Method for modeling roadway and method for recognizing lane markers based on the same

• US 6,133,824 A
• Filed: 08/24/1999
• Issued: 10/17/2000
• Est. Priority Date: 10/13/1998
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kwon, Woong, Lee, Suk-han, Roh, Kyoung-sig, Shin, Dong-mok, Lee, Jae-won, Kim, Dong-yoon
• Primary Examiner(s): Lee, Benjamin C.
• Application Number:
  US09/379,594
• Time in Patent Office: 420 Days
• Field of Search: 340/435, 340/439, 340/937, 340/436, 348/118, 180/168, 180/167, 382/168, 382/199, 382/281, 382/291, 382/103, 382/104, 701/28, 701/300, 701/301
• US Class Current: 340/435
• CPC Class Codes: B60Q 9/008 for anti-collision purposes
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• 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

A method for modeling a roadway and a method for recognizing lane markers based on the modeling method. The method for recognizing lane markers of roadway for a vehicle by getting image information about the roadway and information about the speed and steering angle using a camera and a sensor attached to the vehicle, includes the steps of modeling the actual roadway on which the vehicle travels, as a structure having a plurality of rectangular plates linked to each other. The modeled plates are overlayed onto the image information about the actual roadway, photographed by the camera, pixels forming the lane markers are extracted, and linear lane marker information is then obtained from the pixels forming the land markers. Then, the linear lane marker information is overlayed onto the modeled plates to recalculate lane marker information using the plates as a frame, and predetermined limitations of the features of the lane markers are applied to the plates onto which the linear lane marker information has been overlayed, to optimize the lane marker information. Then, the roadway on which the vehicle is traveling, is remodeled using the optimized lane marker information, the information about the speed and steering angle of the vehicle measured by the sensor, and the information about the modeled plates, and the position and orientation of the remodeled plates are calculated. Therefore, roadway recognition can be easily achieved using a modeled structure of the roadway, in which a plurality of rectangular plates are linked. Also, the model roadway is repeatedly mapped onto the actual roadway image, so that reliability in recognition of roadway increases.

Claims

1. A method for modeling a roadway as a structure having a plurality of rectangular plates linked to each other, the modeled structure being expressed as the following matrix equation (1):

space="preserve" listing-type="equation">P.sub.i =[w.sub.i l.sub.i α

.sub.i β

.sub.i γ

.sub.i ].sup.T(

     1)

wherein it is assumed that a vehicle is placed at the center of the bottom line of a plate P_i having a width of w_i and a length of l_i the Z_i axis is the traveling direction of the vehicle, the X_i axis is lateral to the vehicle, the Y_i axis is perpendicular to the plate P_i, β

_i and α

_i represent error angles of the X_i and Z_i axes of the plate P_i with respect to the X.sub.(i-1) and Z.sub.(i-1) axes of the plate P.sub.(i-1) linked immediately before the current plate P_i, respectively, and γ

_i represents error angle between the Y_i axis perpendicular to the roadway and the direction perpendicular to the vehicle.

2. The method of claim 1, wherein assuming that a matrix having information about the length l_i of plates P_i is referred to as G, a transformation matrix for rotating the X_i axis by α

_i is referred to as R_X.sbsb.i.sub.,α

.sbsb.i, a transformation matrix for rotating the Z_i axis by γ

_i is referred to as R_Z.sbsb.i.sub.,γ

.sbsb.i, and a transformation matrix for rotating the Y_i axis by β

_i is referred to as R_Y.sbsb.i.sub.,β

.sbsb.i, the transformation relation T_i-1,i between the previous plate P_i- and the current plate P_i can be expressed as the following matrix equation (2);

space="preserve" listing-type="equation">T.sub.i-1,i =G R.sub.X.sbsb.i.sub.,α

.sbsb.i R.sub.Z.sbsb.i.sub.i γ

.sbsb.i R.sub.Y.sbsb.i.sub.,β

.sbsb.i (

     2)

3.

3. A method for recognizing lane markers of a roadway for a vehicle by getting image information about the roadway and information about the speed and steering angle using a camera and a sensor attached to the vehicle, comprising:

modeling the actual roadway on which the vehicle travels, as a structure having a plurality of rectangular plates linked to each other;

overlaying the modeled plates onto the image information about the actual roadway, photographed by the camera, extracting pixels forming the lane markers, and obtaining linear lane marker information from the pixels forming the land markers;

overlaying the linear lane marker information onto the modeled plates to recalculate lane marker information using the plates as a frame;

applying predetermined limitations of the features of the lane markers to the plates onto which the linear lane marker information has been overlayed, to optimize the lane marker information; and

remodeling the roadway on which the vehicle is traveling, using the optimized lane marker information, the information about the speed and steering angle of the vehicle measured by the sensor, and the information about the modeled plates, and calculating the position and orientation of the remodeled plates.

4. The method of claim 3, wherein the actual roadway is modeled as the structure having a plurality of rectangular plates linked to each other, expressed as the following matrix equation (1):

space="preserve" listing-type="equation">P.sub.i =[w.sub.i l.sub.i α

.sub.i β

.sub.i γ

.sub.i ].sup.T(

     1)

wherein it is assumed that a vehicle is placed at the center of the bottom line of a plate P_i having a width of w_i and a length of l_i, the Z_i axis is the traveling direction of the vehicle, the X_i axis is lateral to the vehicle, the Y_i axis is perpendicular to the plate P_i, β

_i and α

_i represent error angles of the X_i and Z_i axes of the plate P_i with respect to the X.sub.(i-1) and Z.sub.(i-1) axes of the plate P.sub.(i-1) linked immediately before the current plate P_i, respectively, and γ

_i represents error angle between the Y_i axis perpendicular to the roadway and the direction perpendicular to the vehicle.

5. The method of claim 4, wherein the predetermined limitations of the lane markers are that the lane markers based on the linear lane marker information overlayed onto the plates are parallel to the side frames of the plates and the width of the land markers based on the linear lane marker information is equal to the width of the roadway.