# US 9,436,878 B2 · Lane mark recognition device

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- Number: US 9,436,878 B2
- Document ID: US9436878B2
- Status: Granted
- Kind: B2
- Application number: 14/658,620
- Filed: 2015-03-16
- Published: 2015-10-01
- Granted: 2016-09-06
- Earliest claimed: 2014-04-01
- Assignees: Honda Motor Co., Ltd.
- Applicants: Honda Motor Co., Ltd.
- Inventors: Yosuke Sakamoto
- Web page: https://patentgrep.com/patent/US9436878B2

## CPC

- G06T 7/13: Edge detection
- B62D 15/025: {Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation (B62D1/28 takes precedence)}
- G06V 10/56: relating to colour
- G06V 10/60: relating to illumination properties, e.g. using a reflectance or lighting model
- G06V 20/588: {Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road}
- G06T 2207/10024: Color image
- G06T 2207/30256: Lane; Road marking
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M)
- G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING

## Abstract

An edge image generating unit 12 generates an edge image, into which edge points whose variation in luminance relative to a surrounding portion is equal to or more than a predetermined value have been extracted, from an image captured by a camera 2. A candidate image portion extracting unit 13 extracts a candidate image portion, which is a candidate for an image portion of a lane mark, from the edge image. A lane mark recognizing unit 14 detects a lane mark candidate on the basis of the candidate image portion and, in the case of having detected a plurality of lane mark candidates 51b to 54b and 61b to 63b adjacent to each other, compares the luminance of a corresponding area in the captured image for each of the lane mark candidates and recognizes the lane mark candidate 51b to 54b having the maximum luminance value as a lane mark.

## Claims

### Claim 1

A lane mark recognition device which recognizes a lane mark provided on a road based, comprising:
a vehicle having a camera configured to capture an image of surroundings of the vehicle; and
an electronic control unit including at least a processor and a non-transitory computer readable medium containing instructions for controlling the processor to:
generate an edge image, into which edge points whose variation in luminance relative to a surrounding portion is equal to or more than a predetermined value have been extracted, from the image captured by the camera;
extract a candidate image portion, which is a candidate for an image portion of the lane mark, from the edge image; and
detect a lane mark candidate based on the candidate image portion and, in a case of having detected at least a pair of lane mark candidates determine whether a distance between the pair of lane mark candidates on the road is equal to or less than a threshold value, and in a case that the distance is equal to or less than a threshold value, calculate a reference value based on a luminance of a corresponding area in the captured image with respect to each of the at least a pair of lane mark candidates and recognize a lane mark candidate having a maximum reference value as a lane mark; and
perform steering control of the vehicle so that the vehicle travels within a lane demarcated by the lane mark.

### Claim 2 (depends on 1)

The lane mark recognition device according to claim 1, wherein:
the camera is a color camera;
the lane mark recognizing unit recognizes a lane mark having a specific color; and
the reference value is a value indicating a degree of the specific color of the corresponding area.

### Claim 3 (depends on 1)

The lane mark recognition device according to claim 1, wherein the reference value is a luminance value of the corresponding area.

### Claim 4 (depends on 1)

The lane mark recognition device according to claim 1, wherein the lane mark recognizing unit determines whether or not the plurality of lane mark candidates include a continuous-line lane mark and a dashed-line lane mark in a case where a difference in the reference value between the plurality of lane mark candidates adjacent to each other is equal to or less than a predetermined value and recognizes the plurality of lane mark candidates as a composite-line lane mark in a case where the plurality of lane mark candidates include the continuous-line lane mark and the dashed-line lane mark.

### Claim 5

A vehicle comprising:
a camera which captures an image of surroundings;
an edge image generating unit which generates an edge image, into which edge points whose variation in luminance relative to a surrounding portion is equal to or more than a predetermined value have been extracted, from the image captured by the camera;
a candidate image portion extracting unit which extracts a candidate image portion, which is a candidate for an image portion of a lane mark, from the edge image;
a lane mark recognizing unit which detects a lane mark candidate based on the candidate image portion and, in a case of having detected at least a pair of lane mark candidates determines whether a distance between the pair of lane mark candidates on the road is equal to or less than a threshold value, and in a case that the distance is equal to or less than a threshold value, calculates a reference value based on a luminance of a corresponding area in the captured image with respect to each of the at least a pair of lane mark candidates and recognizes a lane mark candidate having a maximum reference value as a lane mark; and
a steering control unit which performs steering control of the vehicle so that the vehicle travels within a lane demarcated by the lane mark recognized by the lane mark recognizing unit.

### Claim 6

A lane mark recognition method of recognizing a lane mark provided on a road based on an image of surroundings of a vehicle captured by a camera mounted in the vehicle, comprising:
an edge image generating step of generating an edge image, into which edge points whose variation in luminance relative to a surrounding portion is equal to or more than a predetermined value have been extracted, from the image captured by the camera;
a candidate image portion extracting step of extracting a candidate image portion, which is a candidate for an image portion of the lane mark, from the edge image;
a lane mark recognizing step of detecting a lane mark candidate based on the candidate image portion and, in a case of having detected at least a pair of lane mark candidates determining whether a distance between the pair of lane mark candidates on the road is equal to or less than a threshold value, and in a case that the distance is equal to or less than a threshold value, calculating a reference value based on a luminance of a corresponding area in the captured image with respect to each of the at least a pair of lane mark candidates and recognizing a lane mark candidate having a maximum reference value as a lane mark; and
a steering control step which performs steering control of the vehicle so that the vehicle travels within a lane demarcated by the lane mark recognized in the lane mark recognizing step.