U.S. patent application number 11/589737 was filed with the patent office on 2008-05-01 for vision system for automatically aligning a passenger boarding bridge with a doorway of an aircraft and method therefor.
This patent application is currently assigned to DEW Engineering and Development Limited. Invention is credited to Neil Hutton.
Application Number | 20080098538 11/589737 |
Document ID | / |
Family ID | 39328402 |
Filed Date | 2008-05-01 |
United States Patent
Application |
20080098538 |
Kind Code |
A1 |
Hutton; Neil |
May 1, 2008 |
Vision system for automatically aligning a passenger boarding
bridge with a doorway of an aircraft and method therefor
Abstract
A vision system for use with an automated control system of a
passenger boarding bridge includes an inclinometer for determining
tilt data relating to deviation of the aircraft-engaging end of the
passenger boarding bridge relative a horizontal reference plane.
The system also includes an imager disposed near the
aircraft-engaging end of the passenger boarding bridge, for
capturing image data relating to a portion of the aircraft
proximate an expected stopping location of the doorway. A memory
element having template image data stored retrievably therein is
also provided. The template image data relates to at least a
template image including a feature that is indicative of the
location of the doorway of the aircraft. The vision system further
includes an image data processor for determining alignment data for
use in aligning the aircraft-engaging end of the passenger boarding
bridge with the doorway of the aircraft. The alignment data being
determined based upon the tilt data, the image data, and the
template image data.
Inventors: |
Hutton; Neil; (Ottawa,
CA) |
Correspondence
Address: |
FREEDMAN & ASSOCIATES
117 CENTREPOINTE DRIVE, SUITE 350
NEPEAN, ONTARIO
K2G 5X3
omitted
|
Assignee: |
DEW Engineering and Development
Limited
Ottawa
CA
|
Family ID: |
39328402 |
Appl. No.: |
11/589737 |
Filed: |
October 31, 2006 |
Current U.S.
Class: |
14/71.5 |
Current CPC
Class: |
B64F 1/3055
20130101 |
Class at
Publication: |
14/71.5 |
International
Class: |
E01D 1/00 20060101
E01D001/00 |
Claims
1. A vision system for use with an automated control system of a
passenger boarding bridge, the automated control system for
aligning an aircraft-engaging end of the passenger boarding bridge
with a doorway of an aircraft that is stopped within a defined
parking space adjacent to the passenger boarding bridge, the vision
system comprising: an imager disposed proximate the
aircraft-engaging end of the passenger boarding bridge for
capturing image data relating to a portion of the aircraft that is
proximate an expected stopping location of the doorway; an
inclinometer for determining tilt data relating to a sensed
deviation of the aircraft-engaging end of the passenger boarding
bridge relative a horizontal reference plane; a distance sensor
disposed proximate the aircraft-engaging end of the passenger
boarding bridge for sensing a distance to the portion of the
aircraft that is proximate the expected stopping location of the
doorway; a memory element having template image data stored
retrievably therein, the template image data comprising at least a
template image including a feature that is indicative of the
location of the doorway of the aircraft; and, an image data
processor for transforming the template image data based on the
tilt data and the sensed distance, for determining a correlation
between the feature that is indicative of the location of the
doorway of the aircraft in the transformed template image data and
a corresponding feature in the captured image data, and for
determining alignment data for use in aligning the
aircraft-engaging end of the passenger boarding bridge with the
doorway of the aircraft based on the determined correlation.
2. A vision system according to claim 1, wherein the imager
comprises a digital camera.
3. A vision system according to claim 1, wherein the imager
comprises a plurality of digital cameras including a first digital
camera having a first main optical axis and a second digital camera
having a second main optical axis, the first main optical axis
being angularly separated from the second main optical axis in the
horizontal plane.
4. A vision system according to claim 3, wherein the first main
optical axis and the second main optical axis define an acute angle
therebetween.
5. A vision system according to claim 4, wherein the acute angle is
between about 5.degree. and about 25.degree..
6. A vision system according to claim 3, wherein the first main
optical axis is substantially perpendicular to the portion of the
aircraft when the aircraft is stopped within the defined parking
space.
7. A vision system according to claim 1, wherein the imager
supports imaging based on the ultraviolet (UV) region of the
electromagnetic spectrum.
8. A vision system according to claim 1, wherein the imager
supports imaging based on the infrared (IR) region of the
electromagnetic spectrum.
9. A vision system according to claim 1, wherein the distance
sensor comprises a laser range finder.
10. A vision system according to claim 1, wherein the distance
sensor comprises a plurality of laser range finders that are
separated spatially one from another and that are mounted
separately proximate the aircraft-engaging end of the passenger
boarding bridge.
11. A vision system according to claim 1, comprising a
distance-measuring device disposed at a reference location that is
remote from the aircraft-engaging end of the passenger boarding
bridge and from the aircraft.
12. A vision system according to claim 11, wherein the
distance-measuring device is a laser range finder.
13. A vision system according to claim 12, wherein the laser range
finder is an element of a visual docking guidance system (VDGS)
that is associated with the defined parking space adjacent to the
passenger boarding bridge, and that is in communication with the
automated control system.
14. A method for aligning an aircraft-engaging end of a passenger
boarding bridge with a doorway of an aircraft, the aircraft stopped
within a defined parking space adjacent to the passenger boarding
bridge, the method comprising: positioning the passenger boarding
bridge relative to the aircraft, such that the aircraft-engaging
end of the passenger boarding bridge is adjacent to an expected
stopping location of the doorway of the aircraft; capturing image
data using an imager that is disposed proximate the
aircraft-engaging end of the passenger boarding bridge, the image
data including features that are located within a portion of the
aircraft that is proximate the expected stopping location of the
doorway; sensing orientation data including tilt data, the
orientation data relating to a current orientation of the
aircraft-engaging end of the passenger boarding bridge when the
aircraft-engaging end of the passenger boarding bridge is
positioned adjacent to the expected stopping location of the
doorway of the aircraft; retrieving template image data relating to
the doorway of the aircraft; transforming the template image data
based on the sensed orientation data; comparing the captured image
data with the transformed template image data, to determine
instruction data relating to a horizontal movement and a vertical
movement for aligning the aircraft-engaging end of the passenger
boarding bridge with the doorway of the aircraft; providing the
instruction data to an automated control system of the passenger
boarding bridge; and, under the control of the automated control
system, performing the horizontal movement and the vertical
movement for aligning the aircraft-engaging end of the passenger
boarding bridge with the doorway of the aircraft.
15. A method according to claim 14, comprising providing the imager
with a wide-angle lens.
16. A method according to claim 14, wherein sensing orientation
data including tilt data comprises using an inclinometer disposed
proximate the aircraft-engaging end of the passenger boarding
bridge for sensing tilt of the aircraft-engaging end of the
passenger boarding bridge relative a horizontal reference
plane.
17. A method according to claim 14, wherein sensing orientation
data comprises sensing a distance between the aircraft-engaging end
of the passenger boarding bridge and the aircraft.
18. A method according to claim 14, wherein the template image data
comprises data relating to at least an image including a feature
that is indicative of the location of the doorway of the
aircraft.
19. A method according to claim 18, wherein comparing the captured
image data with the transformed template image data comprises
determining a correlation between the feature that is indicative of
the location of the doorway of the aircraft in the transformed
template image data and a corresponding feature in the captured
image data.
20. A method according to claim 14, comprising guiding the aircraft
to the defined parking space using a visual docking guidance system
(VDGS).
21. A method according to claim 20, comprising using a sensor of
the VDGS for identifying the type and subtype of the aircraft.
22. A method for aligning an aircraft-engaging end of a passenger
boarding bridge with a doorway of an aircraft, comprising: using a
visual docking guidance system (VDGS), guiding the aircraft to a
predetermined stopping position adjacent to the passenger boarding
bridge; positioning the aircraft-engaging end of the passenger
boarding bridge at a known position for capturing an image of a
portion of the aircraft that is proximate an expected stopping
location of the doorway; using an imager disposed proximate the
aircraft-engaging end of the passenger boarding bridge, capturing
an image of the portion of the aircraft that is proximate the
expected stopping location of the doorway; sensing orientation data
relating to tilt of the aircraft-engaging end of the passenger
boarding bridge relative a horizontal reference plane, and relating
to distance between the aircraft-engaging end of the passenger
boarding bridge and the portion of the aircraft that is proximate
the expected stopping location of the doorway; retrieving a
template image from a memory element, the template image relating
to the doorway of the aircraft; transforming the template image
based on the sensed orientation data; based on a comparison between
the transformed template image and the captured image, determining
instruction data for moving the aircraft-engaging end of the
passenger boarding bridge into an aligned condition with the
doorway of the aircraft from the known position; and, under the
control of an automated control system of the passenger boarding
bridge, moving the aircraft-engaging end of the passenger boarding
bridge in accordance with the instruction data, so as to align the
aircraft-engaging end of the passenger boarding bridge with the
doorway of the aircraft.
23. A method according to claim 22, wherein moving the
aircraft-engaging end of the passenger boarding bridge in
accordance with the instruction data is performed without capturing
an additional image during the course of the movement.
24. A method according to claim 22, comprising determining a type
and sub-type of the aircraft, wherein the known position is a
predetermined photo position for the determined type and sub-type
of the aircraft.
25. A method according to claim 24, wherein the instruction data
includes at least horizontal movement instruction data and vertical
movement instruction data for effecting a displacement of the
aircraft-engaging end of the passenger boarding bridge from the
predetermined photo position.
26. A method according to claim 25, comprising correcting the
vertical movement instruction based on a bridge specific correction
factor.
27. A method according to claim 26, wherein the bridge specific
correction factor is based on a known ground surface elevation
profile between the photo position and the predetermined stopping
position of the aircraft.
28. A method for aligning an aircraft-engaging end of a passenger
boarding bridge with a doorway of an aircraft, the aircraft stopped
within a defined parking space adjacent to the passenger boarding
bridge, the method comprising: moving the aircraft-engaging end of
the passenger boarding bridge to a known position adjacent to an
expected stopping location of the doorway of the aircraft;
capturing first image data using a first imager that is disposed
proximate the aircraft-engaging end of the passenger boarding
bridge, the first image data relating to a first portion of the
aircraft that is proximate the expected stopping location of the
doorway; capturing second image data using a second imager disposed
proximate the aircraft-engaging end of the passenger boarding
bridge, the second image data relating to a second portion of the
aircraft that is proximate the expected stopping location of the
doorway; sensing orientation data including tilt data, the
orientation data relating to an orientation of the
aircraft-engaging end of the passenger boarding bridge after moving
to the known position; retrieving template image data relating to
the doorway of the aircraft; transforming the template image. data
based on the sensed orientation data; comparing separately the
captured first image data and the captured second image data with
the transformed template image data, so as to determine
independently first alignment data and second alignment data,
respectively; selecting one of the first alignment data and the
second alignment data based on a predefined selection criterion;
and aligning the aircraft-engaging end of the passenger boarding
bridge with the doorway of the aircraft based upon the selected one
of the first alignment data and the second alignment data.
29. A method according to claim 28, comprising determining a type
and sub-type of the aircraft, wherein the known position is a
predetermined photo position for the determined type and sub-type
of the aircraft.
30. A method according to claim 29, wherein the selected one of the
first alignment data and the second alignment data includes at
least horizontal movement instruction data and vertical movement
instruction data for effecting a displacement of the
aircraft-engaging end of the passenger boarding bridge from the
predetermined photo position.
31. A method according to claim 30, comprising correcting the
vertical movement instruction based on a bridge specific correction
factor.
32. A method according to claim 31, wherein the bridge specific
correction factor is based on a known ground surface elevation
profile between the photo position and the predetermined stopping
position of the aircraft.
33. A method according to claim 28, wherein sensing orientation
data including tilt data comprises using an inclinometer disposed
proximate the aircraft-engaging end of the passenger boarding
bridge for sensing tilt of the aircraft-engaging end of the
passenger boarding bridge relative a horizontal reference
plane.
34. A method according to claim 28, wherein sensing orientation
data comprises sensing a distance between the aircraft-engaging end
of the passenger boarding bridge and the aircraft.
Description
FIELD OF THE INVENTION
[0001] The instant invention relates generally to passenger
boarding bridges, and more particularly to a vision system and
method for automated passenger boarding bridges.
BACKGROUND
[0002] In order to make aircraft passengers comfortable, and in
order to transport them between an airport terminal building and an
aircraft in such a way that they are protected from the weather and
from other environmental influences, passenger boarding bridges are
used which are telescopically extensible and the height of which is
adjustable. For instance, an apron drive bridge includes a
plurality of adjustable modules, including: a rotunda, a telescopic
tunnel, a bubble section, a cab, and elevating columns with wheel
carriage. Other common types of passenger boarding bridges include
radial drive bridges and over-the-wing (OTW) bridges. These types
of passenger boarding bridges are adjustable, for instance to
compensate for different sized aircraft and to compensate for
imprecise parking of aircraft at an airport terminal.
[0003] Historically, the procedure for aligning the passenger
boarding bridge with the doorway of an aircraft has been a time
consuming and labor intensive operation. First, the pilot taxis the
aircraft along a lead-in line to a final parking position within a
gate area. Typically, the lead-in line is a physical marker that is
painted onto the tarmac, and is used for guiding the aircraft along
a predetermined path to a final parking position. Additional
markings in the form of stop lines, one for each type of aircraft,
are provided at predetermined positions along the lead-in line.
Thus, when the nose gear of a particular type of aircraft stops
precisely at the stop line for that type of aircraft, then the
aircraft is known to be at its final parking position. Of course,
the pilot's view of the tarmac surface from the cockpit of an
aircraft is limited. This is particularly true for larger aircraft,
such as for instance a Boeing 747-X00. Typically, the pilot has
relied upon instructions that are provided by a human ground
marshal together with up to two "wing walkers" to follow the
lead-in line. Optionally, stop bars are located on a pole that is
fixedly mounted to the ground surface, including appropriate stop
bars for each type of aircraft using the gate. Alternatively, a
tractor or tug is used to tow the aircraft along the lead-in line
to its final parking position.
[0004] More recently, sophisticated Visual Docking Guidance Systems
have been developed to perform the function of the human ground
marshal or tug operator. In particular, a Visual Docking Guidance
System (VDGS) senses the aircraft as it approaches the final
parking position and provides instructions to the pilot via an
electronic display device. The electronic display device is mounted
at a location that makes it highly visible to the pilot when viewed
from the cockpit of an aircraft. Typically, the instructions
include a combination of alphanumeric characters and symbols, which
the pilot uses to guide the aircraft precisely to the final parking
position for the particular type of aircraft. The high capital cost
of the VDGS system is offset by reduced labor costs and the
efficiency that results from stopping the aircraft more precisely
than is possible under the guidance of a human ground marshal.
[0005] Of course, even when the aircraft is stopped precisely at
the final parking position for that type of aircraft, still there
is the matter of moving the passenger boarding bridge into an
aligned relationship with a doorway of the parked aircraft. In the
case of an apron drive bridge this may involve extending the bridge
by 10 to 20 meters or more from a stowed position. Unfortunately,
driving the bridge over such a long distance is time consuming
because often the rate at which the bridge is moved is limited so
as to reduce the risk of colliding with ground service vehicles or
personnel, and to avoid causing serious damage to the aircraft in
the event of a collision therewith. Manual, semi-automated and
automated bridge alignment systems are known for moving the
passenger boarding bridge relative to the parked aircraft.
[0006] A manual bridge alignment system requires that a human
operator is present to perform the alignment operation each time an
aircraft arrives. Delays occur when the human operator is not
standing-by to perform the alignment operation as soon as the
aircraft comes to a stop. In addition, human operators are prone to
errors that may result in the passenger boarding bridge being
driven into the aircraft or into a piece of ground service
equipment. Such collisions involving the passenger boarding bridge
are costly and also result in delays. In order to avoid causing a
collision, human operators tend to err on the side of caution and
drive the passenger boarding bridge slowly and cautiously.
[0007] Semi-automated bridge alignment systems are also known,
whereby the bridge is moved rapidly to a preset position under the
control of a computer. WO 96/08411, filed Sep. 14, 1995 in the name
of Anderberg, describes a semi-automated system for controlling the
movement of a passenger boarding bridge. When an aircraft has
landed, a central computer transmits information relating to the
type of the approaching aircraft to a local computer of the
passenger boarding bridge. The local computer accesses a database
and retrieves information relating to the positions of the doors
for the type of aircraft that has landed, as well as information
relating to the expected final parking position for the type of
aircraft. The local computer uses the retrieved information to
determine an absolute position of the door to which the bridge is
to be aligned. Accordingly, the passenger boarding bridge is moved
under computer control to a position that is close to the
determined position of the door, for example within 2-10 meters.
Optionally, the bridge is preset to this position before the
aircraft stops moving.
[0008] WO 01/34467, filed Nov. 8, 2000 also in the name of
Anderberg, teaches that the above system is reliable only for
movement to a position that is close to the parked aircraft. Thus,
the bridge has to be operated manually during the remaining 2-10
meters of its movement. The WO 01/34467 reference also teaches an
improvement to the above system, in which electromagnetic sensors
are disposed along the outboard end of the passenger boarding
bridge for transmitting a set of electromagnetic pulses in
different directions and for detecting electromagnetic pulses after
reflection from an aircraft. Based on the elapsed time between
transmitting and detecting the electromagnetic pulses in different
directions, a profile of distance as a function of direction is
obtained. From the measured distance versus direction profile and
the information that is stored in the computer, it is then possible
to maneuver the bridge the rest of the way from the preset position
to the door of the parked aircraft. Unfortunately, when the
aircraft fails to stop at the expected final parking position, the
preset position will be misaligned with the actual position of the
aircraft door, and human intervention will be required in order to
complete the alignment operation.
[0009] Other automated systems have been proposed, such as for
instance an automated passenger boarding bridge that uses video
cameras in the control of the bridge as described by Schoenberger
et al. in U.S. Pat. No. 5,226,204. The system uses video cameras to
capture images of an aircraft with which the bridge is to be
aligned, which images are provided to a computer for image
processing. An object of the image processing is to locate doors
along the lateral surface of the aircraft facing the passenger
boarding bridge. The bridge is then moved automatically along a
direction toward a predetermined door of the parked aircraft.
Unfortunately, the system that is described in U.S. Pat. No.
5,226,204 suffers from several disadvantages. For instance, a
sophisticated image processing system is required in order to
locate a doorway along the side of an aircraft from a distance of
up to 15 meters or more. In addition, the "blob" approach and edge
detection image processing techniques that are mentioned in the
reference are computationally expensive and inherently slow. It is
a further disadvantage that factors such as the weather, ambient
lighting conditions, markings on the aircraft and the presence of
intervening ground support vehicles may also become very
significant over such large distances. Furthermore, the bridge is
still required to move a significant distance after the aircraft
has come to a stop, which increases the time that is needed to
complete the alignment and poses a hazard to ground service
vehicles and personnel.
[0010] Yet another type of system is disclosed in published United
States patent application 2005/0198750 A1, filed Feb. 26, 2003 in
the name of Spencer et al. In particular, reflective targets are
affixed to the outside surface of an aircraft around the doorway to
which the passenger boarding bridge is to be aligned. A plurality
of cameras disposed aboard the passenger boarding bridge is used to
image the targets during the alignment procedure, and provides
image data to a "computer means" for processing thereby. While the
use of reflective targets for identifying the doorway of the
aircraft is advantageous in that it simplifies image processing,
never-the-less airlines are reluctant to apply targets to their
aircraft and furthermore regulatory approval may be necessary in
order to do so. In addition, the system is likely to fail if the
targets become obscured due to dirt, scuffs, tearing or the build
up of snow, etc. Another disadvantage of the system that is
described by Spencer et al. is that the targets are imaged
continuously as the bridge moves into alignment with the doorway of
the aircraft. Continuous imaging, and the associated processing of
image data, is necessary in order to update the alignment data so
as to compensate for initial low accuracy of the system as well as
unexpected movement of the bridge during alignment, such as for
instance movement resulting from uneven ground surface adjacent the
passenger boarding bridge. Accordingly, the bridge is required to
move a significant distance at relatively slow speed, which may
unacceptably increase alignment time.
[0011] Accordingly, there is a long-standing and unfulfilled need
for a bridge alignment system that is capable of safely and
reliably aligning a passenger boarding bridge with an aircraft,
absent intervention by a human operator. It would be advantageous
to provide a system that overcomes at least some of the
above-mentioned disadvantages of the prior art.
SUMMARY OF EMBODIMENTS OF THE INVENTION
[0012] In accordance with an aspect of the instant invention there
is provided a vision system for use with an automated control
system of a passenger boarding bridge, the automated control system
for aligning an aircraft-engaging end of the passenger boarding
bridge with a doorway of an aircraft that is stopped within a
defined parking space adjacent to the passenger boarding bridge,
the vision system comprising: an imager disposed proximate the
aircraft-engaging end of the passenger boarding bridge for
capturing image data relating to a portion of the aircraft that is
proximate an expected stopping location of the doorway; an
inclinometer for determining tilt data relating to a sensed
deviation of the aircraft-engaging end of the passenger boarding
bridge relative a horizontal reference plane; a distance sensor
disposed proximate the aircraft-engaging end of the passenger
boarding bridge for sensing a distance to the portion of the
aircraft that is proximate the expected stopping location of the
doorway; a memory element having template image data stored
retrievably therein, the template image data comprising at least a
template image including a feature that is indicative of the
location of the doorway of the aircraft; and, an image data
processor for transforming the template image data based on the
tilt data and the sensed distance, for determining a correlation
between the feature that is indicative of the location of the
doorway of the aircraft in the transformed template image data and
a corresponding feature in the captured image data, and for
determining alignment data for use in aligning the
aircraft-engaging end of the passenger boarding bridge with the
doorway of the aircraft based on the determined correlation.
[0013] In accordance with another aspect of the instant invention
there is provided a method for aligning an aircraft-engaging end of
a passenger boarding bridge with a doorway of an aircraft, the
aircraft stopped within a defined parking space adjacent to the
passenger boarding bridge, the method comprising: positioning the
passenger boarding bridge relative to the aircraft, such that the
aircraft-engaging end of the passenger boarding bridge is adjacent
to an expected stopping location of the doorway of the aircraft;
capturing image data using an imager that is disposed proximate the
aircraft-engaging end of the passenger boarding bridge, the image
data including features that are located within a portion of the
aircraft that is proximate the expected stopping location of the
doorway; sensing orientation data including tilt data, the
orientation data relating to a current orientation of the
aircraft-engaging end of the passenger boarding bridge when the
aircraft-engaging end of the passenger boarding bridge is
positioned adjacent to the expected stopping location of the
doorway of the aircraft; retrieving template image data relating to
the doorway of the aircraft; transforming the template image data
based on the sensed orientation data; comparing the captured image
data with the transformed template image data, to determine
instruction data relating to a horizontal movement and a vertical
movement for aligning the aircraft-engaging end of the passenger
boarding bridge with the doorway of the aircraft; providing the
instruction data to an automated control system of the passenger
boarding bridge; and, under the control of the automated control
system, performing the horizontal movement and the vertical
movement for aligning the aircraft-engaging end of the passenger
boarding bridge with the doorway of the aircraft.
[0014] In accordance with another aspect of the instant invention
there is provided a method for aligning an aircraft-engaging end of
a passenger boarding bridge with a doorway of an aircraft,
comprising: using a visual docking guidance system (VDGS), guiding
the aircraft to a predetermined stopping position adjacent to the
passenger boarding bridge; positioning the aircraft-engaging end of
the passenger boarding bridge at a known position for capturing an
image of a portion of the aircraft that is proximate an expected
stopping location of the doorway; using an imager disposed
proximate the aircraft-engaging end of the passenger boarding
bridge, capturing an image of the portion of the aircraft that is
proximate the expected stopping location of the doorway; sensing
orientation data relating to tilt of the aircraft-engaging end of
the passenger boarding bridge relative a horizontal reference
plane, and relating to distance between the aircraft-engaging end
of the passenger boarding bridge and the portion of the aircraft
that is proximate the expected stopping location of the doorway;
retrieving a template image from a memory element, the template
image relating to the doorway of the aircraft; transforming the
template image based on the sensed orientation data; based on a
comparison between the transformed template image and the captured
image, determining instruction data for moving the
aircraft-engaging end of the passenger boarding bridge into an
aligned condition with the doorway of the aircraft from the known
position; and, under the control of an automated control system of
the passenger boarding bridge, moving the aircraft-engaging end of
the passenger boarding bridge in accordance with the instruction
data, so as to align the aircraft-engaging end of the passenger
boarding bridge with the doorway of the aircraft.
[0015] In accordance with another aspect of the instant invention
there is provided a method for aligning an aircraft-engaging end of
a passenger boarding bridge with a doorway of an aircraft, the
aircraft stopped within a defined parking space adjacent to the
passenger boarding. bridge, the method comprising: moving the
aircraft-engaging end of the passenger boarding bridge to a known
position adjacent to an expected stopping location of the doorway
of the aircraft; capturing first image data using a first imager
that is disposed proximate the aircraft-engaging end of the
passenger boarding bridge, the first image data relating to a first
portion of the aircraft that is proximate the expected stopping
location of the doorway; capturing second image data using a second
imager disposed proximate the aircraft-engaging end of the
passenger boarding bridge, the second image data relating to a
second portion of the aircraft that is proximate the expected
stopping location of the doorway; sensing orientation data
including tilt data, the orientation data relating to an
orientation of the aircraft-engaging end of the passenger boarding
bridge after moving to the known position; retrieving template
image data relating to the doorway of the aircraft; transforming
the template image data based on the sensed orientation data;
comparing separately the captured first image data and the captured
second image data with the transformed template image data, so as
to determine independently first alignment data and second
alignment data, respectively; selecting one of the first alignment
data and the second alignment data based on a predefined selection
criterion; and, aligning the aircraft-engaging end of the passenger
boarding bridge with the doorway of the aircraft based upon the
selected one of the first alignment data and the second alignment
data.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Exemplary embodiments of the invention will now be described
in conjunction with the following drawings, in which similar
reference numbers designate similar items:
[0017] FIG. 1 is a simplified top view showing a passenger boarding
bridge that is equipped with an apparatus according to an
embodiment of the instant invention, the passenger boarding bridge
located at a photo position for the specific type and sub-type of
the parked aircraft;
[0018] FIG. 2 is a simplified block diagram showing the components
of the camera enclosure that is disposed at the aircraft engaging
end of the passenger boarding bridge of FIG. 1, according to a
first embodiment of the instant invention;
[0019] FIG. 3 is a simplified block diagram showing the connections
between components of a vision system according to the first
embodiment of the instant invention;
[0020] FIG. 4 is a simplified block diagram showing the components
of the camera enclosure that is disposed at the aircraft engaging
end of the passenger boarding bridge of FIG. 1, according to a
second embodiment of the instant invention;
[0021] FIG. 5 is a simplified block diagram showing the connections
between components of a vision system according to the second
embodiment of the instant invention;
[0022] FIG. 6 is a simplified flow diagram of a method according to
an embodiment of the instant invention;
[0023] FIG. 7 is a simplified flow diagram of another method
according to an embodiment of the instant invention;
[0024] FIG. 8 is a simplified flow diagram of another method
according to an embodiment of the instant invention;
[0025] FIG. 9 is a simplified block diagram showing the connections
between components of a vision system according to a third
embodiment of the instant invention; and,
[0026] FIG. 10 is a simplified block diagram showing the
connections between components of a vision system according to a
fourth embodiment of the instant invention.
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0027] The following description is presented to enable a person
skilled in the art to make and use the invention, and is provided
in the context of a particular application and its requirements.
Various modifications to the disclosed embodiments will be readily
apparent to those skilled in the art, and the general principles
defined herein may be applied to other embodiments and applications
without departing from the spirit and the scope of the invention.
Thus, the present invention is not intended to be limited to the
embodiments disclosed, but is to be accorded the widest scope
consistent with the principles and features disclosed herein.
[0028] Referring to FIG. 1, shown is a simplified top view of a
passenger boarding bridge that is equipped with an apparatus
according to a first embodiment of the instant invention, the
passenger boarding bridge being located at a photo position for the
specific type and sub-type of the parked aircraft. The aircraft 100
is stopped within or proximate a parking space that is defined
adjacent to the passenger boarding bridge 102. The passenger
boarding bridge 102 includes a passageway 104 extending between a
terminal building 106 and a pivotal cabin 108. The cabin 108 is
open at an aircraft-engaging end 110 thereof. A controller 112 of
an automated bridge alignment system is provided within the cabin
108 of the passenger boarding bridge 102. Optionally, the
controller 112 is disposed within another portion of the passenger
boarding bridge 102, or within terminal building 106. The
controller 112 is in communication with, and provides instruction
signals to, not illustrated mechanisms of the automated bridge
alignment system, which includes mechanisms for adjusting the
length and the angular orientation of the passageway 104 relative
to the terminal building 106, for tilting and pivoting the cabin
108 relative to the passageway 104, for vertically displacing the
cabin 108 relative to the ground surface etc. The controller 112 is
also in communication with a vision system of the passenger
boarding bridge 102. The vision system includes distributed
components, some of which are optional, and which are disposed in
and about the cabin 108 of passenger boarding bridge 102. In the
specific example that is shown in FIG. 1, the components of the
vision system include a camera enclosure 114, an optional laser
range finder 116, an image data processor 118, and a memory element
120. Collectively, the components of the vision system are used to
identify the location of doorway 122 along the lateral surface of
the aircraft 100, as will be discussed in greater detail in the
following sections. Also shown in FIG. 1 is a visual docking
guidance system (VDGS) 124 as is well known in the art, including a
sensing portion for sensing approach of the aircraft 100 toward the
parking space, and a display portion for providing instructions in
the form of symbols and/or alphanumeric characters, the
instructions for use by the pilot while guiding the aircraft toward
the parking space.
[0029] Referring now to FIG. 2, shown is a simplified block diagram
of the components that are housed within the camera enclosure of
FIG. 1, according to the first embodiment of the instant invention.
In this specific and non-limiting example, the camera enclosure 114
is mounted within the back wall of cabin 108, facing toward the
open end 110 with a downward angle of approximately 200 relative to
the floor surface of cabin 108. The camera enclosure 114 contains
an imager 126. By way of a non-limiting example, the imager 126
comprises a CMOS image sensor, such as for instance a digital
camera available from Allied Vision Technologies. Optionally, the
imager 126 is a digital CCD camera. Optionally, the imager 126 is
provided in the form of a digital camera that is capable of imaging
near infrared (near IR) and/or ultraviolet (UV) radiation, such as
for instance a Fuji S3 UVIR. The imager 126 has a main optical axis
128 that is approximately perpendicular to the lateral surface of
aircraft 100 when the passenger boarding bridge 102 is in the photo
position for that type of aircraft, and when the aircraft 100 is
parked properly at the parking space.
[0030] The camera enclosure 114 also houses an inclinometer 130,
such as for instance a ceramic electrolytic tilt sensor, which is
offset 20.degree. upwards relative to the imager 126. Accordingly,
the inclinometer 130 is approximately parallel to the floor of the
cabin 108. A distance sensor such as for instance a laser range
finder (LRF) 132 also is housed within the camera enclosure 114. In
the specific example that is shown in FIG. 1, the LRF 132 is
disposed above the imager 126 and is also oriented with a downward
angle of approximately 20.degree. relative to the floor surface of
cabin 108. Optionally, the camera enclosure 114 includes a
transparent protective window so as to allow imaging of the
aircraft whilst protecting the delicate inner components from
environmental influences, such as the weather, etc. Optionally the
imager 126 includes a wide-angle lens. Of course, other types of
distance sensors are also envisaged for use with the embodiments of
the instant invention.
[0031] Referring now to FIG. 3, shown is simplified block diagram
indicating the communication pathways between the components of the
vision system and the components of the passenger boarding bridge
control system. The controller 112 is in communication with each
one of the VDGS 124, the LRF 132 and the image data processor 118.
Optionally, the controller 112 is also in communication with the
memory element 120 or is in communication with a different memory
element (not shown). The image data processor 118 is in
communication with the controller 112, the memory element 120, the
imager 126 and the inclinometer 130.
[0032] Operation of the vision system is described in the following
paragraphs, with specific reference being made to the various
components that are shown in FIGS. 1-3. Upon landing, the aircraft
100 taxis along the ground surface toward its assigned gate. The
arrival time and gate assignment for the aircraft 100 are known in
advance, and are available via the flight information and display
system (FIDS) of the airport. As the aircraft approaches the
assigned gate, VDGS 124 initiates a procedure for sensing the
location of the aircraft and for guiding the aircraft from the
sensed location to a parking space that is adjacent to the
passenger boarding bridge 102 of the assigned gate. The manner in
which VDGS 124 operates is well known to one of skill in the art
and will not be described in further detail in this document.
Suffice it to say, VDGS 124 identifies the type and sub-type of the
aircraft during approach to the parking space, and achieves an
aircraft parking precision of at least plus or minus 30 cm from the
expected stopping position for the parking space.
[0033] Separately, data that is indicative of the type and sub-type
of the aircraft 100 is provided to the controller 112, which then
provides a control signal for moving the passenger boarding bridge
102 into a photo position for that particular type and sub-type of
aircraft. For instance, the data is provided manually via an
interface having a different button for each type and sub-type of
aircraft or having a series of alphanumeric buttons. Optionally, a
sensor is used to sense the type and sub-type of the aircraft 100
and sensor data is provided to the controller 112. Further
optionally, the type and sub-type data is provided from the VDGS
124 or from the FIDS of the airport. The photo position is defined
such that the camera enclosure 114 is approximately aligned with
the doorway of the aircraft if the aircraft stops precisely at the
parking space that is adjacent to the passenger boarding bridge
102. Since different aircraft types and sub-types have different
fuselage configurations, that is to say, the doorways are located
at different positions and heights along the side of the aircraft,
most different aircraft types and sub-types are expected to require
a unique photo position. The passenger boarding bridge optionally
is moved to the photo position either before or after the aircraft
100 has come to a stop at the parking space.
[0034] Once the passenger boarding bridge 102 stops at the photo
position and the aircraft 100 stops at the parking space, the LRF
132 is used to sense the distance to the aircraft, which is done
under the control of controller 112. The LRF 132 is disposed above
or adjacent to the imager 126, such that the measured distance
corresponds to the actual distance from the camera enclosure 114 to
the aircraft 100. Controller 112 compares the distance value that
is returned by LRF 132 to a range of expected values. If the
distance value falls within the range of expected values then the
distance value is considered to be valid. However, in some
instances the LRF 132 does not return a valid distance value. For
instance, if the LRF 132 coincidentally is directed toward a window
of the aircraft or toward an area of blue or other dark colored
paint, then the distance value that is returned by LRF 132 will
fall outside the range of expected values and is not likely to be
valid. In such an instance manual alignment of the passenger
boarding bridge may be necessary. Optionally, the controller 112
moves the passenger boarding bridge 102 into a back-up photo
position, and LRF 132 is used in a second attempt to sense the
distance to the aircraft 100. For instance, the bridge is moved
from the photo position to the back-up photo position by reversing
a portion of the movement that brought the bridge into the original
photo position. Since the bridge is merely reversing its original
course in order to arrive at the back-up photo position, there is
very little risk of causing damage to the aircraft or ground
service equipment. If a valid distance value is obtained from the
back-up photo position, then the automated alignment operation
proceeds absent human intervention.
[0035] The controller 112 provides distance value data to the image
data processor 118, as well as data relating to the type and
sub-type of the aircraft. An image is then captured using the
imager 126, and image data relating to the captured image is
provided to the image data processor 118. In addition, tilt data
relating to the pitch and roll of the cabin 108 is measured using
the inclinometer 130 and is also provided to the image data
processor 118. The image data processor 118 then processes the
image data relating to the captured image, making use of the
distance data and the tilt data.
[0036] The image data processing algorithm is based upon a
comparison of features that are contained within the captured image
against a small database of template images stored within memory
element 120 for each different type and sub-type of aircraft. The
database includes a plurality of template images of the outline of
the doorway, and shows distinctive features such as the handle of
the door, the window of the door, the doorway base plate, etc. In
particular, each image of the plurality of template images is
obtained from a known optimal viewing position. Optionally, paint
scheme features are included in at least some images of the
plurality of template images.
[0037] Prior to comparison, the template images are transformed
using the distance data that is provided by the LRF 132, and using
tilt data that is provided by inclinometer 130, respectively. The
transformed template images are then compared to the captured
image, and horizontal and vertical adjustment values are
determined. For instance, it is determined by how much the
passenger boarding bridge would have to move in the horizontal and
vertical directions to cause the features in the real world images
to overlap with the features in the transformed template images. In
addition, a rotational movement of the cabin 108 is determined. The
rotational movement ensures that the aircraft-engaging end 110 of
the cabin 108 is properly aligned with the aircraft fuselage, such
that large gaps do not exist therebetween and pose a hazard to
passengers or crew. The horizontal and vertical adjustment values
may be determined a plurality of times, each time using a different
feature of the aircraft to make the determination.
[0038] After image data processing is complete, the image data
processor 118 returns two values to the controller 112 for
specifying the x-axis (horizontal) and y-axis (vertical) adjustment
to the passenger boarding bridge 100 that is necessary for aligning
the aircraft-engaging end 110 of the cabin 108 precisely with the
doorway 122 of aircraft 100. Of course, a value relating to the
rotational movement of the cabin 108 also is provided to the
controller 112. The controller 112 receives the two values from the
image data processor 118, and retrieves a bridge specific offset
value from memory element 120. For instance, a bridge specific
offset value is stored within memory element 120 for each different
photo position and back-up photo position. The bridge specific
offset value is added to the y-axis adjustment value, so as to
correct for slope or unevenness of the apron surface below the
passenger boarding bridge 102. Based upon the corrected two values,
the controller 112 determines control signals for moving the
passenger boarding bridge 102, and provides the control signals to
mechanisms of the automated bridge alignment system for adjusting
the height and the angular orientation of the passageway 104. A
control signal is also provided for rotationally adjusting the
cabin 108. Thereafter, the length of the passageway 104 is extended
in order to complete the alignment operation with the doorway
122.
[0039] As discussed supra, optionally the imager 126 is provided in
the form of a digital camera that is capable of imaging near IR
and/or UV. Such an imager is capable of imaging heat signatures
around the door or windows of the aircraft. For instance, the IR
signature of the window in the door is different than that of the
aluminum skin of the aircraft fuselage. Furthermore, use of IR
and/or UV imagers may make the paint scheme of the aircraft, which
varies considerably from airline to airline, less of an issue.
[0040] Referring now to FIG. 4, shown is a simplified block diagram
of the components that are housed within the camera enclosure of
FIG. 1, according to a second embodiment of the instant invention.
In this specific and non-limiting example, the camera enclosure 114
is mounted within the back wall of cabin 108, facing toward the
open end 110 with a downward angle of approximately 20.degree.
relative to the floor surface of cabin 108. The camera enclosure
114 contains two imagers 126 and 134. By way of a non-limiting
example, one or both of the two imagers 126 and 134 comprises a
CMOS image sensor, such as for instance a digital camera available
from Allied Vision Technologies. Optionally, one or both of the two
imagers 126 and 134 is a digital CCD camera. Optionally, at least
one of the two imagers 126 and 134 is provided in the form of a
digital camera that is capable of imaging near IR and/or UV, such
as for instance a Fuji S3 UVIR. The imager 126 has a main optical
axis 128 that is approximately perpendicular to the lateral surface
of aircraft 100 when the passenger boarding bridge 102 is in the
photo position for that type of aircraft, and when the aircraft 100
is properly parked at the parking space. The imager 134 is disposed
adjacent to the imager 126 and has a main optical axis 136 that is
directed approximately 17.degree. away from the main optical axis
128 of imager 126. In other words, the main optical axes 128 and
136 of the two imagers 126 and 134, respectively, form an acute
angle of approximately 17.degree. facing toward the aircraft
100.
[0041] The camera enclosure 114 also houses an inclinometer 130,
such as for instance a ceramic electrolytic tilt sensor, which is
offset 20.degree. upwards relative to the imagers 126 and 134.
Accordingly, the inclinometer 130 is approximately parallel to the
floor of the cabin 108. A distance sensor such as for instance a
laser range finder (LRF) 132 also is housed within the camera
enclosure 114. In the specific example that is shown in FIG. 1, the
LRF 132 is disposed above the imagers 126 and 134 and is also
oriented with a downward angle of approximately 20.degree. relative
to the floor surface of cabin 108. Optionally, the camera enclosure
114 includes a transparent protective window so as to allow imaging
of the aircraft whilst protecting the delicate inner components
from environmental influences, such as the weather, etc. Of course,
other types of distance sensors are also envisaged for use with the
embodiments of the instant invention.
[0042] Referring now to FIG. 5, shown is simplified block diagram
indicating the communication pathways between the components of the
vision system and the components of the passenger boarding bridge
control system, according to the second embodiment of the instant
invention. FIG. 5 includes a second LRF 116, which is not housed
within the camera enclosure 114 but rather is mounted separately
within the back wall of cabin 108, and approximately parallel to
the floor surface of cabin 108. Optionally, the second LRF 116 is
not mounted approximately parallel to the floor surface of cabin
108. The controller 112 is in communication with each one of the
VDGS 124, the first LRF 132, the second LRF 116 and the image data
processor 118. Optionally, the controller 112 is also in
communication with the memory element 120 or is in communication
with a different memory element (not shown). The image data
processor 118 is in communication with the controller 112, the
memory element 120, the first imager 126, the second imager 134,
and with the inclinometer 130.
[0043] Operation of the vision system is described in the following
paragraphs, with specific reference being made to the various
components that are shown in FIG. 1 and FIGS. 4-5. Upon landing,
the aircraft 100 taxis along the ground surface toward its assigned
gate. The arrival time and gate assignment for aircraft 100 are
known in advance, and are entered into the flight information and
display system (FIDS) of the airport. As the aircraft approaches
the assigned gate, VDGS 124 initiates a procedure for sensing the
location of the aircraft and for guiding the aircraft from the
sensed location to a parking space that is adjacent to the
passenger boarding bridge 102 of the assigned gate. The manner in
which VDGS 124 operates is well known to one of skill in the art
and will not be described in further detail in this document.
Suffice it to say, VDGS 124 identifies the type and sub-type of the
aircraft during approach to the parking space, and achieves an
aircraft parking precision of at least plus or minus 30 cm from the
expected stopping position for the parking space.
[0044] Separately, data that is indicative of the type and sub-type
of the aircraft 100 is provided to the controller 112, which then
provides a control signal for moving the passenger boarding bridge
102 into a photo position for that particular type and sub-type of
aircraft. For instance, the data is provided manually via an
interface having a different button for each type and sub-type of
aircraft or having a series of alphanumeric buttons. Optionally, a
sensor is used to sense the type and sub-type of the aircraft 100
and sensor data is provided to the controller 112. Further
optionally, the type and sub-type data is provided from the VDGS or
from the FIDS of the airport. The photo position is defined such
that the camera enclosure 114 is approximately aligned with the
doorway of the aircraft if the aircraft stops precisely at the
parking space that is adjacent to the passenger boarding bridge
102. Since different aircraft types and sub-types have different
fuselage configurations, that is to say, the doorways are located
at different positions and heights along the side of the aircraft,
most different aircraft types and sub-types will require a unique
photo position. The passenger boarding bridge optionally is moved
to the photo position either before or after the aircraft has come
to a stop at the parking space.
[0045] Once the passenger boarding bridge 102 stops at the photo
position and the aircraft 100 stops at the parking space, the LRFs
132 and 116 are used to sense the distance to the aircraft 100,
which is done under the control of controller 112. The LRF 132 is
disposed above or adjacent to the imagers 126 and 134, such that
the measured distance corresponds to the actual distance from the
camera enclosure 114 to the aircraft 100. Controller 112 compares
the distance value that is returned by LRF 132 to a range of
expected values. If the distance value falls within the range of
expected values then the distance value is considered to be valid.
However, in some instances the LRF 132 does not return a valid
distance value. For instance, if the LRF 132 coincidentally is
directed toward a window of the aircraft or toward an area of blue
or other dark colored paint, then the distance value that is
returned by LRF 132 will fall outside the range of expected values
and is not likely to be valid. In such an instance the controller
112 compares the distance value that is measured using the second
LRF 116 to a second range of expected values. If the distance value
that is measured by the second LRF 116 falls within the second
range of expected values, then it is considered to be valid for use
during alignment. Since the second LRF 116 is not disposed above or
adjacent to the imagers 126 and 134, it is necessary to scale the
distance that is returned by the second LRF 116 in order to
determine the actual distance to the aircraft relative to the
camera enclosure 114. If neither the first LRF 132 nor the second
LRF 116 returns a valid distance value, then the automated
alignment operation is aborted and a human operator is paged to
complete the alignment manually. Optionally, the bridge is moved
into a back-up photo position for the determined type and sub-type
of the aircraft, and fresh distance values are measured using the
first LRF 132 and the second LRF 116. For instance, the bridge is
moved from the photo position to the back-up photo position by
reversing a portion of the movement that brought the bridge into
the photo position. Since the bridge is merely reversing its
original course in order to arrive at the back-up photo position,
there is very little risk of causing damage to the aircraft or
ground service equipment. If a valid distance value is obtained
from the back-up photo position, then the automated alignment
operation proceeds absent human intervention.
[0046] The controller 112 provides distance value data to the image
data processor 118, as well as data relating to the type and
sub-type of the aircraft. An image is then captured using each of
the two imagers 126 and 134, and image data relating to each
captured image is provided to the image data processor 118. In
addition, tilt data relating to the pitch and roll of the cabin 108
is measured using the inclinometer 130 and is also provided to the
image data processor 118. The image data processor then processes
separately the image data relating to each of the two captured
images, making use of the distance data and the tilt data.
[0047] More specifically, the image data processing algorithm is
based upon a comparison of features that are contained within the
captured images against a small database of template images stored
within memory element 120 for each different type and sub-type of
aircraft. The database includes a plurality of template images of
the outline of the doorway, and shows distinctive features such as
the handle of the door, the window of the door, the doorway base
plate, etc. Optionally, paint scheme features are included in at
least some of the plurality of template images. Each image of the
plurality of template images is obtained from a known optimal
viewing position.
[0048] Prior to comparison, the template images are transformed
using distance data provided by one of the LRFs 132 and 1 16, and
using tilt data provided by inclinometer 130, respectively. The
transformed template images are then compared separately to the two
captured images, and horizontal and vertical adjustment values are
determined. For instance, it is determined by how much the
passenger boarding bridge would have to move in the horizontal and
vertical directions to cause the features in the real world images
to overlap with the features in the transformed template images. In
addition, a rotational movement of the cabin 108 is determined. The
rotational movement ensures that the aircraft-engaging end 110 of
the cabin 108 is properly aligned with the aircraft fuselage, such
that large gaps do not exist therebetween and pose a hazard to
passengers or crew. The horizontal and vertical adjustment values
may be determined a plurality of times for each captured image,
each time using a different feature of the aircraft to make the
determination. The determination of which one of the two captured
images yields the best values may then be determined
statistically.
[0049] After image data processing is complete, the image data
processor 118 returns two values to the controller 112 for
specifying the x-axis (horizontal) and y-axis (vertical) adjustment
to the passenger boarding bridge that is necessary for aligning the
aircraft-engaging end 110 of the cabin 108 precisely with the
doorway 122 of aircraft 100. Of course, a value relating to the
rotational movement of the cabin 108 also is provided to the
controller 112. The controller 112 receives the two values from the
image data processor 118, and retrieves a bridge specific offset
value from memory element 120. For instance, a bridge specific
offset value is stored within memory element 120 for each different
photo position. The bridge specific offset value is added to the
y-axis value, and corrects for slope or unevenness of the apron
surface below the passenger boarding bridge 102. Based upon the
corrected two values, the controller 112 determines control signals
for moving the passenger boarding bridge 102, and provides the
control signals to mechanisms of the automated bridge alignment
system for adjusting the height and the angular orientation of the
passageway 104. A control signal is also provided for rotationally
adjusting the cabin 108. Thereafter, the length of the passageway
104 is extended in order to complete the alignment operation with
the doorway 122.
[0050] Although both images are processed fully, the two values
that are returned to controller 112 are based upon only one or the
other of the two captured images. If neither one of the two
captured images is determined to be suitable for use then an error
message is generated, and bridge alignment is performed in a manual
fashion. This may occur, for instance, when the aircraft is
improperly parked and therefore neither image contains features
that are indicative of the doorway 122. Optionally, a confidence
score is associated with the values that are obtained using each of
the two captured images, and those values having the highest
confidence score are used for aligning the passenger boarding
bridge 102.
[0051] As discussed supra, at least one of the imagers 126 and 134
optionally is provided in the form of a digital camera that is
capable of imaging near IR and/or UV. Such an imager is capable of
imaging heat signatures around the door or windows of the aircraft.
For instance, the IR signature of the window in the door is
different than that of the aluminum skin of the aircraft fuselage.
Furthermore, use of IR and/or UV imagers may make the paint scheme
of the aircraft, which varies considerably from airline to airline,
less of an issue.
[0052] Referring now to FIG. 6, shown is a simplified flow diagram
of a method according to an embodiment of the instant invention. In
particular, the method is for aligning an aircraft-engaging end of
a passenger boarding bridge with a doorway of an aircraft, the
aircraft stopped within a defined parking space adjacent to the
passenger boarding bridge. At step 600 the passenger boarding
bridge is positioned relative to the aircraft, such that the
aircraft-engaging end of the passenger boarding bridge is adjacent
to an expected stopping location of the doorway of the aircraft.
The passenger boarding bridge is said to be at a photo position,
which is a predefined position for capturing image data relating to
a specific type and sub-type of aircraft. At step 602 image data is
captured using an imager that is disposed proximate the
aircraft-engaging end of the passenger boarding bridge. The
captured image data includes features that are located within a
portion of the aircraft that is proximate the expected stopping
location of the doorway. At step 604 orientation data including
tilt data is sensed, the orientation data relating to a current
orientation of the aircraft-engaging end of the passenger boarding
bridge when the aircraft-engaging end of the passenger boarding
bridge is positioned adjacent to the expected stopping location of
the doorway of the aircraft. At step 606 template image data
relating to the doorway of the aircraft is retrieved from a memory
element. At step 608 the template image data is transformed based
on the sensed orientation data. At step 610 the captured image data
is compared with the transformed template image data, to determine
instruction data relating to a horizontal movement and a vertical
movement for aligning the aircraft-engaging end of the passenger
boarding bridge with the doorway of the aircraft. At step 612 the
instruction data is provided to an automated control system of the
passenger boarding bridge. At step 614, under the control of the
automated control system, the horizontal movement and the vertical
movement are performed for aligning the aircraft-engaging end of
the passenger boarding bridge with the doorway of the aircraft. As
described supra, in addition to the horizontal and vertical
movement there is also a rotational movement of the cabin 108,
which ensures proper alignment of the aircraft-engaging end 110 of
the cabin 108 with the aircraft fuselage.
[0053] Referring now to FIG. 7, shown is a simplified flow diagram
of a method according to an embodiment of the instant invention. In
particular, the method is for aligning an aircraft-engaging end of
a passenger boarding bridge with a doorway of an aircraft. At step
700 a visual docking guidance system (VDGS) is used to guide the
aircraft to a predetermined stopping position adjacent to the
passenger boarding bridge. At step 702 the aircraft-engaging end of
the passenger boarding bridge is positioned at a known position for
capturing an image of a portion of the aircraft that is proximate
an expected stopping location of the doorway. At step 704 an imager
disposed proximate the aircraft-engaging end of the passenger
boarding bridge is used to capture an image of the portion of the
aircraft that is proximate the expected stopping location of the
doorway. At step 706 orientation data is sensed, the orientation
data relating to tilt of the aircraft-engaging end of the passenger
boarding bridge relative a horizontal reference plane, and relating
to a distance between the aircraft-engaging end of the passenger
boarding bridge and the portion of the aircraft that is proximate
the expected stopping location of the doorway. At step 708 a
template image is retrieved from a memory element, the template
image relating to the doorway of the aircraft. At step 710 the
template image is transformed based on the sensed orientation data.
At step 712 instruction data is determined based on a comparison
between the transformed template image and the captured image, the
instruction data for moving the aircraft-engaging end of the
passenger boarding bridge into an aligned condition with the
doorway of the aircraft. At step 714, under the control of an
automated control system of the passenger boarding bridge, the
aircraft-engaging end of the passenger boarding bridge is moved in
accordance with the instruction data, so as to align the
aircraft-engaging end of the passenger boarding bridge with the
doorway of the aircraft.
[0054] Referring now to FIG. 8, shown is a simplified flow diagram
of a method according to an embodiment of the instant invention. In
particular, the method is for aligning an aircraft-engaging end of
a passenger boarding bridge with a doorway of an aircraft, the
aircraft stopped within a defined parking space adjacent to the
passenger boarding bridge. At step 800 moving the aircraft-engaging
end of the passenger boarding bridge to a known position adjacent
to an expected stopping location of the doorway of the aircraft;
capturing first image data using a first imager that is disposed
proximate the aircraft-engaging end of the passenger boarding
bridge, the first image data relating to a first portion of the
aircraft that is proximate the expected stopping location of the
doorway; capturing second image data using a second imager disposed
proximate the aircraft-engaging end of the passenger boarding
bridge, the second image data relating to a second portion of the
aircraft that is proximate the expected stopping location of the
doorway; sensing orientation data including tilt data, the
orientation data relating to an orientation of the
aircraft-engaging end of the passenger boarding bridge after moving
to the known position; retrieving template image data relating to
the doorway of the aircraft; transforming the template image data
based on the sensed orientation data; comparing separately the
captured first image data and the captured second image data with
the transformed template image data, so as to determine
independently first alignment data and second alignment data,
respectively; selecting one of the first alignment data and the
second alignment data based on a predefined selection criterion;
and aligning the aircraft-engaging end of the passenger boarding
bridge with the doorway of the aircraft based upon the selected one
of the first alignment data and the second alignment data.
[0055] At least two operating modes may be envisaged for those
embodiments of the instant invention that include only a single
imager 126. In a first operating mode the single imager 126
comprises a wide-angle lens that is capable of imaging a portion of
an aircraft that is sufficiently large to reliably capture features
that are useful for locating the doorway. It is optional but
advantageous to obtain distance values using two separate LRFs when
operating in the first operating mode. In a second operating mode
the bridge is moved to a first photo position and the single imager
126 is used to capture a first image, then the bridge is moved to a
second photo position and the single imager 126 is used to capture
a second image. Since the bridge is necessarily moved from one
photo position to another photo position when operating in the
second operating mode, reliable operation may be achieved even
using only a single LRF.
[0056] FIG. 9 is a simplified block diagram showing the connections
between components of a vision system according to another
embodiment of the instant invention. In FIG. 9, the camera
enclosure 114 is identical to the one that is described supra with
reference to FIG. 2. The connections are also similar to the ones
described with reference to FIG. 3, except that a second LRF 116 is
provided. Accordingly, FIG. 9 shows a system including an imager
126 and two separate laser range finders 132 and 116. As discussed
with reference to FIG. 5, once the passenger boarding bridge 102
stops at the photo position and the aircraft 100 stops at the
parking space, the LRFs 132 and 116 are used to sense the distance
to the aircraft 100, which is done under the control of controller
112. Controller 112 compares the distance value that is returned by
LRF 132 to a range of expected values. If the distance value falls
within the range of expected values then the distance value is
considered to be valid. However, in some instances the LRF 132 does
not return a valid distance value. For instance, if the LRF 132
coincidentally is directed toward a window of the aircraft or
toward an area of blue or other dark colored paint, then the
distance value that is returned by LRF 132 will fall outside the
range of expected values and is not likely to be valid. In such an
instance the controller 112 compares the distance value that is
measured using the second LRF 116 to a second range of expected
values. If the distance value that is measured by the second LRF
116 falls within the second range of expected values, then it is
considered to be valid for use during alignment. If neither the
first LRF 132 nor the second LRF 116 returns a valid distance
value, then the automated alignment operation is aborted and a
human operator is paged to complete the alignment manually.
[0057] FIG. 10 is a simplified block diagram showing the
connections between components of a vision system according to yet
another embodiment of the instant invention. The vision system of
FIG. 10 is similar to the vision system that was described with
reference to FIGS. 2 and 3, except that LRF 132 within camera
enclosure 114 is omitted, and LRF 116 is provided at a location
within the cabin 108 that is spatially separated from the camera
enclosure 114.
[0058] Numerous other embodiments may be envisaged without
departing from the spirit and scope of the invention.
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