Lane detection sensor and navigation system employing the same

• US 5,922,036 A
• Filed: 05/28/1997
• Issued: 07/13/1999
• Est. Priority Date: 05/28/1996
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Kaneko, Mamoru, Iisaka, Atsushi, Yasui, Nobuhiko
• Primary Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US08/864,428
• Time in Patent Office: 776 Days
• Field of Search: 701/28, 701/23, 701/30, 701/93, 701/96, 701/98, 701/117, 701/300, 701/301, 340/435, 340/436, 340/937, 340/439, 340/905, 340/990, 348/118, 348/113, 382/168, 382/281, 382/104, 382/154
• US Class Current: 701/28
• CPC Class Codes: B60T 2201/08 Lane monitoring; Lane Keeping Systems
• CPC Class Codes: B60T 2201/089 using optical detection
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS
• CPC Class Codes: G06V 10/48 by mapping characteristic values of the pattern into a parameter space, e.g. Hough transformation
• CPC Class Codes: G06V 20/588 Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road
• CPC Class Codes: G08G 1/04 using optical or ultrasonic detectors

Abstract

A lane detection sensor for detecting opposite lane markers of a road, comprising: an image shooting member for shooting an image of the road ahead of a running motor vehicle; an image data memory for storing data on the image of the road from the image shooting member; a contour point extracting member for extracting, by using the data on the image of the road stored in the image data memory, contour points corresponding to the lane markers of the road; a curve detecting member for calculating polynomial curves by using the contour points corresponding to the lane markers of the road from the contour point extracting member; a Hough transformation limiting member for bounding a region of Hough transformation by using coefficients of the polynomial curves calculated by the curve detecting member; a Hough transformation member for performing Hough transformation by using the polynomial curves from the curve detecting member and the region of Hough transformation bounded by the Hough transformation limiting member; and a Hough transformation detecting member which obtains a maximum value of accumulators in Hough space so as to detect a curve corresponding to the maximum value of the accumulators.

Claims

1. A lane detection sensor for detecting opposite lane markers of a road, comprising:

an image shooting means for shooting an image of the road ahead of a running motor vehicle;

an image data memory means for storing data on the image of the road from the image shooting means;

a contour point extracting means for extracting, by using the data on the image of the road stored in the image data memory means, contour points corresponding to the lane markers of the road;

a curve detecting means for calculating polynomial curves by using the contour points corresponding to the lane markers of the road extracted by the contour point extracting means;

a Hough transformation limiting means for bounding a region of Hough transformation by using coefficients of the polynomial curves calculated by the curve detecting means;

a Hough transformation means for performing Hough transformation by using the polynomial curves from the curve detecting means and the region of Hough transformation bounded by the Hough transformation limiting means; and

a Hough transformation detecting means for obtaining a maximum value of accumulators in Hough space so as to detect a curve corresponding to the maximum value of the accumulators.

2. A lane detection sensor as claimed in claim 1, wherein the curve detecting means is for calculating a plurality of the polynomial curves by using plural ones of the contour points and the Hough transformation means is for adding a predetermined numerical value to an array of the accumulators corresponding to the coefficients of the polynomial curves in Hough space bounded by the Hough transformation limiting means.

3. A lane detection sensor for detecting opposite lane markers of a road, comprising:

an image shooting means for shooting an image of the road ahead of a running motor vehicle;

an image data memory means for storing data on the image of the road from the image shooting means;

a contour point extracting means for extracting, by using the data on the image of the road stored in the image data memory means, contour points corresponding to the lane markers of the road;

a divisional curve detecting means for vertically dividing the image into a plurality of image sections and calculating a polynomial curve in each of the image sections from the contour points contained in each of the image sections;

a divisional curve storage means for storing the polynomial curve calculated by the divisional curve detecting means;

a resolution changing means for drawing the polynomial curve stored in the divisional curve storage means on the image and lowering resolution of the image;

a curve contour point detecting means for obtaining further contour points by using the lower resolution image from the resolution changing means; and

an overall curve detecting means for obtaining a further polynomial curve by using the further contour points obtained by the curve contour point detecting means.

4. A lane detection sensor for detecting opposite lane markers of a road, comprising:

an image shooting means for shooting an image of the road ahead of a running motor vehicle;

a contour point extracting means for extracting from data on the image of the road from the image shooting means, contour points corresponding to the lane markers of the road;

a map data base for storing data on the road on a map;

a GPS (global positioning system) calculating means for estimating the position of the motor vehicle upon reception of electromagnetic wave a signal from a GPS;

a wheel speed measuring means for measuring a wheel speed of the motor vehicle;

a map matching means for estimating position of the motor vehicle on the map through map matching based on pulses of the wheel speed from the wheel speed measuring means and the data on the road on the map from the map data base;

a vehicle position determining means for determining the position of the motor vehicle accurately by using the position of the motor vehicle estimated by the GPS calculating means from the GPS and the position of the motor vehicle estimated by the map matching means;

a data retrieval means for retrieving data on the road ahead of the running motor vehicle from the map data base on the basis of the position of the motor vehicle determined by the vehicle position determining means; and

an extraction means from preliminarily calculating the shape of the road on the image on the basis of the data retrieved by the data retrieval means and obtaining a correlation between the calculated shape of the road and the shape of the road predicted from the contour points of the contour point extracting means so as to extract the lane markers of the road.

5. A lane detection sensor for detecting opposite lane markers of a road, comprising:

an image shooting means for shooting an image of the road ahead of a running motor vehicle;

a contour point extracting means for extracting from data on the image of the road from the image shooting means, contour points corresponding to the lane markers of the road;

a pattern storage means for preliminarily storing a plurality of patterns of the shape of the road as observed from the image shooting means disposed at a height from a road surface and at a dip relative to the horizon; and

a lane detection means for obtaining a correlation between the contour points extracted by the contour points extracting means and the plurality of patterns of the shape of the road stored in the pattern storage means so as to detect the lane markers of the road.

6. An arithmetic unit for calculating a radius of curvature of a road ahead of a running motor vehicle, comprising:

an image shooting means for shooting an image of the road;

a contour point extracting means for extracting from data on the image of the road from the image shooting means, contour points corresponding to opposite lane markers of the road;

a tangent calculating means for obtaining, by using the contour points from the contour point extracting means, two tangents at two positions spaced arbitrary distances from a point ahead of the motor vehicle;

a coordinate transformation means for transforming the two tangents from the tangent calculating means into a real global system of coordinates; and

a calculating means for approximately calculating from an angle formed between the two tangents in the real global system of coordinates, the radius of curvature of a lane on which the motor vehicle is running.

7. A navigation system comprising:

an image shooting means for shooting an image of a road ahead of a running motor vehicle;

a contour point extracting means for extracting from data on the image of the road from the image shooting means, contour points corresponding to opposite lane markers of the road;

a lane detecting means for detecting, by using the contour points from the contour point extracting means, the road on which the motor vehicle is running and the lane markers of lanes of the road;

a map data base for storing data on the road on a map;

a GPS (global positioning system) calculating means for estimating the current position of the motor vehicle upon reception of signal from a GPS;

a road condition detecting means for obtaining width and the number of the lanes from position and shape of the lane markers in the image from the lane detecting means;

a road condition storage means for storing, in accordance with the current position of the motor vehicle from the GPS calculating means, the width and the number of the lanes from the road condition detecting means in association with the data on the road on the map of the map data base; and

a display means for displaying the current position of the motor vehicle from the GPS calculating means, the data on the road on the map from the map data base and data on the road on which the motor vehicle is running, from the road condition storage means.

8. A navigation system comprising:

an image shooting means for shooting an image of a road ahead of a running motor vehicle;

a contour point extracting means for extracting from data on the image of the road from the image shooting means, contour points corresponding to opposite lane markers of the road;

a lane detecting means for detecting, by using the contour points from the contour point extracting means, the road on which the motor vehicle is running and the lane markers of lanes of the road;

a map data base for storing data on the road on a map;

a destination input means for inputting a destination of the motor vehicle;

a running route determining means for determining a running route of the motor vehicle from the destination of the destination input means and the data on the road on the map of the map data base;

a GPS (global positioning system) calculating means for estimating the current position of the motor vehicle upon reception of a signal from a GPS;

a road condition detecting means for obtaining the number of the lanes and data on a lane having the motor vehicle running thereon, from a position and shape of the lane markers in the image from the lane detecting means;

a guide means for obtaining, by using the data on the road on the map from the map data base, the running route from the running route determining means, the estimated current position of the motor vehicle from the GPS calculating means and the number of the lanes and the data on the lane having the motor vehicle running thereon from the road condition detecting means, a lane to be taken so as to determine a shifting direction of the motor vehicle and position of the lane to be taken; and

a data conveying means for informing a driver of the motor vehicle of data on the shifting direction of the motor vehicle and the position of the lane to be taken, from the guide means.