reflected light. A MEMS mirror device, a polygon mirror, or the like can also be used as the reflected light deflection element 21 .

The light-receiving element 22 is a photodetector capable of receiving reflected light and generating a light-receiving signal, which is an electrical signal. For example, an avalanche photodiode (APD) or the like can be used as the light receiving element 22 .

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

The light source control unit 31 controls light emission of the light source 11 . Specifically, for example, the light emission is controlled by referring 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 inclination angles of the light reflecting surfaces of the emitted light deflecting element 12 and the reflected light deflecting element 21 . Specifically, the mirror control unit 32 controls the emitted light deflection element 12 so that the scanning target area is scanned by the pulsed light emitted by the light source 11 and reflected by a light reflecting surface (not shown). do. Further, the mirror control unit 32 controls the reflected light deflecting element so that the direction of the light reflecting surface of the emitted light reflecting member of the emitted 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 interlocked. 21.

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

Specifically, the distance measurement unit 40 determines the emission time of one pulsed light emitted by the light source 11 and the light received by the plurality of light receiving units 20 as reflected light from the object in the scanning target area. acquires the time of light reception detected by each of Then, based on the time difference between the emission time and the light reception time, the length of the optical path from the light source 11 to 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 projection system of the distance measuring device 100. As shown in FIG. In FIG. 2 , emitted light EL emitted from a light source 11 is incident on an emitted light deflection element 12 . The emitted light deflection element 12 reflects the incident emitted light EL toward the scan target region R. As shown in FIG.

Specifically, the emitted light deflecting element 12 reflects the light beam toward the scanning target region R in a manner of scanning by swinging the movable portion MR. As a result, the irradiation direction of the emitted light EL reflected by the emitted light deflection element 12 changes. Specifically, the emitted light EL is reflected by the emitted light deflection element 12 so that a Lissajous trajectory is drawn on a virtual plane VS, which is a virtual plane in the reflection direction of the emitted light EL. The distance measuring device 100 performs distance measurement of an object OB existing in a scanning target area R. FIG. Note that the virtual surface VS does not actually exist. Also, the trajectory drawn on the virtual plane VS may not be the Lissajous trajectory. The trajectory drawn on the virtual plane VS may be, for example, a trajectory obtained by raster scanning.

FIG. 3 is a conceptual diagram showing the operation of the light receiving system of the distance measuring device 100. As shown in FIG. In FIG. 3 , when an object OB exists in the scanning target area R, the reflected light RL reflected from the object OB is incident on the reflected light deflection element 21 and is incident on the light receiving element 22 . The light receiving element 22 converts the incident reflected light RL into an electric signal and supplies the electric signal to the distance measuring section 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 section 10 and the light receiving section 20. As shown in FIG. As shown in FIG. 4 , each light receiving section 20 is arranged apart from light projecting section 10 in the direction perpendicular to optical axis FX of light projecting section 10 . Specifically, a pair of light receiving units 20 are arranged at symmetrical positions with respect to the optical axis FX of the light projecting unit 10 as a central axis. The pair of light receiving portions 20 are provided at three mutually different locations.

Each of the light receiving sections 20 is arranged on an arc AR of a circle centered at a predetermined point P1 on the optical axis FX of the light projecting section 10 . Each of the light receiving sections 20 is arranged at a position where the lengths of lines L1 to L6 connecting the respective light receiving sections 20 with a point P1 within a predetermined area RA on the optical axis FX of the light projecting section 10 are equal. .

The angle between the line L1 and the optical axis FX at the point P1 on the optical axis FX of the light projecting section 10 is defined as an angle θ1. The angle between the line L2 and the optical axis FX at the point P1 on the optical axis FX of the light projecting section 10 is defined as an angle θ2. The angle between the line L3 and the optical axis FX at the point P1 on the optical axis FX of the light projecting section 10 is defined as the angle θ3. A line L1 connecting P1 forms an angle with the optical axis FX of the light projecting section 10 . The angle θ2 is the angle between the optical axis FX of the light projecting unit 10 and 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. The angle θ3 is the angle between the optical axis FX of the light projecting unit 10 and 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.

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

Since the light-receiving units 20 are arranged so that the distance from the predetermined point P1 on the optical axis FX of the light-projecting unit 10 to each light-receiving unit 20 is constant, the distance from the predetermined point P1 to each light-receiving unit 20 The time of flight, that is, the time from when the emitted light EL is emitted from the light projecting section 10 until each of the light receiving sections 20 receives the reflected light RL can be made constant.

As described above, according to the distance measuring device 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 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 a plurality of light receiving units 20, the aperture of each light receiving unit 20 can be made smaller than when the light receiving system is configured with one light receiving unit 20. Therefore, it is possible to configure each light receiving unit 20 to be small, and it is possible to reduce the size of the distance measuring device 100 .

Further, the distance measuring apparatus 100 performs distance measurement based on the light receiving signals generated by the individual light receiving sections 20. As a result, even if the apertures of the individual light receiving sections 20 are small, the distance measuring apparatus 100 The receiving system can have a high aperture. Therefore, the distance measuring device 100 has a sufficient SN ratio and can be miniaturized.

In this embodiment, the light projecting section 10 has the light source 11 and the emitted light deflection element 12 , but the light projecting section 10 may have the light receiving element 22 . When the light projecting section 10 is configured in this manner, it is preferable to include a beam splitter that splits the emitted light EL and the reflected light RL.

A range finder 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 . It should be noted that the same reference numerals are assigned to the same portions of the same configuration as in the first embodiment, and the description thereof will be omitted, and the same will be applied hereinafter.

FIG. 5 shows an arrangement example of the light projecting section 10 and the light receiving section 20 of the distance measuring device 100 according to this embodiment. As shown in FIG. 5 , lines L2 and L5 connecting the light receiving section 20 and the point P1 intersect at a point P1 within a predetermined area RA on the optical axis FX of the light projecting section 10 . Lines L3 and L4 connecting the light receiving portion 20 and the point P2 are located on the optical axis FX within the region RB located in the direction approaching the light projecting portion 10 from the predetermined region RA on the optical axis FX of the light projecting portion 10. Intersect at point P2. Further, lines L1 and L6 connecting the light receiving portion 20 and the point P3 are located in an area RC located further away from the light projecting portion 10 than the predetermined area RA on the optical axis FX of the light projecting portion 10. Intersect at point P3 above.

That is, rangefinder 100 has one light receiving section group G1 including two light receiving sections 20 where lines L2 and L5 intersect optical axis FX of light projecting section 10 at point P1 in area RA. Rangefinder 100 also has one light receiving section group G2 including two light receiving sections 20 where lines L3 and L4 intersect optical axis FX of light projecting section 10 at point P2 in region RB. Further, rangefinder 100 has one light receiving section group G3 including two light receiving sections 20 where lines L1 and L6 intersect optical axis FX of light projecting section 10 at point P3 in 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 and the light receiving unit 20 and the predetermined points intersect each other according to the distance of the light receiving unit 20 from the light projecting unit 10. different. That is, the distance measuring device 100 has three light receiving section groups G1, G2, and G3.

Therefore, when the object OB exists near the point P1 on the optical axis FX of the light projecting unit 10, distance measurement can be performed based on received light received by the two light receiving units 20 included in the light receiving unit group G1. can be done. Similarly, when the object OB exists near the point P2 on the optical axis FX, distance measurement can be performed based on the received light signals generated by the two light receiving sections 20 included in the light receiving section group G2. Further, when the object OB exists near the point P3 on the optical axis FX, distance measurement can be performed based on the received light signals generated by the two light receiving sections 20 included in the light receiving section group G3.

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

A range finder 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 section 20 with respect to the light projecting section 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 this embodiment. In FIG. 6 , the plurality of light receiving units 20 are arranged in a row along the direction perpendicular to the optical axis FX of the light projecting unit 10 .

A pair of light receiving sections 20 are arranged such that the optical axes RX2 and RX5 of the light receiving sections 20 intersect in a predetermined area RA on the optical axis FX of the light projecting section 10 . A pair of light receiving portions 20 are arranged such that the optical axes RX3 and RX4 of the light receiving portions 20 intersect in a predetermined region RB on the optical axis FX of the light projecting portion 10. As shown in FIG. A pair of light receiving portions 20 are arranged such that the optical axes RX1 and RX6 of the light receiving portions 20 intersect in a predetermined region RC on the optical axis FX of the light projecting portion 10 .

Optical axes RX3, RX4 or RX1, RX6 of the plurality of light receiving sections 20 intersect each other in a region RB or RC different from a predetermined region RA on the optical axis FX of the light projecting section 10. are arranged as 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. Each light receiving section 20 is arranged as follows.

That is, rangefinder 100 has one light receiving section group G1 including two light receiving sections 20 whose respective optical axes RX2 and RX5 intersect optical axis FX of light projecting section 10 at point P1 in area RA. Rangefinder 100 also has one light receiving section group G2 including two light receiving sections 20 whose respective optical axes RX3 and RX4 intersect optical axis FX of light projecting section 10 at point P2 in region RB. Further, distance measuring device 100 has one light receiving section group G3 including two light receiving sections 20 whose respective optical axes RX1 and RX6 intersect optical axis FX of light projecting section 10 at point P3 in region RC. In this way, the optical axes of the light receiving units 20 that are farther from the light projecting unit 10 intersect 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 vertically from the light receiving surface 20a of each light receiving section 20 and the optical axis FX of the light projecting section 10 are arranged to form an acute angle. The angle between the optical axes RX1 to RX6 extending vertically from the light receiving surface 20a of each light receiving section 20 and the optical axis FX of the light projecting section 10 becomes smaller as the distance from the light projecting section 10 increases.

As described above, the plurality of light receiving units 20 are arranged in a row along the direction perpendicular to the optical axis FX of the light projecting unit 10 . Therefore, according to the distance measuring device 100 of 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 vertically from the light receiving surface 20a of the light receiving section 20 and the optical axis FX of the light projecting section 10 becomes smaller as the distance from the light projecting section 10 increases. That is, by arranging the light receiving surfaces 20a of the light receiving units 20 corresponding to the light receiving unit groups G1 to G3 at an angle so that the optical axis RX intersects at a predetermined position on the optical axis FX of the light projecting unit 10, the light is reflected. 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 restricted by the maximum angle of the light reflecting surface of the reflected light deflection element 21 that can be designed, and the SN ratio can be increased.

A range finder 100 according to a fourth embodiment will be described. The distance measuring device 100 according to the fourth embodiment differs from the distance measuring devices 100 according to the first to third embodiments in the 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 conditions of the reflected light RL of the light receiving units 20 and performs distance measurement.

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

As shown in FIG. 7, when receiving the light receiving signal from the light receiving unit 20, the distance measuring unit 40 determines whether or not the amount of background light included in the light receiving 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 the predetermined reference value (step S101: N), the light reception signal generated by the light reception unit 20 is used as the light reception signal used for distance measurement. Select (step S102).

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

The distance measurement unit 40 determines whether or not the selection of the received light signals generated by all the light receiving units 20 has been completed (step S104).

When the distance measurement unit 40 determines in step S104 that the selection of the received light signal has not been completed (step S104: N), the process returns to step S101.

When the distance measurement unit 40 determines in step S104 that the selection of the received light signal has been completed (step S104: Y), distance measurement is performed using the received light signal selected in step S102 (step S105).

As described above, the distance measurement unit 40 selects a light receiving signal according to the amount of noise in the light receiving signal generated by each light receiving unit 20 and performs distance measurement. Therefore, according to the range finder 100 of the present embodiment, it is possible to reduce the amount of noise in the received light signal in the process of measuring the range by the range finder 40, that is, to increase the SN ratio. As a result, it is possible to improve the distance measurement accuracy of the distance measuring device 100 .

A range finder 100 according to a fifth embodiment will be described. The distance measuring device 100 according to the fifth embodiment differs from the distance measuring device 100 according to the fourth embodiment in the processing of the distance measuring unit 40 . Specifically, the distance measurement unit 40 measures the distance between the plurality of light receiving units 20 according to the time (hereinafter referred to as measurement time) from the emission of the emitted light EL until each light receiving unit 20 receives the reflected light RL. are used in different ways for ranging.

FIG. 8 shows a processing flow in which the distance measuring unit 40 of the distance measuring device 100 according to the fifth embodiment selects the light receiving unit 20. As shown in FIG. As shown in FIG. 8, when receiving the light receiving signal from the light receiving unit 20, the distance measuring unit 40 determines whether or not the measured time exceeds a predetermined specified time (step S201).

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

When the distance measurement unit 40 determines that the measurement time exceeds the 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 signals used for distance measurement (step S203). .

The distance measurement unit 40 determines whether or not the selection of the received light signals generated by all the light receiving units 20 has been completed (step S204).

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

When the distance measurement unit 40 determines in step S204 that the selection of the light receiving signal has been completed (step S204: Y), distance measurement is performed using the light receiving signal selected in step S202 (step S205).

As described above, the distance measurement unit 40 selects the received light 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 the received light signal to be used for distance measurement processing according to the distance to the object OB.

Therefore, according to the range finder 100 according to the present embodiment, it is possible to measure the range using the received light signal having a close time-of-flight. As a result, it is possible to improve the accuracy of distance measurement by the distance measuring device 100 .

A range finder 100 according to a sixth embodiment will be described. The distance measuring device 100 according to the sixth embodiment differs from the distance measuring device 100 according to the fifth embodiment in the processing of the distance measuring unit 40 . Specifically, the distance measurement unit 40 weights the received light signal 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 device 100 according to the sixth embodiment selects the light receiving unit 20. As shown in FIG. As shown in FIG. 9, when receiving the light receiving signal from the light receiving unit 20, the distance measuring unit 40 determines whether or not the measured time exceeds a predetermined specified time (step S301).

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

The distance measuring unit 40 determines whether the weighting of the light receiving signals generated by all the light receiving units 20 has been completed (step S303).

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

If the distance measurement unit 40 determines in step S303 that the weighting of the received light signals has been completed (step S303: Y), distance measurement is performed using a plurality of weighted received light signals (step S304). Here, the weighting is to reduce the rate of using the received light signal for distance measurement processing for the received light signal whose measurement time is shorter than the specified time, or is, for example, correcting a light receiving signal having a short measurement time so as to approach the measurement time exceeding the specified time.

When the distance measurement unit 40 determines in step S301 that the measured time exceeds the predetermined time (step S301: N), it performs the processing in step S303.

As described above, the distance measuring apparatus 100 performs distance measurement by weighting light reception signals whose measurement time is shorter than the specified time. Therefore, according to the range finder 100 according to the present embodiment, since the range can be measured with the reliability of the data taken into consideration, the range can be measured with high accuracy.

A range finder 100 according to a seventh embodiment will be described. The distance measuring device 100 according to the seventh embodiment differs from the distance measuring device 100 according to the sixth embodiment in the processing of the distance measuring unit 40 . Specifically, the distance measurement unit 40 selects more light receiving units 20 as the measurement time increases. In this embodiment, the distance measuring device 100 will be described as having six light receiving units 20 .

FIG. 10 shows a processing flow in which the distance measuring unit 40 of the distance measuring device 100 according to the seventh embodiment selects the light receiving unit 20. As shown in FIG. As shown in FIG. 10, when receiving the light receiving signal from the light receiving section 20, the distance measuring section 40 determines whether or not the measured time exceeds a predetermined first specified time (step S401).

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

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

When the distance measurement unit 40 determines that the measurement time exceeds the predetermined second specified time (step S404: Y), the three light receiving signals generated by the six light receiving units 20 have relatively short measurement times. One received light signal is 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 measurement unit 40 determines that the measured time does not exceed the predetermined second specified time (step S404: N), the measured time exceeds the third specified time shorter than the second specified time. (step S406).

When the distance measurement unit 40 determines that the measurement time exceeds the predetermined third specified time (step S405: Y), the distance measurement unit 40 determines that the light reception signals generated by the six light reception units 20 have relatively short measurement times. One received light signal is selected (step S407). The distance measurement 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 specified time (step S405: N), the measurement time of the light receiving signals generated by the six light receiving units 20 is relatively short. One received light signal is selected (step S408). The distance measurement unit 40 measures the distance using the received light signal selected in step S408 (step S403).

As described above, the distance measurement unit 40 selects the received light signal used for distance measurement according to the measurement time. That is, when the measurement time is long, the distance between the distance measuring device 100 and the object OB is long, so the difference between the measurement times of the respective light receiving units 20 is short. Therefore, by measuring the distance using the light reception signals of all the light receiving units 20 of the distance measuring device 100, it is possible to measure the distance with high signal strength.

Moreover, 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 receiving signal whose measurement time is relatively short.

In this manner, the distance measurement unit 40 selects the light receiving unit 20 to be used for distance measurement according to the measurement time, thereby performing distance measurement using light reception signals with little error. Therefore, the ranging device 100 can perform highly accurate ranging. In addition, in the present invention, the selection of the received light signal is not limited to the above-described embodiment. For example, a received light signal selected when the measurement time exceeds the first specified time, a received light signal selected when the measured time exceeds the second specified time, and selected when the measured time exceeds the third specified time. The number of light receiving signals and the number of light receiving signals to be selected when the measurement time does not exceed the third specified time may be arbitrarily determined on the condition that the numbers are sequentially smaller.

A range finder 100 according to an eighth embodiment will be described. The distance measuring device 100 according to the eighth embodiment differs from the distance measuring devices 100 according to the first to seventh embodiments in the distance measuring process performed by the distance measuring unit 40 .

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

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 this embodiment. As shown in FIG. 11, the light projecting section 10 is arranged on the central axis CX. The light receiving sections 20A to 20D are arranged in rows in the direction perpendicular to the central axis CX. Specifically, a pair of light receiving portions 20A and 20D are arranged at symmetrical positions with respect to the central axis CX. A pair of light receiving portions 20B and 20C are arranged 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 the emitted light EL at an angle θE with respect to the central axis CX. The emitted light EL reflected by the object OB enters each of the light receiving sections 20A to 20D as reflected light RL.

Here, let distance Z be the distance from the distance measuring device 100 to the object OB. In the drawing, the distances from the respective light receiving sections 20A to 20D to the object OB are different. Specifically, the distance from the light receiving sections 20A to 20D to the object OB increases in the order of the light receiving section 20A, the light receiving section 20B, the light receiving section 20C, and the light receiving section 20D.

FIG. 12 shows the light receiving signal A generated by the light receiving section 20A, the light receiving signal B generated by the light receiving section 20B, the light receiving signal C generated by the light receiving section 20C, and the light receiving signal D generated by the light receiving section 20D. In FIG. 12, the positions of the peaks PK of the light receiving signals A to D differ according to the distance from the light receiving sections 20A to 20D to the object OB. Also, 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.

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

The distance measuring unit 40 measures the distance by correcting each of the light receiving signals A to D generated by the plurality of light receiving units 20A to 20D according to the emission angle of the emitted light EL. 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 emitted 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 exit angle θE1, the correction amount from the reference time for one light receiving unit 20 is ΔTA1 seconds. The amount of correction from the reference time for the other light receiving units 20 under the same conditions is ΔTB1 seconds. As described above, the distance measurement unit 40 has a table storing values indicating the amount of correction from the reference time corresponding to the installation position of each light receiving unit 20 .

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

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

FIG. 15 shows a synthesized 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 greater than the noise at a predetermined position. Therefore, it becomes easy to determine the peak PK. In addition, since the positions of the peaks PK of the light receiving signals A to D match each other, it is possible to accurately measure the distance to the object OB.

In this manner, the distance measurement unit 40 increases the signal intensity of the reflected light RL from the object OB by aligning the received light signals, thereby reducing the amount of noise in the reflected light RL. Therefore, according to the range finder of this embodiment, it is possible to measure the range with high accuracy. Note that the table of Table 1 is not limited to the above, and stores a value indicating the amount of correction of the time from the reference time corresponding to each light receiving unit 20 from the reference time measured by the light receiving unit 20 as a reference. good too.

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

Even if the light receiving signals A to D are corrected in this way, it is possible to align the peak positions of the light receiving signals A to D, and the distance measuring apparatus 100 can measure the distance with high accuracy.

100 Distance measuring device 10 Light projecting unit 11 Light source 12 Emitted light deflection element 20 Light receiving unit 21 Reflected light deflection element 22 Light receiving element 40 Distance measuring unit FX Optical axes RX1 to RX6 of light emitting unit Optical axes of light receiving unit

Claims (7)

a light projecting unit including a light source for emitting emitted light , an emitted light deflection element having an emitted light reflecting member for variably deflecting the direction of the emitted light, and an opening through which the emitted light is emitted to the outside ;
Each is arranged apart from the light projecting unit in a direction perpendicular to the light projecting center axis which is the center axis of the opening of the light projecting unit, and the direction of the reflected light reflected by the target object is variably deflected from the emitted light. a plurality of light receiving units each including a reflected light deflecting element having a reflected light reflecting member and a light receiving element receiving the reflected light deflected by the reflected light deflecting element;
has
In the plurality of light receiving portions, a light receiving center axis extending vertically from a light receiving surface of each light receiving portion intersects the light projecting center axis at a plurality of positions on the light projecting center axis . rangefinder. 2. The distance measuring device according to claim 1, wherein the plurality of light receiving units are arranged in a line along a direction perpendicular to the center axis of light projection . 3. The distance measuring device according to claim 1, wherein a position where the center axis of light projection and the center axis of light reception intersect varies depending on the distance of the light receiving section from the light projecting section. 2. The light- receiving central axis of each of the plurality of light-receiving parts intersects on the light-projecting central axis farther from the light-projecting part as the light-receiving part is farther from the light-projecting part. 4. The distance measuring device according to any one of 3 . The plurality of light receiving units are
a light-receiving portion group including a pair of light-receiving portions each having a light- receiving central axis intersecting the light-projecting central axis in one region;
5. The light-receiving unit group according to claim 1 , further comprising a pair of light-receiving units whose respective light- receiving central axes intersect the light-projecting central axis in another region. rangefinder. The light receiving portions constituting the pair of light receiving portions in each of the one light receiving portion group and the other light receiving portion group are arranged at positions facing each other across the light projection central axis . The distance measuring device according to claim 5 . 7. The distance measurement according to any one of claims 1 to 6 , wherein the reflected light reflecting member of each of the light receiving units swings in conjunction with the emitted light reflecting member of the light projecting unit. Device.

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