Mobile body recognizing apparatus and motor vehicle monitoring apparatus

• US 6,636,257 B1
• Filed: 08/06/1999
• Issued: 10/21/2003
• Est. Priority Date: 08/11/1998
• Status: Expired due to Fees

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Ohta, Naoya, Harada, Ichiro
• Primary Examiner(s): Kelley, Chris
• Assistant Examiner(s): Parsons, Charles
• Application Number:
  US09/430,746
• Time in Patent Office: 1,537 Days
• Field of Search: 348/113, 348/118, 348/119, 348/148, 382/103, 382/104, 382/106, 340/937, 340/933, 364/424.01, 364/424.033, 356/3.16, 701/23
• US Class Current: 348/148
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves
• CPC Class Codes: G08G 1/165 for passive traffic, e.g. including static obstacles, trees
• 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 given visual field is divided into a plurality of areas, and brightness information in the areas is detected at predetermined time intervals and stored as information of a mobile body in a memory of a motor vehicle monitoring apparatus on a motor vehicle. The bright information detected in the areas at different times is then read from the memory, and a motion of the brightness information between adjacent ones of the areas is detected as a one-dimensional optical flow. The detected one-dimensional optical flow is compared with a one-dimensional optical flow generated from a road due to the speed of the motor vehicle, for thereby detecting another motor vehicle which is moving toward the motor vehicle.

Claims

1. An apparatus for recognizing a mobile body, comprising:

information extracting means for extracting only brightness information from a plurality of visual areas;

space differential calculating means for determining a rate of change in space of said brightness information between adjacent ones of said visual areas;

time differential calculating means for determining a rate of change in time of said brightness information between adjacent ones of said visual areas; and

mobile body detecting means for detecting a motion of a mobile body between the visual areas from said rate of change in space of said brightness information and said rate of change in time of said brightness information.

2. An apparatus according to claim 1, wherein said filters comprise Gaussian filter circuits for attenuating the brightness information in peripheral portions of said visual areas to a level lower than the brightness information in central portions of said visual areas.

3. An apparatus according to claim 2, wherein said filters comprise optical lenses having a lower transmittance for the brightness information in peripheral portions of said visual areas than in central portions of said visual areas.

4. An apparatus according to claim 1, wherein said information extracting means comprises CCD camera.

5. An apparatus according to claim 1, wherein said information extracting means comprises a plurality of photodiodes associated with said visual areas, respectively.

6. An apparatus according to claim 1, wherein said mobile body detecting means comprises means for stopping detecting the motion of the mobile body if an absolute value of said rate of change in space of said brightness information as determined by said space differential calculating means is smaller than a predetermined reference value.

7. An apparatus according to claim 1, wherein said mobile body detecting means comprises means for determining a one-dimensional optical flow V representing the motion of the mobile body according to the equation:

8. An apparatus according to claim 1, wherein said mobile body detecting means comprises means for storing time-series information of the mobile body at respective times, and detecting the motion of said mobile body based on the continuity of the stored time-series information at the respective times.

13. An apparatus according to claim 1, wherein said information extracting means comprises a brightness input device which sets said plurality of visual areas in an image, and a sum of said visual areas is less than the entire area of the image.

9. An apparatus mounted on a motor vehicle for monitoring another motor vehicle which is moving relatively to the motor vehicle, comprising:

information extracting means for extracting only brightness information from a plurality of visual areas;

space differential calculating means for determining a rate of change in space of said brightness information between adjacent ones of said visual areas;

time differential calculating means for determining a rate of change in time of said brightness information between adjacent ones of said visual areas; and

other motor vehicle detecting means for detecting a motion of said other motor vehicle between the visual areas from said rate of change in space of said brightness information and said rate of change in time of said brightness information.

10. An apparatus according to claim 9, wherein said other motor vehicle detecting means comprises means for calculating a one-dimensional optical flow representing the motion of the mobile body from said rate of change in time of said brightness information and said rate of change in space of said brightness information, and comparing the calculated one-dimensional optical flow with a one-dimensional optical flow of a mobile body other than said other motor vehicle, which is estimated based on a speed of said motor vehicle, thereby to detect said other motor vehicle which moves relatively to said motor vehicle.

11. An apparatus according to claim 10, wherein said other motor vehicle detecting means comprises means for determining said other motor vehicle as moving toward said motor vehicle or said other motor vehicle as moving away from said motor vehicle, from a result of comparison between the one-dimensional optical flows.

12. An apparatus according to claim 9, wherein said other motor vehicle detecting means comprises means for storing time-series information of the other motor vehicle at respective times, and detecting the motion of said other motor vehicle based on the continuity of the stored time-series information at the respective times.

14. An apparatus according to claim 9, wherein said information extracting means comprises a brightness input device which sets said plurality of visual areas in an image, and a sum of said visual areas is less than the entire area of the image.

15. An apparatus for recognizing a mobile body, comprising:

an input device which sets a plurality of visual areas in an image and extracts only brightness information from said visual areas;

a space differential calculator which determines a rate of change in space of the extracted brightness information between adjacent ones of said visual areas;

a time differential calculator which determines a rate of change in time of the extracted brightness information between adjacent ones of said visual areas; and

a mobile body detector which detects motion of a mobile body between the visual areas based on the calculated rate of change in space and rate of change in time of said space differential calculator and time differential calculator.

16. An apparatus according to claim 15, wherein said mobile body detector stops detecting motion of the mobile body if an absolute value of the rate of change by space of the extracted brightness information as determined by said space differential calculator is less than a predetermined reference value.

17. An apparatus according to claim 15, wherein said apparatus is adapted to be mounted on a motor vehicle, said mobile body detector calculates a one dimensional optical flow representing the motion of the mobile body from the calculated rate of change in space and rate of change in time of said space differential calculator and time differential calculator, and compares said one-dimensional optical flow with a one-dimensional optical flow of a different mobile body estimated based on a speed of the motor vehicle, to detect the mobile body which moves relative to the motor vehicle.

18. An apparatus according to claim 15, wherein a sum of said visual areas is less than the entire area of the image.