Method for dynamically calibrating vehicular cameras
First Claim
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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Abstract
A method for dynamically correcting misalignment of a vehicular camera includes fixedly disposing a camera at a vehicle and operating the camera to acquire multiple frames of image data while the vehicle is moving generally in a straight line. A plurality of sets of feature points are selected in an image frame, with each set including a first feature point and a second feature point. For each set of feature points, a motion trajectory of that set'"'"'s feature points is tracked in subsequent image frames. For each tracked first and second feature points, a vanishing point is established in the image plane. Based on the established vanishing point, a vanishing line is determined in the image plane. When the vanishing line is determined to be non-horizontal in the image plane, at least one of pitch, roll or yaw of the camera is adjusted to correct rotational misalignment of the camera.
291 Citations
20 Claims
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1. A method for dynamically correcting rotational misalignment of a vehicular camera, the method comprising:
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(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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for dynamically correcting rotational misalignment of a vehicular camera, the method comprising:
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(a) fixedly disposing a camera at a portion of a vehicle, said camera having a field of view exterior of the equipped vehicle and wherein said camera comprises a wide angle lens; (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 in motion moving in a straight line and (ii) while the equipped vehicle is moving along a curve; (d) removing distortion caused by use of the wide angle lens; (e) 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; (f) 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; (g) 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; (h) wherein a second set of feature points comprises a third feature point and a fourth feature point; (i) 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; (j) 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; (k) 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; (l) determining whether the vanishing line is horizontal or non-horizontal in the image plane; and (m) 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. - View Dependent Claims (15, 16, 17)
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18. A method for dynamically correcting rotational misalignment of a vehicular camera, the method comprising:
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(a) fixedly disposing a camera at a portion of a vehicle, said camera having a field of view exterior of the equipped vehicle and wherein said camera comprises a wide angle lens; (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) removing distortion caused by use of the wide angle lens; (e) receiving vehicle data via a communication bus of the equipped vehicle, the received vehicle data including speed data and steering angle data of the equipped vehicle; (f) 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; (g) 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; (h) 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; (i) wherein a second set of feature points comprises a third feature point and a fourth feature point; (j) 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; (k) 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; (l) 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; (m) determining whether the vanishing line is horizontal or non-horizontal in the image plane; and (n) 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. - View Dependent Claims (19, 20)
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Specification