Apparatus for detecting the travel path of a vehicle using image analysis

• US 5,301,115 A
• Filed: 05/31/1991
• Issued: 04/05/1994
• Est. Priority Date: 06/01/1990
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Nouso, Kazunori
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US07/707,144
• Time in Patent Office: 1,040 Days
• Field of Search: 364/443, 364/444, 364/424.02, 364/572, 364/575, 364/424.01, 364/460, 358/103, 180/167, 180/168, 180/169
• US Class Current: 701/300
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30256 Lane; Road marking
• CPC Class Codes: G06T 7/12 Edge-based segmentation
• CPC Class Codes: G06V 10/44 Local feature extraction by analysis of parts of the pattern, e.g. by detecting edges, contours, loops, corners, strokes or intersections; Connectivity analysis, e.g. of connected components
• 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

Abstract

An apparatus for detecting a vehicle path along which a vehicle is traveling. An image of a road presented in front of the vehicle is inputted at intervals of time. The inputted image is processed to detect edge points forming edges in the inputted image and edge gradients at the respective edge points. At least one straight line is assumed. Edge points at which the edge gradients are in a predetermined range determined by the gradient of the assumed straight line are extracted. The extracted edge points are used to calculate an approximate straight line. The approximate straight line has a greatest number of extracted edge points at which the edge gradients are substantially the same. The assumed straight line and the approximate straight line are averaged to provide a new straight line representing one of road sides and/or lane markers.

Claims

1. An apparatus for detecting a vehicle path along which a vehicle is traveling, comprising:

image input means for inputting an image of a road presented in front of the vehicle at intervals of time;

edge point detecting means for processing the inputted image to detect edge points forming edges in the inputted image and edge gradients at the respective edge points;

means for assuming at least one straight line having a gradient;

means for extracting edge points at which the edge gradients are in a predetermined range determined by the gradient of the assumed straight line;

means for calculating an approximate straight line from the extracted edge points, the approximate straight line having a greatest number of extracted edge points at which the edge gradients are substantially the same; and

means for averaging the assumed straight line and the approximate straight line to provide a new straight line representing one of road sides and/or lane markers;

memory means for storing the new straight line;

the assumed straight line being a last straight line stored in the memory means just before the new straight line is stored.

2. The apparatus as claimed in claim 1, wherein the edge point extracting means includes means for setting a window near the assumed straight line, and means for searching edge points within the window to extract the edge points.

3. The apparatus as claimed in claim 1, wherein the averaging means includes means for providing a first weight for the approximate straight line and a second weight to the assumed straight line, means for increasing the first weight and decreasing the second weight as the greatest number of the extracted edge points increases, and means for averaging the weighted straight lines.

4. An apparatus for detecting a vehicle path along which a vehicle is traveling, comprising:

image input means for inputting an image of a road presented in front of the vehicle at intervals of time;

edge point detecting means for processing the inputted image to detect edge points forming edges in the inputted image and edge gradients at the respective edge points;

means for assuming at least one straight line having a gradient;

means for extracting edge points at which the edge gradients are in a predetermined range determined by the gradient of the assumed straight line;

means for calculating an approximate straight line from the extracted edge points, the approximate straight line having a greatest number of extracted edge points at which the edge gradients are substantially the same; and

means for averaging the assumed straight line and the approximate straight line to provide a new straight line representing one of road sides and/or lane markers;

the straight line assuming means including means for assuming first and second straight lines having different gradients;

the edge point extracting means including means for extracting edge points at which the edge gradients are in a first predetermined range determined by the gradient of the first assumed straight line, and means for extracting edge points at which the edge gradients are in a second predetermined range determined by the gradient of the second assumed straight line;

the approximate straight line calculating means including means for calculating a first approximate straight line from the extracted edge points, the first approximate straight line having a greatest number of extracted edge points at which the edge gradients are substantially the same in the first predetermined range, and means for calculating a second approximate straight line from the extracted edge points, the second approximate straight line having a greatest number of extracted edge points at which the edge gradients are substantially the same in the second predetermined range; and

the averaging means including means for averaging the first approximate straight line and the first assumed straight line to provide a first new straight line representing one of road sides and/or lane markers, and means for averaging the second approximate straight line and the second assumed straight line to provide a second new straight line representing another road side or lane marker.

5. The apparatus as claimed in claim 4, further including means for detecting left and right lane markers defining an existing lane on which the vehicle is traveling, means for detecting edge points existing between the left and right lane markers, and means for detecting an obstacle when edge points exist continuously between the left and right lane markers for a first time.

6. The apparatus as claimed in claim 4, further including means for calculating an approximate curve of secondary degree from the edge points extracted for calculating one of the first and second approximate straight lines, and means for calculating a degree of curvature of the existing lane based upon the calculated approximate curve.

7. An apparatus for detecting a vehicle path along which a vehicle is traveling, comprising:

image input means for inputting an image of a road presented in front of the vehicle at intervals of time;

edge points detecting means for processing the inputted image to detect edge points forming edges in the inputted image and edge gradients at the respective edge points;

means for assuming at least one straight line having a gradient;

means for extracting edge points at which the edge gradients are in a predetermined range determined by the gradient of the assumed straight line;

means for calculating an approximate straight line from the extracted edge points, the approximate straight line having a greatest number of extracted edge points at which the edge gradients are substantially the same; and

means for averaging the assumed straight line and the approximate straight line to provide a new straight line representing one of road sides and/or lane markers;

the straight line assuming means including means for assuming first, second and third straight lines having different gradients;

the edge point extracting means including means for extracting edge points at which the edge gradients are in a first predetermined range determined by the gradient of the assumed first straight line, means for extracting edge points at which the edge gradients are in a second predetermined range determined by the gradient of the assumed second straight line, and means for extracting edge points at which the edge gradients are in a third predetermined range determined by the gradient of the assumed third straight line;

the approximate straight line calculating means including means for calculating a first approximate straight line having a greatest number of extracted edge points at which the edge gradients are substantially the same in the first predetermined range, means for calculating a second approximate straight line from the extracted edge points, the second approximate straight line having a greatest number of extracted edge points at which the edge gradients are substantially the same in the second predetermined range, and means for calculating a third approximate straight line from the extracted edge points, the third approximate straight line having a greatest number of extracted edge points at which the edge gradients are substantially the same in the third predetermined range; and

the averaging means including means for averaging the first approximate straight line and the assumed first straight line to provide a first new straight line representing one of the road sides and/or lane markers, means for averaging the second approximate straight line and the assumed second straight line to provide a second new straight line representing another road side or lane marker, and means for averaging the third approximate straight line and the assumed third straight line to provide a third new straight line representing another road side or lane marker.

8. The apparatus as claimed in claim 7, further including means for detecting left and right lane markers defining an existing lane on which the vehicle is traveling, means for detecting edge points existing between the left and right lane markers, and means for detecting an obstacle when edge points exist continuously between the left and right lane markers for a first time.

9. The apparatus as claimed in claim 7, further including means for calculating an approximate curve of secondary degree from the edge points extracted for calculating one of the first, second and third approximate straight lines, and means for calculating a degree of curvature of the existing lane based upon the calculated approximate curve.