U.S. patent application number 14/107739 was filed with the patent office on 2014-06-26 for light detecting and ranging sensing apparatus and methods.
This patent application is currently assigned to POUCH HOLDINGS LLC. The applicant listed for this patent is Pouch Holdings LLC. Invention is credited to James A. Haslim, Nicholas M. Iturraran, Michael D. Karasoff, Brent S. Schwarz.
Application Number | 20140176933 14/107739 |
Document ID | / |
Family ID | 50930503 |
Filed Date | 2014-06-26 |
United States Patent
Application |
20140176933 |
Kind Code |
A1 |
Haslim; James A. ; et
al. |
June 26, 2014 |
LIGHT DETECTING AND RANGING SENSING APPARATUS AND METHODS
Abstract
According to one aspect, an optical apparatus for a light
detecting and ranging (LiDAR) sensing system is provided. The
optical apparatus can comprise an optical directing device; and a
multi clad optical fiber, wherein said multi clad optical fiber
comprises a core, at least one inner cladding, and an outer
cladding. The core is arranged to receive optical rays transmitted
from a light source of said sensing system and route said
transmitted optical rays on an optical path leading to optical
directing device. The optical directing device is configured both
to direct said routed transmitted optical rays on an optical path
leading to a target to be sensed and direct optical rays reflected
from said target on an optical path leading to said inner cladding
of said multi clad optical fiber. The inner cladding is configured
to receive said reflected optical rays and route said reflected
optical rays on an optical path leading to a detector for receiving
reflected optical rays of said sensing system.
Inventors: |
Haslim; James A.; (Dublin,
CA) ; Karasoff; Michael D.; (San Francisco, CA)
; Iturraran; Nicholas M.; (Lodi, CA) ; Schwarz;
Brent S.; (Redwood City, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Pouch Holdings LLC |
San Francisco |
CA |
US |
|
|
Assignee: |
POUCH HOLDINGS LLC
SAN FRANCISCO
CA
|
Family ID: |
50930503 |
Appl. No.: |
14/107739 |
Filed: |
December 16, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61738646 |
Dec 18, 2012 |
|
|
|
Current U.S.
Class: |
356/4.01 |
Current CPC
Class: |
G01S 17/42 20130101;
G01S 7/4812 20130101; G01S 7/4818 20130101; G01S 17/06 20130101;
G01S 7/4817 20130101; G02B 6/262 20130101 |
Class at
Publication: |
356/4.01 |
International
Class: |
G01S 17/06 20060101
G01S017/06 |
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
11. An optical apparatus for use in a LiDAR sensing system, the
optical apparatus comprising: an optical circulator positioned to
receive and direct optical rays; an optical directing device; an
optical detector; and an optical fiber, wherein the optical fiber
is positioned to receive outgoing optical rays directed to the
optical fiber by the optical circulator and to direct the outgoing
optical rays toward the optical directing device, the optical
directing device is configured to focus the outgoing optical rays
toward a target, and further to focus reflected optical rays
reflected from the target toward the optical fiber, the optical
fiber is positioned to receive the reflected optical rays focused
from the optical directing device and to direct the reflected
optical rays toward the optical circulator, and the optical
circulator is positioned to direct the reflected optical rays
toward the detector.
12. The optical apparatus of claim 11, wherein the optical
circulator receives the outgoing optical rays from a light source
and blocks the reflected optical rays from returning to the light
source.
13. The optical apparatus of claim 11, wherein the optical fiber is
a multi-clad fiber comprising a core, an inner cladding, and an
outer cladding.
14. The optical apparatus of claim 11, wherein the optical
directing device consists of a single lens.
15. The optical apparatus of claim 11, wherein the optical
directing device consists of a single mirror.
16. The optical apparatus of claim 11, wherein the optical
directing device comprises at least one of a lens and a mirror, and
both the outgoing and reflected optical rays are directed by the
same at least one of a lens and a mirror.
17. The optical apparatus of claim 11, comprising a plurality of
detectors, the reflected optical rays being split among the
plurality of detectors.
18. The optical apparatus of claim 11, wherein the detector is an
avalanche photodiode.
19. A LiDAR sensor comprising the optical apparatus of claim 11,
and further comprising a laser configured to generate the outgoing
optical rays.
20. The LiDAR sensor of claim 19, comprising a plurality of the
optical apparatuses of claim 1 and lasers configured to generate
the outgoing optical rays.
21. An optical apparatus for use in a LiDAR sensing system, the
optical apparatus comprising: an optical directing device
comprising at least one of a lens and a mirror; an optical
detector; and an optical fiber, wherein the optical fiber is
positioned to receive outgoing optical rays directed to the optical
fiber from a light source and to direct the outgoing optical rays
toward the optical directing device, the optical directing device
is configured to focus the outgoing optical rays toward a target
through the at least one of a lens and a mirror, and further to
focus reflected optical rays reflected from the target toward the
optical fiber through the same at least one of a lens and a mirror,
and the optical fiber is positioned to receive the reflected
optical rays focused from the optical directing device and to
direct the reflected optical rays toward the detector.
22. The optical apparatus of claim 21, wherein the optical fiber is
a multi-clad fiber comprising a core, an inner cladding, and an
outer cladding.
23. The optical apparatus of claim 21, wherein the optical
directing device consists of a single lens.
24. The optical apparatus of claim 21, wherein the optical
directing device consists of a single mirror.
25. The optical apparatus of claim 21, wherein the optical
directing device consists of a plurality of optical elements
selected from the group consisting of lenses and mirrors.
26. The optical apparatus of claim 21, comprising a plurality of
detectors, the reflected optical rays being split among the
plurality of detectors.
27. The optical apparatus of claim 21, wherein the detector is an
avalanche photodiode.
28. A LiDAR sensor comprising the optical apparatus of claim 21,
and further comprising a laser configured to generate the outgoing
optical rays.
29. The LiDAR sensor of claim 28, comprising a plurality of the
optical apparatuses of claim 1 and lasers configured to generate
the outgoing optical rays.
30. A LiDAR sensor comprising a means for elimination of the
parallax error problem, said LiDAR sensor further comprising an
optical circulator.
31. A LiDAR sensor comprising a means for elimination of the
parallax error problem, wherein at least one of a lens and a mirror
is configured to both direct outgoing optical rays toward a target
and direct reflected optical rays toward a detector.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority benefit under 35 U.S.C.
.sctn.119(e) to U.S. Provisional Patent Application Ser. No.
61/738,646 (filed 18 Dec. 2012), the entirety of which is hereby
expressly incorporated by reference herein.
[0002] A portion of the disclosure of this patent document contains
material which is subject to copyright protection. The copyright
owner has no objection to the facsimile reproduction by any-one of
the patent document or the patent disclosure, as it appears in the
Patent and Trademark Office patent file or records, but otherwise
reserves all copyright rights whatsoever.
BACKGROUND
[0003] 1. Technical Field
[0004] Embodiments relate to optical apparatus and, more
particularly but not exclusively, to light detecting and range
sensor (LiDAR) optical apparatus. Embodiments also relate to
optical methods, and more particularly but not exclusively, to
light detecting and range sensor (LiDAR) optical methods.
Embodiments also relate to LiDAR sensors.
[0005] 2. Description of the Related Art
[0006] Light detecting and ranging (LiDAR) sensors are utilized in
a variety of applications to measure the distance to a target, to
determine the location of a target, the speed of a target, the
shape of a target, the reflectance of a target or other target
associated parameter.
[0007] There is a need to provide an improved optical apparatus and
method for light detecting and range sensing.
SUMMARY
[0008] According to one aspect, an optical apparatus for a light
detecting and ranging (LiDAR) sensing system is provided. The
optical apparatus can comprise an optical directing device; and a
multi clad optical fiber, wherein said multi clad optical fiber
comprises a core, at least one inner cladding, and an outer
cladding. The core is arranged to receive optical rays transmitted
from a light source of said sensing system and route said
transmitted optical rays on an optical path leading to optical
directing device. The optical directing device is configured both
to direct said routed transmitted optical rays on an optical path
leading to a target to be sensed and direct optical rays reflected
from said target on an optical path leading to said inner cladding
of said multi clad optical fiber. The inner cladding is configured
to receive said reflected optical rays and route said reflected
optical rays on an optical path leading to a detector for receiving
reflected optical rays of said sensing system.
[0009] By configuring the multi-clad optical fiber and optical
directing device to direct the transmitted optical rays on an
optical pathway leading to the target and direct the reflected
optical rays on an optical pathway leading to the detector in the
aforesaid manner, parallax error problems that occur in LiDAR
sensors using separate optical lenses for directing transmitted and
reflected optical rays respectively, are eliminated.
[0010] According to another aspect, a method for a light detecting
and ranging (LiDAR) sensing system is provided. The method can
comprise receiving, in a core of a multi clad optical fiber,
optical rays transmitted from a light source of said sensing
system; routing said transmitted optical rays through said core,
directing said transmitted optical rays routed through said core on
an optical path leading to a target to be sensed; receiving optical
rays reflected from said target and directing said reflected
optical rays to an inner cladding of said multi clad optical fiber;
and routing said reflected optical rays through said inner cladding
for receiving by a detector of said sensing system.
[0011] According to yet other aspects, one or more light detecting
and ranging (LiDAR) sensors are provided including the aforesaid
optical apparatus.
[0012] According to yet other aspects, one or more methods of light
detecting and ranging (LiDAR) sensors are provided including the
aforesaid optical methods.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic system diagram illustrating a light
detecting and ranging (LiDAR) sensing system according to an
embodiment;
[0014] FIG. 2 depicts a light detecting and ranging (LiDAR) sensing
system according to an embodiment;
[0015] FIG. 3 depicts a light detecting and ranging (LiDAR) sensing
system according to an embodiment;
[0016] FIG. 4 depicts a light detecting and ranging (LiDAR) sensing
system including an optical circulator according to an embodiment;
and
[0017] FIG. 5 depicts a light detecting and ranging (LiDAR) sensing
system including an optical circulator according to an
embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] In the following description, for purposes of explanation
and not limitation, specific details are set forth, such as
particular embodiments, procedures, techniques, etc. in order to
provide a thorough understanding of the present invention. However,
it will be apparent to one skilled in the art that the present
invention may be practiced in other embodiments that depart from
these specific details.
[0019] Technical features described in this application can be used
to construct various embodiments of methods and apparatus for light
detecting and range sensing. In one approach, a light detecting and
ranging (LiDAR) sensor uses an optical directing device; a multi
clad optical fiber, a light source, and a detector. Optical
coupling operably couples the light source to a core of the
multi-clad optical fiber. Optical coupling operably couples the
inner cladding to the detector. The core of the multi-clad fiber is
arranged to receive optical rays transmitted from the light source
and route the transmitted optical rays on an optical path leading
to the optical directing device. The optical directing device is
configured both to direct the transmitted optical rays routed
through the core towards a target to be sensed and direct optical
rays reflected from the target on an optical path leading to the
inner cladding of the optical fiber. The inner cladding is
configured to receive the reflected optical rays and route the
reflected optical rays on an optical path leading to the detector.
The detector is configured to detect the reflected optical
rays.
[0020] Applicant has identified that LiDAR sensors hitherto now
used an approach in which optical rays had been routed from a laser
out through a lens, and the returning light had been directed back
through a separate lens toward a detector. Such an approach
suffered from a parallax error that is created by the distance
between the positions of the transmitting and receiving lenses. The
parallax error manifested itself in a reduced amount of optical ray
reaching the detector and a subsequent weaker signal. The weaker
signal reduced the sensor's overall performance for measuring
distances and calculating reflectance values for objects near the
sensor. One or more embodiments described herein has several
advantages over existing LiDAR sensors. The first is the
elimination of a lens. This reduces the LiDAR's bill of material
and eliminates the parallax error. Eliminating the lens also
eliminates the time and labor of aligning the second lens. This
approach also has fewer connections, which subsequently improves
reliability, as cable connections are a common point of failure in
existing LiDAR sensors.
[0021] Reference will now be made to the drawings in which the
various elements of embodiments will be given numerical
designations and in which embodiments will be discussed so as to
enable one skilled in the art to make and use the invention.
[0022] Referring to FIG. 1 of the accompanying drawings, which
illustrates a light detecting and ranging sensor (LiDAR) system
according to one embodiment, in one non-limiting example,
double-clad optical fiber is used to transmit and receive optical
rays within the LiDAR sensor. The optical rays can be pulsed
optical rays. Using double-Clad Optical Fiber enables a single Lens
for the transmission and reception of optical rays for the Light
Detecting and Ranging Sensor. The multi-clad optical fiber
transmits and receives optical rays, eliminating the need for a
second lens and the parallax error. A laser fires an optical ray
that travels through the core of a multi-clad optical fiber and is
projected through an optical directing device. In the example of
FIG. 1, the optical directing device is a single lens. When the
optical ray returns, the optical ray is focused by the same lens
back into the inner cladding of the same multi-clad optical fiber
and continues its journey to a detector for processing into an
analog signal.
[0023] The LiDAR sensor of FIG. 1 transmits and receives optical
rays to measure the sensor's distance to a target and calculate a
reflectance value for that target. The process starts when the
laser fires an optical rays into the core of a multi-clad optical
fiber, and the optical rays is transmitted through a lens towards
targets down range. The optical rays strikes a target and is
reflected back towards the same lens. The lens focuses the
reflected optical rays into the inner cladding of the multi-clad
fiber and onto the detector. In other embodiments, the optical
directing device can be for example a parabolic reflector. In yet
other examples, any component(s) or mechanism that is capable of
focusing the optical rays down into the multi clad optical fiber
can serve as the optical directing device.
[0024] In another approach, optical circulator is integrated into
the design to capture the optical rays received by the core of the
multi-clad fiber. The optical circulator directs the optical rays
out through the core and direct the optical ray received by the
core to the optical directing device. Reflected optical rays that
returns through the optical directing device is focused into both
the inner cladding and core of the multi-clad fiber. Reflected
optical rays received into the core returns to the optical
circulator. The optical rays that enter the optical circulator exit
it towards the detector. The optical circulator blocks the
reflected optical rays from returning to the light source. The
optical circulator also blocks optical rays from passing directly
through it to the detector.
[0025] In yet another approach, the number of detectors in the
design is increased to increase the dynamic range of reflected
optical rays the sensor can process. The reflected optical rays is
either split evenly among multiple detectors so that highly
reflective targets do not saturate any one detector or the
reflected optical rays or split unevenly so that at least one
detector is not saturated by highly reflective targets.
[0026] In yet another approach, the sensor system of one or more
embodiments is integrated into a multiple laser/multiple detector
LiDAR sensor design for three dimensional scanning. Normally, a
multiple channel LiDAR sensor requires each laser emitter and
detector pair to be precisely aligned. Additionally if the sensor
design transmits through one lens and received through a second
lens, parallax errors will be present. Integrating this invention
into a multiple channel LiDAR sensor enables multiple laser emitter
and detector pairs to be intrinsically self-aligned and eliminates
the need to align separate physical elements and prevents parallax
errors. The sensor system of the one or more embodiments also
enables manufacture of a multiple laser LiDAR sensor with smaller
dimensions.
[0027] Reference will now be made to examples of embodiments
employing the aforementioned approaches. FIG. 2 depicts a light
detecting and ranging (LiDAR) sensing system according to an
embodiment. In the example of FIG. 2, the LiDAR sensing system is
an air-coupled LiDAR sensor. The light detecting and ranging
(LiDAR) sensor device has a light source, which in this example is
a laser 1. The sensor also has an optical fiber 2, detector 3,
which in this example is an avalanche photodiode (APD). In other
examples, other types of diodes or light to electrical transducers
can be used as the detector. Also included in the sensor is a multi
clad optical fiber 5, optical directing device in the form of lens
6, lens 9, minor with hole 9 and optical lenses 8 & 10.
Multi-clad optical fiber 5 has a core, inner cladding and outer
cladding. Optical elements 2, 4, 8, 9 and 10 form optical coupling
that couples the fiber core to laser 1 and optically couples the
fiber inner cladding to the detector 3.
[0028] In FIG. 2, the fiber core is arranged to receive optical
rays transmitted from the light source 1 and route the transmitted
optical rays towards optical lens 6. Optical lens 6 is configured
both to direct the transmitted optical rays routed through the core
towards a target surface 7 to be sensed and direct optical rays
reflected from the target towards the inner cladding of the optical
fiber 5. The inner cladding is configured to receive the reflected
optical rays and route the reflected optical rays towards the
detector 11. The detector is configured to detect the reflected
optical rays. In other embodiments, the optical directing device
can be for example a parabolic reflector. In yet other examples,
any component(s) or mechanism that is capable of focusing the
optical rays down into the multi clad optical fiber can serve as
the optical directing device.
[0029] The commercial advantage of using the LiDAR sensor of the
one or more embodiments are: [0030] 1. Elimination of the parallax
error problem that creates inaccuracies in distance measurements
and reflective calculations in targets near the sensor. The LiDAR
of one more embodiments will be more accurate at closer ranges then
known LiDAR sensors. [0031] 2. A simpler design that is easier and
less expensive to build. It has only one lens instead of two. It
eliminates the need to precisely align the laser emitter and
detector behind this lens. The embodiments are more reliable in the
field than competitors' LiDAR sensors. Small displacements of the
double clad fiber relative to the lens, caused by vibration or
temperature change, will not result in a loss of alignment between
the laser emitter and detector.
[0032] Referring now to FIG. 3, which depicts a light detecting and
ranging (LiDAR) sensing system according to another embodiment; the
LiDAR sensor system has a laser 1, optical fiber 2, multi-clad
optical fiber 3, an optical directing device in the form of optical
lens 4, optical fiber splice location 6, a plurality of optical
lenses 8, a plurality of optical fibers 7 and a plurality of
avalanche photodiode-detectors 9. Multi-clad optical fiber 3 has a
core, an inner cladding and outer cladding. In this example, the
core of the multi-clad fiber is optically coupled to the light
source 1 by optical fiber 2. The inner cladding of the multi-clad
fiber 3 is optically coupled to the plurality of photo detectors by
optical fibers 7.
[0033] In FIG. 3, the core of the multi-clad fiber 3 is arranged to
receive optical rays transmitted from light source 1 via coupling
fiber 2 and route the transmitted optical rays towards the optical
lens 4. The optical lens 4 is configured both to direct the
transmitted rays routed through the core towards a target 5 to be
sensed and direct reflected optical rays from the target towards
the inner cladding of the multi-clad fiber 3. The inner cladding is
configured to receive the reflected optical rays and route the
reflected optical rays towards the optical splicing location 6. At
the optical splicing location the fiber splits the reflected
optical rays routed through the inner cladding into a plurality of
reflected optical ray beams. The plurality of LiDAR detectors 9 are
optically coupled to the multi-clad inner cladding by fibers 7 to
respectively to detect the reflected plurality of beams. In other
embodiments, the optical directing device can be for example a
parabolic reflector. In yet other examples, any component(s) or
mechanism that is capable of focusing the optical rays down into
the multi clad optical fiber can serve as the optical directing
device. In other examples, other types of diodes or light to
electrical transducers can be used as each detector 9. Also, in
other examples, the detectors 9 may be different from one
another.
[0034] FIG. 4 depicts a light detecting and ranging (LiDAR) sensing
system according to another embodiment. In the example of FIG. 4,
the LiDAR sensing system comprises an air-coupled LiDAR sensor as
shown in FIG. 2 and an optical circulator integrated in the system.
The light detecting and ranging (LiDAR) sensor system shown in FIG.
4 has a light source, which in this example is a laser 1, optical
fibers 2, detectors 3, which in this example are avalanche
photodiode-detector, multi clad optical fiber 5, optical directing
device in the form of optical lens 6, minor with hole 9 and further
optical lenses 4, 8, 10 and 11. Multi-clad optical fiber has a
core, inner cladding and outer cladding. Optical fiber 2 and lens
11 optical couples detector 3 to the optical circulator port (3).
Optical fibers 2, lenses 4, 8, 10 and mirror with hole 9 form
optical couplings which couple the laser 1 to port (1) of the
optical circulator 12 and on to fiber core via circulator port (2)
and which optically couple the fiber inner cladding to another
detector 3, which in this example is avalanche
photodiode-detector.
[0035] In FIG, 4, optical circulator 12 is arranged to direct
optical rays transmitted from the light source 1 of the sensing
system through port (1) and on towards the fiber core via port (2)
and to block any of these transmitted optical rays from reaching
detector 3 coupled to port 3. The multi clad fiber core is arranged
to receive the optical rays from the optical circulator port 2 via
the optical coupling and route the transmitted optical rays towards
optical lens 6. Optical lens 6 is configured both to direct the
routed transmitted optical rays on to a target to be sensed and
direct reflected optical rays from target 7 towards the inner
cladding of the multi clad fiber. The inner cladding is configured
to receive the reflected optical rays and route the reflected
optical rays for receiving by the detector of the sensing system.
Optical circulator 12 is arranged to allow any reflected optical
rays, received and routed by the core of the optical fiber to port
(2) of optical circulator, to reach other detector 3 via circulator
port (3). In other embodiments, the optical directing device can be
for example a parabolic reflector. In yet other examples, any
component(s) or mechanism that is capable of focusing the optical
rays down into the multi clad optical fiber can serve as the
optical directing device. In other examples, other types of diodes
or light to electrical transducers can be used as each detector 3.
Also, in other examples, the detectors 9 may be different from one
another.
[0036] Referring to FIG. 5, which depicts a light detecting and
ranging (LiDAR) sensing system including an optical circulator
according to another embodiment; the sensing system comprises an
LiDAR sensor as shown in FIG. 3 and an optical circulator 10
integrated in the sensor system.
[0037] In FIG. 5, optical rays are transmitted from light source 1
through coupling fiber 2 into port(1) of optical circulator 10 and
out of optical circulator port (2) to the core of the multi clad
fiber 3 which is arranged to receive and route the transmitted
optical rays towards optical directing device in the form of
optical lens 4. Optical circulator 10 blocks the optical rays
transmitted from light source 1 from reaching the detector 9
optically coupling circulator port 3. Optical lens 4 is configured
both to direct the routed transmitted rays on to a target 5 to be
sensed and direct reflected optical rays from a target 5 towards
the inner cladding of the optical fiber. The inner cladding is
configured to receive the reflected optical rays and route the
reflected optical rays to splicing location 6. At the optical
splicing location, the fiber splits the reflected optical rays
routed through the inner cladding into a plurality of reflected
optical ray beams. A plurality of avalanche photodiode detectors 9,
in addition to the detector coupled to port 3, is respectively
optically coupled to the multi-clad inner cladding by coupling
fibers 7 to respectively detect the reflected plurality of beams.
Optical circulator 10 is arranged to allow any reflected optical
rays, received and routed by the core of the optical fiber towards
the optical circulator, to reach detector 9 coupled to port 3.
Optical lenses 8 are configured to focus the optical rays to the
detectors 9. In other embodiments, the optical directing device can
be for example a parabolic reflector. In yet other examples, any
component(s) or mechanism that is capable of focusing the optical
rays down into the multi clad optical fiber can serve as the
optical directing device. In other examples, other types of diodes
or light to electrical transducers can be used as each detector 9.
Also, in other examples, one or more of the detectors 9 can be a
different type of detector.
[0038] Specific reference to components, process steps, and other
elements are not intended to be limiting. It will be further noted
that the Figures are schematic and provided for guidance to the
skilled reader and are not necessarily drawn to scale. Rather, the
various drawing scales, aspect ratios, and numbers of components
shown in the Figures may be purposely distorted to make certain
features or relationships easier to understand.
[0039] While preferred embodiments of the present invention have
been described and illustrated in detail, it is to be understood
that many modifications can be made to the embodiments, and
features can be interchanged between embodiments, without departing
from the spirit of the invention.
* * * * *