JP2023116125A - Measuring apparatus - Google Patents

Abstract

To provide a measuring apparatus capable of improving resolution.SOLUTION: A measuring apparatus comprises a light emission section including a light-emitting element emitting light to an object, and a light receiving element receiving light of the light emission section reflected by the object. An instant angle of view in a first direction of the light-emitting element is smaller than an instant angle of view in the first direction of the light receiving element.SELECTED DRAWING: Figure 5

Description

The present invention relates to measuring devices.

Patent Literature 1 describes a distance measuring device that measures the distance to a reflecting object based on the flight time of light from when pulsed light is emitted until when reflected light is received.

JP 2021-152536 A

When using a measurement device such as LiDAR, it is preferable to improve the resolution of the acquired image as much as possible.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a measuring apparatus capable of improving resolution.

In order to achieve the above object, as one aspect of the present invention, a light-emitting portion having a light-emitting element that emits light toward an object, a light-receiving element that receives the light of the light-emitting portion reflected by the object, wherein the instantaneous angle of view of the light emitting element in the first direction is smaller than the instantaneous angle of view of the light receiving element in the first direction.

In addition, the problems disclosed by the present application and their solutions will be clarified by the description of the mode for carrying out the invention and the drawings.

ADVANTAGE OF THE INVENTION According to this invention, the measuring apparatus which can improve a resolution is provided.

It is a figure which shows the structure of the measuring device 1 in 1st Embodiment. 2 is an explanatory diagram of the functional configuration of the measuring device 1 in the first embodiment; FIG. 3 is a diagram of a light source 12 and a light receiving sensor 22; FIG. In order to facilitate understanding, the diagram is a perspective view from the rear surface (-Z side). FIG. 10 is a diagram showing the relationship between the irradiation areas of the light emitting element 123, the light receiving element 222, and the object 90; 4 is a diagram showing time histories of light emission positions and irradiation positions in a range R and a region S in the first embodiment; FIG. 4 is a timing chart for explaining an example of a measuring method; It is a figure which shows the structure of the measuring device 100 in 2nd Embodiment. It is a figure of the light source 112 and the light receiving sensor 22 in 2nd Embodiment. For easy understanding, the perspective view from the back side (-Z side) is used. FIG. 10 is a diagram showing the time history of irradiation positions in the second embodiment; (a) an example of one-dimensional array, (b) an example of one-dimensional array and one-dimensional scanning, and (c) an example of combined configuration of light-emitting elements and light-receiving elements in modifications.

EMBODIMENT OF THE INVENTION Hereinafter, it demonstrates, referring drawings for the form for implementing this invention. In the following description, the same or similar configurations may be denoted by common reference numerals, and redundant description may be omitted.

===First embodiment===
(overview)
FIG. 1 is an explanatory diagram of the overall configuration of the measuring device 1 according to the first embodiment. In FIG. 2, functional blocks related to each functional unit in the measuring device 1 are shown.

The measuring device 1 is a device that measures the distance to the object 90 . The measurement apparatus 1 emits measurement light, detects the reflected light reflected by the surface of the object 90, and measures the time from the emission of the measurement light to the reception of the reflected light. is measured by the TOF method (Time of flight). The measuring device 1 has an irradiation section 10 , a light receiving section 20 , a control section 30 and a storage section 50 .

The irradiation unit 10 irradiates the measurement light toward the object 90 . The irradiating unit 10 irradiates measurement light at a predetermined angle of view. The irradiation section 10 has a light source 12 and a projection optical system 14 . The light source 12 emits light. The light source 12 is composed of, for example, a surface emitting laser (VCSEL). The light projection optical system 14 is an optical system that irradiates the object 90 with light emitted from the light source 12 .

In the following description, the direction along the optical axis of the projection optical system 14 (indicated by the dashed-dotted line in FIG. 1) is defined as the Z direction. Note that the object 90 to be measured by the measuring device 1 is separated from the measuring device 1 in the Z direction. A direction perpendicular to the Z direction and in which the light projecting optical system 14 and the light receiving optical system 24 are arranged is defined as the Y direction. A direction perpendicular to the Z direction and the Y direction is defined as the X direction.

The light projection optical system 14 is an optical system for irradiating the object 90 with the light emitted from the light source 12 . A light source 12 is arranged in the focal plane of the projection optical system 14 . The light projecting optical system 14 irradiates the object 90 with light emitted from a light emitting element 123 (described later) of the light source 12 as collimated light. The light projecting optical system 14 is composed of a lens group composed of a plurality of (for example, 5 to 7) lenses (in FIG. 1, the lens group of the light projecting optical system 14 is simply shown). ing).

The light receiving unit 20 receives reflected light from the object 90 . The light receiving section 20 receives reflected light from the object 90 . The light receiving section 20 has a light receiving sensor 22 and a light receiving optical system 24 .

The light-receiving optical system 24 is an optical system for causing the light-receiving sensor 22 to receive the reflected light from the object 90 . A light receiving sensor 22 is arranged in the focal plane of the light receiving optical system 24 . The light-receiving optical system 24 collects the light reflected by the object 90 onto a light-receiving element 222 (described later) of the light-receiving sensor 22 . The light-receiving optical system 24, like the light-projecting optical system 14, is each composed of a lens group composed of a plurality of (for example, 5 to 7) lenses (in FIG. 1, the light-receiving optical system 24 lens group is simply shown).

Detailed configurations of the light source 12 and the light receiving sensor 22 will be described later.

The control unit 30 controls the measuring device 1 (FIG. 2). The control unit 30 controls irradiation of light from the irradiation unit 10 . Further, the control unit 30 measures the distance to the object 90 by the TOF method (time of flight) based on the output result of the light receiving unit 20 . The control unit 30 has an arithmetic device and a storage device (not shown). The arithmetic device is, for example, an arithmetic processing device such as a CPU or GPU. A part of the arithmetic device may be composed of an analog arithmetic circuit.

The storage unit 50 is configured by a main storage device and an auxiliary storage device, and is a device that stores programs and data. Various processes for measuring the distance to the object 90 are executed by the arithmetic device executing the program stored in the storage unit 50 .

The storage unit 50 can store data acquired by the control unit 30 . For example, data obtained by the light receiving unit 20 receiving the reflected light is stored in the storage unit 50 and used for subsequent analysis processing and the like.

The control section 30 has a setting section 32 , a timing control section 34 and a distance measurement section 36 . The setting unit 32 performs various settings. The timing control section 34 controls the processing timing of each section. For example, the timing control unit 34 controls the timing of emitting light from the light source 12 and the like. The distance measuring unit 36 measures the distance to the object 90 . The distance measurement section 36 has a signal processing section 362 , a time detection section 364 and a distance calculation section 366 . The signal processing section 362 processes the output signal of the light receiving sensor 22 . The time detection unit 364 detects the time of flight of light (time from irradiation of light to arrival of reflected light). The distance calculator 366 calculates the distance to the object 90 .

(light source and light receiving sensor)
The light source 12 has a light emitting surface parallel to the XY plane (surface parallel to the X direction and the Y direction), as shown in FIG. The light emitting surface is configured in a rectangular shape. The light emitted from the light source 12 is applied to the object 90 via the light projecting optical system 14 .

The light source 12 has a plurality of light emitting elements 123 arranged two-dimensionally. In the first embodiment, each light emitting element 123 corresponds to one pixel of the image generated by the controller 30. FIG.

The light receiving sensor 22 has a plurality of light receiving elements 222 arranged two-dimensionally, as shown in FIG. The light receiving element 222 outputs a signal corresponding to the amount of light received. Various types of elements can be considered as specific examples of the light receiving element 222, and one example is SPAD (Single Photon Avalanche Diode). A light-receiving element 222 composed of a SPAD outputs a pulse signal when it detects a photon. The light emitting element 123 irradiates the object 90 with light through the light projecting optical system 14 .

The correspondence between the light receiving elements 222 that receive the light emitted by a certain light emitting element 123 is determined in advance. More specifically, a plurality of light receiving elements 222 are associated with one light emitting element 123 so as to be able to receive reflected light. is conjugate.

In this embodiment, as shown in FIGS. 3 and 4, four light emitting elements 123 are associated with one light receiving element 222. FIG. In FIG. 3, the ranges of the four light emitting elements 123 and the light receiving elements 222 that are in a corresponding relationship are indicated by a thick line as a range R. As shown in FIG. A range R is formed in each row of a, b, c, . . . and each column of 1, 2, 3, .

In other words, the light receiving element 222 can receive the reflected light of the four light emitting elements 123 within the corresponding range R. For example, the light receiving element 222 in row a, column 1 can receive and detect light emitted from four light emitting elements 123 in range R in row a, column 1. At this time, the measurement light emitted from the light emitting element 123 is reflected by the area S on the object 90 and is received by the corresponding light receiving element 222 (FIG. 4).

The instantaneous angle of view of the light receiving element 222 is at least twice the instantaneous angle of view of the light emitting element 123 , and the light receiving element 222 can receive light emitted by the corresponding four light emitting elements 123 . For example, the instantaneous angle of view is set to 0.1 degrees for the light emitting element 123 and 0.2 degrees for the light receiving element 222 . Since the instantaneous angle of view of the light receiving element 222 is at least twice that of the light emitting element 123, the light receiving element 222 can receive light from the four light emitting elements 123 within the corresponding range R.

The number, arrangement, or instantaneous angle of view of the light-emitting elements 123 and the light-receiving elements 222 are not limited to those described above. For example, one light receiving element 222 may be associated with nine light emitting elements 123 so as to be able to receive light. Alternatively, the light source 12 and the light receiving sensor 22 may be arranged one-dimensionally (that is, linearly). In either configuration, the instantaneous angle of view of the light receiving element 222 is larger than the instantaneous angle of view of the light emitting element 123 .

(Processing during measurement)
Control of the light-emitting element 123 by the controller 30 (timing controller 34) during measurement is performed in each range R, as shown in FIG. The control unit 30 (timing control unit 34) may cause the light source 12 of the irradiation unit 10 to emit pulsed light at a predetermined cycle.

Specifically, the control unit 30 sequentially causes the four light emitting elements 123 within each range R to emit light in a predetermined order and at a constant cycle. In the examples of FIGS. 3 and 5, the +XY side, +X+Y side, −XY side, and −X+Y side of the light emitting elements 123 in each range R sequentially emit light at regular time intervals and are repeated. Along with this, within each region S, four different positions on the +XY side, the +X+Y side, the -XY side, and the -X+Y side are sequentially irradiated with the measurement light. The corresponding light receiving element 222 sequentially receives the pulsed reflected light corresponding to the four light emitting elements 123, as shown in FIG.

Data obtained by receiving the reflected light by the light receiving unit 20 is stored in the storage unit 50 and processed as follows.

FIG. 6 is a timing chart for explaining an example of the measuring method. The upper part of FIG. 6 shows the timing (emission timing) at which the light source 12 emits pulsed light. The center of FIG. 6 shows the timing (arrival timing) at which the pulsed reflected light arrives. The light receiving element 222 outputs a signal corresponding to the amount of light received. The lower part of FIG. 6 shows the output signal of the light receiving element 222 .

The distance measurement unit 36 (signal processing unit 362 ) of the control unit 30 detects the arrival timing of the reflected light based on the output signal of the light receiving element 222 . For example, the signal processor 362 detects the arrival timing of the reflected light based on the peak timing of the output signal of the light receiving element 222 . In addition, in order to remove the influence of disturbance light (for example, sunlight), the signal processing unit 362 may obtain the arrival timing of the reflected light based on the peak of the signal obtained by cutting the DC component of the output signal of the light receiving element 222. good.

Next, the distance measurement unit 36 (time detection unit 364) detects the time Tf from when the light is emitted to when the reflected light arrives, based on the light emission timing and the light arrival timing. The time Tf corresponds to the time it takes the light to make a round trip between the measurement device 1 and the object 90 . Then, the distance measuring section 36 (distance calculating section 366) calculates the distance to the object 90 based on the time Tf.

Through the above processing, the control unit 30 can generate an image having pixels corresponding to the light emitting elements 123, calculate the distance to the object 90 for each pixel, and generate a distance image.

=== Second Embodiment ===
A measuring device 100 according to the second embodiment will be described below with reference to FIGS. 7 to 9. FIG.

The irradiation unit 110 of the measurement device 100 includes a light source 112 having a configuration different from that of the light source 12 . Moreover, the measuring device 100 further includes a scanning unit 40 (FIG. 7). Other configurations of the measuring device 100 are the same as those of the measuring device 1 . Below, the same reference numbers are attached to the same configurations or parts as those of the measuring apparatus 1 of the first embodiment, and the description thereof is omitted.

The scanning unit 40 has a function of scanning the measurement light by changing the irradiation angle of the measurement light. Various scanning methods such as photonic crystals and liquid crystals can be employed. For example, the scanning unit 40 may have a mirror that rotates or moves, such as a galvanometer scanner or a MEMS mirror, and the laser beam may be reflected by the mirror and scanned with the laser beam. The mirrors may be one or more plane mirrors, or may be formed in a polyhedral shape. Alternatively, the scanning unit 40 may include a driving device such as a motor, and the measurement light may be scanned by moving the light projecting optical system 14 in the XY directions.

The light source 112 includes light emitting elements 123, and the number of light emitting elements 123 is the same as the number of light receiving elements 222 unlike the first embodiment. As shown in FIG. 8, the light emitting elements 123 are arranged one by one within the range R, and the light receiving element 222 can receive the light of one corresponding light emitting element 123 .

The light receiving sensor 22 has a plurality of light receiving elements 222 arranged two-dimensionally, as shown in FIG. This configuration is the same as the first embodiment. The light receiving elements 222 are arranged in the same number of rows and the same number of columns as the light emitting elements 123 .

Control by the control section 30 (timing control section 34) during measurement is performed as shown in FIG. The control unit 30 causes the light emitting element 123 to emit light in each range R at regular intervals. At the same time, the control unit 30 controls the scanning unit 40 to change the direction of the scanning light each time the light emitting element 123 emits light. Specifically, as shown in FIG. 10, four different positions (+XY side, +X+Y side, −XY side, −X+Y side) in the region S are sequentially irradiated with the measurement light, and this is repeated. .

By changing the emission direction of the measurement light in this manner, measurement can be performed by irradiating the measurement light onto four measurement points in one region S. FIG. Each measurement point corresponds to a pixel in the acquired image.

The control of the signal processing unit 362 and the method of generating the distance image are the same as in the first embodiment.

By performing such processing, the control unit 30 can generate a distance image having pixels four times the number of light emitting elements 123 and calculate the distance to the object 90 for each pixel.

=== Variation ===
Although the light-emitting elements 123 and the light-receiving elements 222 are arranged two-dimensionally in the X and Y directions in each of the above-described embodiments, they can be arranged one-dimensionally. Specifically, as shown in the light source 312 and the light receiving sensor 322 in FIG. 10A, the light emitting elements 123 or the light receiving elements 222 may be arranged only in the X direction or the Y direction. It is also possible to have a configuration with only one element (single element).

Further, in each of the above-described embodiments, the scanning unit 40 scans the measurement light in the X direction and the Y direction, but scanning may be performed in one direction (one dimension). For example, as shown in the light source 412 and the light receiving sensor 422 in FIG. 10B, the light emitting elements 123 are arranged one-dimensionally in the X direction, and the scanning unit 40 scans the measurement light in the X direction. It is possible to increase the number of pixels.

As other modifications, combinations of the arrangement of the light emitting elements 123 and the light receiving elements 222 and the scanning method of the scanning unit 40 are listed in FIG. These are only examples, and other arrangements and scanning methods are also conceivable.

＝＝＝Summary＝＝＝
In each of the above-described embodiments and modifications, the measurement apparatus 1 and 100 include the light source 12 (corresponding to the light emitting unit) having the light emitting element 123 that emits light toward the object 90, and the light source reflected by the object 90. and a light receiving element 222 for receiving light of 12, 112, and the instantaneous angle of view of the light emitting element 123 in the X direction or the Y direction (corresponding to the first direction) is larger than the instantaneous angle of view of the light receiving element 222 in the first direction. small.

With the above configuration, it is possible to generate an image having more pixels and measurement points than the number of light receiving elements 222, that is, having a high resolution. In other words, the number of light-receiving elements 222 is small compared to the number of pixels of the image, and the measurement apparatus 1, 100 can be configured with a simple configuration.

The light sources 12 and 112 have a plurality of light emitting elements 123 (corresponding to first light emitting elements) arranged in the first direction, and the light receiving element 222 can receive reflected light from the plurality of light emitting elements 123 arranged in the first direction. is. Also, the instantaneous angle of view of the light emitting element 123 in the first direction is smaller than the instantaneous angle of view of the light receiving element 222 in the first direction.

In the above configuration, since the light receiving element 222 receives light from the plurality of light emitting elements 123, it is possible to generate an image having more pixels and measurement points than the number of light receiving elements 222, that is, having high resolution.

The light source 12 has a plurality of light emitting elements 123 (corresponding to second light emitting elements) arranged in a second direction that intersects the first direction, and the light receiving element 222 receives reflected light from the plurality of light emitting elements 123 arranged in the second direction. can be received.

In the above configuration, the light receiving element 222 can receive light from the plurality of light emitting elements 123 arranged two-dimensionally, so the light-receiving element 222 can obtain pixels arranged two-dimensionally. It is possible to generate images with high resolution.

The light source 12 switches the light emitting element 123 to emit light each time it emits light.

With the above configuration, it is possible to generate an image having more pixels and measurement points than the number of light receiving elements 222, that is, having a high resolution.

The measurement apparatus 100 further includes a scanning unit 40 that scans the light emitted from the light emitting element 123 in at least one of a first direction and a second direction intersecting the first direction.

Since the scanning unit 40 is used to scan the measurement light in the above configuration, the number of the light emitting elements 123 can be further reduced.

The light sources 12 and 112 can scan light to different positions in the first direction, and the light receiving element 222 can receive reflected light of the light irradiated to different positions.

With the above configuration, it is possible to generate an image in which the light receiving result at each position is used as a pixel. Moreover, since the measurement light is scanned, the number of pixels is increased more than the number of the light emitting elements 123, and an image with high resolution can be generated.

The measuring devices 1 and 100 measure the result of light received by the light receiving element 222 when the light source 12 irradiates the light at the first position, and the light source 12 at the second position different in the first direction from the first position. and a light receiving result received by the light receiving element 222 when the light is irradiated.

In the above configuration, by storing the results of light reception at different positions, it is possible to analyze the results of light reception for each position and generate an image using the results of light reception at each position as pixels.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments and includes various modifications. In addition, the above-described embodiment describes the configuration in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations. Moreover, it is possible to add, delete, or replace a part of the configuration of the above embodiment with another configuration.

1, 100 measuring devices 10, 110 irradiation units 12, 112 light source 14 light projecting optical system 20 light receiving unit 22 light receiving sensor 222 light receiving element 24 light receiving optical system 90 object

Claims (7)

a light-emitting unit having a light-emitting element that emits light toward an object;
a light-receiving element that receives the light of the light-emitting unit reflected by the object;
The measuring device, wherein an instantaneous angle of view of the light emitting element in the first direction is smaller than an instantaneous angle of view of the light receiving element in the first direction. The light emitting unit has a plurality of first light emitting elements arranged in the first direction as the light emitting elements,
2. The measuring device according to claim 1, wherein said light receiving element is capable of receiving reflected light from said plurality of first light emitting elements arranged in said first direction. The light emitting unit has, as the light emitting elements, a plurality of second light emitting elements arranged in a second direction intersecting the first direction,
3. The measuring device according to claim 2, wherein said light receiving element is capable of receiving reflected light from said plurality of second light emitting elements arranged in said second direction. 4. The measuring device according to claim 2, wherein said light emitting unit switches said light emitting element to emit light each time it emits light. 4. The apparatus according to any one of claims 1 to 3, further comprising a scanning unit that scans the light emitted from the light emitting element in at least one of the first direction and a second direction crossing the first direction. measuring device. The light emitting unit can scan light to a first position and a second position that are different in the first direction,
The measuring device according to any one of claims 1 to 5, wherein the light receiving element is capable of receiving reflected light of light irradiated to the first position and the second position. The light-receiving result received by the light-receiving element when the light-emitting unit irradiates the light at the first position, and the light-emitting unit irradiates the light at the second position different from the first position in the first direction. 7. The measuring apparatus according to any one of claims 1 to 6, further comprising a storage unit for storing a light receiving result received by said light receiving element when said light receiving element receives light.

Images