Collision alarm method and apparatus for vehicles

• US 6,246,961 B1
• Filed: 06/08/1999
• Issued: 06/12/2001
• Est. Priority Date: 06/09/1998
• Status: Expired due to Fees

• Current Assignee: Yazaki Corporation
• Original Assignee: Yazaki Corporation
• Inventors: Ishikawa, Naoto, Miyaoka, Hirosada, Sasaki, Kazuyuki, Nakajima, Masato
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Donnelly, Arthur D.
• Application Number:
  US09/327,573
• Time in Patent Office: 735 Days
• Field of Search: 701/301, 701/117, 701/28, 356/1
• US Class Current: 701/301
• CPC Class Codes: B60W 2050/143 Alarm means
• CPC Class Codes: B60W 2420/403 Image sensing, e.g. optical camera
• CPC Class Codes: B60W 2554/00 Input parameters relating to objects
• CPC Class Codes: B60W 30/095 Predicting travel path or likelihood of collision
• CPC Class Codes: B60W 30/0953 the prediction being responsive to vehicle dynamic parameters
• CPC Class Codes: B60W 30/0956 the prediction being responsive to traffic or environmental parameters
• CPC Class Codes: B60W 40/10 related to vehicle motion
• CPC Class Codes: B60W 50/14 Means for informing the driver, warning the driver or prompting a driver intervention
• CPC Class Codes: G06V 20/58 Recognition of moving objects or obstacles, e.g. vehicles or pedestrians; Recognition of traffic objects, e.g. traffic signs, traffic lights or roads
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes
• CPC Class Codes: G08G 1/167 Driving aids for lane monitoring, lane changing, e.g. blind spot detection

Abstract

A collision alarm method and apparatus for vehicles in which, in order to detect and alarm of danger of collision, the time of possible collision is calculated by a danger judgement means from optical flow. In order for an image processing means to detect the optical flow, a horizontal or vertical noticeable edge is used, which edge is extracted from two images obtained at different times with an image photographing means. The collision alarm method and apparatus for vehicles detect danger of collision at high speed and gives a timely alarm so as to enable collision avoiding action to be securely taken.

Claims

1. A method of alarming of collision for vehicles comprising the steps of:

photographing from a first vehicle with a photographing means fixedly oriented in a predetermined direction to obtain two images of an environment at different times, said environment including a second vehicle;

detecting in a previously-obtained one of said two images a first horizontal or vertical noticeable edge derived from said second vehicle;

detecting in a subsequently-obtained one of said two images a second noticeable edge derived from said second vehicle, which corresponds to said first noticeable edge, with a correlation window set around said first and second noticeable edge;

detecting an optical flow from said first and second noticeable edge;

calculating a time of possible collision with said second vehicle based on said optical flow detected; and

judging and alarming of danger of said possible collision with said second vehicle on said calculated time of said possible danger.

2. The method according to claim 1, wherein said two images are obtained by photographing with said photographing means fixedly oriented so as to provide a diagonal backward view of said first vehicle.

3. The method according to claim 1, wherein said two images are obtained by photographing with said photographing means fixedly oriented so as to provide a forward view of said first vehicle.

4. The method according to claim 1, wherein said two images have a plurality of said corresponding noticeable edges derived from two or more said second vehicles, and said step of calculating a time of possible collision comprises calculating said time of possible collision based on said optical flow detected from each of said corresponding noticeable edges derived from said second vehicles, and gathering said corresponding noticeable edges in groups according to said times of possible collisions, each of said groups of said corresponding noticeable edges being derived from one or another of said second vehicles, and said step of judging and alarming of danger comprises judging and alarming of said danger of said possible collision with said one or another of said second vehicles.

5. The method according to claim 4, wherein said two images are obtained by photographing with said photographing means fixedly oriented so as to provide a diagonal backward view of said first vehicle.

6. The method according to claim 1, wherein a time interval for obtaining said two images is varied in compliance with a size of said first and second noticeable edge on said two images.

7. The method according to claim 1, wherein said two images have a plurality of said corresponding noticeable edges derived from two or more said second vehicles, and said step of calculating a time of possible collision comprises gathering said corresponding noticeable edges in groups according to positions and components of a direction of y- or x-coordinate of optical flows detected on said two images from said corresponding noticeable edges, each of said groups of said corresponding noticeable edges being derived from one or another of said second vehicles, and calculating said time of possible collision based on said optical flow or flows detected from each of said groups of said corresponding noticeable edges, and said step of judging and alarming of danger comprises judging and alarming of said danger of said possible collision with said one or another of said second vehicles.

8. An apparatus for alarming of collision for vehicles comprising:

photographing means fixedly oriented in a predetermined direction on a first vehicle for photographing to obtain two images of an environment at different times, said environment including a second vehicle;

image processing means for detecting in a previously-obtained one of said two images a first horizontal or vertical noticeable edge derived from said second vehicle, detecting in a subsequently-obtained one of said two images a second noticeable edge derived from said second vehicle, which corresponds to said first noticeable edge, with a correlation window set around said first an second noticeable edge, and detecting an optical flow from said first and second noticeable edge; and

danger judgement means for calculating a time of possible collision with said second vehicle based on said optical flow detected by said image processing means, and judging and alarming of danger of said possible collision with said second vehicle on said calculated time of said possible danger.