Apparatus for monitoring surroundings of vehicle and method of calibrating the same

• US 10,810,712 B2
• Filed: 09/28/2018
• Issued: 10/20/2020
• Est. Priority Date: 09/29/2017
• Status: Active Grant

• Current Assignee: DENSO Corporation, Ricoh Company Limited, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: DENSO Corporation
• Inventors: Terada, Toshihiko, Kuwahara, Masaki, Ito, Hiroaki, Uchida, Naohide, Kishiwada, Jun
• Primary Examiner(s): Osinski, Michael S
• Application Number:
  US16/145,898
• Publication Number:
  US 20190102869A1
• Time in Patent Office: 753 Days
• CPC Class Codes: G06T 2207/10012 Stereo images
• CPC Class Codes: G06T 2207/20021 Dividing image into blocks, subimages or windows
• CPC Class Codes: G06T 2207/30252 Vehicle exterior; Vicinity of vehicle
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 5/80 Geometric correction
• CPC Class Codes: G06T 7/593 from stereo images
• CPC Class Codes: G06T 7/85 Stereo camera calibration
• CPC Class Codes: H04N 13/246 Calibration of cameras
• CPC Class Codes: H04N 2013/0081 Depth or disparity estimation from stereoscopic image signals
• CPC Class Codes: H04N 23/81 for suppressing or minimising disturbance in the image signal generation
• CPC Class Codes: H04N 23/90 Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums

Abstract

In an apparatus for monitoring surroundings of a vehicle based on a plurality of images captured by a plurality of imagers through a windshield of the vehicle, an image acquirer is configured to acquire the plurality of images captured by the plurality of imagers, and a distortion corrector is configured to correct the plurality of images based on an optical distortion distribution of the windshield.

Claims

1. An apparatus for monitoring surroundings of a vehicle based on a plurality of images captured by a plurality of imagers through a windshield of the vehicle, the apparatus comprising:

a processor to perform the function of;

an image acquirer configured to acquire the plurality of images captured by the plurality of imagers;

a correction parameter calculator configured to calculate a correction parameter used for calibration of the apparatus based on an amount of lens distortion of the plurality of imagers and an optical distortion distribution of the windshield; and

a distortion corrector configured to correct the plurality of images based on the calculated correction parameter.

2. The apparatus according to claim 1, wherein the optical distortion distribution of the windshield is a distribution of amounts of distortion corresponding to positions of pixel regions on each of the plurality of images.

3. The apparatus according to claim 1, further comprising a storage storing optical distortion distributions of the windshield and the correction parameter calculated by the correction parameter calculator,

wherein the distortion corrector is configured to correct the plurality of images based on the correction parameter read from the storage.

4. The apparatus according to claim 1, further comprising a distortion calculator configured to calculate the optical distortion distribution of the windshield.

6. The apparatus according to claim 1, wherein the optical distortion distribution of the windshield is precalculated based on a plurality of images captured by the plurality of imagers through the windshield of the vehicle.

7. The apparatus according to claim 1, wherein the optical distortion distribution of the windshield is calculated based on numerical values representing a shape and optical properties of the windshield.

8. The apparatus according to claim 1, wherein the optical distortion distribution is calculated for each type of vehicle carrying the apparatus.

9. The apparatus according to claim 1, wherein the optical distortion distribution is calculated for each individual vehicle carrying the apparatus.

5. A method of calibrating an apparatus for monitoring surroundings of a vehicle based on a plurality of images captured by a plurality of imagers through a windshield of the vehicle, the method comprising:

acquiring the plurality of images captured by the plurality of imagers;

calculating a correction parameter used for calibration of the apparatus based on an amount of lens distortion of the plurality of imagers and an optical distortion distribution of the windshield; and

correcting the plurality of images based on the calculated correction parameter.