Road sensor system

• US 6,658,137 B1
• Filed: 03/24/2000
• Issued: 12/02/2003
• Est. Priority Date: 04/19/1999
• 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: Yuhara, Horimitsu, Aoki, Tomoyoshi
• Primary Examiner(s): Johns, Andrew W.
• Assistant Examiner(s): NAKHJAVAN, SHERVIN K
• Application Number:
  US09/534,349
• Time in Patent Office: 1,348 Days
• Field of Search: 382/104, 382/163, 382/193, 382/194, 382/225, 382/278, 340/903, 340/932, 340/937, 340/938, 340/942, 340/435, 340/436, 340/437, 340/146.2, 340/5.1, 701/28, 701/65, 701/116, 701/117, 701/300, 701/301, 701/302, 348/148, 348/149
• US Class Current: 382/104
• CPC Class Codes: B60R 16/0237 circuits concerning the atmospheric environment meteorology G01W
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves
• CPC Class Codes: G08G 1/04 using optical or ultrasonic detectors

Abstract

A road sensor system is provided which comprises at least one imaging sensor, an extraction means that captures brightness values for a plurality of windows corresponding to the area immediately in front of the vehicle from an image that is captured from the imaging sensor and is divided into a plurality of windows. It extracts a reference brightness value on the basis of the plurality of brightness values. The system includes a judgment means that compares the brightness value of at least one other window with the reference brightness value and judges that the window belongs to the road area if the difference is smaller than a predetermined value. The road area is determined by detecting the road surface based on brightness rather than the distance to the road surface.

Claims

1. A road sensor system adapted to be carried on a vehicle, the system comprising:

an image sensor for capturing an image; and

a processor that performs the function of dividing said image captured by the image sensor into a plurality of windows and determining at least one brightness value of the window immediately in front of the vehicle, said brightness value being determined on the basis of the windows;

wherein said processor compares the brightness value of another window with said at least one brightness value and determines that said another window belongs to a road area if the difference is within a predetermined range;

wherein said at least one brightness value is a reference brightness value, said reference brightness value being progressively generated.

2. A road sensor system of claim 1, wherein the brightness value of the window that has newly been determined to belong to the road area replaces the reference brightness value.

3. A road sensor system of claim 1, further comprising:

at least two image sensors placed at a predetermined spacing, wherein said processor measures the distance to an object based on the images captured by the image sensors.

4. A road sensor system of claim 3 wherein said processor determines that a window being studied belongs to the road area if the distance measured for said window is within a predetermined range of the other windows that have been determined to belong to the road area even when the brightness comparison indicates that the window being studied does not belong to the road area.

5. A road sensor system of claim 3 wherein said processor determines that the window being studied belongs to a marking on the road if the distance measured for said window is within a predetermined range of the other windows that have been determined to belong to the road area even when the brightness comparison indicates that the window being studied does not belong to the road area.

6. A road sensor system of claim 1 wherein each window comprises one or more pixels.

7. A road detecting system adapted to be carried on a vehicle comprising:

at least one image sensor for capturing an image;

means for cutting out a plurality of windows from the image captured by said image sensor;

means for determining brightness value of each of said windows;

means for comparing said brightness value with a reference brightness value to determine that each of said window belongs to a road area if the reference is within a predetermined range, wherein said reference brightness value is progressively generated.

8. A road detecting system of claim 7, wherein the brightness value of the window that has newly been determined to belong to the road area replaces the reference value.

9. A road detecting system of claim 7, further comprising:

means for measuring distance from the image sensor to an object for each of the windows; and

means for determining that a window being studied belongs to the road area if the distance measured for the window is within a predetermined range of the other windows that have been determined to belong to the road area even when the brightness comparison indicates that the window being studied does not belong to the road area.

10. A method of determining road area comprising the steps of:

capturing an image of the view in front of a vehicle and dividing the image into a plurality of windows;

acquiring brightness values respectively for a plurality of windows;

extracting a reference brightness value on the basis of the plurality of brightness values; and

comparing the brightness value of other windows with the reference brightness value for determining each of the other windows to be in a road area if the difference is within a predetermined range, wherein said reference brightness value is progressively generated.

11. A method of claim 10, further comprising the step of setting the brightness value of the other window newly determined to be a road area as a new reference brightness value.

12. A method of claims 10, further comprising the step of:

providing at least two imaging sensors at a predetermined spacing; and

measuring the distance to an object on the basis of two or more images obtained by the two or more imaging sensors.

13. A method of claim 12, further comprising the step of determining that a window being studied belongs to a marking on the road if the distance measured for the window being studied is within a predetermined range of the distance of one or more windows that have been determined to belong to the road area.

14. The method of claim 10, wherein extracting a reference brightness value on the basis of a plurality of brightness values includes:

averaging the brightness values for at least two of the plurality of windows to produce an average brightness value; and

excluding each of the plurality of windows that varies by a predetermined brightness value from the average brightness value.