KR102087081B1 - Light focusing system for detection distance enhancement of area sensor type lidar - Google Patents

Abstract

Disclosed is a light focusing technique for improving a measurement distance of an image sensor system lidar. In the distance measuring system for measuring the distance to the surrounding object, the distance measuring sensor unit comprising a LiDAR (Light Detection And Ranging) sensor, the distance measuring sensor unit, the light focusing structure for focusing the light emitted from the light source And a light focusing structure focusing the light reflected by the object and returning the light.

Description

LIGHT FOCUSING SYSTEM FOR DETECTION DISTANCE ENHANCEMENT OF AREA SENSOR TYPE LIDAR}

The following description relates to a technique for improving the measurement distance of LiDAR (Light Detection And Ranging), a three-dimensional distance measurement technology using light.

Recently, researches on a technology for measuring distance using LiDAR (Light Detection And Ranging), a 3D distance measurement technology, have been conducted.

As an example of a distance measurement technology, Korean Patent Publication No. 10-2013-0050410 (published May 16, 2013) discloses a technology for a vehicle black box equipped with a near-field radar sensor for measuring a distance from a vehicle in front of the vehicle. It is.

In general, a lidar is a technique for measuring physical properties such as distance, concentration, speed, and shape of a measurement object from the time and intensity of returning a scattered or reflected laser beam, a change in frequency, and a change in polarization state. That is, the radar can also measure the distance using a laser using the same principle as the radar obtains the distance by observing the round trip time to the object using the ultrashort wave.

Lidar sensors may be classified into a time of flight (ToF) method and a phase-shift method according to a laser signal modulation method. ToF method is the most commonly used because the light source is relatively inexpensive. The ToF method measures the distance by measuring the time at which the laser emits a pulse signal and the pulse signals reflected from objects within the measurement range arrive at the receiver. The phase shift method calculates time and distance by emitting a laser beam that is continuously modulated at a specific frequency and measuring the amount of phase change of the signal reflected back from an object within the measurement range.

The Lidar sensor may be classified into a scan method and an image sensor (area sensor) method according to an area measuring method. The scan method scans by rotating the light source and the detector to measure a large area, and produces a 3D result by measuring point-by-point, which has a high resolution and a wide measuring range, Due to the large size and expensive disadvantages. The lidar of the image sensor method means a solid-state lidar using a camera sensor. The image sensor method measures a predetermined area at a time similar to camera shooting. While the image sensor method can be manufactured in a small size and inexpensive, the measurement range is narrow and many devices are used in parallel.

In an image sensor type lidar, a light focusing system capable of improving a measurement distance under a limited light quantity of a light source through direction control and focusing of a light source is provided.

In the distance measuring system for measuring the distance to the surrounding object, the distance measuring sensor unit comprising a LiDAR (Light Detection And Ranging) sensor, the distance measuring sensor unit, the light focusing structure for focusing the light emitted from the light source And a light focusing structure focusing the light reflected by the object and returning the light.

According to one aspect, the distance measuring unit may include a structure in which a light control diffuser (diffuser) for controlling the direction of the light emitted from the light source is disposed at the output terminal of the light source.

According to another aspect, the distance measuring sensor unit may include a structure in which an optical separation focusing element for separating the light emitted from the light source and focusing the separated light is disposed at the output terminal of the light source.

According to another aspect, the optical separation focusing element may be configured of a MLA (Micro Lens Array) or a DOE (Diffractive Optical Element) for separating the light emitted from the light source.

According to another aspect, the distance measuring unit may include at least one of collimating optics and beam expanding optics as a device for processing light emitted from the light source.

According to another aspect, the distance measuring sensor unit may include a structure in which an optical focusing element for focusing the returned light is disposed at a front end of the sensor measuring the returned light.

According to another aspect, the distance sensor may be configured as an image sensor type lidar sensor for measuring a predetermined area at a time.

In the distance measuring system for measuring the distance to the surrounding object, the distance measuring sensor unit comprising a LiDAR (Light Detection And Ranging) sensor of the image sensor method for measuring a predetermined area at a time, wherein the distance measuring sensor unit, And a structure in which a light control diffuser is disposed at an output end of the light source to control a direction of light emitted from the light source.

In the distance measuring system for measuring the distance to the surrounding object, the distance measuring sensor unit comprising a LiDAR (Light Detection And Ranging) sensor of the image sensor method for measuring a predetermined area at a time, wherein the distance measuring sensor unit, Provided to the output terminal of the light source provides a distance measuring system comprising a structure in which a light separation focusing element for separating the light from the light source and focus the separated light is disposed.

In the distance measuring system for measuring the distance to the surrounding object, the distance measuring sensor unit comprising a LiDAR (Light Detection And Ranging) sensor of the image sensor method for measuring a predetermined area at a time, wherein the distance measuring sensor unit, It provides a distance measuring system comprising a structure in which a light converging element for converging the returned light is disposed in front of the sensor for measuring the light that is reflected by the object from the light source and returned.

According to embodiments of the present invention, in the lidar of the image sensor method, the light efficiency may be improved by controlling the direction of the light source and focusing the light to improve the measurement distance under the limited amount of light of the light source.

1 is a diagram illustrating an example of a distance measurement environment according to an embodiment of the present invention.
2 is a block diagram illustrating an example of an internal configuration of a distance measurement system according to an embodiment of the present invention.
3 to 4 illustrate an example of a light focusing structure for improving a measurement distance in an embodiment of the present invention.
5 illustrates another example of a light focusing structure for improving a measurement distance in an embodiment of the present invention.
6 to 7 illustrate an example of a light separation focusing structure in an embodiment of the present invention.
8 to 9 illustrate another example of the light separation focusing structure in one embodiment of the present invention.
10 to 11 illustrate another example of a light focusing structure for improving a measuring distance in an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Embodiments of the present invention relate to a technique for improving a measurement distance of a lidar, which is a three-dimensional distance measurement technique.

Embodiments including those specifically disclosed herein can improve the measurement distance under the limited amount of light of the light source in the image sensor type lidar, thereby having significant advantages in terms of efficiency, accuracy, miniaturization, cost reduction, etc. To achieve them.

1 is a diagram illustrating an example of a distance measurement environment according to an embodiment of the present invention.

The distance measuring environment of FIG. 1 is a distance measuring system for measuring a distance between a vehicle 10 and an object 20 mounted on the inside or outside of the vehicle 10 and positioned near the vehicle 10, for example, another vehicle. An example including (100) is shown. 1 is not limited to the environment as shown in FIG. 1 as an example for describing the invention.

The distance measurement system 100 may be a fixed terminal or a mobile terminal implemented with a computer device. Examples of the distance measurement system 100 include a black box device, a navigation terminal, a smart phone, and the like.

The distance measuring system 100 is a LiDAR (Light Detection And Ranging) device, which emits the laser 1 and returns the time, intensity, and frequency at which the laser 2 scattered or reflected by the surrounding object 20 returns. The distance to the object 20 can be measured from the change of the, the change of the polarization state, and the like.

2 is a block diagram illustrating an example of an internal configuration of a distance measurement system according to an embodiment of the present invention.

As shown in FIG. 2, the distance measuring system 100 is a component for measuring a distance from a surrounding object as a processor 110, a memory 120, a permanent storage device 130, a bus 140, and input / output. The interface 150, the network interface 160, and the distance measuring sensor unit 170 may be included. Here, the distance measuring unit 170 includes a light source unit 171 for irradiating the light source and a light receiving unit 172 for measuring the reflected light source.

The processor 110 may include or be part of any device capable of processing a sequence of instructions as a component for measuring distance to a surrounding object using lidar data. Processor 110 may include, for example, a processor within a computer processor, mobile device or other electronic device, and / or a digital processor. The processor 110 may be connected to the memory 120 through the bus 140.

Memory 120 may include volatile memory, permanent, virtual, or other memory for storing information used by or output by distance measurement system 100. The memory 120 may include, for example, random access memory (RAM) and / or dynamic RAM (DRAM). Memory 120 may be used to store any information, such as status information of distance measurement system 100. Memory 120 may also be used to store instructions of distance measurement system 100, including, for example, instructions for distance measurement. The distance measurement system 100 may include one or more processors 110 as needed or where appropriate.

Bus 140 may include a communication infrastructure that enables interaction between various components of distance measurement system 100. The bus 140 may carry data, for example, between components of the distance measurement system 100, for example, between the processor 110 and the memory 120. Bus 140 may include wireless and / or wired communication media between the components of distance measurement system 100 and may include parallel, serial, or other topology arrangements.

Persistent storage 130 may be a memory or other permanent storage device, such as used by distance measurement system 100 to store data for a predetermined extended period of time (eg, relative to memory 120). It may include components. Persistent storage 130 may include a nonvolatile main memory as used by processor 110 in distance measurement system 100. Persistent storage 130 may include, for example, flash memory, hard disk, optical disk, or other computer readable medium.

The input / output interface 150 may include interfaces for a keyboard, mouse, voice command input, display, or other input or output device. Configuration commands and / or input for distance measurement may be received via the input / output interface 150.

Network interface 160 may include one or more interfaces to networks, such as a local area network or the Internet. Network interface 160 may include interfaces for wired or wireless connections. Configuration commands and / or input for distance measurement may be received via network interface 160.

The distance sensor 170 may be implemented as a lidar sensor, and may generate a sensing signal for distance measurement between the vehicle 10 and the surrounding object 20, and the processor 110 may include a distance sensor unit ( The distance between the vehicle 10 and the surrounding object 20 may be measured by using a sensing signal (ie, LiDAR data) input from 170.

Also, in other embodiments, the distance measurement system 100 may include more components than the components of FIG. 2. However, there is no need to clearly show most prior art components. For example, the distance measuring system 100 may be implemented to include at least some of the input / output devices connected to the above-described input / output interface 150 or may include a transceiver, a global positioning system (GPS) module, a camera, and various sensors. It may further include other components such as a database, a database, and the like.

Embodiments of the present invention relate to a technique for measuring distance using LiDAR data, which may be applied to a vehicle driving assistance system such as free driving and unmanned driving, but is not limited thereto.

In the embodiment of the present invention, the distance measuring sensor unit 170 may be configured as a lidar sensor of an image sensor type. In this case, the lidar sensor of the image sensor method means a solid-state lidar using a camera sensor, and the image sensor method measures a predetermined area at once at a time similar to the flash light of the camera. It is.

In the case of the image sensor method, a light source is widely scattered through a diffuser to measure an area, and thus the light efficiency is lowered as the light source is distributed far more widely than a specific position to be measured.

As a method of improving the short measuring distance of the image sensor method, there is a method of simply increasing the output of the light source. The short measuring distance of the image sensor type can be improved by using a high power LiDAR light source, but the output of the light source increases the laser safety standard (class 1) and generates a lot of heat due to the high power. Thermal damage can occur on lidar lenses, scatterers, substrates, and the like.

In the exemplary embodiment of the present invention, the distance measuring sensor unit 170 may include a light focusing structure capable of improving a short measuring distance of an image sensor method while complying with a class 1 laser safety standard.

First Example

3 to 4 illustrate an example of a light focusing structure for improving a measurement distance in an embodiment of the present invention.

Referring to FIG. 3, the distance sensor unit 170 may include a light focusing structure that may improve light efficiency by concentrating the light source through direction control of the light source. In other words, the distance sensor 170 may concentrate and transmit light only on the surface to be measured by controlling the direction of the light source.

To this end, as shown in FIG. 4, the distance measuring sensor unit 170 includes a light control diffuser configured to control the light direction of the light source 401 (corresponding to the light source unit 171) as a lidar light focusing structure. ) 402. In this case, the light control diffuser 402 may be disposed at the output terminal of the light source 401 in the distance measuring sensor 170.

The light control diffuser 402 refers to a direction control element of the light source 401, for example, a light shaping diffuser (LSD), an engineered diffuser, a beam shaper, a DOE (diffractive optical). Element) and the like can be used.

The distance measuring sensor unit 170 according to the first embodiment concentrates the light emitted from the light source 401 on the desired surface through the light control diffuser 402 to increase the light efficiency, thereby short measuring the image sensor type lidar. Can improve the distance.

2nd Example

5 illustrates another example of a light focusing structure for improving a measurement distance in an embodiment of the present invention.

As shown in FIG. 5, the distance sensor 170 is a light focusing structure of a lidar that separates the light of the light source 501 (corresponding to the light source 171) and focuses the separated light. Element 503 may be included. The light separation focusing element 503 may be disposed at the output terminal of the light source 501 in the distance sensor 170.

When it is difficult to secure sufficient light efficiency only by the direction control of the light source 501, the light separation focusing element 503 which separates light into the distance measuring sensor unit 170 and focuses each of the separated light beams to transmit light only to a specific position is provided. Applicable

For optical separation, MLA (Micro Lens Array) or DOE (Diffractive Optical Element) can be used, and when such devices are used, hundreds of pixels can be generated.

If the light rays are not sufficiently separated, the resolution may be lowered. However, when the power of the light source 501 is limited, it is the only way to increase the power of each of the separated light beams even if the resolution is increased to improve the measurement distance.

A detailed light separation focusing structure of the distance measuring sensor 170 according to the second embodiment will be described in detail as follows.

6 to 7 illustrate an example of a light separation focusing structure in an embodiment of the present invention.

For example, referring to FIG. 6, a light separation focusing element 603 may be configured using a micro lens array (MLA) to separate light from the light source 501.

By disposing the light separation focusing element 603 using the MLA at the output end of the light source 501, the light of the light source 501 may be separated through the MLA, and then the respective beams may be focused to transmit light to a specific position. .

FIG. 7 is an enlarged view of the internal structure of the optical separation focusing element 603 using MLA.

Specifically, the optical splitting focusing element 603 is a collimating optics 71, beam expanding optics 72, MLA 73, and focusing optics 74. It may include.

Parallelizing optical system 71 and beam expanding optical system 72 is a device for processing the beam before entering the MLA (73), parallelizing optical system 71 serves to adjust the degree of collimation of the light source 501 And, the beam expanding optical system 72 serves to make the collimated light to the desired size.

In particular, in the light splitting focusing element 603, the MLA 73 separates light which passes through the parallelizing optical system 71 and the beam expanding optical system 72 in order to increase the power of the light beam within the limited amount of light of the light source 501. Play a role.

Finally, the light separation focusing element 603 may focus each of the light beams separated by the MLA 73 through the focusing optical system 74 to transmit light to a specific position.

8 to 9 illustrate another example of the light separation focusing structure in one embodiment of the present invention.

As another example, referring to FIG. 8, the optical separation focusing element 803 may be configured by using a diffractive optical element (DOE) for optical separation of the light source 501.

By arranging the light separation focusing element 803 using DOE at the output end of the light source 501, the light of the light source 501 may be separated through the DOE, and then the respective beams may be focused to transmit light to a specific position. .

9 is an enlarged view of an internal structure of the optical separation focusing element 803 using DOE.

Specifically, the optical splitting focusing element 803 may include collimating optics 91, beam expanding optics 92, and DOE 93.

The parallelizing optical system 91 and the beam expanding optical system 92 are elements for processing a beam before entering the DOE 93, and the parallelizing optical system 91 controls the degree of collimation of the light source 501. And, the beam expanding optical system 92 serves to make the collimated light to the desired size.

In particular, in the light splitting focusing element 803, the DOE 93 separates light which passes through the parallelizing optical system 91 and the beam expanding optical system 92 in order to increase the power of the light beam within the limited amount of light of the light source 501. It focuses.

The light separation focusing element 803 having the above-described configuration may separate light from the light source 501 through the DOE 93 and focus each of the separated light beams to transmit light to a specific position.

Therefore, the light separation focusing element 603 using MLA or the light separation focusing element 803 using DOE is disposed at the output end of the light source 501 to improve light efficiency through separation and focusing along the direction of the light source 501. Can be improved.

The third Example

FIG. 10 illustrates another example of a light focusing structure for improving a measuring distance in an embodiment of the present invention.

The distance sensor unit 170 according to the third embodiment may include a light focusing structure that focuses an optical signal reflected by an object and improves light efficiency.

As illustrated in FIG. 10, the distance sensor 170 may include an optical focusing element that focuses an optical signal at the front end of the measurement sensor 1004 (corresponding to the light receiver 172) for measuring the returned optical signal ( 1005) may be disposed. In this case, the light converging structure of the first embodiment and / or the second embodiment may be included in the light source side of the distance measuring sensor 170.

Referring to FIG. 11, instead of focusing light at the light source side of the distance sensor unit 170, an optical signal returned from a side of measuring an optical signal reflected by an object is introduced into the measurement sensor 1004. Prior to focusing first through the light focusing element 1005, the light detection efficiency of the measurement sensor 1004 may be improved.

The optical focusing element 1005 may use a micro lens array (MLA) or the like as an element for separating and focusing the returned optical signal. For example, the MLA may be disposed before Lidar's measurement sensor 1004 to focus the returned light and transmit the light to the measurement sensor 1004.

Accordingly, the optical signal returned to the distance sensor unit 170 is focused through the optical focusing element 1005 disposed at the front end of the measurement sensor 1004 to increase the optical signal and improve the short measurement distance of the image sensor system lidar. You can.

In constructing the distance sensor unit 170, it is also possible to combine two or more different types of light focusing structures described in the first, second and third embodiments. For example, the light focusing structures of the first and second embodiments may be applied together, or the light focusing structures of the first and / or second embodiments may be applied together with the light focusing structures of the third embodiment. .

As described above, according to the exemplary embodiments of the present invention, in the image sensor type lidar, the light efficiency may be improved by controlling the direction of the light source and focusing the light to improve the measurement distance under the limited amount of light of the light source.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the devices and components described in the embodiments may include a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a programmable PLU (programmable). It can be implemented using one or more general purpose or special purpose computers, such as logic units, microprocessors, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to the execution of the software. For the convenience of understanding, the processing apparatus may be described as one used, but those skilled in the art will appreciate that the processing apparatus includes a plurality of processing elements and / or a plurality of types of processing elements. It can be seen that it may include. For example, the processing device may include a plurality of processors or one processor and one controller. In addition, other processing configurations are possible, such as parallel processors.

The software may include a computer program, code, instructions, or a combination of one or more of the above, and may configure the processing device to operate as desired, or process independently or collectively. You can command the device. The software and / or data may be embodied in any type of machine, component, physical device, computer storage medium or device in order to be interpreted by or provided to the processing device or to provide instructions or data to the processing device. have. The software may be distributed over networked computer systems so that they may be stored or executed in a distributed manner. Software and data may be stored on one or more computer readable recording media.

The method according to the embodiment may be embodied in the form of program instructions that can be executed by various computer means and recorded on a computer readable medium. In this case, the medium may be to continuously store a computer executable program or to temporarily store the program for execution or download. In addition, the medium may be a variety of recording means or storage means in the form of a single or several hardware combined, not limited to a medium directly connected to any computer system, it may be distributed on the network. Examples of media include magnetic media such as hard disks, floppy disks and magnetic tape, optical recording media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, And ROM, RAM, flash memory, and the like, configured to store program instructions. In addition, examples of another medium may include a recording medium or a storage medium managed by an app store that distributes an application, a site that supplies or distributes various software, a server, or the like.

Although the embodiments have been described by the limited embodiments and the drawings as described above, various modifications and variations are possible to those skilled in the art from the above description. For example, the described techniques may be performed in a different order than the described method, and / or components of the described systems, structures, devices, circuits, etc. may be combined or combined in a different form than the described method, or other components. Or even by substitution or replacement by equivalents, an appropriate result can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims are within the scope of the claims that follow.

Claims (11)

In the distance measuring system for measuring the distance to the surrounding object,
Distance sensor unit consisting of a LiDAR (Light Detection And Ranging) sensor that measures a certain area at once
Including,
The distance measuring sensor unit,
A light concentrating structure for increasing the power of light rays within a limited amount of light of a light source, wherein a light separation focusing element for generating a plurality of light rays by separating the light from the light source at the output end of the light source is arranged Including structure that becomes,
The optical splitting focusing element may include a micro lens array (MLA) for separating light emitted from the light source into a plurality of beams and focusing optics for focusing each beam separated by the MLA,
The optical separation focusing element is a device for processing light emitted from the light source before entering the MLA and collimated through collimating optics and collimating optical system for adjusting the degree of collimation of the light source. Includes Beam Expanding Optics to make the light the size you want,
The MLA is to split the light through the parallelizing optical system and the beam expanding optical system in turn into a plurality of light rays
Distance measuring system, characterized in that. The method of claim 1,
The distance measuring sensor unit,
And a light control diffuser configured to control a direction of light emitted from the light source at an output end of the light source.
Distance measuring system, characterized in that. delete delete delete The method of claim 1,
The distance measuring sensor unit,
And a light converging element for concentrating the returned light at a front end of the sensor which measures the light returned from the light source and reflected by the object.
Distance measuring system, characterized in that. delete In the distance measuring system for measuring the distance to the surrounding object,
Distance sensor unit consisting of a LiDAR (Light Detection And Ranging) sensor that measures a certain area at once
Including,
The distance measuring sensor unit,
A light control diffuser is arranged at an output end of the light source to control the direction of light emitted from the light source, and a light focusing structure for increasing light power within a limited amount of light of the light source. And a light separation focusing element configured to separate light emitted from the light source to generate a plurality of light rays, and to focus each light ray,
The optical splitting focusing element may include a micro lens array (MLA) for separating light emitted from the light source into a plurality of beams and focusing optics for focusing each beam separated by the MLA,
The optical separation focusing element is a device for processing light emitted from the light source before entering the MLA and collimated through collimating optics and collimating optical system for adjusting the degree of collimation of the light source. Includes Beam Expanding Optics to make the light the size you want,
The MLA is to split the light through the parallelizing optical system and the beam expanding optical system in turn into a plurality of light rays
Distance measuring system, characterized in that. delete The method of claim 8,
The distance measuring sensor unit,
And a light converging element for concentrating the returned light at a front end of the sensor which measures the light returned from the light source and reflected by the object.
Distance measuring system, characterized in that. delete

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