Measurement device

Abstract

This measurement device comprises: a light source that emits irradiation light for irradiating an object; an adjuster that adjusts the focal position of the irradiation light; a scanner that changes the irradiation angle of the irradiation light; a photodetector that detects reflected light from the object and outputs a signal; and a processing circuit. The processing circuit: causes the adjuster to adjust the focal position to a first focal position; causes the scanner to set the irradiation angle to a first irradiation angle group to irradiate the object with the irradiation light; generates a first distance information group on the basis of the reflected light; causes the adjuster to adjust the focal position to a second focal position; causes the scanner to set the irradiation angle to a second irradiation angle group to irradiate the object with the irradiation light; generates a second distance information group on the basis of the reflected light; and generates and outputs a third distance information group on the basis of the first and second distance information groups.

Description

Measuring equipment

[0001] The present disclosure relates to a measurement device.

[0002] Conventionally, LiDAR (Light Detection and Ranging) technology exists, which generates measurement data related to the distance and / or speed of an object by illuminating the object with laser light and detecting the light reflected from the object. A typical example of a measurement device using LiDAR technology includes a light source, a photodetector, and a processing circuit. The light source emits light to illuminate the object. The photodetector detects the light reflected from the object and outputs a signal corresponding to the time delay of the reflected light. The processing circuit acquires distance information about the object based on the signal output from the photodetector and outputs a ranging result. Examples of ranging methods include the Time of Flight (ToF) method and the Frequency Modulated Continuous Wave (FMCW) method.

[0003] If the measurement device further includes a scanner that changes the irradiation angle of the irradiation light, multiple locations on the object can be set as multiple irradiation points, and the multiple irradiation points can be sequentially irradiated with the irradiation light. As a result, distance information for the multiple irradiation points on the object can be mapped one-dimensionally or two-dimensionally, making it possible to measure the shape of the object. Patent Document 1 discloses an example of a measurement device that measures the shape of an object using such a method.

[0004] JP 2013-117453 A

[0005] The present disclosure provides a measurement device that can generate distance information for multiple irradiation points on an object with high accuracy in a shorter time.

[0006] A measurement device according to one aspect of the present disclosure includes a light source that emits illumination light to illuminate an object, an adjuster that adjusts the focus position of the illumination light, a scanner that changes the illumination angle of the illumination light, a photodetector that detects reflected light from the object and outputs a signal, and a processing circuit, wherein the processing circuit causes the adjuster to adjust the focus position to a first focus position, causes the scanner to set the illumination angle to a first illumination angle group to illuminate the object with the illumination light, generates a first distance information group based on the reflected light, causes the adjuster to set the focus position to a second focus position different from the first focus position, causes the scanner to set the illumination angle to a second illumination angle group to irradiate the object with the illumination light, generates a second distance information group based on the reflected light, and generates and outputs a third distance information group based on the first distance information group and the second distance information group.

[0007] A comprehensive or specific aspect of the present disclosure may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable recording disk, or as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. The computer-readable recording medium may include, for example, a non-volatile recording medium such as a CD-ROM (Compact Disc-Read Only Memory). An apparatus may consist of one or more devices. When an apparatus consists of two or more devices, the two or more devices may be located in a single device or may be located separately in two or more separate devices. In this specification and claims, the term "apparatus" may refer not only to a single device but also to a system consisting of multiple devices. The multiple devices included in a "system" may include devices installed in remote locations away from other devices and connected via a communication network.

[0008] According to the technology of the present disclosure, it is possible to realize a measurement device that can generate distance information for multiple irradiation points on an object with high accuracy in a shorter time.

[0009] FIG. 1A is a block diagram schematically illustrating a configuration of a measurement apparatus according to an exemplary embodiment of the present disclosure. FIG. 1B is a diagram schematically illustrating an example configuration of a focus adjuster and a scanner. FIG. 1C is a diagram schematically illustrating an example configuration of a processing device. FIG. 2A is a diagram schematically illustrating an example table for adjusting the focus position. FIG. 2B is a diagram schematically illustrating another example table for adjusting the focus position. FIG. 3A is a block diagram schematically illustrating a configuration of a measurement apparatus according to another exemplary embodiment of the present disclosure. FIG. 3B is a block diagram schematically illustrating a configuration of a measurement apparatus according to yet another exemplary embodiment of the present disclosure. FIG. 4 is a diagram schematically illustrating time changes in the frequencies of reference light and reflected light when the object is stationary. FIG. 5 is a flowchart schematically illustrating example 1 of a measurement operation executed by a processing circuit in the measurement apparatus according to this embodiment. FIG. 6A is a diagram schematically illustrating an example of a table generated by the processing circuit in step S102 shown in FIG. 5 for example 1 of the measurement operation. FIG. 6B is a diagram schematically illustrating an example of a table generated by the processing circuit in step S103 shown in FIG. 5 for measurement operation example 1. FIG. 6C is a diagram schematically illustrating an example of a table generated by the processing circuit in step S104 shown in FIG. 5 for measurement operation example 1. FIG. 7A is a flowchart showing details of the processing operation of step S102 shown in FIG. 5 for measurement operation example 1. FIG. 7B is a flowchart showing details of the processing operation of step S103 shown in FIG. 5. FIG. 7C is a flowchart showing details of the processing operation of step S104 shown in FIG. 5 for measurement operation example 1. FIG. 8A is a diagram showing a first table acquired by a first scan operation. FIG. 8B is a diagram showing a second table acquired by a second scan operation. FIG. 8C is a diagram for explaining the process of generating a third table. FIG. 9A is a diagram schematically illustrating an example of a table generated by the processing circuit in step S102 shown in FIG. 5 for measurement operation example 2. Fig. 9B is a diagram schematically illustrating an example of a table generated by the processing circuit in step S103 shown in Fig. 5 for measurement operation example 2. Fig. 10A is a flowchart illustrating details of the processing operation of step S102 shown in Fig. 5 for measurement operation example 2.FIG. 10B is a flowchart showing details of the processing operation of step S103 shown in FIG. 5 for measurement operation example 2. FIG. 10C is a flowchart showing details of the processing operation of step S104 shown in FIG. 5 for measurement operation example 2. FIG. 11 is a flowchart schematically showing measurement operation example 3 executed by the processing circuit in the measurement device according to this embodiment. FIG. 12 is a flowchart showing details of the processing operation of step S804 shown in FIG. 11 for measurement operation example 3. FIG. 13 is a flowchart schematically showing measurement operation example 4 executed by the processing circuit in the measurement device according to this embodiment. FIG. 14 is a flowchart showing details of the processing operation of step S1004 shown in FIG. 13 for measurement operation example 4. FIG. 15A is a diagram schematically showing an example of a table generated by the processing circuit in step S102 shown in FIG. 5 for measurement operation example 5. FIG. 15B is a diagram schematically showing an example of a table generated by the processing circuit in step S103 shown in FIG. 5 for measurement operation example 5. FIG. 16A is a flowchart showing details of the processing operation of step S102 shown in FIG. 5 for measurement operation example 5. Fig. 16B is a flowchart showing details of the processing operation of step S103 shown in Fig. 5 for measurement operation example 5. Fig. 16C is a flowchart showing details of the processing operation of step S104 shown in Fig. 5 for measurement operation example 5.

[0010] In the present disclosure, all or part of a circuit, unit, device, component, or part, or all or part of a functional block in a block diagram, may be implemented by one or more electronic circuits, including, for example, a semiconductor device, a semiconductor integrated circuit (IC), or an LSI (large scale integration). The LSI or IC may be integrated on a single chip or may be configured by combining multiple chips. For example, functional blocks other than memory elements may be integrated on a single chip. While the terms LSI and IC are used here, the term may be changed depending on the degree of integration, and may be referred to as a system LSI, a VLSI (very large scale integration), or an ULSI (ultra large scale integration). A Field Programmable Gate Array (FPGA), which is programmed after the LSI is manufactured, or a reconfigurable logic device, which can reconfigure the connection relationships within the LSI or set up circuit sections within the LSI, can also be used for the same purpose.

[0011] Furthermore, all or part of the functions or operations of a circuit, unit, device, component, or section can be implemented by software processing. In this case, the software is recorded on one or more non-transitory recording media such as ROMs, optical disks, hard disk drives, etc., and when the software is executed by a processor, the functions specified in the software are executed by the processor and peripheral devices. A system or device may include one or more non-transitory recording media on which the software is recorded, a processor, and required hardware devices, such as interfaces.

[0012] In this disclosure, "light" refers to electromagnetic waves including not only visible light (wavelength of about 400 nm to about 700 nm), but also ultraviolet light (wavelength of about 10 nm to about 400 nm) and infrared light (wavelength of about 700 nm to about 1 mm). In this specification, ultraviolet light may be referred to as "ultraviolet light," and infrared light may be referred to as "infrared light."

[0013] Exemplary embodiments of the present disclosure will be described below. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not recited in the independent claims that represent the highest concepts will be described as optional components. Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Furthermore, in each figure, substantially identical components are assigned the same reference numerals, and duplicated descriptions may be omitted or simplified.

[0014] First, the findings that form the basis of this disclosure will be described.

[0015] When an irradiation point on an object is irradiated with irradiation light, if the intensity of the reflected light from the irradiation point is low, the accuracy of distance information for the irradiation point decreases. The measurement device disclosed in Patent Document 1 includes a configuration called a low-precision ranging system and a configuration called a high-precision ranging system in order to increase the intensity of the reflected light. The low-precision ranging system measures the distance to the irradiation point on the object, and based on the distance measurement results, the high-precision ranging system adjusts the focus position of the irradiation light to measure the distance to the irradiation point on the object. By adjusting the focus position of the irradiation light, the spot size of the irradiation light at the irradiation point can be minimized. As a result, the intensity of the reflected light from the irradiation point increases, making it possible to generate distance information for the irradiation point with high accuracy.

[0016] On the other hand, in the measurement device disclosed in Patent Document 1, when generating distance information for multiple irradiation points on an object, the focus position of the irradiation light in the high-precision distance measurement system is adjusted for each irradiation point based on the distance measurement results in the low-precision distance measurement system. In this measurement device, it takes time to generate distance information for multiple irradiation points because the focus position of the irradiation light has to be adjusted for each irradiation point.

[0017] The present inventors have devised a measurement device according to an embodiment of the present disclosure that solves the above-mentioned problems. The measurement device according to this embodiment will be described below.

[0018] (Embodiments) In the following, an example of the configuration of a measurement device according to an embodiment of the present disclosure will be described, followed by examples 1 to 5 of measurement operations.

[0019] [Measurement Apparatus Utilizing ToF LiDAR Technology] First, with reference to FIGS. 1A to 1C, an example configuration of a measurement apparatus according to an embodiment of the present disclosure that utilizes ToF LiDAR technology will be described. FIG. 1A is a block diagram schematically illustrating the configuration of a measurement apparatus according to an exemplary embodiment of the present disclosure. FIG. 1A also illustrates an object 10 to be measured. The measurement apparatus 100A illustrated in FIG. 1A measures the shape of the object 10 using ToF LiDAR technology. As illustrated in FIG. 1A, the measurement apparatus 100A includes a light source 20, a focus adjuster 30, a scanner 40, a photodetector 50, and a processing device 60. In this specification, the focus adjuster 30 will also be simply referred to as the "adjuster 30." In FIG. 1A, thick lines with arrows represent the flow of light, and thin lines with arrows represent the flow of signals. This also applies to other figures.

[0020] FIG. 1B is a diagram schematically illustrating an example configuration of the focus adjuster 30 and the scanner 40 shown in FIG. 1A. As shown in FIG. 1B, the focus adjuster 30 includes an optical element 32, a lens 34, and an actuator 36. The optical element 32 may be, for example, an optical fiber. The scanner 40 includes a mirror 42 and a driver 44 that changes the orientation of the mirror 42. FIG. 1C is a diagram schematically illustrating an example configuration of the processing device 60 shown in FIG. 1A. As shown in FIG. 1C, the processing device 60 includes a processing circuit 62 and a memory 64 such as a ROM or a RAM.

[0021] In the measurement device 100A according to this embodiment, an irradiation point 12 on the object 10 is irradiated with irradiation light 20La that is emitted from the light source 20 and whose focus position is adjusted by the focus adjuster 30, and the distance from the measurement device 100A to the irradiation point 12 is measured based on reflected light 20Lb from the irradiation point 12. In this specification, the distance from the measurement device 100A to the irradiation point 12 is simply referred to as the "distance of the irradiation point 12."

[0022] As will be explained in detail later, the measuring apparatus 100A according to this embodiment performs the following operations.

[0023] - The focus position is set to the first focus position, and a first scanning operation is performed to irradiate multiple irradiation points 12 on the object 10 with the irradiation light 20La, thereby generating a first distance information group including multiple first distance information.

[0024] The focus position is set to a second focus position, and a second scanning operation is performed to irradiate multiple irradiation points 12 on the object 10 with the irradiation light 20La, thereby generating a second distance information group including multiple pieces of second distance information. The second focus position is different from the first focus position. The multiple irradiation points 12 in the second scanning operation may all coincide with the multiple irradiation points 12 in the first scanning operation, or may only partially coincide with them. Alternatively, the multiple irradiation points 12 in the second scanning operation may all be different from the multiple irradiation points 12 in the first scanning operation.

[0025] A third distance information group including a plurality of pieces of third distance information is generated based on the first and second distance information groups. Specifically, a plurality of pieces of third distance information that satisfy a predetermined condition regarding accuracy is selected from the plurality of pieces of first and second distance information.

[0026] The measurement apparatus 100A according to this embodiment requires fewer operations to switch the focus position, and therefore can generate accurate distance information about the object 10 in a shorter time. The same applies to the measurement apparatuses 100B and 100C described below.

[0027] The components of the object 10 and the measuring device 100A will be described below.

[0028] <Object 10> The object 10 may be, for example, a structure at a construction site or a large product manufactured in a factory. The structure may be formed from, for example, concrete members, metal members, or wood. The factory product may be, for example, an automobile, a home appliance, or a machine part. Note that, although a large object 10 is given as an example of the measurement target in this specification, a non-large object may also be used as the measurement target depending on the application.

[0029] <Light Source 20> The light source 20 emits irradiation light 20La for irradiating the object 10. The irradiation light 20La may be, for example, laser light having high coherence. The wavelength of the laser light may be, for example, within the near-infrared wavelength range of 700 nm or more and 2000 nm or less. Sunlight includes near-infrared light and visible light, and the amount of near-infrared light is less than the amount of visible light. Therefore, using near-infrared light as the laser light can reduce the influence of sunlight as noise. The wavelength of the laser light does not necessarily have to be within the near-infrared wavelength range. The wavelength of the laser light may be within the visible light wavelength range of 400 nm or more and 700 nm or less, or may be within the ultraviolet wavelength range.

[0030] The light source may comprise, for example, a distributed feedback (DFB) laser diode, an external cavity (EC) laser diode, or a vertical cavity surface emitting (VCSEL) laser diode, which are inexpensive, small, and capable of single-mode oscillation.

[0031] <Focus adjuster 30> As shown in Fig. 1B, the focus adjuster 30 receives a control signal sent from the processing circuit 62 and adjusts the focus position of the irradiation light 20La. The control signal includes information about the position of the lens 34. The "control signal (lens position)" in Fig. 1B refers to a control signal that includes information about the position of the lens 34.

[0032] The optical element 32 may be, for example, an optical fiber. The optical element 32 emits the illumination light 20La in a diffused state into the air. The lens 34 focuses the diffused illumination light 20La. The scanner 40 reflects the illumination light 20La toward the object 10 using a mirror 42. As a result, an illumination point 12 on the object 10 is illuminated with the illumination light 20La. The illumination light 20La reaches the illumination point 12 as a beam.

[0033] The point where the spot size of the irradiated light 20La is smallest is defined as the focal point, and the distance from the principal point of the lens 34 to the focal point is defined as the focal position. The distance from the principal point of the lens 34 to the reflection point of the mirror 42 is defined as f ａ , the distance from the reflection point of the mirror 42 to the focus position is fｂ Then, the focus position f ｐ is f ｐ = f ａ +f ｂ The reflection point of the mirror 42 is the center of the area where the irradiated light 20La is incident on the mirror 42. The distance from the reflection point of the mirror 42 to the irradiated point 12 is defined as the measured distance d. When the focal point coincides with the irradiated point 12, f ｂ = d, and the intensity of the reflected light 20Lb is the highest. ｂ The focus position that satisfies ##EQU1## is the optimum focus position, and the distance information of the irradiation point 12 can be generated most accurately.

[0034] Upon receiving the control signal, the actuator 36 moves the lens 34 in the direction of its optical axis. The distance between a certain reference position and the principal point of the lens 34 in the direction of the optical axis is defined as the lens position. The lens position is assumed to be a. The reference position may be, for example, the end of the optical element 32 on the lens 34 side. The actuator 36 adjusts the lens position a to move the focus position f ｐ can be varied.

[0035] <Scanner 40> As shown in Fig. 1B, the scanner 40 changes the irradiation angle of the irradiation light 20La in response to a control signal sent from the processing circuit 62. The control signal includes information about the irradiation angle. The "control signal (irradiation angle)" in Fig. 1B refers to a control signal that includes information about the irradiation angle.

[0036] The mirror 42 may be, for example, a MEMS (Micro Electro Mechanical System) mirror, a galvanometer mirror, or a polygon mirror. In response to the control signal, the driver 44 changes the orientation of the mirror 42. As a result, the irradiation angle θ of the irradiation light 20La reflected by the mirror 42 changes, and the position of the irradiation point 12 on the target object 10 changes.

[0037] Instead of changing the orientation of the mirror 42, the position of the irradiation point 12 on the object 10 may be changed by changing the orientation of the focus adjuster 30 itself or the optical element 32 and lens 34 included in the focus adjuster 30.

[0038] <Photodetector 50> Upon receiving a control signal sent from the processing circuit 62, the photodetector 50 detects the reflected light 20Lb from the object 10 and outputs a photodetection signal corresponding to the intensity of the reflected light 20Lb. The control signal includes information on the detection timing and / or the output timing of the photodetection signal. Note that the processing circuit 62 may sample the photodetection signal at a predetermined timing while the photodetector 50 is constantly detecting the reflected light 20Lb. In this case, the processing circuit 62 does not need to send the above control signal, and the photodetector 50 does not need to receive the above control signal.

[0039] The photodetector 50 includes one or more photodiodes. The photodiodes output signals corresponding to the intensity of the reflected light 20Lb. The photodetector 50 may include a preamplifier that amplifies the signals.

[0040] 1C , the processing circuit 62 includes a control circuit 62a, a drive circuit 62b, and a signal processing circuit 62c. The control circuit 62a sends a control signal including lens position information to the focus adjuster 30 to control the focus adjuster 30. The control circuit 62a sends information including the irradiation angle to the scanner 40 to control the scanner 40. The control circuit 62a sends a control signal including information on detection timing and / or output timing to the photodetector 50 to control the photodetector 50.

[0041] The control circuit 62a controls the drive circuit 62b by sending a control signal including information on the intensity and emission timing of the irradiation light 20La to the drive circuit 62b. The drive circuit 62b drives the light source 20 by sending a drive signal to the light source 20. The drive signal may be, for example, a voltage signal or a current signal. It can also be said that the control circuit 62a controls the light source 20 via the drive circuit 62b. The control circuit 62a controls the signal processing circuit 62c by sending a control signal including information on signal processing to the signal processing circuit 62c.

[0042] The signal processing circuit 62c generates and outputs distance information of the illumination points 12 using ToF LiDAR technology. The ToF method may be a direct ToF method or an indirect ToF method. By mapping all of the distance information of the multiple illumination points 12 shown in FIG. 1A one-dimensionally or two-dimensionally, the shape of the target object 10 can be measured.

[0043] The memory 64 stores a table for adjusting the focus position. 2A and 2B are diagrams showing examples of the table for adjusting the focus position. The table shown in FIG. 2A shows the focus position f ｉ and lens position a ｉ The table shown in FIG. 2B is a table that associates the relationship between the distance d ｉ and lens position a ｉ The subscript "i" indicates that the value in the list is the ith one from the top.

[0044] The control circuit 62a determines the focus position f from the table shown in FIG. ｉ Lens position a corresponding to ｉ The information of the lens position a ｉ Alternatively, the control circuit 62a may transmit a control signal including the information of the above-mentioned f ｐ = d + f ａ Based on the relationship, the distance d is set to the focus position f ｐ Then, the lens position a is calculated from the table shown in FIG. ｉ Alternatively, the control circuit 62a may obtain the information on the distance d from the table shown in FIG. ｉ Lens position a corresponding to ｉ The information of the lens position a ｉ The control circuit 62a may transmit a control signal including the information of the lens position a to the focus adjuster 30 by using a conversion formula without using the table described above. ｉ may be calculated.

[0045] The signal processing circuit 62c may input the distance information of the irradiation point 12 to a display (not shown). The display displays the distance information of the irradiation point 12. Alternatively, the signal processing circuit 62c may input the output distance information of the irradiation point 12 to another device. The other device performs a specific operation based on the distance information of the irradiation point 12. The other device may be, for example, a vehicle or an industrial robot.

[0046] The computer programs executed by the control circuit 62a and the signal processing circuit 62c are stored in memory 64. The processing circuit 62 and memory 64 may be integrated on a single circuit board or provided on separate circuit boards. The control circuit 62a, drive circuit 62b, and signal processing circuit 62c included in the processing circuit 62 may be distributed across multiple circuits. The processing device 60, or parts thereof, may be installed in a remote location away from the other components and control the light source 20, focus adjuster 30, scanner 40, and photodetector 50 via a wired or wireless communication network.

[0047] [Measurement Apparatus Utilizing FMCW-Based LiDAR Technology] Next, with reference to FIGS. 3A and 3B , an example configuration of a measurement apparatus according to an embodiment of the present disclosure that utilizes FMCW-based LiDAR technology, i.e., FMCW-LiDAR technology, will be described. FIG. 3A is a block diagram schematically illustrating the configuration of a measurement apparatus according to another exemplary embodiment of the present disclosure. The measurement apparatus 100B shown in FIG. 3A measures the shape of an object 10 using FMCW-LiDAR technology. The measurement apparatus 100B shown in FIG. 3A differs from the measurement apparatus 100A shown in FIG. 1A in the following three respects. First, the light source 20 emits frequency-modulated light 20L0. Second, the measurement apparatus 100B includes an interference optical system 70A between the light source 20 and the focus adjuster 30. Third, the measurement apparatus 100B includes an optical element 80.

[0048] The components of the measurement apparatus 100B will be described below, focusing on the differences from the measurement apparatus 100A shown in FIG. 1A.

[0049] <Light Source 20> The light source 20 emits frequency-modulated light 20L0. The light 20L0 may be, for example, laser light. The frequency of the light 20L0 may be changed over time in a constant time period, for example, in a triangular or sawtooth waveform. The time period may be, for example, 1 μsec or more and 10 ms or less. The time period may vary. The frequency change width may be, for example, 100 MHz or more and 1 THz or less. The wavelength of the light 20L0 is the same as the wavelength of the above-mentioned irradiation light 20La.

[0050] As described above, the laser diode included in the light source 20 is capable of modulating the frequency of the light 20L0 in accordance with the amount of current applied thereto.

[0051] <Interference optical system 70A> The interference optical system 70A includes a first optical splitter 72 and a second optical splitter 74. The first optical splitter 72 and the focus adjuster 30 are connected by an optical fiber. The same applies to the connections between the first optical splitter 72 and the second optical splitter 74, the second optical splitter 74 and the photodetector 50, and the second optical splitter 74 and the optical element 80.

[0052] The first optical splitter 72 separates and outputs the light 20L0 emitted from the light source 20 into a reference light 20L1 and an irradiation light 20La for irradiating the object 10. The intensity of the reference light 20L1 may be, for example, 1% to 10% of the intensity of the light 20L0 input to the first optical splitter 72. The first optical splitter 72 inputs the output reference light 20L1 to the second optical splitter 74 and inputs the output irradiation light 20La to the focus adjuster 30.

[0053] The second optical splitter 74 inputs interference light 20L2, which is obtained by superimposing and interfering the reference light 20L1 and the reflected light 20Lb, to the photodetector 50. The photodetector 50 detects the interference light 20L2 and outputs a photodetection signal corresponding to the intensity of the interference light 20L2.

[0054] <Optical Element 80> The optical element 80 causes the reflected light 20Lb to enter an optical fiber connecting the optical element 80 and the second optical splitter 74. The optical element 80 may include, for example, at least one selected from the group consisting of a condenser lens, a collimator lens, a diffusing lens, and a diffraction grating.

[0055] The measurement apparatus according to an embodiment of the present disclosure that utilizes FMCW-LiDAR technology is not limited to the measurement apparatus 100B shown in FIG. 3A . FIG. 3B is a block diagram that schematically illustrates the configuration of a measurement apparatus according to yet another exemplary embodiment of the present disclosure. Like the measurement apparatus 100B shown in FIG. 3A , the measurement apparatus 100C shown in FIG. 3B measures the shape of the target object 10 using FMCW-LiDAR technology. The measurement apparatus 100C shown in FIG. 3B differs from the measurement apparatus 100B shown in FIG. 3A in the following two respects. First, the measurement apparatus 100C includes an interference optical system 70B instead of the interference optical system 70A shown in FIG. 3A . Second, the measurement apparatus 100C does not include the optical element 80 shown in FIG. 3A .

[0056] The components of the measurement apparatus 100C will be described below, focusing on the differences from the measurement apparatus 100B shown in FIG. 3A.

[0057] 3A , the interference optical system 70B includes an optical circulator 76. The first optical splitter 72 and the optical circulator 76 are connected by optical fibers. The same applies to the connections between the first optical splitter 72 and the second optical splitter 74, the optical circulator 76 and the focus adjuster 30, the optical circulator 76 and the second optical splitter 74, and the second optical splitter 74 and the photodetector 50.

[0058] The first optical splitter 72 inputs the output reference light 20L1 to the second optical splitter 74, and inputs the output irradiation light 20La to the optical circulator .

[0059] The optical circulator 76 outputs the illumination light 20La from the first optical splitter 72 and inputs the illumination light 20La to the focus adjuster 30. The optical circulator 76 further outputs the reflected light 20Lb that passes through the scanner 40 and the focus adjuster 30 in this order and inputs it to the second optical splitter 74.

[0060] In the measurement device 100C, unlike the measurement device 100B shown in Figure 3A, the optical path of the irradiation light 20La from the interference optical system 70B to the object 10 and the optical path of the reflected light 20Lb from the object 10 to the interference optical system 70B overlap coaxially.

[0061] In the measurement device 100C, not only is the focus position adjusted to be located on the object 10, but the focus point of the reflected light 20Lb is also adjusted to be located at the edge of the optical element 32 shown in FIG. 1B. Therefore, compared to the measurement device 100B shown in FIG. 3A, the intensity of the interference light 20L2 can be increased, further widening the range of distances that can be measured. The optical element 32 emits the irradiated light 20La into the air. The irradiated light 20La passes through the lens 34 and the scanner 40, in this order, before entering the object 10. The optical element 32 further receives the reflected light 20Lb, and inputs the reflected light 20Lb to the photodetector 50 via the optical circulator 76 and the second optical splitter 74, in this order. The measurement device 100C employs a coaxial optical system in which the optical paths of the irradiated light 20La and the reflected light 20Lb overlap on the same axis. This simplifies the configuration of the measurement device 100C and enables stable measurements.

[0062] 3A and 3B, the signal processing circuit 62c included in the processing device 60 generates and outputs distance information of the irradiation point 12 using FMCW-LiDAR technology. The signal processing circuit 62c may also generate and output velocity information of the irradiation point 12 using FMCW-LiDAR technology.

[0063] [FMCW-LiDAR Technology] Next, the FMCW-LiDAR technology will be briefly described with reference to Fig. 4. Details of the FMCW-LiDAR technology are disclosed in, for example, Non-Patent Document 1.

[0064] FIG. 4 is a diagram schematically illustrating the time changes in the frequency of the reference light 20L1 and the reflected light 20Lb when the object is stationary. The solid line in FIG. 4 represents the reference light 20L1, and the dashed line in FIG. 4 represents the reflected light 20Lb. The frequency of the reference light 20L1 shown in FIG. 4 repeatedly changes over time in a triangular waveform. That is, the frequency of the reference light 20L1 alternates between up-chirp and down-chirp. The frequency increase during the up-chirp period and the frequency decrease during the down-chirp period are equal to each other. The frequency of the reflected light 20Lb is shifted in the positive direction along the time axis compared to the frequency of the reference light 20L1. The amount of time shift of the reflected light 20Lb is equal to the time it takes for the illumination light 20La to be emitted from the measurement device 100B or 100C to the outside, reflected by the object 10, and returned as the reflected light 20Lb. As a result, the interference light 20L2, which is the result of superimposition and interference of the reference light 20L1 and the reflected light 20Lb, has a frequency corresponding to the frequency difference between the frequency of the reflected light 20Lb and the frequency of the reference light 20L1. The double-headed arrow in FIG. 4 represents the frequency difference between the two. The photodetector 50 outputs a signal indicating the intensity of the interference light 20L2. This signal is called a beat signal. The frequency of the beat signal, i.e., the beat frequency, is equal to the frequency difference. The signal processing circuit 62c can generate distance information of the object 10 from the beat frequency.

[0065] When the object 10 is stationary, the beat frequency during the up-chirp period is equal to the beat frequency during the down-chirp period. If the increase or decrease in the frequency of light during the up-chirp period or the down-chirp period is Δf, the time required for the change in Δf is Δt, the speed of light is c, and the difference between the optical path length of the reference light 20L1 and the sum of the optical path lengths of the illumination light 20La and the reflected light 20Lb is 2d, then the beat frequency during the up-chirp period or the down-chirp period is ｂｅａｔ is expressed by the following equation (1).

[0066] The beat frequency f in equation (1) ｂｅａｔis obtained by multiplying the time rate of change of frequency Δf / Δt by the time (2d / c) taken for the irradiated light 20La to be emitted from the distance measuring device to the outside, reflected by the object, and returned as reflected light.

[0067] When the object 10 moves, the frequency of the reflected light 20Lb undergoes a Doppler shift in the positive or negative direction along the frequency axis compared to the frequency of the reference light 20L1. In this case, the beat frequency during the up-chirp period differs from the beat frequency during the down-chirp period. The signal processing circuit 62c can generate velocity information and distance information of the object 10 from the frequency difference and average of these beat frequencies.

[0068] [Example 1 of Measurement Operation] Next, Example 1 of measurement operation of the measuring devices 100A to 100C according to this embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart that schematically shows Example 1 of measurement operation executed by the processing circuitry 62 in the measuring devices 100A to 100C according to this embodiment. The processing circuitry 62 executes the operations of steps S101 to S105 shown in Fig. 5.

[0069] <Step S101> Before executing the scanning operation, the processing circuitry 62 selects a different focus position f １ , f ２ Determine the focus position f １ , f ２ may be fixed when the measuring devices 100A to 100C are shipped, or may be set by the user before the measurement operation is performed.

[0070] Different focus positions f １ , f ２ may be separated within the range of the space of the measurement target including the object 10. When the object 10 is located close to the focus position, the signal intensity of the light detection signal output by the photodetector 50 after detecting the reflected light from the object 10 becomes high. １ , f ２ are separated within the range of the space to be measured, the distance information of the object 10 can be measured more accurately over a wider range.

[0071] Different focus positions f １ , f２ The distance between the focus positions f may be greater than the focal depth of the lens 34. The focal depth of the lens 34 is a distance range on the optical axis of the lens 34, centered on the distance of the focus position, at which a certain level of signal strength or more can be obtained. １ and the focus position f ２ If the focal depths of the target object 10 and the focal depths of the target object 10 do not overlap, the distance information of the target object 10 can be measured over a wider range with higher accuracy.

[0072] <Step S102> The processing circuit 62 sets the focus position to focus position f １ and executes a first scanning operation in which the illumination light 20La is emitted at the first illumination angle group, thereby generating a first distance information group corresponding to the first illumination angle group. The first illumination angle group includes a plurality of first illumination angles, each of which is an illumination angle θ １i (1≦i≦l). The first distance information group includes a plurality of first distance information, such as an irradiation angle θ １i Distance information d corresponding to (1≦i≦l) １i (1≦i≦l).

[0073] <Step S103> The processing circuit 62 sets the focus position to focus position f ２ and executes a second scanning operation in which the illumination light 20La is emitted at the second illumination angle group, thereby generating a second distance information group corresponding to the second illumination angle group. The second illumination angle group includes a plurality of second illumination angles, each of which is an illumination angle θ ２ｊ (1≦j≦m). The second distance information group includes a plurality of second distance information, such as an irradiation angle θ ２ｊ Distance information d corresponding to (1≦j≦m) ２ｊ (1≦j≦m) Irradiation angle θ ２ｊ (1≦j≦m) is the irradiation angle θ １ｉ (1≦i≦l) ２ｊ (1≦j≦m) are all irradiation angles θ １ｉ It may be the same as (1≦i≦l).

[0074] <Step S104> The processing circuitry 62 generates a third distance information group based on the first and second distance information groups. More specifically, the processing circuitry 62 calculates the distance between the first and second irradiation angles θ１ｉ Evaluation parameter e １ｉ and irradiation angle θ ２ｊ Evaluation parameter e ２ｊ Based on this, the first distance information d １ｉ and second distance information d ２ｊ The processing circuitry 62 further determines whether the third distance information d ３ｋ (1≦k≦n) is included in the third distance information group.

[0075] The third distance information group includes distance information d ３ｋ The third distance information group includes distance information d ３ｋ Irradiation angle θ corresponding to (1≦k≦n) ３ｋ (1≦k≦n). As a result of the above, the third set of distance information may be different from the first and second sets of distance information, or may be identical to either the first or second set of distance information.

[0076] In the first example of the measurement operation, as will be described later, the more identical irradiation angles there are among the plurality of first irradiation angles and the plurality of second irradiation angles, the more the number of third irradiation angles increases.

[0077] <Step S105> Processing circuitry 62 outputs the third distance information group. The destination of the third distance information group may be, for example, a host system, a display, or a control system for a vehicle or a moving object.

[0078] The processing circuitry 62 may output a third irradiation angle group in addition to the third distance information group. The set of distance information group and angle information group can be said to be a point group in a polar coordinate system as seen from the measurement devices 100A to 100C. This point group in the polar coordinate system may be converted into a point group in a Cartesian coordinate system and output.

[0079] In the above example, the number of focus positions determined is two, but it may be three or more. That is, the number of focus positions determined is two or more. The greater the number of focus positions, the smaller the focus deviation for all irradiation points 12, so the intensity of the light detection signal increases and the measurement accuracy improves. On the other hand, the closer the number of focus positions determined is to two, the fewer the number of scanning operations, so the measurement speed improves. The number of focus positions can be determined by the user, taking into consideration the balance between measurement accuracy and measurement speed.

[0080] Next, examples of tables generated by the processing circuitry 62 in steps S102 to S104 will be described with reference to FIGS. 6A to 6C.

[0081] 6A and 6B are diagrams each showing an example of a table generated by the processing circuitry 62 in steps S102 and S103 shown in FIG. 5 for measurement operation example 1. As shown in FIGS. 6A and 6B, a table is generated for each focus position. The first table shown in FIG. 6A includes at least a first group of illumination angles, a first group of evaluation parameters, and a first group of distance information. The second table shown in FIG. 6B includes at least a second group of illumination angles, a second group of evaluation parameters, and a second group of distance information. In the examples shown in FIGS. 6A and 6B, each table includes the coordinates of an illumination point group, but this is not limited to this example. The coordinates of the illumination point group can be calculated from the illumination angle and distance, so this is not essential.

[0082] The first irradiation angle group is a group consisting of a plurality of irradiation angles when scanning with the irradiation light 20La by the scanner 40. The same applies to the second irradiation angle group.

[0083] The first evaluation parameter group is a group consisting of multiple evaluation parameters used to generate the third distance information group. The same applies to the second evaluation parameter group. Each evaluation parameter may be, for example, signal strength. The signal strength may be expressed, for example, by a relative ratio to a predetermined voltage amplitude. The predetermined voltage amplitude may be, for example, 1 V, and the unit of the relative ratio may be, for example, dB. Alternatively, the signal strength may be expressed by the intensity value itself. The unit of the intensity value may be, for example, W.

[0084] The first distance information group is a group consisting of a plurality of pieces of distance information generated by the processing circuitry 62. The same applies to the second distance information group.

[0085] 6C is a diagram schematically illustrating an example of a table generated by the processing circuitry 62 in step S104 shown in FIG. 5 for the first example of the measurement operation. As shown in FIG. 6C , the third table includes at least a third illumination angle group and a third distance information group. The third distance information group is a group consisting of a plurality of distance information selected from the first distance information group and the second distance information group based on the first evaluation parameter group and the second evaluation parameter group. Since the third table is generated after the evaluation, it does not need to include the evaluation parameter group, but may include the evaluation parameter group. The third illumination angle group is a group consisting of a plurality of illumination angles corresponding to the plurality of distance information included in the third distance information group.

[0086] Next, the processing operations of steps S102 to S104 shown in FIG. 5 will be described in detail with reference to FIGS. 7A to 7C.

[0087] Fig. 7A is a flowchart showing details of the processing operation of step S102 shown in Fig. 5 for measurement operation example 1. The processing circuitry 62 executes the operations of steps S201 to S206 shown in Fig. 7A.

[0088] <Step S201> The processing circuit 62 controls the focus adjuster 30 to set the focus position f １ Adjust to.

[0089] <Step S202> The processing circuitry 62 causes the scanner 40 to set the irradiation angle of the irradiation light 20La to one of the irradiation angles included in the first irradiation angle group, and causes the light source 20 to emit the irradiation light 20La to illuminate the irradiation point 12 to be measured with the irradiation light 20La. In the measurement device 100B shown in FIG. 3A and the measurement device 100C shown in FIG. 3B, the light source 20 emits the light 20L0, but since the light 20L0 includes the irradiation light 20La, it can be said that the light source 20 emits the irradiation light 20La.

[0090] <Step S203> The processing circuitry 62 causes the photodetector 50 to detect the reflected light 20Lb or the interference light 20L2 and output a photodetection signal. Note that the processing circuitry 62 may sample the photodetection signal at a predetermined timing while the photodetector 50 is constantly detecting the reflected light 20Lb or the interference light 20L2.

[0091] <Step S204> The processing circuitry 62 calculates the distance and signal strength of the irradiation point 12 based on the light detection signal. When FMCW-LiDAR technology is used, the processing circuitry 62 performs a Fourier transform on the time waveform of the light detection signal to obtain the frequency of the beat signal, converts the frequency to distance, and obtains this as distance information. At the same time, the processing circuitry 62 calculates the peak strength of the beat signal and obtains this as signal strength.

[0092] <Step S205> The processing circuit 62 stores in the memory 64 the irradiation angle, signal intensity, and distance information (θ １ｉ , s １ｉ , d １ｉ The memory 64 stores a first table shown in FIG. 6A.

[0093] <Step S206> The processing circuitry 62 determines whether or not all irradiation points 12 have been irradiated in the first scanning operation. If the determination is Yes, the processing circuitry 62 ends the first scanning operation. If the determination is No, the processing circuitry 62 executes the operation of step S202.

[0094] To briefly summarize the first scan operation described above, it can be said that the processing circuitry 62 executes the following operations: The same applies to examples 2 to 5 of the measurement operation described below.

[0095] The focus adjuster 30 sets the focus position to the first focus position f １ Adjust to.

[0096] The scanner 40 is caused to set the irradiation angle to the first irradiation angle group and irradiate the object 10 with the irradiation light 20La.

[0097] A first distance information group is generated based on the reflected light from the object 10.

[0098] Fig. 7B is a flowchart showing details of the processing operation of step S103 shown in Fig. 5. The processing circuit 62 executes the operations of steps S301 to S306 shown in Fig. 7B.

[0099] <Step S301> The processing circuit 62 controls the focus adjuster 30 to set the focus position f ２ Adjust to.

[0100] <Step S302> The processing circuit 62 causes the scanner 40 to set the irradiation angle of the irradiation light 20La to one of the irradiation angles included in the second irradiation angle group, and causes the light source 20 to emit the irradiation light 20La to irradiate the irradiation point 12 to be measured with the irradiation light 20La.

[0101] <Step S303> The processing circuitry 62 causes the photodetector 50 to detect the reflected light 20Lb or the interference light 20L2 and output a photodetection signal.

[0102] <Step S304> The processing circuitry 62 calculates the distance and signal intensity of the irradiation point 12 based on the light detection signal.

[0103] <Step S305> The processing circuit 62 stores in the memory 64 the irradiation angle, signal intensity, and distance information (θ ２ｊ , s ２ｊ , d ２ｊ The memory 64 stores the table shown in FIG. 6B.

[0104] <Step S306> The processing circuitry 62 determines whether all irradiation points 12 have been irradiated in the second scanning operation. If the determination is Yes, the processing circuitry 62 ends the second scanning operation. If the determination is No, the processing circuitry 62 executes the operation of step S302.

[0105] To briefly summarize the second scan operation described above, it can be said that the processing circuitry 62 executes the following operations: The same applies to examples 2 to 5 of the measurement operation described below.

[0106] The focus adjuster 30 sets the focus position to the second focus position f ２ Adjust to.

[0107] The scanner 40 is caused to set the irradiation angle to the second irradiation angle group and irradiate the object 10 with the irradiation light 20La.

[0108] A second distance information group is generated based on the reflected light from the object 10.

[0109] Fig. 7C is a flowchart showing details of the processing operation of step S104 shown in Fig. 5 for measurement operation example 1. The processing circuitry 62 executes the operations of steps S401 to S406 shown in Fig. 7C.

[0110] <Step S401> The processing circuit 62 obtains the first table shown in FIG. 6A from the memory 64, and selects one irradiation angle θ from the first irradiation angle group included in the first table. １ａ Select .

[0111] <Step S402> The processing circuit 62 obtains the second table shown in FIG. 6B from the memory 64, and determines the irradiation angle θ from the second irradiation angle group included in the second table. １ａ If the determination is Yes, the processing circuit 62 searches for an irradiation angle θ １ａ The irradiation angle θ ２ｂ In this specification, the irradiation angle θ １ａ and irradiation angle θ ２ｂ"A match" does not only mean that the two match perfectly, but also means that the absolute value of the difference between the two is equal to or less than a predetermined value. The predetermined value is any value greater than 0° and equal to or less than 5°, and may be 1°, for example. If the determination is No, the processing circuit 62 executes the operation of step S406.

[0112] <Step S403> The processing circuit 62 determines the irradiation angle θ from the first evaluation parameter group included in the first table shown in FIG. 6A. １ａ The signal strength s corresponding to １ａ and selects the irradiation angle θ from the second evaluation parameter group included in the second table shown in FIG. ２ｂ The signal strength s corresponding to ２ｂ The processing circuitry 62 further selects the signal strength s １ａ and signal strength s ２ｂ Compare the highs and lows.

[0113] <Step S404> The processing circuit 62 calculates the signal strength s １ａ and signal strength s ２ｂ distance information d １a and distance information d ２ｂ The distance information d corresponding to the higher signal strength ３ｋ is adopted and included in the third distance information group.

[0114] <Step S405> The processing circuit 62 stores the distance information and the corresponding irradiation angle (θ ３ｋ , d ３ｋ The memory 64 stores a third table shown in FIG. 6C.

[0115] <Step S406> The processing circuit 62 determines whether all the illumination angles included in the first illumination angle group have been compared with all the illumination angles included in the second illumination angle group. If the determination is Yes, the processing circuit 62 ends the processing operation. If the determination is No, the processing circuit 62 executes the operation of step S401 again.

[0116] As described above, the measurement devices 100A to 100C according to this embodiment measure distance information and signal intensity for multiple irradiation points for each of multiple different focus positions. Furthermore, for the same irradiation point when irradiated at multiple different focus positions, the distance information with the higher signal intensity is adopted. As a result, a third table including a third irradiation angle group and a third distance information group is generated. In contrast, the measurement device disclosed in Patent Document 1 adjusts the focus position of the irradiation light in the high-precision ranging system for each irradiation point based on the ranging results in the low-precision ranging system.

[0117] Therefore, in comparison with the measurement device disclosed in Patent Document 1, the measurement devices 100A to 100C according to this embodiment can generate distance information of the irradiation point 12 on the object 10 with high accuracy while minimizing the time required for focus adjustment.

[0118] Furthermore, measurement apparatuses 100A to 100C according to this embodiment use a common configuration for determining the focus position and measuring the distance, whereas the measurement apparatus disclosed in Patent Document 1 uses different configurations, such as a low-precision distance measurement system and a high-precision distance measurement system.

[0119] Therefore, the measurement devices 100A to 100C according to this embodiment can generate distance information of the irradiation point 12 on the object 10 with a simpler configuration than the measurement device disclosed in Patent Document 1.

[0120] Next, an example will be described with reference to Figures 8A to 8C. In the example, a measurement device 100C shown in Figure 3B was used, which employs a coaxial optical system and utilizes FMCW-LiDAR technology.

[0121] First, the first and second scanning operations were performed to measure distance information and signal intensity of a plurality of irradiation points 12 on the object 10. The irradiation angle range was from −40° to 40°, and the irradiation light 20La was irradiated in 10° increments.

[0122] A collimator lens capable of converging and diverging the irradiation light 20La was used as the lens 34 of the focus adjuster 30. The focal length of the collimator lens was f=40 mm. The focus positions were set to 1 m and 3.5 m in the first and second scanning operations, respectively. A white diffuser plate with a stepped shape was used as the target 10.

[0123] 8A and 8B are diagrams showing first and second tables acquired by the first and second scanning operations, respectively, illustrating an object 10. In the example shown in FIGS. 8A and 8B, the measurement device 100C shown in FIG. 3B measures distances to multiple irradiation points on the object 10 from above the object 10.

[0124] As shown in Figures 8A and 8B, the first and second scan operations were able to measure the distance information and signal strength of all irradiation points. As shown in Figure 8A, it was found that the signal strength was high at irradiation points close to the first focus position, and as shown in Figure 8B, the signal strength was high at irradiation points far away close to the second focus position.

[0125] 8C is a diagram for explaining the process of generating the third table. In FIG. 8C, from top to bottom, the first table, the second table, and the third table are shown. However, the first and second tables each have a column for determining whether or not to adopt distance information.

[0126] As shown in Fig. 8C , for each irradiation angle, the signal strength included in the first evaluation parameter group was compared with the signal strength included in the second evaluation parameter group, and the distance information with the higher signal strength was adopted. In the example shown in Fig. 8C , the adopted distance information is marked with a circle. In this manner, a third table including a third irradiation angle group and a third distance information group is generated. Even for the same irradiation angle, a higher signal strength reduces the variation in distance information. This improves reproducibility and increases the accuracy of the distance information.

[0127] From the above examples, it has been confirmed that the measurement device 100C according to this embodiment can generate distance information of the irradiation point 12 on the object 10 with high accuracy, while minimizing the time required for focus adjustment, with a simple configuration. Similar effects can be expected from the measurement devices 100A and 100B according to this embodiment.

[0128] [Measurement Operation Example 2] Next, measurement operation example 2 will be described with reference to Figures 9A to 10C. In measurement operation example 2, the processing circuit 62 executes the operations of steps S101 to S105 shown in Figure 5, similarly to measurement operation example 1. Measurement operation example 2 differs from measurement operation example 1 in that the variability in distance information is used as the evaluation parameter, rather than signal strength. In the following, the standard deviation of distance is exemplified as the variability in distance information.

[0129] 9A and 9B are diagrams each schematically illustrating an example of a table generated by the processing circuitry 62 in steps S102 and S103 shown in FIG. 5 for measurement operation example 2. In the first table shown in FIGS. 9A and 9B, each evaluation parameter included in the first and second evaluation parameter groups may be, for example, a standard deviation of distance. Each distance information included in the first and second distance information groups may be, for example, an average value of distance. To determine the standard deviation and average value of distance, multiple measurements are performed for each irradiation angle. For measurement operation example 2, the table generated by the processing circuitry 62 in step S104 shown in FIG. 5 is the same as the third table shown in FIG. 6C.

[0130] Fig. 10A is a flowchart showing details of the processing operation of step S102 shown in Fig. 5 for measurement operation example 2. The processing circuitry 62 executes the operations of steps S501 to S506 shown in Fig. 10A.

[0131] <Step S501> The processing circuit 62 controls the focus adjuster 30 to set the focus position f １ Adjust to.

[0132] <Step S502> The processing circuit 62 causes the scanner 40 to set the irradiation angle of the irradiation light 20La to one of the irradiation angles included in the first irradiation angle group, and causes the light source 20 to emit the irradiation light 20La multiple times, thereby irradiating the irradiation point 12 to be measured with the irradiation light 20La multiple times.

[0133] <Step S503> The processing circuitry 62 causes the photodetector 50 to detect the reflected light 20Lb or the interference light 20L2 and output a photodetection signal multiple times.

[0134] <Step S504> The processing circuitry 62 calculates the standard deviation and average value of the distance of the irradiation point 12 based on the plurality of light detection signals.

[0135] <Step S505> The processing circuit 62 stores in the memory 64 the irradiation angle, the standard deviation of the distance, and the average value of the distance (θ １ｉ , σ １ｉ , d １ｉ The memory 64 stores a first table shown in FIG. 9A.

[0136] <Step S506> The processing circuitry 62 determines whether or not all irradiation points 12 have been irradiated in the first scanning operation. If the determination is Yes, the processing circuitry 62 ends the first scanning operation. If the determination is No, the processing circuitry 62 executes the operation of step S502.

[0137] Fig. 10B is a flowchart showing details of the processing operation of step S103 shown in Fig. 5 for measurement operation example 2. The processing circuitry 62 executes the operations of steps S601 to S606 shown in Fig. 10B.

[0138] <Step S601> The processing circuit 62 controls the focus adjuster 30 to set the focus position f ２ Adjust to.

[0139] <Step S602> The processing circuit 62 causes the scanner 40 to set the irradiation angle of the irradiation light 20La to one of the irradiation angles included in the second irradiation angle group, and causes the light source 20 to emit the irradiation light 20La multiple times to irradiate the irradiation point 12 to be measured with the irradiation light 20La multiple times.

[0140] <Step S603> The processing circuitry 62 causes the photodetector 50 to detect the reflected light 20Lb or the interference light 20L2 and output a photodetection signal multiple times. Note that the processing circuitry 62 may sample the photodetection signal at a predetermined timing while the photodetector 50 is constantly detecting the reflected light 20Lb or the interference light 20L2.

[0141] <Step S604> The processing circuitry 62 calculates the standard deviation and average value of the distance of the irradiation point 12 based on the plurality of light detection signals.

[0142] <Step S605> The processing circuit 62 stores in the memory 64 the irradiation angle, the standard deviation of the distance, and the average value of the distance (θ ２ｊ , σ ２ｊ , d ２ｊ The memory 64 stores the second table shown in FIG.

[0143] <Step S606> The processing circuitry 62 determines whether or not all irradiation points 12 have been irradiated in the second scanning operation. If the determination is Yes, the processing circuitry 62 ends the second scanning operation. If the determination is No, the processing circuitry 62 executes the operation of step S602.

[0144] Fig. 10C is a flowchart showing details of the processing operation of step S104 shown in Fig. 5 for measurement operation example 2. The processing circuitry 62 executes the operations of steps S701 to S706 shown in Fig. 10C.

[0145] <Step S701> The processing circuit 62 obtains the first table shown in FIG. 9A from the memory 64, and selects one irradiation angle θ from the first irradiation angle group included in the first table. １ａ Select .

[0146] <Step S702> The processing circuit 62 obtains the second table shown in FIG. 9B from the memory 64, and determines the irradiation angle θ from the second irradiation angle group included in the second table. １ａ If the determination is Yes, the processing circuit 62 searches for an irradiation angle θ １ａ The irradiation angle θ ２ｂIf the determination is No, the processing circuitry 62 executes the operation of step S706.

[0147] <Step S703> The processing circuit 62 determines the irradiation angle θ from the first evaluation parameter group included in the first table shown in FIG. 9A. １ａ The standard deviation σ of the distances corresponding to １ａ and selects the irradiation angle θ from the second evaluation parameter group included in the second table shown in FIG. ２ｂ The corresponding standard deviation σ ２ｂ The processing circuitry 62 further selects the standard deviation σ １ａ and standard deviation σ ２ｂ Compare the size of.

[0148] <Step S704> The processing circuitry 62 calculates the standard deviation σ １ａ and standard deviation σ ２ｂ distance information d １a and distance information d ２ｂ The distance information d corresponding to the smaller standard deviation ３ｋ is adopted and included in the third distance information group.

[0149] <Step S705> The processing circuit 62 stores the distance information and the corresponding irradiation angle (θ ３ｋ , d ３ｋ The memory 64 stores a third table shown in FIG. 6C.

[0150] <Step S706> The processing circuit 62 determines whether all the illumination angles included in the first illumination angle group have been compared with all the illumination angles included in the second illumination angle group. If the determination is Yes, the processing circuit 62 ends the processing operation. If the determination is No, the processing circuit 62 executes the operation of step S701 again.

[0151] As described above, the measurement devices 100A to 100C according to this embodiment measure the standard deviation and average value of the distances of multiple irradiation points for each of multiple different focus positions. Furthermore, for the same irradiation point when irradiated at multiple different focus positions, the distance information with the smaller standard deviation is adopted. As a result, a third table including a third irradiation angle group and a third distance information group is generated. In contrast, the measurement device disclosed in Patent Document 1 adjusts the focus position of the irradiation light in the high-precision ranging system for each irradiation point based on the ranging results in the low-precision ranging system.

[0152] Therefore, in the measurement devices 100A to 100C of this embodiment, compared to the measurement device disclosed in Patent Document 1, the time required for focus adjustment can be minimized while accurately generating distance information of the irradiation point 12 on the object 10.

[0153] Furthermore, the measurement devices 100A to 100C according to this embodiment can generate distance information of the irradiation point 12 on the object 10 with a simpler configuration than the measurement device disclosed in Patent Document 1.

[0154] [Measurement Operation Example 3] Next, measurement operation example 3 of the measurement devices 100A to 100C according to this embodiment will be described with reference to Fig. 11. Measurement operation example 3 differs from measurement operation examples 1 and 2 in that distance information is adopted by comparing the evaluation parameters contained in the first and second tables with threshold values.

[0155] 11 is a flowchart schematically showing Example 3 of the measurement operation performed by the processing circuitry 62 in the measuring apparatuses 100A to 100C according to this embodiment. The processing circuitry 62 performs the operations of steps S801 to S805 shown in FIG.

[0156] <Step S801> Before executing the scanning operation, the processing circuitry 62 determines the focus position f １ , f ２ and determine the signal strength threshold. １ , f ２is as described in step S101. The signal strength threshold is used to generate the third distance information in step S804. The signal strength threshold may be fixed when the measurement devices 100A to 100C are shipped, or may be set by a user before performing a measurement operation. Alternatively, the signal strength threshold may be set by the measurement devices 100A to 100C based on a predetermined algorithm, depending on the measurement environment.

[0157] <Step S802> The processing circuit 62 sets the focus position to focus position f １ and executes a first scanning operation in which the illumination light 20La is emitted at the first illumination angle group, thereby generating a first distance information group corresponding to the first illumination angle group. １i (1≦i≦l). The first distance information group includes the irradiation angle θ １i Distance information d corresponding to (1≦i≦l) １i (1≦i≦l).

[0158] Details of the processing operation in step S802 are the same as the operations in steps S201 to S206 shown in FIG. 7A.

[0159] <Step S803> The processing circuit 62 sets the focus position to focus position f ２ and executes a second scanning operation in which the illumination light 20La is emitted at the second illumination angle group, thereby generating a second distance information group corresponding to the second illumination angle group. ２ｊ (1≦j≦m). The second distance information group includes the irradiation angle θ ２ｊ Distance information d corresponding to (1≦j≦m) ２ｊ (1≦j≦m) Irradiation angle θ ２ｊ At least one of (1≦j≦m) is the irradiation angle θ １ｉ (1≦i≦l) The irradiation angle θ ２ｊ (1≦j≦m) are all irradiation angles θ １ｉ (1≦i≦l) may be different.

[0160] Details of the processing operation in step S803 are the same as the operations in steps S301 to S306 shown in FIG. 7B.

[0161] <Step S804> The processing circuitry 62 generates a third distance information group corresponding to a third illumination angle group based on the first and second distance information groups. More specifically, the processing circuitry 62 generates a third distance information group corresponding to a third illumination angle group based on the illumination angle θ １ｉ Evaluation parameter e １ｉ and threshold e ｔｈ Based on the comparison with the first distance information d １ｉ Decide whether to adopt the irradiation angle θ ２ｊ Evaluation parameter e ２ｊ and threshold e ｔｈ Based on the comparison with the second distance information d ２ｊ The processing circuit 62 further determines whether to adopt the adopted third distance information d ３ｋ (1≦k≦n) is included in the third distance information group.

[0162] The third distance information group includes distance information d ３ｋ The third distance information group includes distance information d ３ｋ Irradiation angle θ corresponding to (1≦k≦n) ３ｋ (1≦k≦n). As a result of the above, the third set of distance information may be different from the first and second sets of distance information, or may be identical to either the first or second set of distance information.

[0163] In the third example of the measurement operation, as will be described later, the number of third irradiation angles increases as the number of different, non-matching irradiation angles among the plurality of first irradiation angles and the plurality of second irradiation angles increases.

[0164] <Step S805> The processing circuitry 62 outputs a third group of distance information. The third group of distance information may be output to, for example, a host system, a display, or a control system for a vehicle or a moving object. The processing circuitry 62 may output a third group of illumination angles in addition to the third group of distance information.

[0165] Next, the processing operation of step S804 shown in FIG. 11 will be described in detail with reference to FIG.

[0166] Fig. 12 is a flowchart showing details of the processing operation of step S804 shown in Fig. 11 for measurement operation example 3. The processing circuitry 62 executes the operations of steps S901 to S906 shown in Fig. 12.

[0167] <Step S901> The processing circuit 62 obtains the first table shown in FIG. 6A and the second table shown in FIG. 6B from the memory 64, and selects one irradiation angle θ from the first and second irradiation angle groups. １ａ or irradiation angle θ ２ｂ Select .

[0168] <Step S902> The processing circuit 62 determines the selected irradiation angle θ １ａ or irradiation angle θ ２ｂ The signal strength s corresponding to １ａ or signal strength s １ｂ Refer to.

[0169] <Step S903> The processing circuit 62 calculates the signal strength s １ａ or signal strength s １ｂ is higher than the threshold value. If the determination is Yes, the processing circuit 62 executes the operation of step S904. If the determination is No, the processing circuit 62 executes the operation of step S906.

[0170] <Step S904> The processing circuit 62 calculates the signal strength s １ａ or signal strength s １ｂ and include the distance information corresponding to the first and second irradiation angle groups in the third distance information group. For different irradiation angles that do not match in the first and second irradiation angle groups, distance information for which the signal strength corresponding to the irradiation angle is higher than a threshold value is adopted. For the same irradiation angle in the first and second irradiation angle groups, distance information for which the signal strength corresponding to the irradiation angle is higher than a threshold value and is farther away than the threshold value may be adopted.

[0171] <Step S905> The processing circuit 62 stores the distance information and the corresponding irradiation angle (θ ３ｋ , d ３ｋThe memory 64 stores a third table shown in FIG. 6C.

[0172] <Step S906> The processing circuit 62 determines all of the irradiation angles included in the first and second irradiation angle groups. If the determination is Yes, the processing circuit 62 ends the processing operation. If the determination is No, the processing circuit 62 executes the operation of step S901 again.

[0173] As described above, the measurement devices 100A to 100C according to this embodiment measure distance information and signal intensity of multiple irradiation points for each of multiple different focus positions. Furthermore, for different, inconsistent irradiation points when irradiated at multiple different focus positions, distance information for which the signal intensity is greater than a threshold value is used. As a result, a third data table including a third group of irradiation angles and a third group of distance information is generated. In contrast, the measurement device disclosed in Patent Document 1 adjusts the focus position of the irradiation light in the high-precision ranging system for each irradiation point based on the ranging results in the low-precision ranging system.

[0174] Therefore, in comparison with the measurement device disclosed in Patent Document 1, the measurement devices 100A to 100C according to this embodiment can generate distance information of the irradiation point 12 on the object 10 with high accuracy while minimizing the time required for focus adjustment.

[0175] Furthermore, in the measurement devices 100A to 100C according to this embodiment, if a sufficiently large signal intensity is obtained at many different non-coincident irradiation points 12 when irradiated at multiple different focus positions, a group of distance information with high spatial density can be obtained.

[0176] Furthermore, the measurement devices 100A to 100C according to this embodiment can generate distance information of the irradiation point 12 on the object 10 with a simpler configuration than the measurement device disclosed in Patent Document 1.

[0177] In addition, in measurement operation example 1, for different irradiation points that do not match when irradiated at multiple different focus positions, distance information whose signal strength is greater than a threshold value may be used, as in measurement operation example 3.

[0178] [Measurement Operation Example 4] Next, measurement operation example 4 of the measurement devices 100A to 100C according to this embodiment will be described with reference to Fig. 13. Measurement operation example 4 differs from measurement operation example 3 in that the variability in distance information is used as the threshold value instead of signal strength. In the following, the standard deviation of distance is exemplified as the variability in distance information.

[0179] 13 is a flowchart schematically showing Example 4 of the measurement operation executed by the processing circuitry 62 in the measuring apparatuses 100A to 100C according to this embodiment. The processing circuitry 62 executes the operations of steps S1001 to S1005 shown in FIG.

[0180] <Step S1001> Before executing the scanning operation, the processing circuitry 62 determines the focus position f １ , f ２ and determine the threshold value of the standard deviation of the distance. １ , f ２ is as described in step S101. The threshold value of the standard deviation of the distance is used to generate the third distance information in step S1004. The threshold value of the standard deviation of the distance may be fixed when the measurement devices 100A to 100C are shipped, or may be set by a user before a measurement operation is performed. Alternatively, the threshold value of the standard deviation of the distance may be set by the measurement devices 100A to 100C based on a predetermined algorithm, depending on the measurement environment.

[0181] <Steps S1002 to S1005> Steps S1002 to S1005 are the same as steps S802 to S805 shown in Fig. 8. Details of the processing operation of step S1002 are the same as the details of the processing operation of step S802, as are the operations of steps S501 to S506 shown in Fig. 10A. Details of the processing operation of step S1003 are the same as the details of the processing operation of step S803, as are the operations of steps S601 to S606 shown in Fig. 10B.

[0182] Next, the processing operation of step S1004 shown in FIG. 13 will be described in detail with reference to FIG.

[0183] Fig. 14 is a flowchart showing details of the processing operation of step S1004 shown in Fig. 13 for measurement operation example 4. The processing circuitry 62 executes the operations of steps S1101 to S1106 shown in Fig. 14.

[0184] <Step S1101> The processing circuit 62 obtains the first table shown in FIG. 9A and the second table shown in FIG. 9B from the memory 64, and selects one irradiation angle θ from the first and second irradiation angle groups. １ａ or irradiation angle θ ２ｂ Select .

[0185] <Step S1102> The processing circuit 62 determines the selected irradiation angle θ １ａ or irradiation angle θ ２ｂ The standard deviation σ of the distances corresponding to １ａ or standard deviation σ １ｂ Refer to.

[0186] <Step S1103> The processing circuitry 62 calculates the standard deviation σ of the distance. １ａ or standard deviation σ １ｂ If the determination is Yes, the processing circuit 62 executes the operation of step S1104. If the determination is No, the processing circuit 62 executes the operation of step S1106.

[0187] <Step S1104> The processing circuitry 62 calculates the standard deviation σ of the distance. １ａ or standard deviation σ １ｂ and include the distance information corresponding to the first and second irradiation angle groups in the third distance information group. For different irradiation angles that do not match in the first and second irradiation angle groups, distance information in which the standard deviation of the distances corresponding to the irradiation angles is smaller than a threshold value is adopted. For the same irradiation angle in the first and second irradiation angle groups, distance information in which the standard deviation of the distances corresponding to the irradiation angle is smaller than a threshold value and is farther away than the threshold value may be adopted.

[0188] <Step S1105> The processing circuit 62 stores the distance information and the corresponding irradiation angle (θ ３ｋ , d ３ｋ The memory 64 stores a third table shown in FIG. 6C.

[0189] <Step S1106> The processing circuit 62 determines all of the irradiation angles included in the first and second irradiation angle groups. If the determination is Yes, the processing circuit 62 ends the processing operation. If the determination is No, the processing circuit 62 executes the operation of step S1101 again.

[0190] As described above, the measurement devices 100A to 100C according to this embodiment measure the standard deviation and average value of the distances of multiple irradiation points for each of multiple different focus positions. Furthermore, for different, inconsistent irradiation points when irradiated at multiple different focus positions, distance information for which the standard deviation of the distances is smaller than a threshold value is adopted. As a result, a third data table including a third group of irradiation angles and a third group of distance information is generated. In contrast, the measurement device disclosed in Patent Document 1 adjusts the focus position of the irradiation light in the high-precision ranging system for each irradiation point based on the ranging results in the low-precision ranging system.

[0191] Therefore, in comparison with the measurement device disclosed in Patent Document 1, the measurement devices 100A to 100C according to this embodiment can generate distance information of the irradiation point 12 on the object 10 with high accuracy while minimizing the time required for focus adjustment.

[0192] Furthermore, in the measurement devices 100A to 100C according to this embodiment, if a sufficiently small standard deviation of distance is obtained at many different, non-coincident irradiation points 12 when irradiated at multiple different focus positions, a group of distance information with high spatial density can be obtained.

[0193] Furthermore, the measurement devices 100A to 100C according to this embodiment can generate distance information of the irradiation point 12 on the object 10 with a simpler configuration than the measurement device disclosed in Patent Document 1.

[0194] In addition, in measurement operation example 2, for different irradiation points that do not match when irradiated at multiple different focus positions, distance information whose standard deviation of distance is smaller than a threshold value may be used, as in measurement operation example 4.

[0195] [Measurement Operation Example 5] Next, with reference to Figures 15A to 16C, a measurement operation example 5 of the measurement apparatuses 100A to 100C according to this embodiment will be described. In measurement operation example 5, the processing circuitry 62 executes steps S101 to S105 shown in Figure 5, similar to measurement operation example 1. Measurement operation example 5 differs from measurement operation example 1 in that the amount of defocus is used as the evaluation parameter, rather than signal strength. The amount of defocus means the absolute value of the difference between the measured distance and the focus position.

[0196] 15A and 15B are diagrams each schematically illustrating an example of a table generated by the processing circuitry 62 in steps S102 and S103 shown in FIG. 5 for measurement operation example 5. As shown in FIGS. 15A and 15B, a table is generated for each focus position. The first table shown in FIG. 15A includes at least a first illumination angle group, a first evaluation parameter group, and a first distance information group. The second table shown in FIG. 15B includes at least a second illumination angle group, a second evaluation parameter group, and a second distance information group. As shown in FIGS. 15A and 15B, each evaluation parameter included in the first and second evaluation parameter groups may be, for example, a focus deviation amount. In the example shown in FIG. 15A, g １ｉ = |d １ｉ -f １ In the example shown in FIG. ２ｊ = |d ２ｊ -f ２ |It is.

[0197] Fig. 16A is a flowchart showing details of the processing operation of step S102 shown in Fig. 5 for measurement operation example 5. The processing circuitry 62 executes the operations of steps S1201 to S1206 shown in Fig. 16A.

[0198] <Step S1201> The processing circuit 62 controls the focus adjuster 30 to set the focus position f １ Adjust to.

[0199] <Step S1202> The processing circuit 62 causes the scanner 40 to set the irradiation angle of the irradiation light 20La to one of the irradiation angles included in the first irradiation angle group, and causes the light source 20 to emit the irradiation light 20La to irradiate the irradiation point 12 to be measured with the irradiation light 20La.

[0200] <Step S1203> The processing circuitry 62 causes the photodetector 50 to detect the reflected light 20Lb or the interference light 20L2 and output a photodetection signal. Note that the processing circuitry 62 may sample the photodetection signal at a predetermined timing while the photodetector 50 is constantly detecting the reflected light 20Lb or the interference light 20L2.

[0201] <Step S1204> The processing circuitry 62 calculates the distance and the amount of focus deviation of the irradiation point 12 based on the light detection signal.

[0202] <Step S1205> The processing circuit 62 stores in the memory 64 the irradiation angle, the amount of focus deviation, and the distance information (θ １ｉ , g １ｉ , d １ｉ The memory 64 stores a first table shown in FIG.

[0203] <Step S1206> The processing circuitry 62 determines whether or not all irradiation points 12 have been irradiated in the first scanning operation. If the determination is Yes, the processing circuitry 62 ends the first scanning operation. If the determination is No, the processing circuitry 62 executes the operation of step S1202.

[0204] Fig. 16B is a flowchart showing details of the processing operation of step S103 shown in Fig. 5 for measurement operation example 5. The processing circuitry 62 executes the operations of steps S1301 to S1306 shown in Fig. 16B.

[0205] <Step S1301> The processing circuit 62 controls the focus adjuster 30 to set the focus position f ２ Adjust to.

[0206] <Step S1302> The processing circuit 62 causes the scanner 40 to set the irradiation angle of the irradiation light 20La to one of the irradiation angles included in the second irradiation angle group, and causes the light source 20 to emit the irradiation light 20La to irradiate the irradiation point 12 to be measured with the irradiation light 20La.

[0207] <Step S1303> The processing circuitry 62 causes the photodetector 50 to detect the reflected light 20Lb or the interference light 20L2 and output a photodetection signal. Note that the processing circuitry 62 may sample the photodetection signal at a predetermined timing while the photodetector 50 is constantly detecting the reflected light 20Lb or the interference light 20L2.

[0208] <Step S1304> The processing circuitry 62 calculates the distance and the amount of focus deviation of the irradiation point 12 based on the light detection signal.

[0209] <Step S1305> The processing circuit 62 stores in the memory 64 the irradiation angle, the amount of focus deviation, and the distance information (θ ２ｊ , g ２ｊ , d ２ｊ The memory 64 stores a second table shown in FIG. 15B.

[0210] <Step S1306> The processing circuitry 62 determines whether all irradiation points 12 have been irradiated in the second scanning operation. If the determination is Yes, the processing circuitry 62 ends the second scanning operation. If the determination is No, the processing circuitry 62 executes the operation of step S1302.

[0211] Fig. 16C is a flowchart showing details of the processing operation of step S104 shown in Fig. 5 for measurement operation example 5. The processing circuitry 62 executes the operations of steps S1401 to S1406 shown in Fig. 16C.

[0212] <Step S1401> The processing circuit 62 obtains the first table shown in FIG. 15A from the memory 64, and selects one irradiation angle θ from the first irradiation angle group included in the first table. １ａ Select .

[0213] <Step S1402> The processing circuit 62 obtains the second table shown in FIG. 15B from the memory 64, and selects the irradiation angle θ from the second irradiation angle group included in the second table. １ａ If the determination is Yes, the processing circuit 62 searches for an irradiation angle θ １ａ The irradiation angle θ ２ｂ If the determination is No, the processing circuit 62 executes the operation of step S1406.

[0214] <Step S1403> The processing circuit 62 determines the irradiation angle θ from the first evaluation parameter group included in the first table shown in FIG. 15A. １ａ The focus deviation amount g corresponding to １ａ and selects the irradiation angle θ from the second evaluation parameter group included in the second table shown in FIG. 15B. ２ｂ The focus deviation amount g corresponding to ２ｂ The processing circuit 62 further selects the focus deviation amount g １ａ and the amount of focus deviation g ２ｂ Compare the size of.

[0215] <Step S1404> The processing circuit 62 calculates the amount of focus deviation g １ａ and the amount of focus deviation g ２ｂ distance information d １a and distance information d ２ｂ The distance information d corresponding to the smaller focus deviation amount is ３ｋ is adopted and included in the third distance information group.

[0216] <Step S1405> The processing circuit 62 stores the distance information and the corresponding irradiation angle (θ ３ｋ , d ３ｋ The memory 64 stores a third table shown in FIG. 6C.

[0217] <Step S1406> The processing circuit 62 determines whether all the illumination angles included in the first illumination angle group have been compared with all the illumination angles included in the second illumination angle group. If the determination is Yes, the processing circuit 62 ends the processing operation. If the determination is No, the processing circuit 62 executes the operation of step S1401 again.

[0218] As described above, the measurement devices 100A to 100C according to this embodiment measure distance information and focus deviation amounts for multiple irradiation points for each of multiple different focus positions. Furthermore, for the same irradiation point when irradiated at multiple different focus positions, the distance information with the smaller focus deviation amount is adopted. As a result, a third table including a third irradiation angle group and a third distance information group is generated. In contrast, the measurement device disclosed in Patent Document 1 adjusts the focus position of the irradiation light in the high-precision ranging system for each irradiation point based on the ranging results in the low-precision ranging system.

[0219] Therefore, in the measurement devices 100A to 100C of this embodiment, compared to the measurement device disclosed in Patent Document 1, the time required for focus adjustment can be minimized while accurately generating distance information of the irradiation point 12 on the object 10.

[0220] Furthermore, the measurement devices 100A to 100C according to this embodiment can generate distance information of the irradiation point 12 on the object 10 with a simpler configuration than the measurement device disclosed in Patent Document 1.

[0221] In addition, in measurement operation example 5, for different irradiation points that do not match when irradiated at different focus positions, distance information where the defocus amount is smaller than the threshold value may be used. In measurement operation example 4, the defocus amount may be used instead of the standard deviation of the distance.

[0222] [Additional Notes] The above description of the embodiments discloses the following techniques.

[0223] [Technology 1] A measurement device comprising: a light source that emits illumination light to illuminate an object; an adjuster that adjusts a focus position of the illumination light; a scanner that changes the illumination angle of the illumination light; a photodetector that detects reflected light from the object and outputs a signal; and a processing circuit, wherein the processing circuit: causes the adjuster to adjust the focus position to a first focus position; causes the scanner to set the illumination angle to a first illumination angle group so as to illuminate the object with the illumination light; generates a first distance information group based on the reflected light; causes the adjuster to set the focus position to a second focus position different from the first focus position; causes the scanner to set the illumination angle to a second illumination angle group so as to illuminate the object with the illumination light; generates a second distance information group based on the reflected light; and generates and outputs a third distance information group based on the first distance information group and the second distance information group.

[0224] This measurement device can generate distance information for multiple illuminated points on an object with high accuracy in a shorter time.

[0225] [Technology 2] The first irradiation angle group is an irradiation angle θ １ｉ (1≦i≦l), and the second irradiation angle group includes irradiation angles θ ２ｊ (1≦j≦m), and the irradiation angle θ ２ｊ (1≦j≦m) is one or more of the irradiation angles θ １ｉ The measurement device according to the first aspect of the present invention is identical to one or more of (1≦i≦l).

[0226] This measurement device can obtain multiple pieces of distance information with different accuracies for the same irradiation angle when irradiating at multiple different focus positions.

[0227] [Technology 3] The irradiation angle θ ２ｊ (1≦j≦m) are all the same as the irradiation angle θ １ｉ The measuring device according to the second aspect of the present invention is the same as (1≦i≦l).

[0228] This measurement device can increase the number of identical irradiation angles when irradiating at a plurality of different focus positions.

[0229] [Technology 4] The first distance information group is １ｉ Distance information d corresponding to １ｉ (1≦i≦l), and the second distance information group includes the irradiation angle θ ２ｊ Distance information d corresponding to ２ｊ (1≦j≦m), and the processing circuitry is configured to: １ｉ Evaluation parameter e １ｉ and the irradiation angle θ ２ｊ Evaluation parameter e ２ｊ Based on this, the distance information d １ｉ and the distance information d ２ｊ The distance information d ３ｋ The measurement device according to Art. 2 or 3, wherein (1≦k≦n) is included in the third distance information group.

[0230] In this measurement device, for the same irradiation angle included in the first and second irradiation angle groups, the distance information with higher accuracy can be used.

[0231] [Technology 5] The first irradiation angle group is an irradiation angle θ １ｉ (1≦i≦l), and the second irradiation angle group includes irradiation angles θ ２ｊ (1≦j≦m), and the irradiation angle θ ２ｊ At least one of (1≦j≦m) is the irradiation angle θ １ｉ The measuring device according to Art 1, wherein the measuring device is different from any of (1≦i≦l).

[0232] This measurement device can obtain distance information for different, inconsistent irradiation angles when irradiating at a plurality of different focus positions.

[0233] [Technology 6] The irradiation angle θ ２ｊ (1≦j≦m) are all the same as the irradiation angle θ １ｉ (1≦i≦l) different from the measurement device according to Art. 5.

[0234] This measurement device can increase the number of different non-coincident irradiation angles when irradiating at a plurality of different focus positions.

[0235] [Technology 7] The first distance information group is the irradiation angle θ １ｉ Distance information d corresponding to １ｉ (1≦i≦l), and the second distance information group includes the irradiation angle θ ２ｊ Distance information d corresponding to ２ｊ (1≦j≦m), and the processing circuit is configured to １ｉ Evaluation parameter e １ｉ and threshold e ｔｈ Based on the comparison with １ｉ and determining whether to adopt the irradiation angle θ ２ｊ Evaluation parameter e ２ｊ and threshold e ｔｈ Based on the comparison with ２ｊ Determine whether to adopt the distance information d ３ｋ 7. The measurement device according to claim 5, wherein (1≦k≦n) is included in the third distance information group.

[0236] This measurement device can use highly accurate distance information for different, non-coincident irradiation angles included in the first and second irradiation angle groups.

[0237] [Technology 8] The evaluation parameter e １ｉ is the irradiation angle θ １ｉ is the intensity of the signal corresponding to the evaluation parameter e ２ｊ is the irradiation angle θ ２ｊ The measuring device according to Technology 4 or 7, wherein the intensity of the signal corresponds to

[0238] This measuring device can use highly accurate distance information using signal strength as an evaluation parameter.

[0239] [Technology 9] The evaluation parameter e １ｉ is the irradiation angle θ １ｉ The evaluation parameter e is the variation of the distance information corresponding to ２ｊ is the irradiation angle θ ２ｊ The measurement device according to Technology 4 or Technology 7, wherein the variation in distance information corresponds to the above.

[0240] This measuring device can use highly accurate distance information by using the variation in distance information as an evaluation parameter.

[0241] [Technology 10] The evaluation parameter e １ｉ is the distance information d １ｉ and the first focus position, and the evaluation parameter e ２ｊ is the distance information d ２ｊ and the second focus position.

[0242] In this measurement device, the absolute value of the difference between the distance information and the focus position is used as an evaluation parameter, and highly accurate distance information can be adopted.

[0243] The measurement device according to the present disclosure can be used for applications such as measuring the shape of a structure.

[0244] 10 Object 12 Irradiation point 20 Light source 20L Reflected light 20L0 Light 20L1 Reference light 20L2 Interference light 20La Irradiation light 20Lb Reflected light 30 Focus adjuster 32 Optical element 34 Lens 36 Actuator 40 Scanner 42 Mirror 44 Driver 50 Photodetector 60 Processing device 62 Processing circuit 62a Control circuit 62b Drive circuit 62c Signal processing circuit 64 Memory 70A, 70B Interference optical system 72 First optical splitter 74 Second optical splitter 76 Optical circulator 80 Optical element 100A, 100B, 100C Measurement device

Claims

1. A measurement device comprising: a light source that emits illumination light to illuminate an object; an adjuster that adjusts the focus position of the illumination light; a scanner that changes the illumination angle of the illumination light; a photodetector that detects reflected light from the object and outputs a signal; and a processing circuit, wherein the processing circuit: causes the adjuster to adjust the focus position to a first focus position; causes the scanner to set the illumination angle to a first illumination angle group so as to illuminate the object with the illumination light; generates a first distance information group based on the reflected light; causes the adjuster to set the focus position to a second focus position different from the first focus position; causes the scanner to set the illumination angle to a second illumination angle group so as to illuminate the object with the illumination light; generates a second distance information group based on the reflected light; and generates and outputs a third distance information group based on the first distance information group and the second distance information group.

2. The first irradiation angle group is an irradiation angle θ １ｉ (1≦i≦l), and the second irradiation angle group includes irradiation angles θ ２ｊ (1≦j≦m), and the irradiation angle θ ２ｊ (1≦j≦m) is one or more of the irradiation angles θ １ｉ The measurement device of claim 1 , wherein i is equal to one or more of (1≦i≦l).

3. The irradiation angle θ ２ｊ (1≦j≦m) are all the same as the irradiation angle θ １ｉ The measurement device according to claim 2 , wherein i is equal to (1≦i≦l).

4. The first distance information group is the irradiation angle θ １ｉ Distance information d corresponding to １ｉ (1≦i≦l), and the second distance information group includes the irradiation angle θ ２ｊ Distance information d corresponding to ２ｊ (1≦j≦m), and the processing circuitry is configured to: １ｉ Evaluation parameter e １ｉ and the irradiation angle θ ２ｊ Evaluation parameter e ２ｊ Based on this, the distance information d １ｉ and the distance information d ２ｊ The distance information d ３ｋ The measurement device according to claim 2 or 3, wherein (1≦k≦n) is included in the third distance information group.

5. The first irradiation angle group is an irradiation angle θ １ｉ (1≦i≦l), and the second irradiation angle group includes irradiation angles θ ２ｊ (1≦j≦m), and the irradiation angle θ ２ｊ At least one of (1≦j≦m) is the irradiation angle θ １ｉ The measurement device according to claim 1 , wherein i is different from any of (1≦i≦l).

6. The irradiation angle θ ２ｊ (1≦j≦m) are all the same as the irradiation angle θ １ｉ The measurement device according to claim 5 , wherein i is different from (1≦i≦l).

7. The first distance information group is the irradiation angle θ １ｉ Distance information d corresponding to １ｉ (1≦i≦l), and the second distance information group includes the irradiation angle θ ２ｊ Distance information d corresponding to ２ｊ (1≦j≦m), and the processing circuit is configured to １ｉ Evaluation parameter e １ｉ and threshold e ｔｈ Based on the comparison with １ｉ and determining whether to adopt the irradiation angle θ ２ｊ Evaluation parameter e ２ｊ and threshold e ｔｈ Based on the comparison with ２ｊ Determine whether to adopt the distance information d ３ｋ The measurement device according to claim 5 or 6, wherein (1≦k≦n) is included in the third distance information group.

8. The evaluation parameter e １ｉ is the irradiation angle θ １ｉ is the intensity of the signal corresponding to the evaluation parameter e ２ｊ is the irradiation angle θ ２ｊ The measurement device according to claim 4 , wherein the signal intensity corresponds to:

9. The evaluation parameter e １ｉ is the irradiation angle θ １ｉ is the intensity of the signal corresponding to the evaluation parameter e ２ｊ is the irradiation angle θ ２ｊ The measurement device according to claim 7 , wherein the signal intensity corresponds to:

10. The evaluation parameter e １ｉ is the irradiation angle θ １ｉ The evaluation parameter e is the variation of the distance information corresponding to ２ｊ is the irradiation angle θ ２ｊ The measurement device according to claim 4 , wherein the variation in the distance information corresponds to:

11. The evaluation parameter e １ｉ is the irradiation angle θ １ｉ The evaluation parameter e is the variation of the distance information corresponding to ２ｊ is the irradiation angle θ ２ｊ The measurement device according to claim 7 , wherein the variation in the distance information corresponds to:

12. The evaluation parameter e １ｉ is the distance information d １ｉ and the first focus position, and the evaluation parameter e ２ｊ is the distance information d ２ｊ The measurement apparatus according to claim 4 , wherein the absolute value of the difference between the first focus position and the second focus position is 1 / 2.

13. The evaluation parameter e １ｉ is the distance information d １ｉ and the first focus position, and the evaluation parameter e ２ｊ is the distance information d ２ｊ The measurement apparatus according to claim 7 , wherein the absolute value of the difference between the first focus position and the second focus position is 1 / 2.

Images