Measurement device

Abstract

A measurement device (1) is provided with: a light-emitting unit (10) that irradiates measurement light toward a measurement region; a first light receiving unit (20) that receives reflected light from the measurement region; a control unit (40) that controls the light-emitting unit (10) and the first light-receiving unit (20), and that calculates the distance to an object (50) in the measurement region on the basis of the light-receiving result of the first light-receiving unit (20); and a second light receiving unit (30) that receives light having a wavelength different from that of the measurement light from among the light from the measurement region.

Description

Technical Field

[0001] The present invention relates to an assay device. Background Art

[0002] There is known a measuring device that measures the distance to an object by irradiating light and receiving reflected light that is reflected from the object (for example, refer to Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2021-152536 Summary of the invention

[0004] The light received by the measuring device includes not only reflected light but also disturbing light (noise) such as sunlight and light from oncoming vehicles. The above-mentioned measuring device cannot distinguish these lights, so the detection performance may be reduced due to noise when receiving light.

[0005] An object of the present invention is to improve detection performance.

[0006] One of the present inventions for achieving the above-mentioned purpose is a measuring device comprising: a light-emitting unit that irradiates measuring light toward a measuring area; a first light-receiving unit that receives reflected light from the measuring area; a control unit that controls the light-emitting unit and the first light-receiving unit and calculates the distance to an object in the measuring area based on the light reception result of the first light-receiving unit; and a second light-receiving unit that receives light from the measuring area that has a wavelength different from that of the measuring light.

[0007] Effects of the Invention

[0008] According to the present invention, it is possible to improve the detection performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a diagram showing the overall configuration of a measurement device 1 according to this embodiment.

[0010] Figure 2 yes Figure 1 2 is an explanatory diagram of the structure of the first light receiving unit 20 shown.

[0011] Figure 3A yes Figure 1 An explanatory diagram of the signal processing unit 462 shown.

[0012] Figure 3B Yes means Figure 1 The diagram shows the output of the adding unit 462A and the output of the comparing unit 462B.

[0013] Figure 3C is through Figure 3AThe histogram generated by the histogram generating unit 462C and an explanatory diagram of the time of flight TOF detected based on the histogram are shown.

[0014] Figure 4 This is a flowchart for explaining the processing of the control unit 40 according to the first embodiment.

[0015] Figure 5 Yes Figure 1 A flowchart for explaining a modified example of the processing of the control unit 40 shown in FIG.

[0016] Figure 6 Yes Figure 1 Flowchart for explaining another modified example of the processing of the control unit 40 shown in FIG.

[0017] Figure 7 It is an explanatory diagram of the structure of the second light receiving unit 30 of the measuring device 1 according to the second embodiment.

[0018] Figure 8 This is a diagram illustrating the spectrum of a white LED.

[0019] Fig. 9 This is a flowchart showing the processing of the control unit 40 according to the second embodiment.

[0020] Fig.10 This is a flowchart showing a modified example of the processing of the control unit 40 according to the second embodiment. DETAILED DESCRIPTION

[0021] Hereinafter, the mode for implementing the present invention will be described with reference to the drawings. In the following description, common reference numerals are sometimes given to the same or similar structures, and repeated descriptions are omitted.

[0022] (First embodiment)

[0023] <<Outline of measurement device>>

[0024] Figure 1 It is a diagram showing the overall configuration of a measurement device 1 according to this embodiment.

[0025] Figure 1The measuring device 1 shown is a measuring device having a function as a so-called LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging). The measuring device 1 irradiates measuring light (infrared light in this embodiment), measures the time until the measuring light is reflected by the object 50 and returns, and thereby measures the distance to the object 50 by the TOF (Time Of Flight) method. The measuring device 1 of this embodiment is mounted on a vehicle, and the object 50 is another vehicle (oncoming vehicle). In addition, the light (return light) reflected by the object 50 and returned is also called "reflected light".

[0026] like Figure 1 As shown, the measuring device 1 includes a light emitting unit 10 , a first light receiving unit 20 , a second light receiving unit 30 , and a control unit 40 .

[0027] The light emitting unit 10 irradiates the space of the measurement object (hereinafter referred to as the measurement area) with measurement light (here, infrared light). The light emitting unit 10 includes, for example, a surface emitting element array (VCSEL array) having a plurality of surface emitting laser elements (VCSEL (Vertical Cavity Surface Emitting Laser)) arranged one-dimensionally or two-dimensionally, and a light projection optical system such as a lens for adjusting the light distribution of the emitted light (both are not shown).

[0028] The first light receiving unit 20 receives reflected light (infrared light) from the object 50 in the measurement area. In the first light receiving unit 20 of the present embodiment, a SPAD (Single Photon Avalanche Diode) is used as a sensor (light receiving element) for detecting light. The details of the first light receiving unit 20 will be described later.

[0029] The second light receiving unit 30 receives light having a wavelength different from that of the reflected light (for example, sunlight, disturbance light such as light from an oncoming vehicle, etc.) from the light from the measurement region.

[0030] The control unit 40 controls the measuring device 1. The control unit 40 is implemented by hardware structures such as memory, CPU and other components, circuits, etc. The control unit 40 implements predetermined functions by executing programs stored in the memory by the CPU. Figure 1 2 shows various functions realized by the control unit 40. The control unit 40 includes a timing control unit 42, a setting unit 44, a distance measuring unit 46, and a determination unit 48.

[0031] The timing control unit 42 controls various timings such as the timing of irradiating light from the light emitting unit 10 .

[0032] The setting unit 44 performs various settings for the measurement device 1. For example, the setting unit 44 sets the intensity of the measurement light emitted from the light emitting unit 10, the number of accumulations when creating a histogram, a threshold value, and the like.

[0033] The distance measuring unit 46 measures the distance to the object 50. The distance measuring unit 46 includes a signal processing unit 462, a time detection unit 464, and a distance calculation unit 466. The signal processing unit 462 processes the output signal of the first light receiving unit 20. The time detection unit 464 detects the arrival time (light flight time: TOF) until the reflected light reaches the first light receiving unit 20 after the light emitting unit 10 emits the measurement light. The distance calculation unit 466 calculates the distance to the object 50 based on the light flight time TOF.

[0034] The determination unit 48 determines the presence or approach of an oncoming vehicle based on the light reception result of the second light receiving unit 30. The determination by the determination unit 48 will be described later.

[0035] <<About the first light receiving unit 20>>

[0036] Figure 2 yes Figure 1 2 is an explanatory diagram of the structure of the first light receiving unit 20 shown.

[0037] like Figure 2 As shown, the first light receiving unit 20 has a plurality of pixels 22 arranged in a two-dimensional shape. In addition, each pixel, i.e., one pixel 22, has a plurality of light receiving elements 24. Here, each pixel 22 has nine SPADs arranged in three in the X direction (e.g., horizontal direction) and three in the Y direction (e.g., vertical direction) as light receiving elements 24. The light receiving element 24 composed of SPADs outputs a pulse signal if it detects a particle of light (photon (hereinafter also referred to as Photon)).

[0038] <<About Histogram and TOF>>

[0039] Figure 3A yes Figure 1 FIG. 4 is an explanatory diagram of the signal processing unit 462 shown in FIG. Figure 3B Yes means Figure 1 4 is a diagram showing an example of the output of the adder 462A and the output of the comparison unit 462B. The signal processing unit 462 includes the adder 462A, the comparison unit 462B, and the histogram generation unit 462C. Here, the signal processing unit 462 generates a histogram used in the time-correlated single photon counting method (TCSPC) based on the output signal of each pixel 22 of the first light receiving unit 20.

[0040] The adding section 462A adds the output signals of the plurality of light receiving elements 24 (SPAD) constituting the pixel 22. The adding section 462A may add the output signals of the plurality of light receiving elements 24 after adjusting (shaping) the pulse width output by the light receiving element 24. The comparing section 462B compares the output signal of the adding section 462A with a threshold value, and outputs a signal when the output signal of the adding section 462A is greater than or equal to the threshold value. The timing at which the comparing section 462B outputs the signal is considered to be the timing at which the light receiving element 24 of the first light receiving section 20 detects light.

[0041] In addition, the photons of the interfering light are incident on each light receiving element 24 randomly in time. In contrast, the photons of the reflected light are incident on each light receiving element 24 with a predetermined delay time (flight time corresponding to the distance to the object 50) after the light is irradiated. Therefore, in the case where the photons of the interfering light are incident on the light receiving element 24 randomly in time, the probability that the output signal of the adding unit 462A is greater than or equal to the threshold is low. On the other hand, in the case where the photons of the reflected light are incident on the light receiving element 24, the multiple light receiving elements 24 constituting the pixel 22 detect the photons at the same time, so the probability that the output signal of the adding unit 462A is greater than or equal to the threshold is high. Therefore, the output signals of the multiple light receiving elements 24 are added by the adding unit 462A, and the output signal of the adding unit 462A is compared with the threshold by the comparing unit 462B, thereby being able to measure the time when the reflected light is considered to be detected in the light receiving element 24.

[0042] In addition, once the light receiving element 24 detects a photon, a dead time (hold-off-time, dead-time) will occur. However, by adding the output signals of the plurality of light receiving elements 24 (SPAD) by the adding unit 462A, the influence of the dead time can be suppressed.

[0043] Figure 3C is through Figure 3A The histogram generated by the histogram generating unit 462C and an explanatory diagram of the time of flight TOF detected based on the histogram are shown. Figure 3C The horizontal axis is time, and the vertical axis is frequency (number of times). The histogram generating unit 462C repeatedly measures the time when the light receiving element 24 of each pixel 22 of the first light receiving unit 20 detects light based on the output of the comparing unit 462B, and increments the frequency (number of times) associated with the time, thereby generating a histogram. When the histogram generating unit 462C increments the frequency (number of times), instead of incrementing the number by 1, it may increment the number corresponding to the output signal (addition value) of the adding unit 462A.

[0044] In addition, the setting unit 44 (see Figure 1) As described above, the cumulative number of times for generating a histogram is preset. The timing control unit 42 causes the light emitting unit 10 to emit the measuring light multiple times in accordance with the set cumulative number of times. For one emission of the measuring light from the light emitting unit 10, the adding unit 462A outputs a signal once or multiple times. The histogram generating unit 462C increases the frequency (number of times) in accordance with the output signal of the comparing unit 462B until the set cumulative number of times is reached, thereby generating a histogram.

[0045] After the histogram is generated, the time detection unit 464 of the distance measurement unit 46 detects the flight time TOF from the time when the light is irradiated until the reflected light arrives based on the histogram. Figure 3C As shown, the time detection unit 464 of the distance measuring unit 46 detects the time (light flight time TOF) corresponding to the peak value of the frequency of the histogram. Moreover, the distance calculation unit 466 of the distance measuring unit 46 calculates the distance to the object 50 based on the flight time TOF. In addition, during the flight time TOF, the distance traveled by light is twice the distance to the object. Therefore, if the speed of light is Co and the flight time TOF is Tf, the distance L to the object becomes:

[0046] L=(Tf×Co) / 2 · · · · · (1).

[0047] The distance calculation unit 466 calculates the distance to the object 50 according to the formula (1).

[0048] <<About the Second Light Receiving Unit 30>>

[0049] Figure 1 As described above, the second light receiving unit 30 shown receives light of a wavelength different from that of the reflected light (infrared light). Therefore, the second light receiving unit 30 has a sensor (e.g., a photodiode) that can detect light of a wavelength different from that of the reflected light (infrared light) (e.g., sunlight). In addition, the sensor (not shown) of the second light receiving unit 30 is set in the same direction as the light receiving surface of the first light receiving unit 20, and receives light from the measurement area according to the instruction from the control unit 40.

[0050] <<Regarding the processing of the control unit 40>>

[0051] Figure 4 This is a flowchart for explaining the processing of the control unit 40 according to the first embodiment.

[0052] First, the timing control unit 42 of the control unit 40 receives light (interference light, hereinafter referred to as sunlight) of a wavelength different from the measurement light among the light from the measurement area through the second light receiving unit 30 (S101). Then, the setting unit 44 of the control unit 40 sets the intensity of the measurement light (infrared light) irradiated by the light emitting unit 10 based on the light reception result (S102). For example, the intensity of the measurement light is set to be greater as the sunlight is stronger.

[0053] Next, the timing control unit 42 controls the light emitting unit 10 to irradiate the measurement light (infrared light) of the intensity set in step S102 toward the measurement area (S103). In addition, the timing control unit 42 receives light (including reflected light and sunlight) from the measurement area through the first light receiving unit 20 (S104). In addition, the timing control unit 42 causes the first light receiving unit 20 to repeatedly receive light for one light emission.

[0054] The histogram generating unit 462C of the signal processing unit 462 in the distance measuring unit 46 generates a histogram indicating the frequency per unit time based on the output (comparison result) of the comparing unit 462B which compares the output (addition result) of the adding unit 462A with a predetermined threshold value (S105).

[0055] When the cumulative number is not the nth time (ie, less than n) (No in step S106), the process returns to step S103, and the control unit 40 causes the light emitting unit 10 to emit the measuring light again.

[0056] On the other hand, when the cumulative number of times in step S106 is the nth time (step S106 is Yes), the time detection unit 464 of the distance measuring unit 46 finds the peak value of the generated histogram and calculates the time from the timing of light emission to the peak value (time of flight TOF) (S107).

[0057] Next, the distance calculation unit 466 of the distance measuring unit 46 calculates the distance to the object according to the equation (1) using the time of flight TOF ( S108 ).

[0058] As described above, the setting unit 44 of the control unit 40 of the measuring device 1 of this embodiment sets the intensity of the measuring light irradiated by the light emitting unit 10 based on the light reception result of the second light receiving unit 30. Thus, when there is much disturbance light, the intensity of the measuring light is increased, thereby maintaining the detection accuracy. In addition, when there is little disturbance light, the intensity of the measuring light is reduced, thereby reducing the power consumption.

[0059] <Variation 1>

[0060] Figure 5 Yes Figure 1The flowchart for explaining the modification 1 of the processing of the control unit 40 shown in FIG. 1 is shown in FIG. 1 . The configuration of the measurement device 1 is the same as that of the above-mentioned embodiment. The setting unit 44 of the modification 1 determines the cumulative number n based on the light reception result of the second light receiving unit 30 .

[0061] First, the timing control unit 42 of the control unit 40 causes the second light receiving unit 30 to receive light (interference light, such as sunlight) of a wavelength different from the measurement light among the light from the measurement area (S201). Then, the setting unit 44 of the control unit 40 sets (determines) the cumulative number n based on the light reception result (S202). For example, the setting unit 44 sets the cumulative number n to increase as the interference light is stronger.

[0062] Next, the timing control unit 42 controls the light emitting unit 10 to irradiate the measurement light (infrared light) of a predetermined intensity toward the measurement area (S203). Furthermore, the timing control unit 42 causes the first light receiving unit 20 to receive light (including infrared light and sunlight) from the measurement area (S204). In addition, the timing control unit 42 causes the first light receiving unit 20 to repeatedly receive light for one emission.

[0063] The histogram generation unit 462C of the signal processing unit 462 in the distance measuring unit 46 generates a histogram based on the output (comparison result) of the comparison unit 462B which compares the output (addition result) of the addition unit 462A and a predetermined threshold value (S205).

[0064] When the cumulative number is not the nth time (ie, less than n) (No in step S206), the process returns to step S203, and the control unit 40 causes the light emitting unit 10 to emit the measuring light again.

[0065] On the other hand, when the cumulative number is the nth time (Yes in step S206), the time detection unit 464 of the distance measuring unit 46 obtains the peak of the generated histogram and calculates the time from the timing of light emission to its peak, that is, the time of flight TOF (S207).

[0066] Next, the distance calculation unit 466 of the distance measuring unit 46 calculates the distance to the object according to the equation (1) using the time of flight TOF ( S208 ).

[0067] As described above, the setting unit 44 of the modification 1 sets the cumulative number n based on the light receiving result of the second light receiving unit 30. Thus, the cumulative number can be optimized according to the condition of the disturbance light. For example, when there is a lot of disturbance light, the cumulative number n is set to be large, thereby maintaining the detection accuracy. In addition, when there is little disturbance light, the cumulative number n is set to be small, thereby increasing the speed of measurement.

[0068] <Variation 2>

[0069] Figure 6 Yes Figure 1 4. The flowchart of the modification example 2 of the processing of the control unit 40 shown in FIG. 4 is used to explain the modification example 2 of the processing of the control unit 40 shown in FIG. 4. In addition, the structure of the measuring device 1 is the same as that of the above-mentioned embodiment. In the modification example 2, based on the light reception result of the second light receiving unit 30, the threshold value (refer to FIG. 4) compared with the output of the adding unit 462A in the comparing unit 462B is Figure 3A , Figure 3B ) to make settings.

[0070] First, the timing control unit 42 of the control unit 40 causes the second light receiving unit 30 to receive light (interference light, such as sunlight) of a wavelength different from the measurement light among the light from the measurement area (S301). Then, the setting unit 44 of the control unit 40 determines a threshold value based on the light reception result (S302).

[0071] In addition, when the threshold value is a small value, when there is much interfering light, the histogram will be greatly affected by the interfering light, so the detection accuracy of the arrival time of the light may be reduced. On the other hand, when the threshold value is a large value, it may take time to generate a histogram of the specified cumulative number of times. Therefore, in the present embodiment, based on the light receiving result of the second light receiving unit 30, when there is much interfering light, the setting unit 44 sets the threshold value to a large value. Thus, the detection accuracy can be maintained. In addition, based on the light receiving result of the second light receiving unit 30, when there is little interfering light, the setting unit 44 sets the threshold value to a small value. Thus, the generation speed of the histogram can be improved.

[0072] Next, the timing control unit 42 controls the light emitting unit 10 to irradiate the measurement area with the measurement light (infrared light) of a predetermined intensity (S303). Furthermore, the timing control unit 42 causes the first light receiving unit 20 to receive the light (including infrared light and sunlight) from the measurement area (S304). In addition, the timing control unit 42 causes the first light receiving unit 20 to repeatedly receive light for one light emission.

[0073] The histogram generation unit 462C of the signal processing unit 462 in the distance measuring unit 46 generates a histogram based on the output (comparison result) of the comparison unit 462B obtained by comparing the addition result of the addition unit 462A and the threshold value set in step S302 (S305).

[0074] When the cumulative number is not the nth time (ie, less than n) (No in step S306), the process returns to step S303, and the control unit 40 causes the light emitting unit 10 to emit the measurement light again.

[0075] On the other hand, when the cumulative number is the nth time (Yes in step S306), the time detection unit 464 of the distance measuring unit 46 obtains the peak value of the generated histogram and calculates the time from the timing of light emission to its peak value, that is, the time of flight TOF (S307).

[0076] Next, the distance calculation unit 466 of the distance measuring unit 46 calculates the distance to the object 50 according to the equation (1) using the time of flight TOF ( S308 ).

[0077] As described above, the setting unit 44 of the modification 2 sets the threshold value when generating the histogram based on the light receiving result of the second light receiving unit 30. Thus, when there is much disturbance light, the detection accuracy can be maintained by setting the threshold value to a large value. In addition, when there is little disturbance light, the generation speed of the histogram can be increased by setting the threshold value to a small value.

[0078] (Second embodiment)

[0079] Figure 7 It is an explanatory diagram of the structure of the second light receiving unit 30 of the measuring device 1 according to the second embodiment.

[0080] The second light receiving unit 30 of the second embodiment has two sensors (a first sensor 32 and a second sensor 34) having different detection ranges as a sensor for receiving light of a different wavelength from the measurement light (infrared light) irradiated by the light emitting unit 10. As described later, the first sensor 32 is a sensor capable of detecting blue light, and the second sensor 34 is a sensor capable of detecting yellow light.

[0081] In addition, the object 50 (hereinafter referred to as the oncoming vehicle) of the second embodiment has a white LED as a light source of the vehicle's headlights (e.g., low beam, DRL (Daytime Running Lamp), etc.). In addition, the white LED is composed of a combination of a blue LED and a yellow phosphor. That is, the light generated by the blue LED is irradiated through the yellow phosphor. Thus, white light is irradiated. In addition, the second light receiving unit 30 of the measuring device 1 detects the light irradiated from the white LED of the oncoming vehicle.

[0082] Figure 8 This is a diagram illustrating the spectrum of a white LED. Figure 8 The horizontal axis represents the wavelength, and the vertical axis represents the energy of light.

[0083] like Figure 8As shown, the spectrum of the white LED includes two peaks, a peak at about 465nm and a peak at about 560nm. In addition, the peak at about 465nm is the center wavelength of light emitted by the blue LED, and the peak at about 560nm is the center wavelength of light emitted by the yellow phosphor.

[0084] in addition, Figure 8 The region R1 shown is a detectable region of the first sensor 32 that can detect blue light. In addition, the region R2 is a detectable region of the second sensor 34 that can detect yellow light. Figure 8 As shown, the first sensor 32 can detect light with a wavelength of 465 nm, and the second sensor 34 can detect light with a wavelength of 560 nm. In addition, the wavelength of the region R1 detectable by the first sensor 32 corresponds to the "first wavelength", and the wavelength of the region R2 detectable by the second sensor 34 corresponds to the "second wavelength".

[0085] By providing the first sensor 32 and the second sensor 34 having different detection ranges as described above, the presence of the object 50 (oncoming vehicle) can be determined based on the respective detection results (light intensity ratios).

[0086] Fig. 9 This is a flowchart showing the processing of the control unit 40 according to the second embodiment.

[0087] The timing control unit 42 of the control unit 40 causes the second light receiving unit 30 to receive light from the measurement area (S401). In addition, the control unit 40 detects the intensity of blue light, that is, light with a central wavelength of 465 nm, based on the light reception result of the first sensor 32 of the second light receiving unit 30 (S402).

[0088] Furthermore, the control unit 40 detects the intensity of the yellow light, ie, the light having a central wavelength of 560 nm, based on the light reception result of the second sensor 34 of the second light receiving unit 30 ( S403 ).

[0089] Next, the determination unit 48 of the control unit 40 determines whether there is an oncoming vehicle based on the ratio of the intensity of the blue light to the intensity of the yellow light (S404). For example, when the intensity of the blue light is higher than the intensity of the yellow light, the determination unit 48 determines that there is light emitted from the white LED of the oncoming vehicle, that is, the oncoming vehicle exists. In addition, when the intensity of the yellow light is higher than the intensity of the blue light (for example, sunlight, etc.), the determination unit 48 determines that there is no light emitted from the oncoming vehicle, that is, the oncoming vehicle does not exist.

[0090] As described above, the second light receiving unit 30 of the measuring device 1 of the second embodiment includes the first sensor 32 capable of detecting blue light and the second sensor 34 capable of detecting yellow light. Thus, the determination unit 48 can determine the presence or absence of an oncoming vehicle (object 50) based on the ratio of the intensity of the blue light detected by the first sensor 32 and the intensity of the yellow light detected by the second sensor 34.

[0091] <Modification of the Second Embodiment>

[0092] Fig.10 1 is a flowchart showing a modification of the processing of the control unit 40 of the second embodiment. In the modification of the second embodiment, the control unit 40 of the measurement device 1 detects the approach of an oncoming vehicle based on the detection result of the second light receiving unit 30 .

[0093] First, the control unit 40 causes the first sensor 32 and the second sensor 34 of the second light receiving unit 30 to receive light from the measurement area (S501). Here, as in the above-mentioned embodiment, the first sensor 32 receives blue light, and the second sensor 34 receives yellow light. The presence or absence of an oncoming vehicle (object 50) can be detected by the light reception result.

[0094] In addition, the control unit 40 detects the approach of an oncoming vehicle based on the change in the light receiving result (light receiving amount) of the second light receiving unit 30 with the passage of time (S502). For example, when an oncoming vehicle approaches, the light receiving amount of the first sensor 32 and the light receiving amount of the second sensor 34 increase with the passage of time. Thus, the determination unit 48 of the control unit 40 determines that the oncoming vehicle is approaching based on the change in the light receiving result of the second light receiving unit 30.

[0095] Further, the distance measuring unit 46 of the control unit 40 calculates the distance to the oncoming vehicle (object 50 ) based on the light reception result of the first light receiving unit 20 , similarly to the first embodiment ( S503 ).

[0096] Furthermore, the control unit 40 compares the change in the distance to the oncoming vehicle (referenced in the first embodiment) calculated based on the detection result of the first light receiving unit 20 with the change in the light receiving result of the second light receiving unit 30 (S504). Thus, the reliability of measuring the distance to the oncoming vehicle (object 50) can be improved.

[0097] (Summarize)

[0098] The above is a description of the measuring device 1 of the present embodiment. The measuring device 1 includes a light emitting unit 10, a first light receiving unit 20, a second light receiving unit 30, and a control unit 40. The light emitting unit 10 irradiates the measuring light (infrared light) toward the measuring area. The first light receiving unit 20 receives the reflected light from the measuring area, that is, the measuring light reflected by the object 50. The control unit 40 controls the light emitting unit 10 and the first light receiving unit 20, and calculates the distance to the object 50 in the measuring area based on the light reception result of the first light receiving unit 20. The second light receiving unit 30 receives the light of a wavelength different from that of the measuring light among the light from the measuring area. Thus, it is possible to improve the detection performance.

[0099] Furthermore, the control unit 40 calculates the distance to the object 50 based on the light reception result of the second light receiving unit 30. This can suppress the influence of disturbance light (sunlight, etc.), and improve the accuracy of measurement.

[0100] Specifically, the setting unit 44 of the first embodiment sets the intensity of the measurement light irradiated from the light emitting unit 10 based on the light reception result of the second light receiving unit 30. Furthermore, the control unit 40 calculates the distance based on the light reception result of the first light receiving unit 20 when the light emitting unit 10 irradiates the measurement light of the intensity. As described above, the intensity of the measurement light is increased when there is much disturbance light, thereby maintaining the detection accuracy. In addition, the intensity of the measurement light is reduced when there is little disturbance light, thereby reducing the power consumption.

[0101] In addition, the setting unit 44 of the modification 1 of the first embodiment determines the cumulative number of times n based on the light receiving result of the second light receiving unit 30. Moreover, the control unit 40 causes the first light receiving unit 20 to receive the reflected light with the number of the determined cumulative number of times n, and calculates the distance based on the light receiving result of the first light receiving unit 20 corresponding to the cumulative number of times n. Thus, when there is a lot of disturbance light, the cumulative number of times n is set to be large, thereby maintaining the detection accuracy. In addition, when there is little disturbance light, the cumulative number of times n is set to be small, thereby increasing the speed of measurement.

[0102] In addition, the distance measuring unit 46 of the control unit 40 has an adding unit 462A, a comparing unit 462B and a histogram generating unit 462C. The adding unit 462A adds the outputs of a plurality of light receiving elements 24, and the comparing unit 462B compares the output of the adding unit 462A with a threshold value. The histogram generating unit 462C generates a histogram based on the comparison result of the comparing unit 462B. In addition, the time detecting unit 464 detects the arrival time of light, i.e., the time of flight TOF, based on the peak value of the histogram. In the above-mentioned structure, the setting unit 44 of the second modification of the first embodiment sets the threshold value based on the light receiving result of the second light receiving unit 30. Thus, in the case of a lot of interfering light, by setting the threshold value to a large value, the detection accuracy can be maintained. In addition, in the case of a little interfering light, by setting the threshold value to a small value, the generation speed of the histogram can be increased.

[0103] In addition, the control unit 40 of the second embodiment determines whether there is an oncoming vehicle (object 50) based on the light receiving result of the second light receiving unit 30. Specifically, the second light receiving unit 30 of the second embodiment has a first sensor 32 and a second sensor 34 that can detect light of different wavelengths. Moreover, the determination unit 48 of the control unit 40 determines whether there is an oncoming vehicle based on the ratio of the intensity of the light based on the detection result of the first sensor 32 and the intensity of the light based on the detection result of the second sensor 34. Thus, it is possible to improve the detection performance of the oncoming vehicle.

[0104] Furthermore, the first sensor 32 can detect blue light (light with a wavelength of 465 nm), and the second sensor 34 can detect yellow light (light with a wavelength of 560 nm). This makes it possible to detect the light of the white LED of an oncoming vehicle.

[0105] The control unit 40 of the modification of the second embodiment detects the approach of an oncoming vehicle based on changes in the light reception result of the second light receiving unit 30. Thus, the approach of an oncoming vehicle can be detected based on the light reception result of the second light receiving unit 30.

[0106] Furthermore, the control unit 40 of the modification of the second embodiment compares the change in the calculated distance based on the light reception result of the first light receiving unit 20 with the change in the light reception result of the second light receiving unit 30. This can improve the reliability of distance measurement.

[0107] The above-mentioned embodiments are for facilitating the understanding of the present invention, and are not for limiting the interpretation of the present invention. In addition, the present invention can be changed and improved without departing from its gist, and its equivalents are naturally included in the present invention.

[0108] This application is based on Japanese Patent Application No. 2022-018762 filed on February 9, 2022, the contents of which are incorporated herein by reference.

Claims

1. A measuring device, comprising: a light emitting unit for emitting measurement light toward the measurement area; a first light receiving unit for receiving reflected light from the measurement area; a control unit that controls the light emitting unit and the first light receiving unit and calculates a distance to an object in the measurement area based on a light receiving result of the first light receiving unit; as well as The second light receiving unit receives light having a wavelength different from that of the measurement light among the light from the measurement area.

2. The measuring device according to claim 1, wherein The control unit calculates the distance based on a light reception result of the second light receiving unit.

3. The measuring device according to claim 2, wherein: The control unit sets the intensity of the measurement light emitted from the light emitting unit based on the light reception result of the second light receiving unit, The distance is calculated based on the light reception result of the first light receiving section when the measurement light having the intensity corresponding to the light reception result of the second light receiving section is radiated.

4. The measuring device according to claim 2, wherein: The control unit determines the cumulative number of times based on the light receiving result of the second light receiving unit, causing the first light receiving unit to receive the reflected light at the determined cumulative number of times, The distance is calculated based on the light reception result of the first light receiving unit corresponding to the cumulative number of times.

5. The measuring device according to claim 2, wherein: The first light receiving unit has a plurality of light receiving elements. The control unit has: an adding unit that adds outputs of a plurality of light receiving elements; a comparing unit for comparing the addition result of the adding unit with a threshold value; a histogram generating unit that generates a histogram based on the comparison result of the comparing unit; as well as a time detection unit that detects the arrival time of the light based on the peak value of the histogram, and The control unit sets the threshold value based on a result of light reception by the second light receiving unit.

6. The measuring device according to claim 1, wherein The control unit determines whether there is an oncoming vehicle based on the light reception result of the second light receiving unit.

7. The measuring device according to claim 6, wherein: The second light receiving unit includes a first sensor capable of detecting light of a first wavelength and a second sensor capable of detecting light of a second wavelength different from the first wavelength. The control unit determines whether there is the oncoming vehicle based on a ratio of the intensity of the light of the first wavelength based on a detection result of the first sensor and the intensity of the light of the second wavelength based on a detection result of the second sensor.

8. The measuring device according to claim 7, wherein: The first sensor is capable of detecting light with a wavelength of 465 nm. The second sensor can detect light with a wavelength of 560 nm.

9. The measuring device according to claim 7 or 8, wherein The first sensor is capable of detecting blue light. The second sensor is capable of detecting yellow light.

10. The measuring device according to any one of claims 6 to 9, wherein: The control unit detects the approach of the oncoming vehicle based on a change in a light reception result of the second light receiving unit.

11. The measuring device according to claim 10, wherein: The control unit compares a change in the distance calculated based on a result of light reception by the first light receiving unit with a change in a result of light reception by the second light receiving unit.

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