Apparatus for detecting an object located ahead of a vehicle using plural cameras with different fields of view

• US 5,892,855 A
• Filed: 09/27/1996
• Issued: 04/06/1999
• Est. Priority Date: 09/29/1995
• Status: Expired due to Fees

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Saiki, Mitsuyoshi, Soshi, Kunihiko, Satonaka, Hisashi, Kakinami, Toshiaki
• Primary Examiner(s): Kelly, Christopher S.
• Assistant Examiner(s): CHAWAN, SHEELA C
• Application Number:
  US08/720,031
• Time in Patent Office: 921 Days
• Field of Search: 382/103, 382/104, 382/106, 340/907, 340/903, 340/937, 348/148, 348/149, 348/113, 348/118, 348/143, 348/211, 348/119
• US Class Current: 382/291
• CPC Class Codes: B60T 2201/08 Lane monitoring; Lane Keeping Systems
• CPC Class Codes: B60T 2201/089 using optical detection
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means
• CPC Class Codes: G06V 10/48 by mapping characteristic values of the pattern into a parameter space, e.g. Hough transformation

Abstract

An onboard forward monitoring system is disclosed in which three television cameras, each supported by a steering mechanism, take picture of a road surface located forward of a vehicle at near distance, a medium distance and a far distance zone to detect white lines which partition a lane on the road surface, thus detecting a vehicle running ahead on the lane which is defined by the white lines. To enable a reliable detection and tracking of the vehicle running ahead in any zone of the road surface even when the road is curved, the individual television cameras are steered so that a vehicle running ahead is positioned at the center of the screen whenever such vehicle is present and so that a center across the width of the lane is positioned at the center of screen when a vehicle running ahead is not detected.

Claims

1. An apparatus for detecting an object located ahead of a vehicle comprising:

a first camera means for taking a picture of a first scene of a wide view angle inclusive of a road surface located at a near distance forward of the vehicle;

a second camera means for taking a picture of a second scene of narrow view angle inclusive of a road surface located at a far distance forward of the vehicle;

means for detecting an object located forward of the vehicle on the road surface contained in at least one of the first and second scenes on the basis of image data which forms a picture screen of the first and second scene;

first camera direction control means for altering the direction of the first camera transverse to the fore-and-aft axis of the vehicle in a direction such that a substantially full profile of the object located forward of the vehicle and detected in the first scene is contained in the first scene; and

second camera direction control means for altering the direction of the second camera transverse to the fore-and-aft axis of the vehicle in a direction such that a substantially full profile of the object located forward of the vehicle and detected in the second scene is contained in the second scene.

2. An apparatus according to claim 1 in which the first camera direction control means alters the first angle in a direction to bring the substantial center of the object located forward of the vehicle and detected in the first scene to the center of the first scene, and the second camera direction control means alters the second angle in a direction to bring the substantial center of the object located forward of the vehicle and detected in the second scene to the center of the second scene.

3. An apparatus according to claim 2 in which the fis camera means and the second camera means take a picture of white lines located at the left and right end of a lane on which the vehicle is running, the first and the second camera direction control means altering the first and the second angle in a direction to bring a median point between white lines at the left and the right end in each of the first and second scene to the center of each scene.

4. An apparatus according to claim 2 in which the object located forward of the vehicle includes a vehicle running ahead of the first mentioned vehicle, the first and the second camera direction control means altering the first and the second angle in a direction to bring the center position of the vehicle located ahead in each of the first and second scene to the center of each scene.

5. An apparatus according to claim 2 in which said means for detecting an object also detects white lines located at the left and the right end of a lane on which the vehicle is running and detects the presence or absence of any vehicle located forward of the first mentioned vehicle intermediate the detected white lines, the first and the sec camera direction control means altering the first and the second angle in a direction to bring a median point between the detected white lines to the center of each scene whenever any vehicle running ahead is not detected in either the first or second scene, the first and the second camera direction control means being responsive to the detection of a vehicle running ahead by said means for detecting an object to alter the first angle in a direction to bring the detected vehicle to the center of the first scene when the detected vehicle is located in the first scene, the second camera direction control means being responsive to the detection of a vehicle running ahead by said means for detecting an object to alter the second angle in a direction to bring the detected vehicle to the center of the second scene when the detected vehicle is located in the second scene.

6. An apparatus according to claim 1 in which the first camera means includes a first television camera of wide view angle which takes a picture of a road surface located at a near distance forward of the vehicle an a first rotary drive unit for rotatively driving the camera in order to alter the direction of the first television camera transverse to the fore-and-aft axis of the vehicle, and the second camera means includes a second television camera of a narrow view angle which takes a picture of a road surface located at a far distance forward of the vehicle and a second rotary drive unit for rotatively driving the camera in order to alter the direction of the second television camera transverse to the fore-and-aft axis of the vehicle, said means for detecting an object being operable to detect an object located forward of the vehicle as the object appears on the road surface in a picture screen formed by the first and the second television camera, on the basis of image data which forms such picture screen.

7. An apparatus according to claim 6 in which the firs camera direction control means alters the direction of the first television camera through the first rotary drive unit in a direction to bring the substantial center of the object located forward of the vehicle and detected on the picture screen formed by the first television camera to the center of the screen, and the second camera direction control means alters the direction of the second television through the second rotary drive unit in a direction to bring the substantial center of the object located forward of the vehicle and detected on the picture screen formed by the second television camera to the center of the screen.

8. An apparatus according to claim 7 in which said means for detecting an object detects white lines located at the left and the right end of a lane on which the vehicle is running at it appears on the road surface in the screen, based on image data from the first and the second television camera which form a picture screen, and calculates a typical one left end line representative of both white lines at the left end of the picture screens produced by the first and the second television cameras and a typical one right end line representative of white lines at the right end in the picture screens produced by the first and the second television cameras, thus detecting the presence or absence of a vehicle running ahead in a region sandwiched between the left end and the right end line.

9. An apparatus according to claim 8 in which the first and the second camera direction control means alters the direction of the first and the second television camera through the first and second rotary drive unit respectively, respectively in a direction such that a median line between the left end and the right end line is brought to the center of the respective picture screens produced by the first and the second television cameras when said means for detecting an object does not detect a vehicle running ahead in a region sandwiched between the left end and the right end line, and is also responsive to the detection by said means for detecting an object of a vehicle running ahead to alter the direction of the first television camera through the first rotary drive unit in a direction to bring the vehicle running ahead which is detected to the center of the picture screen produced by the first television camera when the vehicle detected lies in a region of the picture screen produced by the first television camera which is sandwiched between the left end and the right end line, and to alter the direction of the second television camera through the second rotary drive unit in a direction to bring the vehicle running ahead which is detected to the center of the picture screen produced by the second television camera when the detected vehicle lies in a region of the picture screen produced by the second television camera which is sandwiched between the left end and the right end line.

10. An apparatus for detecting an object located ahead of a vehicle comprising:

a first television camera of wide view angle which takes a picture of a road surface located at a near distance forward of the vehicle;

a first rotary drive unit for rotatively driving the camera to alter the direction of the first television camera transverse to the fore-and-aft axis of the vehicle;

a second television camera of a medium view angle which takes a picture of a road surface located at a medium distance forward of the vehicle;

a second rotary drive unit for rotatively driving the camera to alter the direction of the second television camera transverse to the fore-and-aft axis of the vehicle;

a third television camera of a narrow view angle which takes a picture of a road surface located at a far distance forward of the vehicle;

a third rotary drive unit for rotatively driving the camera to alter the direction of the third television camera transverse to the fore-and-aft axis of the vehicle;

means for detecting an object located forward of the vehicle as it appears on a road surface in the picture screen of each camera, based on image data from the first, the second and the third television cameras, each of which produce a picture screen;

and camera direction control means for altering the direction of the first television camera, through the first rotary drive unit, in a direction to bring the object located forward of the vehicle and detected on the picture screen produced by the first television camera to the center of the picture screen, for altering the direction of the second television camera, through the second rotary drive unit, in a direction to bring the object located forward of the vehicle and detected on the picture screen produced by the second television camera to the center of the picture screen, and for altering the direction of the third television camera, through the third rotary drive unit, in a direction to bring the object located forward of the vehicle which is detected on the picture screen produced by the third television camera to the center of the picture screen.

11. An apparatus according to claim 10 in which the camera direction control means alters the direction of the first television camera, through the first rotary drive unit, in a direction to bring a substantial center of the object located forward of the vehicle and detected on the picture screen produced by the first television camera to the center of the picture screen, alters the direction of the second television camera, through the second rotary drive unit, in a direction to bring a substantial center of the object located forward of the vehicle which is detected on the picture screen produced by the second television camera to the center of the picture screen, and alters the direction of the third television camera, through the third rotary drive unit, in a direction to bring a substantial center of the object located forward of a vehicle which is detected on the picture screen produced by the third television camera to the center of the picture screen.

12. An apparatus according to claim 11 in which said means for detecting an object detects white lines located at the left and right ends of a lane on which the vehicle is running as the lines appear on the road surface in a picture screen, based on image data from the first, the second and the third television cameras, each of which produce a picture screen, and calculates one left end line which is representative of three white lines located at the left end of the lane on picture screens produced by the first, the second and third television cameras and one right end line which is representative of three white lines located at the right end, thereby detecting the presence or absence of a vehicle running ahead in a region which is sandwiched between the left end and the right end line.

13. An apparatus according to claim 12 in which the camera direction control means alters the direction of the first, the second and the third television cameras through the first, the second and the third rotary drive unit, respectively, in a direction to bring a median line between the left end and the right end line to the center of the picture screen produced by the first, the second and the third television cameras whenever said means for detecting an object does not detect a vehicle running ahead in a region sandwiched between the left end and the right end line, and also responsive to the detection by said means for detecting an object of the presence of a vehicle running ahead to alter the direction of the first television camera through the first rotary drive unit in a direction to bring the detected vehicle running ahead to the center of the picture screen produced by the first television camera when the detected vehicle lies in a region on the picture screen produced by the first television camera which is sandwiched between the left end and the right end line, to alter the direction of the second television camera through the second rotary drive unit in a direction to bring the detected vehicle running ahead to the center of the picture screen produced by the second television camera when the detected vehicle lies in a region on the picture screen produced by the second television camera which is sandwiched between the left end and the right end line, and to alter the direction of the third television camera through the third rotary drive unit a direction to bring the detected vehicle running ahead to the center of the picture screen produced by the third televison camera when the detected vehicle lies in a region on the picture screen produced by the third television camera which is sandwiched between the left end and the right end line.