U.S. patent application number 09/782040 was filed with the patent office on 2001-08-16 for lane guidance display method, and navigation device and recording medium for realizing the method.
Invention is credited to Ata, Teruaki, Hamada, Hiroyuki, Sakamoto, Kiyomi, Yamashita, Atsushi.
Application Number | 20010013837 09/782040 |
Document ID | / |
Family ID | 18561697 |
Filed Date | 2001-08-16 |
United States Patent
Application |
20010013837 |
Kind Code |
A1 |
Yamashita, Atsushi ; et
al. |
August 16, 2001 |
Lane guidance display method, and navigation device and recording
medium for realizing the method
Abstract
Based on searched route information and map data, a target
intersection for guidance is specified S11. For the specified
target intersection, lane data regarding the number of lanes and
lane control of roads being connected thereto is read, and then
recommended lane information which indicates which lane to take
when entering the target intersection and to exit therefrom is
generated S12. Based on information about the target intersection
and the lane data, generated is a simplified intersection image of
the target intersection for lane guidance S13. Based on the
recommended lane information, a running path which passes through
the recommended lanes for entering into and exiting from the target
intersection is generated, and is combined with the intersection
image S14. Then, lane guidance information for displaying the
resultant intersection image is outputted with a predetermined
timing S15. As such, guidance can be visually made on a screen
indicating which lanes to take to enter into and exit from the
intersection.
Inventors: |
Yamashita, Atsushi; (Osaka,
JP) ; Sakamoto, Kiyomi; (Ikoma, JP) ; Hamada,
Hiroyuki; (Yawata, JP) ; Ata, Teruaki; (Osaka,
JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
18561697 |
Appl. No.: |
09/782040 |
Filed: |
February 14, 2001 |
Current U.S.
Class: |
340/988 ;
340/990; 340/995.1; 701/533 |
Current CPC
Class: |
G08G 1/0969 20130101;
G01C 21/3658 20130101 |
Class at
Publication: |
340/988 ;
340/995; 340/990; 701/201; 701/202; 701/211 |
International
Class: |
G08G 001/123 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 16, 2000 |
JP |
2000-37873 |
Claims
What is claimed is:
1. A lane guidance display method for guiding, on a screen, a
vehicle which lane to take to go through an intersection, said
method comprising the steps of: searching for a guidance route from
a departure point to a destination or a stopover based on map data
including lane data, which is regarding the number of lanes and
lane control of roads to be connected to the intersection;
specifying an intersection for guidance (hereinafter, refers to as
a target intersection) located on said guidance route; determining,
based on said guidance route and said lane data, the recommended
enter lane for entering said target intersection and the
recommended exit lane for exiting therefrom; and guiding the
vehicle by displaying said recommended enter and exit lanes on the
screen.
2. The lane guidance display method according to claim 1, wherein
said guiding step comprises the steps of: generating an
intersection image of said target intersection for lane guidance
based on said lane data; generating a running path for said target
intersection which passes through both said recommended enter lane
and said recommended exit lane; and displaying, on the screen, a
lane guidance intersection image which is a combination of said
intersection image and said running path.
3. The lane guidance display method according to claim 2, wherein,
when said target intersection is plurally in proximity in a row,
said intersection image generated in said intersection image
generating step is a combination of the target intersections in
proximity, and said running path generated in said running path
generating step passes through said target intersections in
proximity.
4. The lane guidance display method according to claim 2, wherein,
specified as said target intersection in said specifying step are
all of the intersections found on said guidance route; and
displayed plurally and collectively in said displaying step is said
lane guidance intersection image in order of said target
intersections on said guidance route.
5. The lane guidance display method according to claim 2, wherein
said running path generated in said running path generating step is
represented by one or more successive arrows directing from said
recommended enter lane to said recommended exit lane.
6. The lane guidance display method according to claim 2, wherein,
in said determining step, additionally calculated for each exit
lane is a lane level of recommendation, which is represented by
discrete or successive numbers, and said running path generated in
said running path generating step is represented, in various
manners depending on said lane level of recommendation, by one or
more successive arrows directed from said recommended enter lane to
said recommended exit lane.
7. The lane guidance display method according to claim 5, wherein,
in said determining step, a ground for said recommended enter and
exit lanes is additionally found, and in said displaying step, an
image based on said ground is displayed together with said lane
guidance intersection image.
8. The lane guidance display method according to claim 6, wherein,
in said determining step, a ground for said recommended enter and
exit lanes is additionally found, and in said displaying step, an
image based on said ground is displayed together with said lane
guidance intersection image.
9. A navigation device for guiding a vehicle on a screen from a
departure point to a destination or a stopover, said device
comprising: a map data storage part for storing map data including
lane data, which is regarding the number of lanes and lane control
of roads to be connected to an intersection; a route search part
for searching for, based on said map data, a guidance route from
the departure point to the destination or the stopover; a vehicle
position detection part for detecting a vehicle position on said
map data; a target intersection operation part for searching for
and specifying, based on said guidance route and said map data, an
intersection for guidance on said guidance route (hereinafter,
refers to as a target intersection); the recommended lane operation
part for determining, based on said guidance route, said lane data,
and said target intersection, the recommended enter lane and the
recommended exit lane for said target intersection; a guidance part
for generating, based on said recommended enter and exit lanes and
said lane data, lane guidance data required for display on the
screen; and an output part for displaying guidance on the screen
according to said lane guidance data.
10. The navigation device according to claim 9, wherein, as said
lane guidance data, said guidance part generates an intersection
image for lane guidance based on said lane data for said target
intersection, generates a running path which passes through said
recommended enter lane and said recommended exit lane for said
target intersection, and generates a lane guidance intersection
image which is a combination of said intersection image and said
running path.
11. The navigation device according to claim 10, wherein, when said
target intersection is plurally in proximity in a row, said
intersection image generated by said guidance part is a combination
of the target intersections in proximity, and said running path
generated thereby passes through said target intersections in
proximity.
12. The navigation device according to claim 10, wherein said
target intersection operation part specifies all of the
intersections found on said guidance route as said target
intersection, and said guidance part outputs said lane guidance
data to said output part to plurally and collectively display said
lane guidance intersection image in order of said target
intersections on said guidance route.
13. The navigation device according to claim 10, wherein said
running path generated by said guidance part is represented by one
or more successive arrows directing from said recommended enter
lane to said recommended exit lane.
14. The navigation device according to claim 10, wherein
additionally calculated by said recommended lane operation part is
a lane level of recommendation for each exit lane represented by
discrete or successive numbers, and said running path generated by
said guidance part is represented, in various manners depending on
said lane level of recommendation, by one or more successive arrows
directed from said recommended enter lane to said recommended exit
lane.
15. The navigation device according to claim 13, wherein said
recommended lane operation part additionally finds a ground for
said recommended enter and exit lanes, and said guidance part
outputs said lane guidance data to said output part to display an
image based on said ground together with said lane guidance
intersection image.
16. The navigation device according to claim 14, wherein said
recommended lane operation part additionally finds a ground for
said recommended enter and exit lanes, and said guidance part
outputs said lane guidance data to said output part to display an
image based on said ground together with said lane guidance
intersection image.
17. A recording medium on which a lane guidance display method for
guiding, on a screen, a vehicle which lane to take to go through an
intersection is recorded as a program executable on a computer,
said program at least carries out the steps of: searching for a
guidance route from a departure point to a destination or a
stopover based on map data including lane data, which is regarding
the number of lanes and lane control of roads to be connected to
the intersection; specifying an intersection for guidance
(hereinafter, refers to as a target intersection) located on said
guidance route; determining, based on said guidance route and said
lane data, the recommended enter lane for entering said target
intersection and the recommended exit lane for exiting therefrom;
generating an intersection image of said target intersection for
lane guidance based on said lane data; generating a running path
for said target intersection which passes through both said
recommended enter lane and said recommended exit lane; and
displaying, on the screen, a lane guidance intersection image which
is a combination of said intersection image and said running
path.
18. The recording medium according to claim 17, wherein said
running path generated in said running path generating step is
represented by one or more successive arrows directing from said
recommended enter lane to said recommended exit lane.
19. The recording medium according to claim 17, wherein, in said
determining step, additionally calculated for each exit lane is a
lane level of recommendation, which is represented by discrete or
successive numbers, and said running path generated in said running
path generating step is represented, in various manners depending
on said lane level of recommendation, by one or more successive
arrows directed from said recommended enter lane to said
recommended exit lane.
20. The recording medium according to claim 18, wherein, in said
determining step, a ground for said recommended enter and exit
lanes is additionally found, and in said displaying step, an image
based on said ground is displayed together with said lane guidance
intersection image.
21. The recording medium according to claim 19, wherein, in said
determining step, a ground for said recommended enter and exit
lanes is additionally found, and in said displaying step, an image
based on said ground is displayed together with said lane guidance
intersection image.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a lane guidance display
method, and a navigation device and a recording medium for
realizing the method. More specifically, the lane guidance display
method is employed by the navigation device mounted in a vehicle,
for example, and used to guide the vehicle on a display which lane
to take to enter an intersection or exit therefrom. The recording
medium contains a program for executing this method.
[0003] 2. Description of the Background Art
[0004] There have been developed various navigation devices which
are of a type mounted in a vehicle, for example, to guide a vehicle
from a departure point to a destination or a stopover. Displayed by
such conventional navigation device is a map covering a driving
route with heading direction by voice, optionally, when needed. For
example, before an intersection at where the vehicle is supposed to
turn left, the driver hears such voice as "please take a left turn
at the next intersection".
[0005] At an intersection on a road with several lanes, the driver
may need to follow lane control when turning right or left, or
going straight. If this is the case, such guidance as "take a left
turn at the next intersection" is not helpful enough for the driver
to decide which lane to take. The driver has to look for traffic
signs and road markings, for example, for information relating such
lane control. The problem herein is, if the driver is unfamiliar
with the road, he/she may often find it difficult to decide which
lane to take until the last minute. The reason lies in the fact
that such information relating lane control (traffic signs, and the
like) is often presented in the very close vicinity of the
intersection. Therefore, when the driver is unfamiliar with the
road, such conventional route guidance does not provide him/her
with much assistance, and consequently results in sudden lane
change or failure in lane change, preventing the driver from
keeping track of the searched route.
[0006] To get around such problem, the recent type of navigation
device has started to guide the vehicle on the lane basis for
additional guidance. For example, Japanese Patent Laid-Open
Publication No. 2000-18956 discloses such vehicle-mounted
navigation device, providing a lane guidance by voice for every
intersection on a driving route between a departure point and a
destination or a stopover in consideration of heading direction.
For example, when the vehicle is supposed to turn left at the next
intersection, the driver hears a voice saying "please move into a
far left lane, and keep going" before hearing "please take a left
turn at the next intersection".
[0007] Here, if the driver is unskilled in driving or unfamiliar
with the area, he/she may also want to know on which lane he/she is
supposed to be when exiting the intersection. That is, in a case
where the vehicle needs to make turns in a row, for example first
left and then right, in a short distance on the roads with several
lanes, the most preferred is taking a far right lane after turning
left.
[0008] In such conventional navigation device as offering the lane
guidance only when the vehicle comes in close vicinity of an
intersection ahead, if the lane guidance cannot catch up with such
successive turns, one mistake of exiting from a wrong lane at the
first intersection will lead to failure in entering an appropriate
lane at the next intersection. This is because, the driver is more
likely to miss information relating lane control when exiting from
the intersection than entering. As a result, as described above,
this leads to sudden lane change or failure in lane change,
preventing the driver from keeping track of the searched route.
[0009] In the above conventional navigation device, lane guidance
is offered by voice as appropriate together with the map of running
route on the display. The issue here is, the driver needs to
correctly understand what the voice is saying (for example,
distinguish between "left turn" and "right turn"), and such lane
guidance by voice is not understandable at a glance and intuitive
as map display. Further, if the driver fails to hear the lane
guidance (for example, due to loud music or the driver being on the
cellular phone), the lane guidance does not provide him/her much
assistance.
SUMMARY OF THE INVENTION
[0010] Therefore, an object of the present invention is to provide
a lane guidance display method for displaying a map of running
route and guiding a vehicle which lane to take both at entering an
intersection and exiting therefrom, a navigation device for
employing the method, and a recording medium containing a program
for executing the method.
[0011] The present invention has the following features to attain
the object above.
[0012] A first aspect of the present invention is directed to a
lane guidance display method for guiding, on a screen, a vehicle
which lane to take to go through an intersection, the method
comprising the steps of:
[0013] searching for a guidance route from a departure point to a
destination or a stopover based on map data including lane data,
which is regarding the number of lanes and lane control of roads to
be connected to the intersection;
[0014] specifying an intersection for guidance (target
intersection) located on the guidance route;
[0015] determining, based on the guidance route and the lane data,
the recommended enter lane for entering the target intersection and
the recommended exit lane for exiting therefrom; and
[0016] guiding the vehicle by displaying the recommended enter and
exit lanes on the screen.
[0017] As described above, in the first aspect, lanes recommended
respectively for entering into and exiting from a target
intersection on a guidance route are determined, and then guidance
is preformed. Accordingly, a vehicle can be guided with such lanes
helpful for smooth travel, and therefore lane guidance offered
thereby is driver friendly.
[0018] Preferably, the guiding step comprises the steps of:
[0019] generating an intersection image of the target intersection
for lane guidance based on the lane data;
[0020] generating a running path for the target intersection which
passes through both the recommended enter lane and the recommended
exit lane; and
[0021] displaying, on the screen, a lane guidance intersection
image which is a combination of the intersection image and the
running path.
[0022] As such, the lanes recommended for entering into and exiting
from the intersection (recommended lanes) are represented by a
running path connecting the recommended lanes on an intersection
image (simplified, for example) of the target intersection.
Accordingly, guidance can be visually offered on a map covering the
running route on a screen. Thus, a driver of the vehicle can
understand at a glance how to go through the intersection by taking
which lane, and lane guidance made thereby is driver friendly.
[0023] Also preferably, when the target intersection is plurally in
proximity in a row, the intersection image generated in the
intersection image generating step is a combination of the target
intersections in proximity, and
[0024] the running path generated in the running path generating
step passes through the target intersections in proximity.
[0025] As such, by generating and displaying an intersection image
which is a combination of several target intersections, even if a
vehicle successively makes left and right turns in a short distance
and thus guidance cannot catch up therewith, the driver can figure
out at a glance how to go through the intersection by taking which
lane in advance.
[0026] Also preferably, specified as the target intersection in the
specifying step are all of the intersections found on the guidance
route; and
[0027] displayed plurally and collectively in the displaying step
is the lane guidance intersection image in order of the target
intersections on the guidance route.
[0028] As such, the driver can grasp recommended lanes for the
entire route in advance with no consideration for the distance
between the actual intersections and direction.
[0029] Here, the running path generated in the running path
generating step may be represented by one or more successive arrows
directing from the recommended enter lane to the recommended exit
lane.
[0030] In this manner, lane guidance offered thereby is driver
friendly as allowing the driver to understand how to go through the
intersection by taking which lane at a glance.
[0031] Further, in the determining step, additionally calculated
for each exit lane maybe a lane level of recommendation, which is
represented by discrete or successive numbers, and
[0032] the running path generated in the running path generating
step may be represented, in various manners depending on the lane
level of recommendation, by one or more successive arrows directed
from the recommended enter lane to the recommended exit lane.
[0033] In this manner, the running path can be represented by such
successive arrows in various manners depending on the lane level of
recommendation. This leaves lane selection to the driver's
discretion by showing him/her the level of recommendation for each
exit lane, and in this sense, lane guidance offered thereby is
driver friendly.
[0034] Still further, in the determining step, a ground for the
recommended enter and exit lanes may be additionally found, and
[0035] in the displaying step, an image based on the ground may be
displayed together with the lane guidance intersection image.
[0036] In this manner, together with the running path represented
by such successive arrows, the driver can see the grounds for the
lane recommendation, therefore can rest assured in addition to the
effects achieved in the foregoing.
[0037] A second aspect of the present invention is directed to a
navigation device for guiding a vehicle on a screen from a
departure point to a destination or a stopover, the device
comprising:
[0038] a map data storage part for storing map data including lane
data, which is regarding the number of lanes and lane control of
roads to be connected to an intersection;
[0039] a route search part for searching for, based on the map
data, a guidance route from the departure point to the destination
or the stopover;
[0040] a vehicle position detection part for detecting a vehicle
position on the map data;
[0041] a target intersection operation part for searching for and
specifying, based on the guidance route and the map data, an
intersection for guidance on the guidance route (target
intersection);
[0042] the recommended lane operation part for determining, based
on the guidance route, the lane data, and the target intersection,
the recommended enter lane and the recommended exit lane for the
target intersection;
[0043] a guidance part for generating, based on the recommended
enter and exit lanes and the lane data, lane guidance data required
for display on the screen; and
[0044] an output part for displaying guidance on the screen
according to the lane guidance data.
[0045] Preferably, as the lane guidance data, the guidance part
[0046] generates an intersection image for lane guidance based on
the lane data for the target intersection,
[0047] generates a running path which passes through the
recommended enter lane and the recommended exit lane for the target
intersection, and
[0048] generates a lane guidance intersection image which is a
combination of the intersection image and the running path.
[0049] Also preferably, when the target intersection is plurally in
proximity in a row, the intersection image generated by the
guidance part is a combination of the target intersections in
proximity, and the running path generated thereby passes through
the target intersections in proximity.
[0050] Also preferably, the target intersection operation part
specifies all of the intersections found on the guidance route as
the target intersection, and
[0051] the guidance part outputs the lane guidance data to the
output part to plurally and collectively display the lane guidance
intersection image in order of the target intersections on the
guidance route.
[0052] Here, the running path generated by the guidance part may be
represented by one or more successive arrows directing from the
recommended enter lane to the recommended exit lane.
[0053] Further, additionally calculated by the recommended lane
operation part may be a lane level of recommendation for each exit
lane represented by discrete or successive numbers, and
[0054] the running path generated by the guidance part may be
represented, in various manners depending on the lane level of
recommendation, by one or more successive arrows directed from the
recommended enter lane to the recommended exit lane.
[0055] Still further, the recommended lane operation part may
additionally find a ground for the recommended enter and exit
lanes, and
[0056] the guidance part may output the lane guidance data to the
output part to display an image based on the ground together with
the lane guidance intersection image.
[0057] As is the second aspect, a navigation device is so
structured as to execute the lane guidance display method of the
above first aspect, thereby performing the effective lane guidance
of the present invention.
[0058] A third aspect of the present invention is directed to a
recording medium on which a lane guidance display method for
guiding, on a screen, a vehicle which lane to take to go through an
intersection is recorded as a program executable on a computer, the
program at least carries out the steps of:
[0059] searching for a guidance route from a departure point to a
destination or a stopover based on map data including lane data,
which is regarding the number of lanes and lane control of roads to
be connected to the intersection;
[0060] specifying an intersection for guidance (hereinafter, refers
to as a target intersection) located on the guidance route;
[0061] determining, based on the guidance route and the lane data,
the recommended enter lane for entering the target intersection and
the recommended exit lane for exiting therefrom;
[0062] generating an intersection image of the target intersection
for lane guidance based on the lane data;
[0063] generating a running path for the target intersection which
passes through both the recommended enter lane and the recommended
exit lane; and
[0064] displaying, on the screen, a lane guidance intersection
image which is a combination of the intersection image and the
running path.
[0065] Here, the running path generated in the running path
generating step may be represented by one or more successive arrows
directing from the recommended enter lane to the recommended exit
lane.
[0066] Further, in the determining step, additionally calculated
for each exit lane may be a lane level of recommendation, which is
represented by discrete or successive numbers, and
[0067] the running path generated in the running path generating
step may be represented, in various manners depending on the lane
level of recommendation, by one or more successive arrows directed
from the recommended enter lane to the recommended exit lane.
[0068] Still further, in the determining step, a ground for the
recommended enter and exit lanes may be additionally found, and
[0069] in the displaying step, an image based on the ground may be
displayed together with the lane guidance intersection image.
[0070] As is the third aspect, a program carrying out the lane
guidance display method of the first aspect is recorded on a
medium, whereby the method can be supplied to an existing device in
the form of software.
[0071] These and other objects, features, aspects and advantages of
the present invention will become more apparent from the following
detailed description of the present invention when taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0072] FIG. 1 is a block diagram of the construction of a
navigation device employing a lane guidance display method
according to an embodiment of the present invention;
[0073] FIG. 2 is a flowchart showing an example of the operation of
a target intersection operation part, the recommended lane
operation part, and a guidance part;
[0074] FIG. 3 is an exemplary illustration of an intersection image
generated by the guidance part 7;
[0075] FIG. 4 is an exemplary illustration of an intersection image
generated by combining the running path generated under a first
technique with the intersection image of FIG. 3;
[0076] FIG. 5 is an exemplary illustration of an intersection image
generated by combining the running path generated under a second
technique with the intersection image of FIG. 3;
[0077] FIG. 6 is an exemplary illustration of an intersection image
generated by combining the running path generated under a third
technique with the intersection image of FIG. 3;
[0078] FIG. 7 is an illustration demonstrating a case where two
successive target intersections are in close proximity;
[0079] FIG. 8 is an exemplary illustration of an intersection image
generated under a fourth technique;
[0080] FIG. 9 is an exemplary illustration of an intersection image
displayed under a fifth technique; and
[0081] FIG. 10 is another exemplary illustration of an intersection
image displayed under the fifth technique.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0082] FIG. 1 is a block diagram showing the structure of a
navigation device employing a lane guidance display method
according to an embodiment of the present invention. In FIG. 1, the
navigation device includes an input part 1, a map data storage part
2, a route search part 3, a position detection part 4, a target
intersection operation part 5, the recommended lane operation part
6, a guidance part 7, and an output part 8.
[0083] The lane guidance display method of the present invention is
basically realized by the target intersection operation part 5, the
recommended lane operation part 6, and the guidance part 7. For
easy understanding, the entire navigation device employing the lane
guidance display method will be first outlined. Note that the
constructions of the input part 1, the map data storage part 2, the
route search part 3, the position detection part 4, and the output
part 8 are not restricted to those exemplified in the following
description, and any construction used in known navigation device
may be adopted. Here, the known navigation device is not restricted
to a vehicle-mounted type, and may be in the form of navigation
software operable on computer devices.
[0084] The input part 1 includes a remote controller, a touch
sensor, a keyboard, a mouse, and the like, operated by a user, for
example, and is used to input instructions such as selection of
functions of a map display unit (change of the item to be
processed, switch of the map, change of the hierarchical level, and
the like), setting of a departure point and a destination
(including a stopover, the same is applicable hereinafter), and
selection of a route search mode. Instruction information outputted
from the input part 1 is supplied to the route search part 3 and
the guidance part 7.
[0085] The map data storage part 2 includes an optical disk (CD,
DVD, and the like), a hard disk, a large-capacity memory, and the
like, for storing information relating a road network (map data)
such as the connection status, coordinates, shapes, attributes, and
information about lane control for respective intersections and
roads. The map data is assumed to include information about the
number of lanes and lane control of roads connected to the
respective intersections. The map data may be two-dimensional map
data or three-dimensional map data. The map data stored in the map
data storage part 2 is read and used as appropriate by the route
research part 3, the target intersection operation part 5, the
recommended lane operation part 6, and the guidance part 7.
[0086] The position detection part 4 includes a GPS, a radio beacon
receiver, a vehicle speed sensor, various speed sensors, an
absolute bearing sensor, and the like, for detecting the current
position of a vehicle. Information about the vehicle's current
position provided by the position detection part 4 is supplied to
the route search part 3 and the guidance part 7.
[0087] The route search part 3 reads map data in a necessary range
from the map data storage part 2 according to the instruction
information received from the input part 1. The route search part 3
then determines the departure point and the destination based on
the received instruction information such as location information,
and searches for a minimum-cost route from the departure point to
the destination in consideration of intersection traffic control
and one-way traffic control if any.
[0088] To state a specific example, upon receipt of an instruction
of executing the route search mode from the input part 1, the route
search part 3 sets, as the departure point of the search, either
the departure point inputted into the input part 1 or the vehicle's
current position detected by the position detection part 4, and
sets the destination inputted into the input part 1 as the
destination of the search. The route search part 3 also reads map
data in a range covering the area from the departure point to the
destination from the map data storage part 2. Then, the route
search part 3 searches for a guidance route (for example, a
shortest-time route or a shortest-distance route) from the
departure point to the destination on the read map data. As an
algorithm for the route search executed by the route search part 3,
known Dijkstra algorithm, for example, is used.
[0089] Upon completion of the route search, the route search part 3
outputs the resultant route information to the target intersection
operation part 5, the recommended lane operation part 6, and the
guidance part 7.
[0090] The target intersection operation part 5 searches and
specifies any intersection on the searched route based on the route
information received from the route search part 3 and the map data
(the same map data as the one read by the route search part 3)
received from the map data storage part 2 (hereinafter, thus
specified intersection is referred to as target intersection).
Here, specified may be every intersection found on the searched
route, or only any specific intersection required to be guided in a
predetermined manner. The specific intersection includes that where
roads with several lanes intersect with one another or where the
vehicle is supposed to turn right or left. Information about those
specified target intersections is outputted to the recommended lane
operation part 6 and the guidance part 7.
[0091] For each of those target intersections, the recommended lane
operation part 6 then determines which lane to recommend the driver
respectively for entering and exiting, and generates information
about thus determined recommended lanes. This determination is made
based on the map data (the number of lanes, lane control
information, and the like) received from the map data storage part
2, the route information from the route search part 3, and the
information about those target intersections provided by the target
intersection operation part 5. Thus generated recommended lane
information is outputted to the guidance part 7.
[0092] Upon receipt of an instruction of executing a route guidance
mode from the input part 1, the guidance part 7 generates guidance
information for directional guidance on the map. This is done based
on the route information provided by the route search part 3, the
information about the vehicle's current position received from the
position detection part 4, and the map data received from the map
data storage part 2. The guidance part 7 also executes a
predetermined operation to be described later, based on the map
data, the target intersection information received from the target
intersection operation part 5, and the recommended lane information
provided by the recommended lane operation part 6, and generates
lane guidance information for each of the target intersections. The
guidance part 7 then outputs the guidance information and the lane
guidance information to the output part 8 with a predetermined
timing.
[0093] The output part 8 includes a display device (a liquid
crystal display, a CRT display, and the like) and displays an image
for guidance on a screen based on the guidance information and the
lane guidance information received from the guidance part 7.
[0094] Hereinafter, with reference to FIGS. 2 to 10, the lane
guidance display method of this embodiment will be described in a
concrete manner.
[0095] FIG. 2 is a flowchart showing an example of the operation
executed by the target intersection operation part 5, the
recommended lane operation part 6, and the guidance part 7 of FIG.
1. FIG. 3 is an exemplary illustration of an intersection image
generated by the guidance part 7. FIGS. 4 to 6 are illustrations of
intersection images each generated by combining the intersection
image of FIG. 3 with a running path, which is generated under
later-described first to third techniques, respectively. FIG. 7 is
an illustration demonstrating a case where two successive target
intersections are in close proximity. FIG. 8 is an exemplary
illustration of an intersection image generated under a fourth
technique. FIGS. 9 and 10 are exemplary illustrations of
intersection images displayed under a fifth technique.
[0096] First, referring to FIG. 2, the target intersection
operation part 5 searches and specifies any target intersection for
guidance based on the route information received from the route
search part 3 and the map data received from the map data storage
part 2 (step S11). Then, for each of those specified target
intersections, the recommended lane operation part 6 reads data
relating the number of lanes of roads to be connected, the lane
control, and the like (hereinafter, lane data) from the map data
storage part 2, and generates recommended lane information (step
S12). This recommended lane information indicates which lanes are
recommended for the driver's entering into and exiting from the
intersection. For example, in a case where a vehicle on a 4-lane
road M turns right at an arbitrary target intersection A to enter a
3-lane road N, and then turns left at the next target intersection
B, the recommended lane information to be generated for the target
intersection A is "to enter (road M): far-right lane, to exit (road
N): far-left lane".
[0097] Next, based on the target intersection information provided
by the target intersection operation part 5 and the lane data read
from the map data storage part 2, the guidance part 7 generates an
intersection image for each of the target intersections (step S13).
Here, the intersection image is simplified optimally for lane
guidance, and referred to here is information about the number of
lanes on roads to be connected to the intersection and the bearings
at which the roads are connected thereto. FIG. 3 shows an exemplary
simplified intersection image generated thereby. For each of the
target intersections, the guidance part 7 then generates, based on
the recommended lane information received from the recommended lane
operation part 6, a running path which passes through the
recommended enter and exit lanes. Thus generated running paths are
each combined with the corresponding intersection image (step S14).
The guidance part 7 then outputs the lane guidance information to
the output device 8 with a predetermined timing (for example, 500 m
before the target intersection) to display thus generated
intersection image on a display thereof (step S15).
[0098] Upon completion of steps S11 to S15, displayed for lane
guidance are such simplified images of the target
intersections.
[0099] With reference to FIGS. 4 to 10, next to be described is the
techniques, in more concrete manner, for generating a running path
and combining the path with an intersection image (step S14
described above). In the description below, presumably, the
recommended enter lane is a far right, and the recommended exit
lane a far left.
[0100] First, with a first technique, generated is a running path
represented by one arrow directing from the recommended enter lane
to the recommended exit lane (FIG. 4).
[0101] The first technique allows the driver to understand at a
glance how to go through the intersection by taking which lane. In
this sense, lane guidance offered thereby is driver friendly.
[0102] Next, with a second technique, generated are several running
paths each represented by an arrow, sharing the same recommended
enter lane but directing to each different exit lane. Here, those
arrows are differently colored depending on their level of
recommendation, indicating from which lane the driver is more
advised to exit the intersection (FIG. 5a). The arrows may be
changed in width depending on their level of recommendation (FIG.
5b). With the second technique, the recommended lane operation part
6 needs to calculate, in step S12, the level of recommendation for
each exit lane. The level of recommendation may be represented by
discrete or consecutive numbers. Here, the level of recommendation
can be freely set depending on conditions such as a distance to the
next target intersection, any decrease in road width, or the
presence or absence of a bus stop.
[0103] The second technique also allows the driver to understand at
a glance how to go through the intersection by taking which lane,
and furthermore, leaves lane selection to the driver's discretion
by showing him/her the level of recommendation for each exit lane.
In this sense, lane guidance offered thereby is more driver
friendly.
[0104] Under a third technique, displayed are grounds for lane
recommendation in addition to the running path generated based on
the above first and second techniques (FIGS. 6a and 6b). With the
third technique, the recommended lane operation part 6 needs to
calculate and find, in step S12, the grounds for the lane
recommendation for each target intersection based on the searched
route and the lane data. In FIGS. 6a and 6b, icons are used to show
the driver the distance and the heading direction to the next
intersection, thereby succeeding in explicitly indicating the
driver the grounds for the lane recommendation.
[0105] With the third technique, together with the effects achieved
under the first and second techniques, the driver can additionally
see the grounds for the lane recommendation, therefore can rest
assured.
[0106] Next, a fourth technique is applied to a case where two or
more successive target intersections are in close proximity (see
FIG. 7). Displayed in such case is one intersection image which is
the combination of these target intersection images (see FIG. 8).
In FIGS. 7 and 8, two target intersections x and y are exemplarily
in close proximity.
[0107] With the fourth technique, the target intersection operation
part 5 determines whether two or more target intersections among
those specified in step S11 are located in a row in close
proximity. If determined yes, a flag is set in the target
intersection information. The guidance part 7 then refers to the
flag, and generated in step S13 thereby becomes a simplified
intersection image which is the combination of those target
intersections (combined intersection image). Lastly, the guidance
part 7 represents a running path between the recommended enter lane
and the recommended exit lane by one or more arrows. In FIG. 8. the
running path is exemplarily represented by two arrows.
[0108] The fourth technique is effective for a case where guidance
has to be continuously displayed at short intervals, for example,
where the vehicle successively makes left and right turns in a
short distance by displaying one combined intersection image.
Therefore, the driver can figure out at a glance what is coming and
how to go through the intersections ahead in advance.
[0109] Described next is a fifth technique, which displays all of
the target intersections on the searched route in order (see FIG.
9). With the fifth technique, every intersection image generated by
the guidance part 7 for each target intersection is outputted to
the output part 8 in order from the departure point.
[0110] In this manner, the driver can grasp the entire route in
advance with the information about the recommended lanes for
intersections ahead. Here, the information is presented with no
consideration for the distance between the intersections and
direction. If all intersection images do not fit in a screen, the
screen may be scrolled up manually by the user or automatically. As
shown in FIG. 10, the information may be displayed additionally
with the distance between the intersections, the intersections by
name, roads by number, and the like. Under the fifth technique, a
lane image representing only the lane control information in a
simplified manner may be presented together with the intersection
image.
[0111] As described in the foregoing, with the lane guidance
display method of the present invention, a running path between
recommended lanes for entering into and exiting from a target
intersection is represented by one or more arrows, achieving visual
guidance on a map which covers the running path.
[0112] Accordingly, the lane guidance offered thereby is driver
friendly as the driver can understand at a glance how to go through
a target intersection by taking which lane.
[0113] With the first to fifth techniques, a running path is
presumably represented by one or more arrows directing from the
recommended enter lane to the recommended exit lane, that is, by a
solid line (FIGS. 4 to 6, and 8 to 10). This is not restrictive,
and may be a broken or dotted line as long as it serves as a
running path, may be an arrow structured by small-sized arrows, or
may be represented by successively arranged objects such as circle
(dot) and triangle.
[0114] While the invention has been described in detail, the
foregoing description is in all aspects illustrative and not
restrictive. It is understood that numerous other modifications and
variations can be devised without departing from the scope of the
invention.
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