Distance measuring system, distance measuring device, and distance measuring method

Abstract

The present disclosure relates to a distance measuring system comprising: a light receiving unit that receives light that has been emitted from a light source and reflected by a target object, which is a measurement target object; a distance calculating unit that calculates first distance data indicating the distance to the target object on the basis of a light emission timing at which the light was emitted by the light source and a light reception timing at which the light was received by the light receiving unit; a determining unit that determines whether a nearby scattering body is present between the target object and the light receiving unit; and a correcting unit that, if the determining unit has determined that a nearby scattering body is present, corrects the first distance data on the basis of pre-stored correction data, and outputs second distance data.

Description

Distance measuring system, distance measuring device, distance measuring method

[0001] The present disclosure relates to a ranging system, a ranging device, and a ranging method.

[0002] One of the distance measurement methods is the Time-of-Flight (hereinafter referred to as ToF) method. A distance measurement system using the ToF method measures distance by emitting light and receiving the light that hits an object and is reflected back.

[0003] Conventionally, in a ToF distance measurement system, there is a technique for correcting a calibration parameter for correcting a measurement distance in accordance with the amount of light received by each pixel.

[0004] Japanese Patent Application Laid-Open No. 2023-3094

[0005] However, when measuring the distance to a target object (subject) using a conventional ToF method, if a scatterer is present at a closer distance than the target object, the measured distance to the target object changes, resulting in an incorrect distance being measured.

[0006] If the distance measurement system measures an incorrect distance to a target object, there may be problems such as a decrease in the accuracy of applications that use distance information.

[0007] The present disclosure has been made in consideration of the above-described situation, and provides a ranging system, a ranging device, and a ranging method that can accurately measure the distance to a target object even when a scatterer is present at a closer distance than the target object.

[0008] The distance measuring system disclosed herein includes a light receiving unit that receives light emitted from a light source and reflected by a target object to be measured; a distance calculation unit that calculates first distance data indicating the distance to the target object based on the emission timing when the light source emits light and the reception timing when the light receiving unit receives the light; a determination unit that determines whether a nearby scattering object is present between the target object and the light receiving unit; and a correction unit that, when the determination unit determines that the nearby scattering object is present, corrects the first distance data based on pre-stored correction data and outputs second distance data.

[0009] 1 is a diagram showing the configuration of a ranging system according to a first embodiment. FIG. 1 is a functional block diagram of a calculation unit of a ranging system according to a first embodiment. FIG. 2 is a diagram showing one correction data stored in a memory unit. FIG. 3 is a diagram showing one correction data curve stored in a memory unit. FIG. 4 is a diagram showing a case where a near-field scatterer is present between a camera of the ranging system according to the first embodiment and a target object. FIG. 5 is a diagram showing a plurality of correction data stored in a memory unit. FIG. 6 is a diagram for explaining the definition of a near-field scatterer. FIG. 7 is a flowchart for explaining the operation of the ranging system according to the first embodiment. FIG. 8 is a flowchart for explaining a first correction method by the correction unit of the ranging system according to the first embodiment. FIG. 9 is a flowchart for explaining a second correction method by the correction unit of the ranging system according to the first embodiment. FIG. 10 is a diagram showing a marker installed at a fixed point inside a vehicle. FIG. 11 is a functional block diagram of a calculation unit of a ranging system according to a second embodiment. FIG. 12 is a flowchart for explaining the operation of the ranging system according to the second embodiment. FIG. 13 is a flowchart for explaining a correction method by the correction unit of the ranging system according to the second embodiment. FIG. 14 is a diagram showing a case where a robot having the ranging system according to the second embodiment is used in a factory. FIG. 15 is a functional block diagram of a calculation unit of a ranging system according to a third embodiment. FIG. 16 is a flowchart for explaining the operation of the correction unit of the ranging system according to the third embodiment. FIG. 17 is a diagram showing an example where correction processing is performed on the camera system side of the ranging system. 1 is a diagram showing a case where correction is performed using recognition software that uses a distance measured by a ranging system. 2 is a hardware configuration diagram showing an example of a computer that realizes a calculation device according to an embodiment. 3 is a block diagram showing an example of a schematic configuration of a vehicle control system. 4 is an explanatory diagram showing an example of installation positions of an outside-vehicle information detection unit and an imaging unit.

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted. The description will be given in the following order.

[0011] 1. First Embodiment 1.1. Configuration 1.1.1. Diagram showing the configuration of the ranging system 1 according to the first embodiment 1.1.2. Functional block diagram of the calculation unit 6 of the ranging system 1 according to the first embodiment 1.1.2.1. Correction data 30 1.1.2.2. Definition of near-field scatterer 42 1.2. Operation 1.2.1. Flowchart for explaining the operation of the ranging system 1 according to the first embodiment 1.2.2. Correction method 1.2.2.1. First correction method 1.2.2.2. Second correction method 2. Second Embodiment 2.1. Diagram showing a state in which markers are installed at fixed points inside a vehicle 2.2. Functional block diagram of the calculation unit 6 of the ranging system 1 according to the second embodiment 2.3. Operation 2.3.1. Operation of the ranging system 1 according to the second embodiment 2.3.2. Correction method by the correction unit 23 of the ranging system 1 according to the second embodiment 2.4. Application example 3. 3. Third embodiment 3.1. Functional block diagram of the calculation unit 6 of the distance measurement system 1 according to the third embodiment 3.2. Operation 4. Modification of the correction processing part 5. Effects 6. Other embodiments 7. Hardware configuration 8. Application example to a moving body

[0012] 1. First Embodiment 1.1. Configuration 1.1.1. Diagram showing the configuration of a distance measuring system 1 according to a first embodiment FIG. 1 is a diagram showing the configuration of a distance measuring system 1 according to a first embodiment.

[0013] The distance measuring system 1 corrects the measured distance according to the embodiment of the present disclosure based on pre-corrected correction data. A mirror 11 is provided at a position facing the distance measuring system 1.

[0014] The distance measuring system 1 includes a light emitting unit 2, a light receiving unit 3, a control unit 4, a storage unit 5, a calculation unit 6, and an output terminal 7.

[0015] The light-emitting unit 2 has a function of irradiating light onto the mirror 11, which is the reference object. The light-emitting unit 2 is configured to include, for example, an LED (Light Emitting Diode) light source that emits infrared light, and turns on and off the emission of the infrared light according to the control of the control unit 4. The light-emitting unit 2 can emit infrared light in a predetermined emission pattern (a repetitive on-off pattern).

[0016] The light receiving unit 3 has a function of receiving light irradiated from the light emitting unit 2 and reflected from the mirror, and generating light reception data. The light receiving unit 3 outputs the generated light reception data to the storage unit 5. The light reception data may be various data such as the amount of received light, color, etc. The light receiving unit 3 also has a function of receiving light irradiated from the light emitting unit 2 and reflected from the object X, and generating measurement data used when measuring the distance from the light emitting unit 2 to the object X.

[0017] The light receiving unit 3 may receive light at least by an IR (infrared) method, and may be, for example, an RGB sensor including an infrared sensor.

[0018] In the distance measurement system 1, as described above, the light receiving unit 3 performs distance measurement by receiving light emitted by the light emitting unit 2. Examples of distance measurement methods that use light emitting unit 2 to emit light and light receiving unit 3 to receive light include a method of irradiating pulses of infrared light and directly measuring the time it takes for the light to reflect off the surface of the target object and return (dToF method), and a method of modulating infrared light and calculating based on the phase difference between the phase of the light at the time of irradiation and the phase of the light that is reflected and returned (iToF method).

[0019] The light receiving unit 3 may also measure the distance to the target object using a structure light method, etc. The structure light method is a method of projecting a specially designed light pattern onto the surface of the object and estimating the distance to the object by analyzing the deformation of the projected pattern.

[0020] The control unit 4 has a function of instructing the light-emitting unit 2 and the light-receiving unit 3 to emit light and receive light. The control unit 4 instructs the light-emitting unit 2 to emit light, and the light-emitting unit 2 emits light in response to this instruction. The control unit 4 also instructs the light-receiving unit 3 to receive light, and the light-receiving unit 3 starts receiving light in response to this instruction.

[0021] The storage unit 5 has a function of acquiring and storing the light reception data or measurement data obtained by the light receiving unit 3. The storage unit 5 can store data not only permanently but also temporarily.

[0022] The received light data includes reference data obtained from light reflected from a reference object previously acquired, and detection received light data obtained from light reflected from the reference object when detecting a measurement deviation. The reference data may be reference data previously acquired by receiving light reflected from a reference object at the time of shipping or manufacturing the distance measuring sensor.

[0023] The calculation unit 6 has a function of calculating the distance to the object based on the timing of light emission by the light-emitting unit 2 and the timing of light reception by the light-receiving unit 3. In detail, the calculation unit 6 calculates the distance using the time it takes for light emitted from the light-emitting unit 2 to hit the object and for the light reflected from the object to return to the light-receiving unit. The calculation unit 6 calculates the distance from the distance measuring system 1 to the object X by multiplying the time it takes for light to make a round trip by the speed of light and dividing the result by 2.

[0024] Before calculating the distance to the object X, the calculation unit 6 acquires detection light reception data obtained by irradiating light from the light emitting unit 2 and hitting the mirror 11, which is the reference object, with the light receiving unit 3 receiving the reflected light from the mirror 11.

[0025] The calculation unit 6 has a function of comparing the detection light reception data with the reference data stored in the storage unit 5 and controlling the notification process to the user. The notification process to the user is not limited to display, but may be performed by voice, or a combination of display and voice. Furthermore, the notification process to the user may be a process of changing part of the operation performed by the ranging system 1 or an information processing terminal equipped with the ranging system 1.

[0026] Furthermore, the calculation unit 6 calculates the difference between the reference data and the detection light reception data, determines whether or not the difference exists, and controls the notification process to the user. Specifically, the calculation unit 6 may determine whether or not the difference is within a predetermined range. If the difference is equal to or greater than the predetermined range, it determines that there is a difference between the predetermined data and the detection light reception data, and controls the notification process to the user.

[0027] Furthermore, the calculation unit 6 may control the notification content of the notification process depending on the magnitude relationship between the detection light reception data and the reference data. When the notification process to the user is performed by display, the calculation unit 6 may change the display content depending on the magnitude relationship between the detection light reception data and the reference data.

[0028] Specifically, if the detection light reception data is greater than the reference data, the calculation unit 6 may display a message indicating that the ranging system 1 is faulty. On the other hand, if the detection light reception data is smaller than the reference data, the calculation unit 6 may display a message indicating that the ranging system 1 needs repair. In this way, by changing the display content depending on the magnitude relationship, the calculation unit 6 can add information about the degree of measurement deviation to the detection result of the presence or absence of a measurement deviation, thereby presenting the information about the degree of measurement deviation to the user. Note that, for example, if the difference during deviation detection is greater than a predetermined range, the calculation unit 6 may notify the user by a method other than changing the notification content, such as by preventing the ranging system 1 from operating when measuring a distance.

[0029] The calculation unit 6 outputs the notification content to the output terminal 7 selected based on the difference, and performs notification processing to the user via the output terminal 7.

[0030] Furthermore, the calculation unit 6 has a function of correcting the measurement deviation in addition to notifying the user of the detected measurement deviation.

[0031] The output terminal 7 outputs notification processing to various devices for the user under the control of the calculation unit 6. Specifically, if the notification processing to the user is a display, the output terminal 7 performs the notification processing by a display device, and if the notification processing is a sound, the output terminal 7 performs the notification processing by a sound output device.

[0032] <1.1.2. Functional Block Diagram of the Calculation Unit 6 of the Distance Measuring System 1 According to the First Embodiment> Next, a functional block diagram of the calculation unit 6 of the distance measuring system 1 according to the first embodiment will be described. Fig. 2 is a functional block diagram of the calculation unit 6 of the distance measuring system 1 according to the first embodiment. The calculation unit 6 corrects the distance to the target object when a nearby scatterer is present.

[0033] As shown in FIG. 2, the calculation unit 6 includes a distance calculation unit 21, a determination unit 22, a correction unit 23, and a storage unit 5.

[0034] The distance calculation unit 21 calculates first distance data indicating the distance to the target object based on the light emission timing when the light source emits light and the light reception timing when the light reception unit receives the light.

[0035] The determining unit 22 determines whether or not a nearby scatterer exists between the target object and the light receiving unit.

[0036] The corrector 23 determines whether the distance variation exceeds a predetermined threshold value. When the determiner 22 determines the presence of a near-field scatterer and the distance variation exceeds the predetermined threshold value, the corrector 23 corrects the first distance data based on correction data stored in the memory 5 and outputs second distance data.

[0037] Specifically, correction unit 23 acquires the distance fluctuation corresponding to the measured target object from the correction data, and corrects the measured first distance data to the target object using the acquired distance fluctuation amount to correct second distance data. Then, correction unit 23 outputs the corrected second distance data. That is, correction unit 23 performs distance correction according to the distance to the target object acquired in advance.

[0038] <1.1.2.1. Correction Data 30> Next, the correction data 30 used for correction to obtain the true distance will be described. Fig. 3 is a diagram showing one piece of correction data 30 stored in the storage unit 5. As shown in Fig. 3, one piece of correction data 30 includes the reflectance 31 of the target object, the distance 32 to the nearby scatterer, the measured distance 33 to the target object, and the distance variation amount 34.

[0039] 4 is a diagram showing one correction data curve 35 stored in the storage unit 5. In FIG. 4, the horizontal axis represents the distance to the target object, and the vertical axis represents the distance fluctuation amount 34 of the distance measurement value. The correction data curve 35 is a curve estimated from the correction data 30, and the value of this correction data curve 35 is stored in the storage unit 5. The value of the correction data curve 35 may be a value obtained by a function representing the estimated correction curve.

[0040] As shown in FIG. 4, the correction data curve 35 is a function of the distance variation 34 of the distance measurement value and the distance to the target object, and shows the distance variation 34 of the distance measurement value when the actual distance to the target object is set to 0.

[0041] In the same figure, the correction data curve 35 shows that when the distance to the target object is shorter than the actual distance 36, the distance fluctuation amount 34 of the distance measurement value is negative, and when the distance to the target object is equal to or greater than the actual distance 36, the distance fluctuation amount 34 of the distance measurement value is positive.

[0042] Next, a description will be given of the relationship between the camera 41, the proximity scatterer 42, and the target object 43 of the ranging system 1. Fig. 5 is a diagram showing a case where the proximity scatterer 42 is present between the camera 41 and the target object 43 of the ranging system 1 according to the first embodiment.

[0043] The distance between the camera 41 and the nearby scatterer 42 is z [mm]. When the nearby scatterer 42 is present, the measured distance between the camera 41 and the target object 43 is x±y [mm]. Here, x is the original distance between the camera 41 and the target object 43, and y is the distance variation 34. As shown in FIG. 5 , the distance variation y is a positive or negative value relative to the original distance x.

[0044] The storage unit 5 stores a plurality of types of correction data curves 35 shown in Fig. 4. Fig. 6 is a diagram showing a plurality of correction data curves 51 to 59 stored in the storage unit 5. Fig. 6 shows, as an example, an example in which nine correction data curves 51 to 59 estimated from the correction data 30 are stored. In Fig. 6, the horizontal axis represents the distance [mm] to the target object 43, and the vertical axis represents the distance variation amount 34 (Depth Shift) [mm] of the distance measurement value for each of the correction data curves 51 to 59.

[0045] Correction data curves 51 to 53 show the case where the distance between the camera 41 and the near scatterer 42 is 215 mm and the distance to the near scatterer 42 is short. Correction data curves 54 to 56 show the case where the distance between the camera 41 and the near scatterer 42 is 248 mm and the distance to the near scatterer 42 is medium. Correction data curves 57 to 59 show the case where the distance between the camera 41 and the near scatterer 42 is 361 mm and the distance to the near scatterer 42 is long.

[0046] Correction data curves 51, 54, and 57 represent cases where the reflectance of the target object 43 is low when the reflectance is 31%. Correction data curves 52, 55, and 58 represent cases where the reflectance of the target object 43 is medium when the reflectance is 52%. Correction data curves 53, 56, and 59 represent cases where the reflectance of the target object 43 is high when the reflectance is 80%.

[0047] That is, as shown in FIG. 3, the correction data curve can be stored for each of the reflectance 31 of the target object 43, the distance 32 to the nearby scatterer 42, the measured distance 33 to the target object 43, and the distance variation amount 34.

[0048] For example, in Figure 6, if the distance z between the camera and the nearby scatterer 42 is 215 [mm] and the reflectivity of the target object 43 is low, the distance x±y [mm] between the camera and the target object 43 is measured as 860 [mm].

[0049] In this case, the distance fluctuation amount 34 of the distance measurement value is 140 [mm] from the correction data curve 51. Therefore, the correction unit 23 corrects the distance measurement value of 860 [mm] to 860 [mm] + 140 [mm] = 1000 [mm].

[0050] 6 shows a case where nine correction data curves are stored in the storage unit 5, but correction data curves other than nine may be stored in the storage unit 5. Note that "Kapa Board>90% reflectance" in FIG. 6 indicates that the reflectance of the near-field scatterer used as a reference when creating the correction data in advance is 90% or higher. The near-field scatterer used as a reference is a white evaluation board.

[0051] <1.1.2.2. Definition of Proximity Scatterer 42> Next, the definition of the proximity scatterer 42 will be described. A "proximity scatterer" generally refers to an object that reflects near-infrared light, regardless of whether the reflectance is high or low. The reason that objects with low reflectance are also included in the proximity objects is that if data is prepared in advance, the correction process of the embodiment can be performed.

[0052] In the correction of the first embodiment, the criteria for determining whether a near-field scatterer 42 exists may be, for example, Confidence > 100 and / or Depth < 300 [mm], assuming that the near-field scatterer 42 occupies 10% or more of the captured image (or the angle of view). Here, Confidence generally indicates the reliability of an image acquired simultaneously with a distance image by an iToF (indirect time of flight) sensor, and is also referred to as a light intensity image or a grayscale image. When a near-field scatterer 42 is detected, the object has a certain degree of reflectivity and reflects sufficient light. Therefore, Confidence > 100 is used as an example of the condition for "the presence of a near-field scatterer 42" = "the presence of an obstacle that reflects sufficient light nearby."

[0053] Fig. 7 is a diagram for explaining the definition of the proximity scatterer 42. In Fig. 7, a proximity object 62 is imaged on an imaging plane 61. In the above example, if the proximity object 62 occupies 10% or more of the captured image (or the angle of view), the proximity object 62 is determined to be the proximity scatterer 42.

[0054] <1.2. Operation> <1.2.1. Flowchart for explaining the operation of the distance measuring system 1 according to the first embodiment>

[0055] Next, the operation of the ranging system 1 according to the first embodiment will be described. Here, a case will be described in which the ranging system 1 corrects the amount of ranging fluctuation that occurs when a proximity scatterer 42 is present, with the camera fixed inside the vehicle. Fig. 8 is a flowchart for explaining the operation of the ranging system 1 according to the first embodiment.

[0056] First, the determination unit 22 of the calculation unit 6 of the distance measurement system 1 determines whether or not a proximity scatterer 42 exists between the target object 43 and the light receiving unit (step S1). If a proximity scatterer 42 does not exist in step S1 (No in step S1), the process returns to step S1.

[0057] In step S1, if a nearby scatterer 42 is present (Yes in step S1), the determining unit 22 measures the amount of fluctuation in the measured distance to a fixed point inside the vehicle (step S2).

[0058] Next, the correction unit 23 determines whether the distance variation amount 34 exceeds a preset threshold value (step S3). If the distance variation amount 34 does not exceed the preset threshold value in step S3 (No in step S3), the process ends. On the other hand, if the distance variation amount 34 exceeds the preset threshold value in step S3 (Yes in step S3), the correction unit 23 performs distance correction according to the distance of the target object 43 acquired in advance (step S4).

[0059] Specifically, the correction unit 23 uses the measured amount of variation to correct the measured first distance data to the target object 43 to second distance data of the correct distance based on the correction data stored in the memory unit 5.

[0060] In the first embodiment, the memory unit 5 may store in advance the influence that a nearby scattering object has on the pixels around the imaging surface, and the calculation unit 6 may correct the distance variation when the influence matches the influence stored in the memory unit 5.

[0061] <1.2.2. Correction method> <1.2.2.1. First correction method>

[0062] Next, the first correction method performed by the correction unit 23 will be described. Fig. 9 is a flowchart for explaining the first correction method performed by the correction unit 23 of the distance measurement system 1 according to the first embodiment. The correction unit 23 acquires the distance variation corresponding to the measured target object 43 from the correction data (step S11), and corrects the first distance data to the measured target object 43 using the acquired distance variation amount 34 to correct second distance data (step S12). The correction unit 23 then outputs the corrected second distance data (step S13), and ends the process.

[0063] <1.2.2.2. Second Correction Method> Next, a description will be given of the second correction method performed by the correction unit 23. Fig. 10 is a flowchart for explaining the second correction method performed by the correction unit 23 of the distance measuring system 1 according to the first embodiment.

[0064] The correction unit 23 obtains distance fluctuations corresponding to the measured first distance data to the target object 43 and the third distance data indicating the distance to a nearby object from the correction data (step S21), and corrects the measured first distance data to the target object 43 using the obtained distance fluctuation amount 34 to the correct second distance data (step S22).

[0065] Then, the corrector 23 outputs the corrected second distance data (step S23), and the process ends.

[0066] 2. Second Embodiment Next, a distance measurement system 1 according to a second embodiment will be described. The distance measurement system 1 according to the second embodiment will be described for a case where distance measurement is performed to a fixed point inside a vehicle or a plurality of markers with known reflectances that are grounded inside the vehicle.

[0067] 11 is a diagram showing markers 71-1 to 71-5 installed at fixed points inside a vehicle 70. As shown in FIG. 11, markers 71-1 to 71-4 are installed at fixed points inside the vehicle 70.

[0068] In Fig. 11, marker 71-1 is installed on the left window glass of the front seat, marker 71-2 is installed on the head portion of the rear seat, marker 71-3 is installed on the right window glass of the front seat, and marker 71-4 is installed on the top of the front panel.

[0069] A camera (not shown) is fixed at a predetermined position inside the vehicle interior 70 (for example, near the ceiling of the vehicle interior 70) and measures the distances to the markers 71-1 to 71-4.

[0070] 12 is a functional block diagram of the calculation unit 6 of the ranging system 1 according to the second embodiment. The calculation unit 6 corrects the distance to the marker when a nearby scatterer 42 is present.

[0071] As shown in FIG. 12 , the calculation unit 6 includes a distance calculation unit 121 , a determination unit 122 , a correction unit 123 , and a storage unit 5 .

[0072] The distance calculation unit 121 calculates first distance data indicating the distance to the target object 43 based on the light emission timing when the light source emits light and the light reception timing when the light reception unit receives the light.

[0073] The determination unit 122 detects the marker and determines whether or not a proximity scatterer 42 exists between the target object 43 and the light receiving unit 41. Furthermore, the determination unit 122 measures the amount of fluctuation in the distance measurement value to a marker installed at a fixed point or the like inside the vehicle.

[0074] The corrector 123 determines whether the distance variation amount 34 exceeds a preset threshold. When the determiner 122 determines the presence of a proximity scatterer 42, the corrector 123 corrects the first distance data based on correction data pre-stored in the memory 5 and outputs the second distance data. In other words, the corrector 123 performs distance correction according to the distance to the target object 43 acquired in advance.

[0075] Furthermore, correction unit 123 acquires the distance fluctuation corresponding to measured target object 43 from the correction data, and corrects the measured first distance data to target object 43 to correct second distance data using the acquired distance fluctuation amount 34. Then, correction unit 23 outputs the corrected second distance data.

[0076] <2.3. Operation> <2.3.1. Operation of ranging system 1 according to second embodiment> Next, a description will be given of the operation of ranging system 1 according to the second embodiment. Fig. 13 is a flowchart for explaining the operation of ranging system 1 according to the second embodiment.

[0077] First, the determination unit 122 of the calculation unit 6 of the distance measurement system 1 determines whether a marker has been detected (step S31). If a marker has not been detected in step S31 (No in step S31), the process returns to step S31.

[0078] If a marker is detected in step S31 (Yes in step S31), the determination unit 122 determines whether or not a proximity scatterer 42 exists between the target object 43 and the light receiving unit (step S32). If a proximity scatterer 42 does not exist in step S32 (No in step S32), the process returns to step S31.

[0079] In step S32, if a nearby scatterer 42 is present (Yes in step S32), the decision unit 22 measures the amount of variation in the measured distance to a marker previously installed inside the vehicle (step S33).

[0080] Next, the correction unit 123 determines whether the distance variation amount 34 exceeds a preset threshold value (step S34). If the distance variation amount 34 does not exceed the preset threshold value in step S34 (No in step S34), the process ends. On the other hand, if the distance variation amount 34 exceeds the preset threshold value in step S34 (Yes in step S34), the correction unit 123 performs distance correction according to the distance to the target object 43 acquired in advance (step S35).

[0081] Specifically, correction unit 123 uses the measured amount of variation to correct the measured first distance data to target object 43 to second distance data of the correct distance, based on the correction data stored in storage unit 5. When installing a marker, the distance from the camera and the reflectance may be specified in advance, and these values ​​may be used for exposure (Auto Exposure).

[0082] Furthermore, if the amount of ranging variation is too large and is determined to be abnormal, the ranging system 1 may stop the system downstream of the ranging system 1. Also, if the amount of ranging variation is too large and is determined to be abnormal, the ranging system 1 may be provided with a system that issues a warning.

[0083] <2.3.2. Correction method by the correction unit 23 of the ranging system 1 according to the second embodiment> Next, an example of the correction method of the ranging system 1 according to the second embodiment will be described. Fig. 14 is a flowchart for explaining the correction method by the correction unit 123 of the ranging system 1 according to the second embodiment.

[0084] The correction unit 123 acquires measured distance data indicating the measured distance to the fixed point (step S41). Next, the correction unit 123 acquires a distance fluctuation amount 34 corresponding to the difference between reference distance data indicating the distance to the fixed point and the measured distance data from the correction data (step S42).

[0085] Next, the correction unit 123 corrects the first distance data to the target object 43 measured using the acquired distance variation amount 34 to correct second distance data (step S43), and outputs the second distance data (step S44).

[0086] 2.4. Application Examples The distance measuring system 1 of the present disclosure can also be applied to the field of FA (Factory Automation).

[0087] For example, when a robot picks up or unloads a package for automating logistics, if there is a scatterer in the vicinity of the robot, the measured distance to the package may change.

[0088] The ranging system 1 according to the present disclosure may perform the above-described ranging correction in an FA system (for example, a robot in a factory). Fig. 15 is a diagram showing an example in which a robot 81 having the ranging system 1 according to the second embodiment is used in a factory.

[0089] 15 , a robot 81 has the distance measurement system 1 of the present disclosure, and performs the task of picking up a piece of luggage 82 traveling on a conveyor and unloading the picked-up piece of luggage 82 onto a loading platform 83. When picking up the piece of luggage 82, the robot 81 measures the distance to the piece of luggage 82 and picks up the piece of luggage 82 according to the measured distance. The robot 81 also measures the distance to the loading platform 83 and unloads the picked-up piece of luggage 82 onto the loading platform 83 according to the measured distance.

[0090] In this way, the robot 81 uses distance measurement in the FA field, and may perform distance correction according to the present disclosure when performing distance measurement.

[0091] 3. Third Embodiment Next, a distance measuring system 1 according to a third embodiment will be described. The distance measuring system 1 according to the third embodiment corrects the measured distance by using the reflectance of the target object 43.

[0092] 16 is a functional block diagram of the calculation unit 6 of the distance measurement system 1 according to the third embodiment. As shown in FIG. 16, the calculation unit 6 includes a distance calculation unit 221, a determination unit 222, a correction unit 223, a reflectance estimation unit 224, and a storage unit 5.

[0093] The distance calculation unit 221 calculates first distance data indicating the distance to the target object 43 based on the light emission timing when the light source emits light and the light reception timing when the light reception unit receives the light.

[0094] The determination unit 222 detects the marker and determines whether or not a proximity scatterer 42 exists between the target object 43 and the light receiving unit 41. Furthermore, the determination unit 222 measures the amount of fluctuation in the distance measurement value to a marker installed at a fixed point or the like inside the vehicle.

[0095] The reflectance estimation unit 224 estimates reflectance data of the target object 43 .

[0096] The correction unit 223 acquires the distance fluctuation amount 34 corresponding to the first distance data and reflectance data from the correction data stored in the memory unit 5, corrects the first distance data using the acquired distance fluctuation amount 34, and outputs the second distance data.

[0097] 3.2. Operation Next, a description will be given of the operation of the distance measuring system 1 according to the third embodiment. Fig. 17 is a flowchart for explaining the operation of the correction unit 223 of the distance measuring system 1 according to the third embodiment.

[0098] The correction unit 223 acquires the first distance data to the measured target object 43 and the distance variation corresponding to the first reflectance from the correction data (step S51).

[0099] Next, the correction unit 223 corrects the first distance data to the target object 43 measured using the acquired distance variation amount 34 to correct second distance data (step S52), and outputs the second distance data (step S53).

[0100] 4. Modifications of the Correction Processing Location Next, the correction processing location will be described. In the first to third embodiments described above, the correction of the measurement distance is performed on the camera system side having the ToF sensor, but the correction of the measurement distance may also be performed on the software side of a device downstream of the camera system side as necessary.

[0101] Fig. 18 is a diagram showing an example of a case where correction processing is performed on the camera system side of the ranging system 1. In Fig. 18, an iToF sensor 301 and iToF software 302 of the camera module correspond to the ranging system 1 in Fig. 1. Recognition software 303 and a controller 304 may be included in the ranging system 1, or may be an information device (e.g., a server) external to the ranging system 1.

[0102] 18 , the distance to the object is measured by the iToF sensor 301 of the camera module, and the distance to the object measured by the iToF sensor 311 of the camera module is calculated by the iToF software 302 and corrected. In other words, the correction units 23, 123, and 223 are included in the camera. For example, if the recognition software 303 is incorporated in an external information processing device separate from the ranging system 1, the recognition software 303 receives the distance to the object corrected by the iToF software 302 via a network (not shown). The iToF software 302 then recognizes the received distance to the object corrected and performs processing.

[0103] The controller 304 controls the recognition software 303. The controller 304 is, for example, an ECU (Electric Control Unit) and may be formed as a SoC (System on a Chip).

[0104] Fig. 19 is a diagram showing a case where correction is performed by recognition software 313 that uses the distance measured by the ranging system 1. In Fig. 19, the iToF sensor 311 and iToF software 312 of the camera module correspond to the ranging system 1 in Fig. 1. The recognition software 313 and the controller 314 may be included in the ranging system 1, or may be an information device (e.g., a server) external to the ranging system 1.

[0105] In FIG. 19 , the distance to the object is measured by the iToF sensor 311 of the camera module, and the distance to the object measured by the iToF sensor 311 is calculated by the iToF software 312. For example, if the recognition software 303 is incorporated in an external information processing device separate from the ranging system 1, the recognition software 313 receives the distance to the object calculated by the iToF software 312 via a network (not shown). The recognition software 313 then performs a correction process on the received distance to the object. Furthermore, if the recognition software 313 is incorporated in an external information processing device (not shown) separate from the ranging system 1, the external information processing device may store correction data 30 necessary for the correction process, and the recognition software 313 may perform the correction process using the stored correction data 30. The correction data 30 may be transmitted from the iToF sensor 311 to the recognition software 313 via a network, or may be stored in advance in the external information processing device.

[0106] The controller 314 controls the recognition software 313. The controller 314 is, for example, an ECU (Electronic Control Unit), and may be formed as a SoC (System on a Chip).

[0107] 5. Effects A ranging system according to the present disclosure (ranging system 1 in the embodiment) includes a light receiving unit (light receiving unit 3 in the embodiment) that receives light emitted from a light source and reflected by a target object that is the measurement target, a distance calculation unit (distance calculation unit 21 in the embodiment) that calculates first distance data indicating the distance to the target object based on the emission timing at which the light source emits light and the reception timing at which the light receiving unit receives the light, a determination unit (determination unit 22 in the embodiment) that determines whether or not a proximity scatterer 42 exists between the target object and the light receiving unit, and a correction unit (correction unit 23 in the embodiment) that corrects the first distance data based on pre-stored correction data and outputs second distance data when the determination unit determines that a proximity scatterer 42 exists.

[0108] In this way, when the ranging system of the present disclosure determines that a nearby scattering object 42 is present, it corrects the measured first distance data to the second distance data based on pre-stored correction data, thereby making it possible to obtain an accurate distance even when a nearby scattering object 42 is present.

[0109] In addition, the pre-stored correction data includes a distance to the target object and a distance variation amount to the target object corresponding to the distance, and the correction unit acquires the distance variation amount corresponding to the first distance data from the correction data, corrects the first distance data using the acquired distance variation amount, and outputs second distance data.

[0110] In this way, the distance measuring system according to the present disclosure corrects the first distance data using the pre-stored distance variation rate, and therefore can accurately correct the first distance data.

[0111] The correction data includes a plurality of correction data, each of which includes a distance to a nearby scatterer. The distance calculation unit calculates third distance data indicating the distance to the nearby scatterer. The correction unit acquires distance fluctuation amounts corresponding to the first distance data and the third distance data from the correction data, corrects the first distance data using the acquired distance fluctuation amounts, and outputs second distance data.

[0112] In this way, the ranging system according to the present disclosure obtains correction data based on the first distance data and the third distance data, thereby obtaining more accurate correction data, and as a result, the ranging system can accurately correct the first distance data using the second distance data.

[0113] In addition, the correction data has multiple correction data, and the first distance data is measured distance data indicating the measured distance to a fixed point, and the correction unit 23, 123, 223 obtains from the correction data a distance fluctuation amount corresponding to the difference between reference distance data indicating the distance to the fixed point and the measured distance data, corrects the first distance data using the obtained distance fluctuation amount, and outputs second distance data.

[0114] In this way, the ranging system according to the present disclosure obtains, from the correction data, a distance fluctuation amount corresponding to the difference between the reference distance data indicating the distance to the fixed point and the measured distance data, thereby obtaining more accurate correction data. For example, when the ranging system is used inside a vehicle, the ranging system can correct the distance to the fixed point, and as a result, the ranging system can accurately grasp the state of the vehicle even if the driver acts as a nearby scatterer.

[0115] The correction data also includes a plurality of correction data, each of which has a reflectance of the target object, and a reflectance estimation unit that estimates the reflectance data of the target object. The correction unit acquires a distance variation amount corresponding to the first distance data and the reflectance data from the correction data, corrects the first distance data using the acquired distance variation amount, and outputs second distance data.

[0116] In this way, the distance measuring system according to the present disclosure obtains the distance variation amount corresponding to the first distance data and reflectance data from the correction data, and therefore can obtain more accurate correction data.

[0117] The camera also includes the correction units 23, 123, and 223. In this way, the distance measuring system according to the present disclosure has a correction unit on the camera side, which reduces the burden on the software side that uses the second distance data output from the distance measuring system.

[0118] The distance measurement system also includes a first device having a light receiving unit, a distance calculation unit, and a determination unit, and a second device connected to the first device and having a correction unit, the second device having the correction unit. In this way, in the distance measurement system according to the present disclosure, the latter device has the correction unit, so the distance measurement system can perform correction according to the characteristics of the latter software.

[0119] 6. Other Embodiments The processes according to the above-described embodiments may be implemented in various different forms other than the above-described embodiments. Furthermore, among the processes described in the above-described embodiments, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically using a known method. Furthermore, the process procedures, specific names, and information including various data and parameters shown in the above documents and drawings can be changed as desired unless otherwise specified. For example, the various information shown in each drawing is not limited to the illustrated information.

[0120] Furthermore, the components of each device shown in the figure are conceptual functional components and do not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each device is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

[0121] Furthermore, the above-described embodiments and modifications can be combined as appropriate within the scope of not causing any contradiction in the processing content.

[0122] Furthermore, the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0123] 7. Hardware Configuration FIG. 20 is a hardware configuration diagram showing an example of a computer 1000 that realizes the arithmetic device according to the embodiment.

[0124] The computer 1000 includes a CPU 1100, a RAM 1200, a ROM (Read Only Memory) 1300, a HDD (Hard Disk Drive) 1400, a communication interface 1500, and an input / output interface 1600. The components of the computer 1000 are connected by a bus 1050.

[0125] The CPU 1100 operates and controls each component based on programs stored in the ROM 1300 or the HDD 1400. For example, the CPU 1100 loads the programs stored in the ROM 1300 or the HDD 1400 into the RAM 1200 and executes processing corresponding to the various programs.

[0126] The ROM 1300 stores boot programs such as a Basic Input Output System (BIOS) that is executed by the CPU 1100 when the computer 1000 is started, as well as programs that depend on the hardware of the computer 1000 .

[0127] HDD 1400 is a computer-readable recording medium that non-temporarily records programs executed by CPU 1100 and data used by such programs. Specifically, HDD 1400 is a recording medium that records an application program according to the present disclosure, which is an example of program data 1450.

[0128] The communication interface 1500 is an interface for connecting the computer 1000 to an external network 1550 (e.g., the Internet). For example, the CPU 1100 receives data from other devices and transmits data generated by the CPU 1100 to other devices via the communication interface 1500.

[0129] The input / output interface 1600 is an interface for connecting the input / output device 1650 and the computer 1000. For example, the CPU 1100 receives data from an input device such as a keyboard or a mouse via the input / output interface 1600. The CPU 1100 also transmits data to an output device such as a display, a speaker, or a printer via the input / output interface 1600. The input / output interface 1600 may also function as a media interface for reading programs and the like recorded on a predetermined recording medium. Examples of media include optical recording media such as DVDs (Digital Versatile Discs) and PDs (Phase Change Rewritable Discs), magneto-optical recording media such as MOs (Magneto-Optical Discs), tape media, magnetic recording media, and semiconductor memories.

[0130] Although the CPU 1100 reads and executes the program data 1450 from the HDD 1400, as another example, the CPU 1100 may obtain these programs from other devices via an external network 1550.

[0131] Although the preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the technical scope of the present disclosure is not limited to such examples. It is clear that a person skilled in the art of the present disclosure can conceive of various modified or altered examples within the scope of the technical idea described in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0132] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that will be apparent to those skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0133] 8. Application Examples to Mobile Bodies The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of mobile body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

[0134] FIG. 21 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

[0135] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 21 , the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (Interface) 12053.

[0136] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0137] The body system control unit 12020 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0138] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

[0139] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0140] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0141] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc.

[0142] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0143] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control aimed at preventing glare, such as switching from high beams to low beams.

[0144] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying the passengers of the vehicle or the outside of the vehicle of information. In the example of Fig. 20, the output devices are exemplified by an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

[0145] FIG. 22 is a diagram showing an example of the installation position of the imaging unit 12031.

[0146] In FIG. 22, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0147] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided on the top of the windshield inside the vehicle cabin is mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0148] 22 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.

[0149] At least one of the image capturing units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image capturing units 12101 to 12104 may be a stereo camera made up of multiple image capturing elements, or may be an image capturing element having pixels for phase difference detection.

[0150] For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100), thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of autonomous driving, which runs autonomously without relying on driver operation.

[0151] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines a collision risk that indicates the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0152] At least one of the image capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether a pedestrian is present in the images captured by the image capturing units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0153] The above describes an example of a vehicle control system to which the technology according to the present disclosure can be applied. The technology according to the present disclosure can be applied to the driver state detection unit 12041 of the above-described configuration. Specifically, the ranging system 1 of FIG. 1 can be applied to the driver state detection unit 12041. By applying the technology according to the present disclosure to the driver state detection unit 12041, it is possible to correct the distance to a fixed point inside the vehicle, and as a result, it is possible to accurately grasp the state of the vehicle even if the driver acts as a nearby scatterer.

[0154] The present technology can also be configured as follows.

[0155] (1) A distance measuring system comprising: a light receiving unit that receives light emitted from a light source and reflected by a target object that is a measurement target; a distance calculation unit that calculates first distance data indicating a distance to the target object based on an emission timing when the light source emits light and a reception timing when the light receiving unit receives the light; a determination unit that determines whether a proximity scatterer is present between the target object and the light receiving unit; and a correction unit that, when the determination unit determines the presence of the proximity scatterer, corrects the first distance data based on pre-stored correction data and outputs second distance data. (2) The pre-stored correction data includes a distance to the target object and a distance variation amount to the target object corresponding to the distance, and the correction unit acquires the distance variation amount corresponding to the first distance data from the correction data, and corrects the first distance data using the acquired distance variation amount to output the second distance data. (3) The ranging system according to (2), wherein the correction data has a plurality of correction data, the plurality of correction data having a distance to the near-field scatterer, the distance calculation unit calculates third distance data indicating the distance to the near-field scatterer, the correction unit acquires the distance variation amount corresponding to the first distance data and the third distance data from the correction data, corrects the first distance data using the acquired distance variation amount, and outputs the second distance data. (4) The ranging system according to (2), wherein the correction data has a plurality of correction data, the first distance data is measured distance data indicating a measured distance to a fixed point, and the correction unit acquires the distance variation amount corresponding to a difference between the measured distance data and reference distance data indicating the distance to the fixed point from the correction data, and corrects the first distance data using the acquired distance variation amount, and outputs the second distance data.(5) The ranging system according to (2), wherein the correction data includes a plurality of correction data, the plurality of correction data including reflectances of the target object, and a reflectance estimating unit that estimates reflectance data of the target object, and the correcting unit acquires the first distance data and the distance variation amount corresponding to the reflectance data from the correction data, corrects the first distance data using the acquired distance variation amount, and outputs the second distance data. (6) The ranging system according to any one of (1) to (5), wherein the correcting unit is included in a camera. (7) The ranging system according to any one of (1) to (5), wherein the ranging system includes a first device that includes the light receiving unit, the distance calculation unit, and the determination unit, and a second device that is connected to the first device and has the correcting unit, and the second device has the correcting unit. (8) A distance measuring device comprising: a determination unit that determines whether a proximity scatterer is present between a target object to be measured and a light receiving unit that receives light reflected by the target object, and a correction unit that, when the determination unit determines the presence of the proximity scatterer, corrects first distance data measured to the target object based on pre-stored correction data and outputs second distance data. (9) The distance measuring device described in (8), wherein the pre-stored correction data includes a distance to the target object and a distance variation amount to the target object corresponding to the distance, and the correction unit obtains the distance variation amount corresponding to the first distance data from the correction data, corrects the first distance data using the obtained distance variation amount, and outputs the second distance data. (10) The distance measuring device described in (9), wherein the correction data includes a plurality of correction data, the plurality of correction data includes a distance to the near-field scatterer, and the correction unit acquires the distance variation amount corresponding to the first distance data and third distance data indicating the distance to the near-field scatterer from the correction data, corrects the first distance data using the acquired distance variation amount, and outputs the second distance data.(11) The distance measuring device according to (9), wherein the correction data has a plurality of correction data, the first distance data is measured distance data indicating a measured distance to a fixed point, the correction unit acquires from the correction data the amount of distance variation corresponding to a difference between the measured distance data and reference distance data indicating the distance to the fixed point, corrects the first distance data using the acquired amount of distance variation, and outputs the second distance data. (12) The distance measuring device according to (9), wherein the correction data has a plurality of correction data, the plurality of correction data has a reflectance of the target object, and includes a reflectance measuring unit that measures a first reflectance of the target object, and the correction unit acquires from the correction data the amount of distance variation corresponding to the first distance data and the first reflectance, corrects the first distance data using the acquired amount of distance variation, and outputs the second distance data. (13) A distance measurement method in which a computer receives light emitted from a light source and reflected by a target object to be measured, calculates first distance data indicating the distance to the target object based on the emission timing when the light source emits the light and the reception timing when the light is received, determines whether a nearby scatterer is present between the target object and a light receiving unit that receives the light reflected by the target object, and if the computer determines that a nearby scatterer is present, corrects the first distance data based on pre-stored correction data and outputs second distance data.

[0156] REFERENCE SIGNS LIST 1 Distance measurement system 3 Light receiving unit 5 Storage unit 21, 121, 221 Distance calculation unit 22, 122, 222 Determination unit 23, 123, 223 Correction unit 224 Reflectance estimation unit

Claims

1. A distance measurement system having a light receiving unit that receives light emitted from a light source and reflected by a target object to be measured; a distance calculation unit that calculates first distance data indicating the distance to the target object based on the emission timing when the light source emits light and the reception timing when the light receiving unit receives the light; a determination unit that determines whether a nearby scattering object is present between the target object and the light receiving unit; and a correction unit that, when the determination unit determines the presence of the nearby scattering object, corrects the first distance data based on pre-stored correction data and outputs second distance data.

2. The distance measuring system of claim 1, wherein the pre-stored correction data has a distance to the target object and an amount of distance variation to the target object corresponding to the distance, and the correction unit obtains the amount of distance variation corresponding to the first distance data from the correction data, corrects the first distance data using the obtained amount of distance variation, and outputs the second distance data.

3. The ranging system of claim 2, wherein the correction data has a plurality of correction data, the plurality of correction data has a distance to the nearby scatterer, the distance calculation unit calculates third distance data indicating the distance to the nearby scatterer, and the correction unit acquires the distance variation amount corresponding to the first distance data and the third distance data from the correction data, corrects the first distance data using the acquired distance variation amount, and outputs the second distance data.

4. The distance measuring system of claim 2, wherein the correction data has a plurality of correction data, the first distance data is measured distance data indicating a measured distance to a fixed point, and the correction unit acquires from the correction data the distance fluctuation amount corresponding to the difference between reference distance data indicating the distance to the fixed point and the measured distance data, corrects the first distance data using the acquired distance fluctuation amount, and outputs the second distance data.

5. The ranging system of claim 2, wherein the correction data has a plurality of correction data, the plurality of correction data has a reflectance of the target object, and the system has a reflectance estimation unit that estimates the reflectance data of the target object, and the correction unit acquires the distance variation amount corresponding to the first distance data and the reflectance data from the correction data, corrects the first distance data using the acquired distance variation amount, and outputs the second distance data.

6. The distance measuring system according to claim 1, wherein the correction unit is included in a camera.

7. The distance measuring system according to claim 1, comprising: a first device having the light receiving unit, the distance calculation unit, and the judgment unit; and a second device connected to the first device and having the correction unit, the second device having the correction unit.

8. A distance measuring device having a determination unit which determines whether or not a nearby scattering object is present between a target object to be measured and a light receiving unit which receives light reflected by the target object, and a correction unit which, when the determination unit determines the presence of the nearby scattering object, corrects first distance data measured to the target object based on pre-stored correction data and outputs second distance data.

9. The distance measuring device described in claim 8, wherein the pre-stored correction data has a distance to the target object and an amount of distance variation to the target object corresponding to the distance, and the correction unit obtains the amount of distance variation corresponding to the first distance data from the correction data, corrects the first distance data using the obtained amount of distance variation, and outputs the second distance data.

10. The distance measuring device of claim 9, wherein the correction data includes a plurality of correction data, the plurality of correction data includes a distance to the nearby scatterer, and the correction unit acquires from the correction data the amount of distance variation corresponding to the first distance data and third distance data indicating the distance to the nearby scatterer, corrects the first distance data using the acquired amount of distance variation, and outputs the second distance data.

11. The distance measuring device of claim 9, wherein the correction data has a plurality of correction data, the first distance data is measured distance data indicating a measured distance to a fixed point, and the correction unit acquires from the correction data the amount of distance fluctuation corresponding to the difference between reference distance data indicating the distance to the fixed point and the measured distance data, corrects the first distance data using the acquired amount of distance fluctuation, and outputs the second distance data.

12. The distance measuring device of claim 9, wherein the correction data has a plurality of correction data, the plurality of correction data has reflectance of the target object, and a reflectance measuring unit is provided for measuring a first reflectance of the target object, and the correction unit acquires the first distance data and the distance variation amount corresponding to the first reflectance from the correction data, corrects the first distance data using the acquired distance variation amount, and outputs the second distance data.

13. A distance measuring method in which a computer receives light emitted from a light source and reflected by a target object to be measured, calculates first distance data indicating the distance to the target object based on the emission timing when the light source emits the light and the reception timing when the light is received, determines whether or not a nearby scatterer is present between the target object and a light receiving unit that receives the light reflected by the target object, and if the presence of the nearby scatterer is determined, corrects the first distance data based on pre-stored correction data and outputs second distance data.

Images