Patent Application
20220075034
This application claims priority to Korean Patent Application No. 10-2020-0113217, filed on Sep. 4, 2020 in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.
Example embodiments consistent with the present disclosure relate to three-dimensional (3D) laser scanning, and more particularly, to a light detection and ranging (LiDAR) device and a driving method thereof.
LiDAR is one of the distance measuring techniques with respect to a subject in a three-dimensional (3D) space. Recently, interest in autonomous mobile devices, such as autonomous vehicles or robots has increased along with research on related fields. In some fields, various devices related to autonomous driving have been introduced.
LiDAR may operate like an eye, and thus, may be an essential element in an autonomous vehicle. Accordingly, various LiDAR devices have been introduced so far, but they have not reached a performance level to ensure sufficient autonomous driving.
One or more example embodiments provide driving methods of a LiDAR device to eliminate or minimize defects occurring in an image during a scanning process.
One or more example embodiments also provide LiDAR devices using the driving method thereof.
Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of example embodiments.
According to an aspect of an example embodiment, there is provided a driving method of a light detection and ranging (LiDAR) device, the driving method including performing a vertical scanning with respect to a subject region by using a first light reflector, performing a horizontal scanning of the subject region by using a second light reflector, and controlling a driving current applied to the first light reflector in real time during a horizontal scanning process when the vertical scanning is performed at a height different from a reference height, wherein the first light reflector has a first axis, wherein the second light reflector has a second axis, and wherein the first axis and the second axis are spaced apart from each other and perpendicular to each other.
The controlling the driving current may be performed within a certain range of the horizontal scanning.
The performing the vertical scanning and the performing the horizontal scanning may include performing the vertical scanning and performing the horizontal scanning, respectively, by using a first light source that radiates a first light to the first light reflector.
The performing the vertical scanning and the performing the horizontal scanning may include performing the vertical scanning and performing the horizontal scanning, respectively, by using a second light source that radiates a second light to the first light reflector, the second light source being different from the first light source.
The performing the vertical scanning and the performing the horizontal scanning may include performing the vertical scanning and performing the horizontal scanning, respectively, by using a third light source radiates a third light to the first light reflector, the third light source being different from the first light source and the second light source.
The first light source, the second light source, and the third light source may be provided on a same plane.
The first light source, the second light source, and the third light source may be vertically arranged.
According to another aspect of an example embodiment, there is provided a light detection and ranging (LiDAR) device including a light source unit including a plurality of light sources, a first light reflector configured to perform a vertical scanning, the first light reflector having a first axis, and a second light reflector configured to perform a horizontal scanning, the second light reflector having a second axis that is perpendicular to the first axis.
The plurality of light sources may be provided on a same plane.
The plurality of light sources may be vertically arranged.
The plurality of light sources may be horizontally arranged.
The first light reflector may be configured to rotate around the first axis, and the second light reflector may be configured to rotate around the second axis.
The plurality of light sources may be respectively configured to emit light to a same position on the first light reflector.
The plurality of light sources may include a first light source, a second light source, and a third light source.
The first light source may be configured to emit a first light to the first light reflector based on a rotation angle of the second light reflector being in a first range, the second light source may be configured to emit a second light to the first light reflector based on the rotation angle of the second light reflector being in a second range, the third light source may be configured to emit a third light to the first light reflector based on the rotation angle of the second light reflector being in a third range, wherein the first range, the second range, and the third range are different from each other.
The second light reflector may include a reflector, a rotating shaft, and a rotating device.
The first light reflector may be configured to receive light from the light source unit and reflect the light received to the second light reflector.
The second light reflector may be configured to receive the light reflected from the first light reflector and reflect the light received to a subject.
The first light reflector may be configured to rotate with respect to the first axis to change an incident angle of the light received by the second light reflector.
According to yet another aspect of an example embodiment, there is provided a light detection and ranging (LiDAR) device including a light source unit configured to emit light, the light source unit including a plurality of light sources, a first light reflector configured to receive the light emitted from the light source unit and reflect the light, the first light reflector being configured to rotate around a first axis, and a second light reflector configured to receive the light reflected by the first light reflector and reflect the light received to a subject, the second light reflector being configured to rotate around a second axis that is perpendicular to the first axis.
The above and/or other aspects, features, and advantages of example embodiments will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
Reference will now be made in detail to example embodiments of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, example embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the example embodiments are merely described below, by referring to the figures, to explain aspects. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. For example, the expression, “at least one of a, b, and c,” should be understood as including only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.
Hereinafter, a LiDAR device and a driving method of a LiDAR device according to an example embodiment will be described in detail with reference to the accompanying drawings. In the drawings, thicknesses of layers and regions may be exaggerated for clarity of layers and regions The example embodiments are capable of various modifications and may be embodied in many different forms. In a layer structure described below, when an element or layer is referred to as being “on” or “above” another element or layer, the element or layer may be directly on another element or layer or intervening elements or layers. The electronic device includes a semiconductor device. In the descriptions below, like reference numerals refer to like elements throughout.
Referring to
Next, in the first LiDAR device 100, a light radiation or light scan process with respect to a region where a subject exists will be described.
Light L2 reflected from the first light reflector 12 and incident on the reflector 14A of the second light reflector 14 may be reflected from the light reflective surface S1 of the reflector 14A, and may be reflected in a direction different from an incident direction according to the light reflection condition. A height, that is, a scanning height at which light such as, for example, first light LB0 and second light LB1 reflected by the light reflective surface S1 is radiated to a region where the subject exists which may be a subject region varies depending on an angle of incidence of the light L2 incident on the light reflective surface S1. For example, the Y-axis direction height (position) at which light is scanned in the subject region varies according to a first angle β1 between the light L2 incident on the light reflective surface S1 and the second axis 10A. For example, when the light L2 is incident on the light reflective surface S1 parallel to the second axis 10A, that is, when the first angle β1 is 0°, the light LB0 reflected from the light reflection surface S1 is radiated in parallel to the X-Z plane or a bottom surface of the reflector 14A. When the first angle β1 is 0°, the height (position) in the Y-axis direction at which the first light LB0 reflected from the light reflection surface S1 is scanned to the subject region may be a reference height. When the first angle β is 0°, the light L2 incident on the reflector 14A is parallel to the second axis 10A. In this a case, when the reflector 14A is rotated at a second angle ϕ, the first light LB0 is scanned horizontally in the subject region as much as the rotation range of the reflector 14A, and the height that is scanned may be the same in the entire rotation range. That is, the height (position) in the Y-axis direction scanned by the first light LB0 over the entire rotation range is the same as the reference height. The first graph G0 of
In
Referring to the second to fourth graphs G1, G2, and G3 of
The defect may be eliminated or minimized by correcting the height difference ΔY.
The scan height Ry in the Y-axis direction in the subject region may be determined by Equation 1 below.
Ry=cos(2α)cos β1+sin(2α)sin β1conϕ <Equation 1>
Next, an example for correcting the height difference ΔY based on Equation 1 will be described.
As an example, in order to resolve a height difference ΔY that occurs when the first angle β1 is not 0° and the second angle ϕ is about 40°, the first light reflector 12 is rotated by a third angle β2 from the second angle ϕ at which the height difference ΔY occurs. An incident angle or the first angle β1 of the light L2 incident on the reflector 14A of the second light reflector 14 varies according to the rotation of the first light reflector 12. Accordingly, at the time when the height difference ΔY occurs, the third angle β2 of the first light reflector 12 may be actively controlled until the height difference ΔY is reduced or removed. The first light reflector 12 may be an electrically operated reflective mirror. Accordingly, the third angle β2 of the first light reflector 12 may be controlled by controlling a driving current applied to the first light reflector 12. In an example, the control of the third angle β2 of the first light reflector 12 may be performed until the height difference ΔY is removed. In another example, the third angle β2 of the first light reflector 12 may be controlled until the height difference ΔY is a minimum value. At this point, the minimum value may be a value when the height difference ΔY is less than 10% of the reference height based on the reference height, and in another example, may be a value when the height difference ΔY is less than 5%. The minimum boundary or range may differ depending on LiDAR. When the height difference ΔY is 0, as well as when the height difference ΔY is minimum, the height of the horizontal scan may be regarded as the same. The driving of the first light reflector 12 may be performed with respect to a case that a first angle β1 is not 0° and a second angle ϕ is in a given range greater than 0°. The given range of the second angle ϕ may be ±90° or less, in one example, ±70° or less, in another example ±60° or less, and in another example ±50° or less.
Through the driving of the first light reflector 12, the second to fourth graphs G1, G2, and G3 of
In the driving method described above, when the second angle ϕ is outside of a given range, the height difference ΔY may appear again. For example, when the height difference ΔY occurs as the second angle ϕ is greater than ±50°, an additional LiDAR device may be used for a range where the second angle ϕ is greater than ±50°, and the driving method described above according to
Referring to
Referring to
The disclosed driving method of LiDAR device may correct a height difference in real time during a horizontal scanning process performed at a given vertical scan angle. Accordingly, defects such as, for example, distortion in an image obtained from a region to which a beam is radiated may be removed or minimized. Accordingly, the accuracy and reliability of an image of a subject region obtained by radiating a beam may be improved. Therefore, when the disclosed driving method is applied to a device such as, for example, an autonomous vehicle, an autonomous mobile device, a robot, etc., the accuracy and reliability of an operation of the corresponding device may be increased.
It should be understood that example embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each example embodiment should typically be considered as available for other similar features or aspects in other embodiments.
While example embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2020-0113217 | Sep 2020 | KR | national |
