Method for dynamically calibrating vehicular cameras

  • US 10,202,077 B2
  • Filed: 05/23/2016
  • Issued: 02/12/2019
  • Est. Priority Date: 04/25/2011
  • Status: Active Grant
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First Claim
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1. A method for dynamically correcting rotational misalignment of a vehicular camera, the method comprising:

  • (a) fixedly disposing a camera at a vehicle, said camera having a field of view exterior of the equipped vehicle;

    (b) driving the equipped vehicle so that the equipped vehicle is in motion;

    (c) operating said camera to acquire multiple frames of image data captured by said camera (i) while the equipped vehicle is moving in a straight line and (ii) while the equipped vehicle is moving along a curve;

    (d) selecting a plurality of sets of feature points in an image frame of image data captured by said camera, wherein a first set of feature points comprises a first feature point and a second feature point;

    (e) for the first set of feature points, tracking in subsequent image frames of image data captured by said camera a motion trajectory of that set'"'"'s first feature point and second feature point while the equipped vehicle is moving in the straight line;

    (f) for each tracked first feature point and second feature point while the equipped vehicle is moving in the straight line, establishing a first vanishing point in the image plane;

    (g) wherein a second set of feature points comprises a third feature point and a fourth feature point;

    (h) for the second set of feature points, tracking in subsequent image frames of image data captured by said camera a motion trajectory of that set'"'"'s third feature point and fourth feature point while the equipped vehicle is moving along the curve;

    (i) for each tracked third feature point and fourth feature point while the equipped vehicle is moving along the curve, establishing a second vanishing point in the image plane;

    (j) based on establishing first and second vanishing points in the image plane by tracking respective feature points for a plurality of sets of feature points while the equipped vehicle is moving in the straight line and while the equipped vehicle is moving along the curve, determining a vanishing line in the image plane provided by said camera based on a locus of the first and second vanishing points;

    (k) determining whether the vanishing line is horizontal or non-horizontal in the image plane; and

    (l) when the vanishing line is determined to be non-horizontal in the image plane, adjusting at least one of pitch, roll or yaw of said camera to correct rotational misalignment of said camera.

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