JP7379455B2 - Measuring device, setting device, setting method, correction method, and program - Google Patents

Description

The present invention relates to a technique for performing measurement by irradiating electromagnetic waves.

BACKGROUND ART Technologies have been developed to detect obstacles by scanning objects with electromagnetic waves. Patent Document 1 discloses a technique in which an apparatus installed in a vehicle or the like detects obstacles by irradiating a laser beam and scanning within a target area. Furthermore, Patent Document 1 discloses a technique for changing the horizontal center axis of a scan area depending on the steering angle of a vehicle.

Japanese Patent Application Publication No. 2006-258604

Inside the measurement device, electromagnetic waves emitted from a light source pass through an optical system. At this time, stray light may occur due to some of the electromagnetic waves being reflected by the optical system. Such stray light becomes a factor that lowers the accuracy of measurement by the measuring device.

The present invention has been made in view of the above-mentioned problems, and one object thereof is to provide a technique for suppressing the generation of stray light in a measuring device.

The first invention is an invention of a measuring device. The measuring device includes (1) a measuring section that performs scanning by receiving reflected waves that are emitted from a light source through an optical system and reflected by a reflecting object; It has a control section that controls the timing of irradiating electromagnetic waves using a light source drive signal, and controls the irradiation direction that is the direction in which the electromagnetic waves are irradiated from the measurement section. When the control unit receives a reflected wave other than the reflected wave of the electromagnetic wave irradiated from the measurement unit, the light source is controlled so as not to irradiate the electromagnetic wave in the irradiation direction in which the electromagnetic wave was received. The light source driving signal is generated.

The second invention is an invention of a setting device for setting a measuring device.
The measuring device includes:
An electromagnetic wave irradiated from a light source passes through an optical system and is irradiated to the outside, and a measurement unit performs scanning by receiving the reflected wave reflected by a reflecting object. and a control unit that controls the direction in which the light is irradiated.
The setting device (1) operates the measurement device in which a predetermined signal is set as the drive signal to obtain a measurement result by the measurement device, and (2) obtains a measurement result of the electromagnetic wave irradiated from the measurement unit. By changing the irradiation timing indicated by the predetermined drive signal when a reflected wave other than the reflected wave is received, the number of irradiation times of electromagnetic waves that are received with an intensity equal to or higher than a predetermined value in one scan by the measurement unit less than a predetermined number of times.

The third invention is an invention of a method for setting a measuring device.
The measurement device uses a measurement unit that performs scanning by receiving reflected waves that are emitted from a light source through an optical system and reflected by a reflecting object, and a drive signal. and a control section that controls the direction in which the electromagnetic waves are irradiated from the measurement section.
The setting method includes the following steps: (1) operating the measuring device in which a predetermined signal is set as the drive signal to obtain a measurement result by the measuring device; By changing the irradiation timing indicated by the predetermined drive signal when a reflected wave other than the reflected electromagnetic wave is received, the electromagnetic wave received with an intensity equal to or higher than a predetermined value in one scan by the measurement unit can be changed. and a step of reducing the number of times of irradiation to less than a predetermined number of times.

A fourth invention is an invention of a program that causes a computer to execute each step of the setting method according to claim 5.

The fifth invention is an invention of a measuring device.
The measurement device includes (1) a measurement unit that performs scanning by receiving reflected waves from an electromagnetic wave emitted from a light source through an optical system and reflected by a reflecting object; and (2) a drive unit. It has a control section that uses a signal to control the direction in which the electromagnetic waves are irradiated from the measurement section, and (3) a correction section that corrects the drive signal.
The modification unit changes the irradiation timing indicated by the drive signal when receiving a reflected wave other than the reflected wave of the electromagnetic wave irradiated from the measurement unit, thereby achieving a predetermined timing in one scan by the measurement unit. The number of times of irradiation of electromagnetic waves that are received with an intensity higher than a value is set to be less than a predetermined number of times.

A sixth invention is an invention of a correction method executed by a measuring device.
A correction method performed by a measuring device, comprising:
The measurement device uses a measurement unit that performs scanning by receiving reflected waves that are emitted from a light source through an optical system and reflected by a reflecting object, and a drive signal. and a control section that controls the direction in which the electromagnetic waves are irradiated from the measurement section.
The correction method includes changing the irradiation timing indicated by the drive signal when a reflected wave other than the reflected wave of the electromagnetic wave irradiated from the measurement unit is received, thereby achieving a predetermined timing in one scan by the measurement unit. The method includes the step of reducing the number of times of irradiation of electromagnetic waves received with an intensity equal to or higher than a predetermined number of times to less than a predetermined number of times.

A seventh invention is an invention of a program that causes a computer to execute each step of the correction method according to claim 10.

The eighth invention is an invention of a measuring device.
The measurement device includes: (1) a measurement unit including: (1) a light source; and a reception unit that receives a reflected wave that is emitted from the light source through an optical system and reflected by a reflective object; , (2) a control unit that controls a direction in which the electromagnetic waves are irradiated from the measurement unit.
The control unit irradiates the electromagnetic wave that becomes the reflected wave when the receiving unit receives the reflected wave, which is the electromagnetic wave irradiated from the light source and is reflected at the optical system, with a predetermined intensity or more. Change the irradiation timing.

The ninth invention is an invention of a measuring device.
The measurement device includes: (1) a measurement unit including: (1) a light source; and a reception unit that receives a reflected wave that is emitted from the light source through an optical system and reflected by a reflective object; , (2) when the receiving unit receives the electromagnetic wave irradiated from the light source and the reflected wave reflected by the optical system with a predetermined intensity or more, the receiving unit irradiates the electromagnetic wave that becomes the reflected wave. It has a control unit that executes a process of changing the irradiation timing.
The control unit executes the process when determining that there is no object that reflects the electromagnetic waves in the vicinity of the measuring device and in the direction in which the electromagnetic waves are irradiated.

The above-mentioned objects, and other objects, features, and advantages will become more apparent from the preferred embodiments described below and the accompanying drawings.

1 is a block diagram illustrating a measuring device according to a first embodiment; FIG. It is a figure which illustrates the state of scanning by a measurement part. FIG. 3 is a diagram illustrating the intensity of stray light received by a receiver. FIG. 3 is a diagram illustrating a hardware configuration of a control unit. FIG. 3 is a diagram illustrating a hardware configuration of a measurement unit. FIG. 3 is a diagram illustrating a hardware configuration of a measurement unit that irradiates light. FIG. 2 is a first flowchart illustrating a procedure for generating a light source drive signal. FIG. FIG. 3 is a diagram illustrating a default signal. FIG. 3 is a diagram for explaining a method of identifying the irradiation timing of electromagnetic waves that are the source of stray light. FIG. 3 is a diagram comparing a light source drive signal set in a control unit and a default signal. 12 is a second flowchart illustrating the flow of a procedure for generating a light source drive signal. FIG. 2 is a diagram illustrating a computer for realizing a setting device. FIG. 2 is a diagram illustrating a measuring device installed in a moving body. FIG. 2 is a block diagram illustrating a measuring device according to a second embodiment. FIG. 2 is a first flowchart illustrating a procedure for generating a light source drive signal. FIG. 12 is a second flowchart illustrating the flow of a procedure for generating a light source drive signal. 16 is a block diagram illustrating a measuring device 200 that has a function of identifying a location suitable for executing the operation shown in the flowchart of FIG. 15 and executing the operation at the location. FIG.

Embodiments of the present invention will be described below with reference to the drawings. Note that in all the drawings, similar components are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate.

FIG. 1 is a block diagram illustrating a measuring device 200 according to the first embodiment. In FIG. 1, each block represents a functional unit configuration rather than a hardware unit configuration. The hardware configuration of the measuring device 200 will be described later using FIGS. 4 to 6.

The measurement device 200 includes a measurement section 202 and a control section 204. The measurement unit 202 scans an object by emitting electromagnetic waves and receiving reflected waves of the emitted electromagnetic waves. The control unit 204 controls scanning of the object by the measurement unit 202. Furthermore, the control unit 204 measures the time from when the electromagnetic wave is irradiated by the measuring unit 202 until the reflected wave of the electromagnetic wave is received.

Here, the measurement unit 202 scans the object while changing the irradiation direction of the electromagnetic waves in two dimensions: the height direction and the lateral direction. Note that the height direction means a substantially vertical direction. Moreover, the horizontal direction means a substantially horizontal direction.

FIG. 2 is a diagram illustrating the state of scanning by the measurement unit 202. In this example, raster scanning is being performed within the scanning range 224. In this raster scan, the main scanning direction is the horizontal direction, and the sub-scanning direction is the height direction.

Locus 1 represents the locus of scanning by the measurement unit 202. The direction of irradiation of electromagnetic waves by the irradiator 10 changes along the trajectory 1 with time. Each x mark represents a position through which the electromagnetic waves irradiated from the irradiator 10 pass. That is, the irradiator 10 irradiates electromagnetic waves at the timing when each cross mark is passed.

The measurement unit 202 includes an irradiator 10, an optical system 20, and a receiver 50. The irradiator 10 irradiates electromagnetic waves while changing the irradiation direction. The optical system 20 converges the electromagnetic waves emitted from the irradiator 10. Receiver 50 receives electromagnetic waves.

Here, the receiver 50 is provided to receive electromagnetic waves emitted from the measurement unit 202 that are reflected by an object (hereinafter referred to as reflected waves). However, the electromagnetic waves received by the receiver 50 may include waves other than the reflected waves of the electromagnetic waves emitted from the measurement unit 202. For example, the electromagnetic waves received by the receiver 50 may include electromagnetic waves emitted from the irradiator 10 that are reflected by the surface of the optical system 20 (so-called stray light).

The intensity of the stray light received by the receiver 50 varies depending on the direction in which the electromagnetic waves are irradiated from the irradiator 10. This is because the angle at which the electromagnetic waves enter the optical system 20, the position at which the electromagnetic waves enter the optical system 20, etc. differ depending on the direction in which the electromagnetic waves are irradiated from the irradiator 10.

FIG. 3 is a diagram illustrating the intensity of stray light received by the receiver 50. The irradiator 10 performs raster scanning in which the horizontal direction is the main scanning direction (see FIG. 2). Further, the irradiator 10 emits electromagnetic waves at predetermined intervals (see graph 60). Furthermore, it is assumed that no object exists around the measuring device 200.

A graph 60 represents the timing at which electromagnetic waves are irradiated from the irradiator 10 using pulse signals. Specifically, the irradiator 10 emits electromagnetic waves at the timing when the signal value changes from 0 to 1 in the graph 60. Graph 62 represents the strength of electromagnetic waves received by receiver 50.

Since there are no objects around the measuring device 200, electromagnetic waves reflected by objects are rarely received by the receiver 50. Therefore, in graph 62, the strength of the electromagnetic waves received by receiver 50 is approximately zero at most points in time.

However, at some point in time, the strength of the electromagnetic waves received by receiver 50 increases. This is because stray light is generated by electromagnetic waves irradiated at a specific timing (electromagnetic waves irradiated in a specific direction), and the stray light is received by the receiver 50.

For example, at time t1, stray light is being received by receiver 50. It can be said that this stray light is generated by the electromagnetic waves emitted from the irradiator 10 at time t2. This is because the distance between the irradiator 10 and the optical system 20 is short, so the time difference between the timing at which the irradiator 10 irradiates, which causes stray light, and the timing at which the stray light is received by the receiver 50 is considered to be short. It's for a reason.

If stray light is received by the receiver 50 in this way, the measurement results of the measuring device 200 will become inaccurate. For example, when the measuring device 200 receives an electromagnetic wave with an intensity equal to or higher than a predetermined value, it is assumed that the measuring device 200 determines that it has received a reflected wave reflected by an object. In this case, when the measuring device 200 receives stray light, it incorrectly determines that it has received a reflected wave reflected by an object.

Therefore, in the measuring device 200 of this embodiment, the timing at which electromagnetic waves are irradiated from the irradiator 10 is controlled so that the electromagnetic waves are irradiated from the irradiator 10 while avoiding the timing at which stray light occurs. Specifically, it is necessary to know in advance ``at what timing when irradiating electromagnetic waves will cause stray light to occur'' and to irradiate electromagnetic waves while avoiding that timing. In other words, "in which direction electromagnetic waves will be irradiated will cause stray light" is known in advance, and electromagnetic waves are prevented from being irradiated in that direction.

More specifically, the control unit 204 of the present embodiment determines the number of times the strength of the electromagnetic waves received by the measurement unit 202 exceeds a predetermined level during one scan (for example, one raster scan) by the measurement unit 202. ) is controlled to be less than a predetermined number of times.

By doing so, according to the measuring device 200 of this embodiment, it is possible to prevent stray light from being generated by the electromagnetic waves irradiated from the irradiator 10. Therefore, the accuracy of measurement by the measuring device 200 is improved.

The measuring device 200 of this embodiment will be described in more detail below.

<Example of hardware configuration of measuring device 200>

Each functional component of the measuring device 200 may be realized by hardware that implements each functional component (e.g., a hardwired electronic circuit), or by a combination of hardware and software (e.g., an electronic circuit). It may also be realized by a combination of a circuit and a program that controls it. A case in which each functional component of the measuring device 200 is realized by a combination of hardware and software will be further described below.

<<Example of hardware configuration of control unit 204>>

FIG. 4 is a diagram illustrating the hardware configuration of the control unit 204. The integrated circuit 100 is an integrated circuit that implements the control unit 204. For example, the integrated circuit 100 is an SoC (System On Chip).

Integrated circuit 100 has a bus 102, a processor 104, a memory 106, a storage device 108, an input/output interface 110, and a network interface 112. The bus 102 is a data transmission path through which the processor 104, memory 106, storage device 108, input/output interface 110, and network interface 112 exchange data with each other. However, the method for connecting the processors 104 and the like to each other is not limited to bus connection. The processor 104 is an arithmetic processing device implemented using a microprocessor or the like. The memory 106 is a main storage device implemented using RAM (Random Access Memory) or the like. The storage device 108 is an auxiliary storage device implemented using ROM (Read Only Memory), flash memory, or the like.

The input/output interface 110 is an interface for connecting the integrated circuit 100 with peripheral devices. In FIG. 4, an irradiator drive circuit 30 is connected to the input/output interface 110. The irradiator drive circuit 30 will be described later.

Network interface 112 is an interface for connecting integrated circuit 100 to a communication network. This communication network is, for example, a CAN (Controller Area Network) communication network. Note that the method for connecting the network interface 112 to the communication network may be a wireless connection or a wired connection.

The storage device 108 stores program modules for realizing the functions of the control unit 204. The processor 104 implements the functions of the control unit 204 by reading this program module into the memory 106 and executing it.

The hardware configuration of integrated circuit 100 is not limited to the configuration shown in FIG. 4. For example, program modules may be stored in memory 106. In this case, integrated circuit 100 may not include storage device 108.

<<Hardware configuration example of measurement unit 202>>

FIG. 5 is a diagram illustrating the hardware configuration of the measurement unit 202. The measurement unit 202 includes an irradiator 10, an optical system 20, an irradiator drive circuit 30, and a receiver 50. The irradiator 10 irradiates electromagnetic waves used for scanning an object. Here, the irradiator 10 has a variable irradiation direction, and can irradiate electromagnetic waves in various directions. The irradiator drive circuit 30 is a circuit that drives the irradiator 10. More specifically, the irradiator drive circuit 30 includes a circuit that drives a mechanism (eg, a light source) that irradiates electromagnetic waves, and a circuit that drives a mechanism (eg, a mirror) that changes the irradiation direction of the irradiator 10. The optical system 20 converges the electromagnetic waves emitted from the irradiator 10. The receiver 50 receives reflected waves of electromagnetic waves irradiated to the outside of the measuring device 200.

The control unit 204 detects that the receiver 50 has received the reflected wave. For example, the receiver 50 is configured to transmit a predetermined signal to the control unit 204 in response to receiving the reflected wave. The control unit 204 detects that the reflected wave has been received by the receiver 50 by receiving this predetermined signal.

The control unit 204 measures the elapsed time from when the electromagnetic wave is irradiated from the irradiator 10 until the reflected wave of the electromagnetic wave is received by the receiver 50, and determines the measured time in the irradiation direction of the electromagnetic wave (the irradiation timing of the electromagnetic wave). The information is stored in a storage device (for example, the storage device 108) in association with the above information. This elapsed time is expressed, for example, as a value obtained by multiplying the clock cycle by the number of clock signals counted from the time when the electromagnetic wave is irradiated from the irradiator 10 until the reflected wave of the electromagnetic wave is received. Further, for example, this elapsed time may be expressed by the number of clock signals counted. Based on this elapsed time, for example, the distance between the scanned object and the measuring device 200 can be calculated.

The electromagnetic waves irradiated by the irradiator 10 may be light such as laser light, or may be radio waves such as millimeter waves. Hereinafter, the hardware configuration of the measurement unit 202 when the irradiator 10 irradiates light will be illustrated. A similar configuration can be adopted for the measurement unit 202 when the irradiator 10 irradiates electromagnetic waves.

FIG. 6 is a diagram illustrating the hardware configuration of the measurement unit 202 that irradiates light. The light projector 12 and the light projector drive circuit 32 in FIG. 6 are examples of the irradiator 10 and the irradiator drive circuit 30 in FIG. 5, respectively. The projector 12 has a light source 14 and a movable reflection section 16 . The projector drive circuit 32 includes a light source drive circuit 34 and a movable reflector drive circuit 36.

The light source 14 is any light source that emits light. The light source drive circuit 34 is a circuit that drives the light source 14 by controlling the supply of power to the light source 14 . The light emitted by the light source 14 is, for example, a laser beam. In this case, for example, the light source 14 is a semiconductor laser that emits laser light.

The movable reflection section 16 reflects the light emitted from the light source 14. The light reflected by the movable reflection unit 16 passes through the lens 22 and is then irradiated to the outside of the measurement device 200. Lens 22 is an example of optical system 20 in FIG.

The movable reflection section drive circuit 36 is a circuit that drives the movable reflection section 16. For example, the movable reflection unit 16 includes one mirror configured to be rotatable in at least two directions, a height direction and a lateral direction. This mirror is, for example, a MEMS (Micro Electro Mechanical System) mirror.

The configuration of the movable reflection section 16 is not limited to the configuration shown in FIG. 6. For example, the movable reflection section 16 may be composed of two mirrors whose rotation axes intersect with each other.

The operations of the light source drive circuit 34 and the movable reflection unit drive circuit 36 are controlled by the control unit 204. Specifically, the control unit 204 transmits a drive signal instructing the light source drive circuit 34 to drive the light source 14 . This drive signal is read from the storage device 108, for example. The light source drive circuit 34 drives the light source 14 based on the received drive signal. For example, if the drive signal is a pulse signal consisting of two values, high and low, the light source drive circuit 34 drives the light source 14 at the timing when the pulse signal changes from low to high (the light source 14 emits light). ).

Similarly, the control unit 204 transmits a drive signal instructing the drive circuit 36 of the movable reflection unit to drive the movable reflection unit 16 . This drive signal is also read out from the storage device 108, for example. The movable reflection section drive circuit 36 controls the attitude of the movable reflection section 16 based on this drive signal. This control controls the direction of light irradiation. For example, the direction of light irradiation is controlled as shown by trajectory 1 in FIG.

Furthermore, the measurement unit 202 includes a light receiver 52. Light receiver 52 is an example of receiver 50 in FIG. For example, the light receiver 52 is configured using an APD (Avalanche Photodiode).

Note that the configuration of the measurement unit 202 is not limited to the configuration shown in FIGS. 5 and 6. For example, in FIG. 6, the measurement unit 202 is configured to be able to irradiate light in various directions by reflecting the light emitted from the light source 14 by the movable reflection unit 16. However, the configuration for irradiating light in various directions is not limited to the configuration shown in FIG. 6. For example, the light source 14 itself may have a mechanism for rotating in the height direction and the lateral direction. In this case, the measurement unit 202 can emit light in various directions by controlling the attitude of the light source 14. Furthermore, in this case, the measurement section 202 does not need to include the movable reflection section 16 and the drive circuit 36 for the movable reflection section. Furthermore, in this case, the light source drive circuit 34 includes a drive circuit that causes the light source 14 to emit light and a drive circuit that changes the attitude of the light source 14.

Note that the hardware that implements the control unit 204 (see FIG. 4) and the hardware that implements the measurement unit 202 (see FIGS. 5 and 6) may be packaged in the same housing, or may be packaged in separate housings. May be packaged in the body.

In the following description, unless otherwise specified, a case will be described in which the hardware configuration of the measurement unit 202 is shown in FIG. 6.

<About the method of determining the timing at which the measurement unit 202 irradiates electromagnetic waves>

As described above, in the measuring device 200 of this embodiment, the generation of stray light is suppressed by appropriately setting the timing at which electromagnetic waves are irradiated from the measuring section 202 in advance. This setting is performed, for example, before the measurement device 200 starts operating (for example, before the measurement device 200 is shipped).

The above settings are realized by appropriately generating a drive signal (hereinafter referred to as a light source drive signal) to be transmitted to the light source drive circuit 34. The generated light source drive signal is stored in the storage device 108, for example. The control unit 204 reads out the light source drive signal appropriately generated in advance in this way from the storage device 108 and transmits it to the light source drive circuit 34. By doing so, the irradiator 10 emits electromagnetic waves at appropriate timings where stray light does not occur.

Hereinafter, a method for generating this light source drive signal will be specifically explained. In the following description, it is assumed that the measurement unit 202 performs raster scanning. Further, it is assumed that the light source drive signal transmitted to the light source drive circuit 34 is the aforementioned pulse signal.

Furthermore, in the following description, the generation of the light source drive signal is performed by a computer. The computer that generates the light source drive signal is called a setting device 300. The setting device 300 is realized using any computer such as a PC (Personal Computer), a server device, or a mobile terminal. Note that the light source drive signal may be generated by manually performing a process similar to a series of processes executed by the setting device 300.

The light source drive signal is generated by operating the measurement device 200 in a test environment. The test environment is preferably an environment in which the reflected waves of the electromagnetic waves emitted from the measuring device 200 are not received by the receiver 50, or an environment in which the intensity of the received reflected waves is so small that it can be ignored.

<<Example 1 of procedure for generating light source drive signal>>

FIG. 7 is a first flowchart illustrating a procedure for generating a light source drive signal. The setting device 300 sets a default signal as the light source drive signal used by the control unit 204 to control the measurement unit 202 (S102). Specifically, the setting device 300 causes the storage device 108 included in the control unit 204 to store the default signal.

The default signal is an arbitrary drive signal that is predefined for initializing the control unit 204. For example, the default signal is defined such that electromagnetic wave irradiation is performed multiple times at equal time intervals in one main scan (scan of one horizontal line in trajectory 1). Let the length of this time interval be p clocks (p is a positive integer). FIG. 8 is a diagram illustrating a default signal. Note that the information defining the default signal (which may be the default signal itself) is stored in advance in a storage device included in the setting device 300.

The setting device 300 causes the measuring device 200 to perform measurement (S104). Here, electromagnetic waves are emitted from the measurement unit 202 according to the default signal.

The setting device 300 acquires the measurement result by the measuring device 200 and identifies the irradiation timing of the electromagnetic wave that caused the stray light (S106). Specifically, first, the setting device 300 identifies the point in time when the receiver 50 receives electromagnetic waves (stray light) with an intensity equal to or higher than a predetermined value. The setting device 300 then identifies the irradiation timing of the electromagnetic wave that is the source of the stray light received at that time.

FIG. 9 is a diagram for explaining a method for identifying the irradiation timing of electromagnetic waves that are the source of stray light. In FIG. 9, electromagnetic waves (stray light) having an intensity equal to or higher than a predetermined value are received at clock time c1. Therefore, the setting device 300 specifies the irradiation timing of the electromagnetic wave that is the source of this stray light.

Here, p clock, which is the time interval between the irradiation timings of two consecutive electromagnetic waves, is the time interval between the time when the electromagnetic waves are irradiated from the irradiator 10 and the time when the stray light generated by the electromagnetic waves is received by the receiver 50. sufficiently longer than Therefore, it can be estimated that the irradiation timing of the electromagnetic wave that is the source of the stray light is the latest irradiation timing, which is the clock time c2, among the irradiation timings before time c1 when the stray light is received.

Therefore, the setting device 300 specifies the c2 clock as the irradiation timing of the electromagnetic wave that is the source of stray light.

Note that if stray light occurs multiple times in one scan (irradiation of a series of electromagnetic waves represented by trajectory 1), there will be multiple times when the receiver 50 receives electromagnetic waves with an intensity equal to or higher than a predetermined value. exist. In this case, the setting device 300 specifies the irradiation timing of each of the plurality of electromagnetic waves that generated the stray light from each of these plurality of time points.

In S106, the setting device 300 determines whether one or more irradiation timings of the electromagnetic waves that caused the stray light have been identified (S108). If no irradiation timing of the electromagnetic wave that caused the stray light has been identified (S108: NO), the process in FIG. 7 ends. Therefore, the light source drive signal set in the control unit 204 remains the default signal. In this case, even if the control unit 204 controls the measurement unit 202 using the default signal, no stray light is generated. Therefore, the control unit 204 controls the measurement unit 202 using the default signal even during operation.

On the other hand, if one or more irradiation timings of the electromagnetic waves that caused the stray light are identified (S108: YES), the setting device 300 changes part of the default signal to set the light source drive signal in the control unit 204. is generated (S110). Specifically, the setting device 300 generates a light source drive signal to be set in the control unit 204 by changing only the irradiation timing of the electromagnetic wave in which stray light has occurred among the irradiation timings of the electromagnetic waves in the default signal. In other words, the light source drive signal set in the control unit 204 is such that (1) the irradiation timing of the electromagnetic wave that generated stray light in the default signal is shifted by a predetermined clock k from the irradiation timing in the default signal, and (2) the other The irradiation timing of the electromagnetic waves matches the irradiation timing in the default signal.

In the example of FIG. 7, if even one irradiation timing of the electromagnetic wave that caused the stray light is identified in S108, the default signal is changed. However, the setting device 300 is configured to change a part of the default signal when N or more (N is an integer of 2 or more) or more irradiation timings of electromagnetic waves that generate stray light are identified in S108. Good too. In this case, if the number of irradiation timings of electromagnetic waves that have generated stray light is less than N, it can be determined that the influence of stray light on measurement is small, and the default signal may not be changed.

Further, in S110, instead of changing the irradiation timing of the electromagnetic wave that generated the stray light, the electromagnetic wave may not be irradiated at the irradiation timing of the electromagnetic wave that generated the stray light. By doing so, the influence of stray light can be reduced with simpler processing. Although this method reduces the number of times of irradiation of electromagnetic waves compared to the case of using a default signal, it is considered that the effect on actual use is small unless the timing of irradiation of electromagnetic waves that generate stray light is frequent.

FIG. 10 is a diagram comparing the light source drive signal set in the control unit 204 and the default signal. The relationship between the received wave strength and the default signal in FIG. 10 is the same as that in FIG. 9. Therefore, when electromagnetic waves are emitted from the irradiator 10 according to the default signal, stray light is generated by the electromagnetic waves emitted at time c2 clock. Therefore, the setting device 300 changes the irradiation timing of the electromagnetic wave to be irradiated at the time c2 clock in the default signal to the time c2+k clock in the light source drive signal set in the control unit 204.

Here, since the time interval of the electromagnetic wave irradiation timing is p clocks, the predetermined clock k is determined to satisfy -p/2≦k≦p/2. If p/2 is not an integer, the lower limit of the range of k is the smallest integer greater than or equal to -p/2, and the upper limit of the range of k is the largest integer less than or equal to p/2.

Then, the setting device 300 sets the light source drive signal generated in S110 as the light source drive signal that the control unit 204 uses to control the measurement unit 202 (S112). Specifically, the setting device 300 stores the light source drive signal generated in S110 in the storage device 108 included in the control unit 204.

<<Example 2 of procedure for generating light source drive signal>>

In this example, the setting device 300 generates a light source drive signal to be set in the control unit 204 by entirely shifting the irradiation timing of electromagnetic waves in the default signal. For example, if the default signal is expressed as a function f(t), then the signal obtained by shifting the entire default signal by k clocks is expressed as f(t-k).

However, if a signal obtained by completely shifting the default signal in this way is used as a light source drive signal, there is a possibility that stray light will be newly generated by electromagnetic waves that did not generate stray light with the default signal. Therefore, the setting device 300 generates a light source drive signal using the following procedure, for example.

FIG. 11 is a second flowchart illustrating a procedure for generating a light source drive signal. In this process, the setting device 300 sets a light source drive signal in the control unit 204 such that the number of irradiation timings of electromagnetic waves that generate stray light is less than a predetermined value. It is assumed that this predetermined value is stored in advance in a storage device included in the setting device 300. Note that S102 and S106 in FIG. 11 are the same processes as S102 and S104 in FIG. 7, respectively. Therefore, the processing after S202 will be explained below.

The setting device 300 sets an initial value of 1 to a variable i representing the shift amount (S202). S204 to S222 are loop processing A that is repeatedly executed while the number of irradiation timings of electromagnetic waves that generate stray light is equal to or greater than a predetermined value. In S204, the setting device 300 determines whether the number of irradiation timings of electromagnetic waves that generate stray light is equal to or greater than a predetermined value. If the number of irradiation timings of electromagnetic waves that generate stray light is not equal to or greater than a predetermined value, the process in FIG. 11 ends. On the other hand, if the number of irradiation timings of electromagnetic waves that generate stray light is equal to or greater than the predetermined value, the process in FIG. 11 proceeds to S206.

In S206, the setting device 300 sets a signal obtained by completely shifting the default signal by +i clocks to the control unit 204 as a light source drive signal. The setting device 300 causes the measuring device 200 to perform measurement (S208). The setting device 300 acquires the measurement result by the measuring device 200, and specifies the irradiation timing of the electromagnetic wave that caused the stray light (S210).

The setting device 300 determines whether the number of irradiation timings of electromagnetic waves that generate stray light is equal to or greater than a predetermined value (S212). If the number of irradiation timings of electromagnetic waves that generate stray light is not equal to or greater than the predetermined value (S212: NO), the process in FIG. 11 ends. On the other hand, if the number of irradiation timings of electromagnetic waves that generate stray light is equal to or greater than the predetermined value (S212: YES), the process in FIG. 11 proceeds to S214.

In S214, the setting device 300 sets a signal obtained by shifting the entire default signal by -i clocks to the control unit 204 as a light source drive signal. The setting device 300 operates the measuring device 200 (S216). The setting device 300 acquires the measurement result by the measuring device 200 and identifies the irradiation timing of the electromagnetic wave that caused the stray light (S218). The setting device 300 adds 1 to the shift amount i (S220).

S222 is the end of loop processing A. Therefore, the process in FIG. 11 proceeds to S204.

<Example of hardware configuration of setting device 300>

Each functional component of the setting device 300 may be realized by hardware that implements each functional component (e.g., a hardwired electronic circuit), or by a combination of hardware and software (e.g., an electronic circuit). It may also be realized by a combination of a circuit and a program that controls it. A case in which each functional component of the setting device 300 is realized by a combination of hardware and software will be further described below.

FIG. 12 is a diagram illustrating a computer 400 for realizing the setting device 300. Computer 400 is any computer. For example, the computer 400 is a personal computer (PC), a server machine, a tablet terminal, a smartphone, or the like. The computer 400 may be a dedicated computer designed to implement the setting device 300, or may be a general-purpose computer.

Computer 400 has a bus 402, a processor 404, a memory 406, a storage device 408, an input/output interface 410, and a network interface 112. The bus 402 is a data transmission path through which the processor 404, memory 406, storage device 408, input/output interface 410, and network interface 412 exchange data with each other. However, the method of connecting the processors 404 and the like to each other is not limited to bus connection. The processor 404 is an arithmetic device such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The memory 406 is a main storage device implemented using RAM (Random Access Memory) or the like. The storage device 408 is an auxiliary storage device realized using a hard disk, an SSD (Solid State Drive), a memory card, a ROM (Read Only Memory), or the like. However, the storage device 408 may be configured with hardware similar to the hardware that configures the main storage device, such as RAM.

The input/output interface 410 is an interface for connecting the computer 400 and an input/output device. Network interface 412 is an interface for connecting computer 400 to a communication network. This communication network is, for example, a LAN (Local Area Network) or a WAN (Wide Area Network). The method for connecting the network interface 412 to the communication network may be a wireless connection or a wired connection.

For example, the computer 400 is connected to the measuring device 200 via an input/output interface 410 or a network interface 412.

The storage device 408 stores program modules that implement each function of the setting device 300. The processor 404 reads this program module into the memory 406 and executes it, thereby realizing the function corresponding to this program module.

<Example of installation of measuring device 200>

The measuring device 200 is installed, for example, in a moving object such as a car or a train. The measurement device 200 installed on a moving object is realized as, for example, a lidar (LIDAR: Light Detection and Ranging).

FIG. 13 is a diagram illustrating a measuring device 200 installed in a moving body. In FIG. 13, the measuring device 200 is fixed to the top of a moving body 240. Furthermore, the measuring device 200 is connected to a control device 244. The control device 244 is a control device that controls the moving body 240. For example, the control device 244 is an ECU (Electronic Control Unit).

Here, the control unit 204 may be realized as a part of a control device 244 that controls the moving body 240. In this case, a storage device included in the control device 244 stores a program module that implements the control unit 204 described above.

Note that the location where the measuring device 200 is installed is not limited to the upper part of the moving body 240. For example, the measuring device 200 may be installed inside the moving body 240 (for example, indoors). Furthermore, the measuring device 200 may be installed on an object that does not move.

[Embodiment 2]

FIG. 14 is a block diagram illustrating a measuring device 200 according to the second embodiment. The measuring device 200 of the second embodiment has the same functions as the measuring device 200 of the first embodiment except for the matters described below.

The measuring device 200 of the second embodiment suppresses the generation of stray light by dynamically changing the irradiation timing of electromagnetic waves while the measuring device 200 is in operation. For this purpose, the measuring device 200 of the second embodiment includes a correction section 206.

The modification unit 206 detects the occurrence of stray light in the measuring device 200, and changes the timing at which the irradiator 10 emits electromagnetic waves so as to suppress the influence of the stray light. Specifically, the modification unit 206 changes the irradiation timing of the irradiator 10 when the receiver 50 receives an electromagnetic wave of a predetermined strength or higher. In other words, the modification unit 206 specifies the irradiation timing of the electromagnetic wave that generates stray light, and based on the specified irradiation timing, the correction unit 206 uses the light source drive signal set in the control unit 204 (the light source drive signal stored in the storage device 108 signal).

Here, as explained in the flowchart of FIG. It is desirable to perform this in a situation where there are no objects (for example, terrestrial objects, pedestrians, other vehicles, etc.) that reflect electromagnetic waves around the measuring device 200). For example, it is desirable that the measurement device 200 performs the measurement in a situation where there is no object that reflects electromagnetic waves within the measurement range.

Therefore, as described below, a location suitable for performing the operations shown in the flowchart of FIG. 15 may be specified, and the operations shown in the flowchart of FIG. 15 may be performed at the location. FIG. 17 shows a block diagram illustrating the measuring device 200 in this case.

The current position acquisition unit 208 is configured with a GPS (Global Positioning System), for example, and acquires current position information regarding the current position of the mobile object 240 (or the measuring device 200). Note that the current position acquisition unit may be configured to acquire the current position information from an external device (not shown) through communication or the like.

The map information acquisition unit 210 acquires map information from an external map information distribution server or the like, for example, through communication. Note that the measuring device 200 may include a map information storage unit that stores the acquired map information. Further, the map information storage unit may store predetermined map information in advance.

Here, the map information stored in the map information storage unit includes feature information including various information regarding features. Further, the feature information may be managed and stored separately from the map information. The feature information includes at least information regarding the location of the feature.

The execution position specifying unit 212 performs “stray light generation”, which will be described later, based on the current position information acquired by the current position acquisition unit 208 and the feature information included in the map information acquired by the map information acquisition unit 210. 2. Identify a location or area suitable for executing the process of determining the irradiation timing of electromagnetic waves. Specifically, a position around the current position where there is no feature that reflects electromagnetic waves in the direction in which the electromagnetic waves are irradiated is identified as a position or area suitable for executing the process.

Here, the method by which the modification unit 206 modifies the light source drive signal set in the control unit 204 is similar to the method in which the setting device 300 of the first embodiment generates the light source drive signal set in the control unit 204. The method by which the modification unit 206 modifies the light source drive signal will be exemplified below.

<Example 1 of method for modifying light source drive signal>
FIG. 15 is a first flowchart illustrating a procedure for generating a light source drive signal. The operation shown in the flowchart of FIG. 15 is repeatedly executed, for example, at a predetermined frequency (for example, once per minute). Note that the method of modifying the light source drive signal in the flowchart of FIG. 15 is the same as the method of generating the light source drive signal set in the control unit 204 from the default signal in the flowchart of FIG.

Further, the operation shown in the flowchart of FIG. 15 is repeatedly executed at a predetermined frequency when the mobile object 240 (or measuring device 200) reaches the position or area specified by the execution position specifying unit 212 described above. You may also do so. For example, before starting this operation, the execution position specifying unit 212 specifies in advance a position or area suitable for executing "processing to specify the irradiation timing of the electromagnetic wave that generated stray light", and When the current position indicated by the current position information acquired by the acquisition unit 208 matches the specified position (or is included in the specified area), the operation shown in the flowchart of FIG. 15 is started. . Note that the measuring device 200 may be configured to stop the operation when the current position is outside the specified position or area.

The correction unit 206 acquires the measurement result by the measurement device 200 and identifies the irradiation timing of the electromagnetic wave that caused the stray light (S302). The specific process performed by the modification unit 206 in S302 is the same as the process performed by the setting device 300 in S106.

In S302, the modification unit 206 determines whether one or more irradiation timings of the electromagnetic waves that caused the stray light have been identified (S304). If no irradiation timing of the electromagnetic wave that caused the stray light has been identified (S304: NO), the process in FIG. 15 ends. In this case, no stray light occurs in the control using the current light source drive signal. Therefore, the light source drive signal is not modified.

On the other hand, if one or more irradiation timings of electromagnetic waves that caused stray light are identified (S304: YES), the modification unit 206 modifies a part of the light source drive signal currently set in the control unit 204 (S306 ). Specifically, among the electromagnetic wave irradiation timings in the pre-modified light source drive signal, the modification unit 206 changes only the electromagnetic wave irradiation timing at which stray light has occurred, and sets this as the modified light source drive signal. In other words, in the corrected light source drive signal, (1) the irradiation timing of the electromagnetic wave that caused stray light in the uncorrected light source drive signal is shifted by a predetermined clock k from the irradiation timing in the uncorrected light source drive signal; 2) The irradiation timing of other electromagnetic waves matches the irradiation timing in the light source drive signal before correction. In this way, the relationship between the light source drive signal before modification and the light source drive signal after modification in S306 is similar to the relationship between the default signal and the light source drive signal set in the control unit 204 in S110 of FIG.

<Example 2 of method for modifying light source drive signal>

FIG. 16 is a second flowchart illustrating a procedure for generating a light source drive signal. The operation shown in the flowchart of FIG. 16 is repeatedly executed, for example, at a predetermined frequency (for example, once per minute). Note that the method of modifying the light source drive signal in the flowchart of FIG. 16 is the same as the method of generating the light source drive signal set in the control unit 204 from the default signal in the flowchart of FIG.

The correction unit 206 acquires the measurement result by the measurement device 200 and identifies the irradiation timing of the electromagnetic wave that caused the stray light (S402). The modification unit 206 sets a variable i representing the shift amount to an initial value of 1 (S404). S406 to S418 are loop processing B that is repeatedly executed while the number of irradiation timings of electromagnetic waves that generate stray light is equal to or greater than a predetermined value. In S406, the modification unit 206 determines whether the number of irradiation timings of electromagnetic waves that generate stray light is equal to or greater than a predetermined value. If the number of irradiation timings of electromagnetic waves that generate stray light is not equal to or greater than a predetermined value, the process in FIG. 16 ends. On the other hand, if the number of irradiation timings of electromagnetic waves that generate stray light is equal to or greater than the predetermined value, the process in FIG. 16 proceeds to S408.

In S408, the modification unit 206 sets a signal obtained by shifting the entire light source drive signal before modification by +i clocks to the control unit 204 as the light source drive signal after modification. The modification unit 206 acquires the measurement results of the measurement device 200 operated using the light source drive signal, and identifies the irradiation timing of the electromagnetic wave that caused the stray light (S410).

The modification unit 206 determines whether the number of irradiation timings of electromagnetic waves that generate stray light is equal to or greater than a predetermined value (S412). If the number of irradiation timings of electromagnetic waves that generate stray light is not equal to or greater than the predetermined value (S412: NO), the process in FIG. 16 ends. On the other hand, if the number of irradiation timings of electromagnetic waves that generate stray light is equal to or greater than the predetermined value (S412: YES), the process in FIG. 11 proceeds to S414.

In S414, the modification unit 206 sets a signal obtained by completely shifting the unmodified light source drive signal by −i clocks to the control unit 204 as the modified light source drive signal. The modification unit 206 acquires the measurement results of the measurement device 200 operated using the light source drive signal, and identifies the irradiation timing of the electromagnetic wave that generated the stray light (S416). The modification unit 206 adds 1 to i (S418).

S420 is the end of loop processing B. Therefore, the process in FIG. 11 proceeds to S406.

According to the measuring device 200 of the present embodiment, during the operation of the measuring device 200 (for example, while the measuring device 200 is being used in a car running in automatic driving mode), an error occurs inside the measuring unit 202. Stray light can be suppressed.

Here, even if the measuring device 200 is appropriately set to prevent stray light from occurring before the measuring device 200 starts operating, stray light may occur inside the measuring device 200 while the measuring device 200 is in operation. There is a possibility that it will happen. For example, stray light may occur due to the positional relationship between the irradiator 10 and the optical system 20 being shifted due to vibrations or the like applied to the measuring device 200.

Therefore, the measuring device 200 of this embodiment detects the occurrence of stray light during operation of the measuring device 200, and corrects the light source drive signal. By doing so, generation of stray light inside the measuring device 200 can be suppressed more reliably. Further, by performing the correction in a situation where there are no features around the moving object (measuring device), it becomes possible to perform appropriate correction.

<Example of hardware configuration>

The hardware configuration of the measuring device 200 of the second embodiment is represented, for example, in FIGS. 4 to 6, similarly to the hardware configuration of the measuring device 200 of the first embodiment. Furthermore, in this embodiment, the program module stored in the storage device 108 described above further includes a program that implements the functions described in this embodiment.

Although the modification unit 206 and the control unit 204 are shown as separate functional components in FIG. 14, the modification unit 206 may be a functional component included within the control unit 204. In this case, the processing performed by the modification unit 206 described above can also be expressed as processing performed by the control unit 204.

Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and combinations of the embodiments described above or various configurations other than those described above may also be adopted.

This application claims priority based on Japanese Patent Application No. 2016-232162 filed on November 30, 2016, and the entire disclosure thereof is incorporated herein.

Claims (14)

A measurement unit that performs scanning by receiving reflected waves from an electromagnetic wave emitted from a light source through an optical system and reflected by a reflecting object;
a control unit that controls the timing of irradiating the electromagnetic wave to the light source using a light source drive signal, and controls the irradiation direction that is the direction in which the electromagnetic wave is irradiated from the measurement unit,
The control unit is configured to control, in the irradiation direction in which the reflected wave is received, when the received intensity of the reflected wave is equal to or higher than a predetermined value, or when the time difference between the irradiation timing of the electromagnetic wave and the reception timing of the reflected wave is shorter than a predetermined time. , a measurement device that generates the light source drive signal for controlling the light source so as not to irradiate the electromagnetic wave. A setting device for setting a measuring device,
The measuring device includes:
A measurement unit that performs scanning by receiving reflected waves from an electromagnetic wave emitted from a light source through an optical system and reflected by a reflecting object;
a control unit that uses a drive signal to control the direction in which the electromagnetic waves are irradiated from the measurement unit,
The setting device is
operating the measuring device in which a predetermined signal is set as the driving signal to obtain a measurement result by the measuring device;
By changing the irradiation timing indicated by the predetermined drive signal when a predetermined criterion is satisfied for at least one of the reception intensity of the reflected wave or the reception timing of the reflected wave, A setting device that reduces the number of times a reflected wave with a strength greater than a value is received to less than a predetermined number of times. Using the acquired measurement results, specifying the timing at which the measuring device irradiates electromagnetic waves corresponding to the reflected waves received by the measuring device with an intensity equal to or higher than a predetermined value;
The setting according to claim 2, wherein a signal obtained by changing only the specified timing of the electromagnetic wave irradiation timing indicated by the predetermined signal to a predetermined clock before or after a predetermined clock is set in the control unit as the drive signal. Device. Determining whether or not the number of times that a reflected wave with an intensity equal to or greater than a predetermined value is received in one scan by the measurement unit is equal to or greater than a predetermined number;
3. When it is determined that the number of times is equal to or greater than the predetermined number of times, a signal obtained by shifting the entire predetermined signal before or after a predetermined clock is set in the control unit as the drive signal. Setting device. A method for setting a measuring device, the method comprising:
The measuring device includes:
A measurement unit that performs scanning by receiving reflected waves from an electromagnetic wave emitted from a light source through an optical system and reflected by a reflecting object;
a control unit that uses a drive signal to control the direction in which the electromagnetic waves are irradiated from the measurement unit,
The setting method is
operating the measuring device in which a predetermined signal is set as the driving signal to obtain a measurement result by the measuring device;
By changing the irradiation timing indicated by the predetermined drive signal when a predetermined criterion is satisfied for at least one of the reception intensity of the reflected wave or the reception timing of the reflected wave, A setting method comprising the step of: reducing the number of times a reflected wave having a strength equal to or greater than a value is received to be less than a predetermined number of times. A program that causes a computer to execute each step of the setting method according to claim 5. A measurement unit that performs scanning by receiving reflected waves from an electromagnetic wave emitted from a light source through an optical system and reflected by a reflecting object;
a control unit that uses a drive signal to control a direction in which the electromagnetic waves are irradiated from the measurement unit;
a modification unit that modifies the drive signal;
The correction section is
By changing the irradiation timing indicated by the drive signal when a predetermined criterion is satisfied for at least one of the received intensity of the reflected wave or the received timing of the reflected wave, the irradiation timing indicated by the drive signal is changed to a predetermined value or more in one scan by the measurement unit. A measuring device that reduces the number of times a reflected wave of strength is received to less than a predetermined number of times. The modification unit changes only the irradiation timing of the electromagnetic wave corresponding to the reflected wave received by the measurement unit with an intensity equal to or higher than a predetermined value from among the irradiation timings indicated by the drive signal, before or after a predetermined clock. The measuring device according to item 7. The measuring device according to claim 7, wherein the modification unit changes all the irradiation timings of the electromagnetic waves indicated by the drive signal before or after a predetermined clock. A correction method performed by a measuring device, comprising:
The measuring device includes:
A measurement unit that performs scanning by receiving reflected waves from an electromagnetic wave emitted from a light source through an optical system and reflected by a reflecting object;
a control unit that uses a drive signal to control the direction in which the electromagnetic waves are irradiated from the measurement unit,
The modification method is to change the irradiation timing indicated by the drive signal when a predetermined criterion is satisfied for at least one of the received intensity of the reflected wave or the received timing of the reflected wave, thereby improving the one-time measurement by the measuring unit. A correction method comprising the step of reducing the number of times a reflected wave having an intensity equal to or higher than a predetermined value is received during scanning to less than a predetermined number of times. A program that causes a computer to execute the steps of the correction method according to claim 10. a measuring unit having a light source, and a receiving unit that receives a reflected wave that is emitted from the light source through an optical system and reflected by a reflecting object;
a control unit that controls a direction in which the electromagnetic waves are irradiated from the measurement unit,
The control unit irradiates the electromagnetic wave that becomes the reflected wave when the receiving unit receives the reflected wave, which is the electromagnetic wave irradiated from the light source and is reflected at the optical system, with a predetermined intensity or more. A measurement device that changes the irradiation timing. Using the acquired measurement results, specifying the timing at which the measuring device irradiates electromagnetic waves corresponding to the reflected waves received by the measuring device with an intensity equal to or higher than a predetermined value;
The setting device according to claim 2, wherein the control unit controls the measurement unit so that the light source does not irradiate the electromagnetic wave at the specified timing among the electromagnetic wave irradiation timings indicated by the predetermined signal. . a measuring unit having a light source, and a receiving unit that receives a reflected wave that is emitted from the light source through an optical system and reflected by a reflecting object;
When the receiving unit receives the electromagnetic wave irradiated from the light source and the reflected wave reflected by the optical system with a predetermined intensity or more, change the irradiation timing at which the electromagnetic wave that becomes the reflected wave is irradiated. a control unit that executes processing;
has
The control unit executes the processing when determining that there is no object that reflects the electromagnetic waves in the vicinity of the measurement device and in the direction in which the electromagnetic waves are irradiated. .

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