Autonomous stereo camera calibration
AssigneeRealsense, Inc.
InventorsOskar Pelc, Dmitry Rudoy, Noam Levy
Life of this patent
Estimating the term…
Abstract
Methods, apparatus, systems, and articles of manufacture are disclosed to calibrate a stereo camera. An example apparatus includes means for determining a motion grid between a first image and a second image captured by the stereo camera; means for determining a calibration value to calibrate the stereo camera based on a prior calibration value, a relative orientation between the first image and the second image based on the motion grid, and a metric indicative of calibration improvement; and means for estimating a depth based on the calibration value.
Claims25
An apparatus to calibrate a stereo camera, the apparatus comprising:
- at least one memory;
- machine readable instructions;
- and
- processor circuitry to at least one of instantiate or execute the machine readable instructions to:
- estimate, based on a first calibration value, a second calibration value;
- extract matching points from a motion field between a first image and a second image captured by the stereo camera;
- determine a relative orientation between the first image and the second image based on the matching points;
- estimate a third calibration value based on the second calibration value and the relative orientation;
- model a plurality of relative orientations between the first image and the second image to produce depth estimates;
- estimate a fourth calibration value based on the third calibration value and the depth estimates;
- determine a safety metric;
- determine a fifth calibration value based on the fourth calibration value and the safety metric;
- and
- output the fifth calibration value to calibrate the stereo camera.
A non-transitory machine readable storage medium comprising instructions that, when executed, cause processor circuitry to at least:
- estimate, based on a first calibration value, a second calibration value;
- determine a relative orientation between a first image and a second image captured by a stereo camera based on a motion grid mapping the first image with the second image;
- estimate a third calibration value based on the second calibration value and the relative orientation;
- model a plurality of relative orientations between the first image and the second image to produce depth estimates;
- estimate a fourth calibration value based on the third calibration value and the depth estimates;
- determine a metric indicative of calibration improvement;
- determine a fifth calibration value based on the fourth calibration value and the metric;
- and
- output the fifth calibration value to calibrate the stereo camera.
An apparatus to calibrate a stereo camera, the apparatus comprising:
- motion grid circuitry configured to compute a motion grid between a first image and a second image captured by the stereo camera;
- calibration circuitry configured to output a calibration value to calibrate the stereo camera based on:
- a prior calibration value;
- a relative orientation between the first image and the second image based on the motion grid;
- and
- a metric indicative of calibration improvement;
- and
- means for estimating a depth based on the calibration value.
A non-transitory machine readable medium comprising:
- motion grid instructions to cause at least one machine to determine a motion grid between a first image and a second image captured by a stereo camera;
- calibration instructions to cause the at least one machine to determine a calibration value to calibrate the stereo camera based on:
- a prior calibration value;
- a relative orientation between the first image and the second image based on the motion grid;
- and
- a safety metric;
- and
- depth estimate instructions to cause the at least one machine to estimate a depth based on the calibration value.
A method of calibrating a stereo camera, the method comprising:
- determining, by executing instructions with a processor, a motion grid between a first image and a second image captured by the stereo camera;
- determining, by executing instructions with the processor, a calibration value to calibrate the stereo camera based on:
- a prior calibration value;
- a relative orientation between the first image and the second image based on the motion grid;
- and
- a metric indicative of calibration improvement, the metric based on one or more indicators including:
- an inlier ratio, a motion gradient, a local contrast, a median disparity, or a planarity;
- comparing, by executing the instructions with the processor, the metric to a threshold;
- determining, by executing the instructions with the processor, the calibration value when the metric satisfies the threshold;
- and
- rejecting, by executing the instructions with the processor, the calibration value when the metric does not satisfy the threshold.
Dependencies are inferred from the claim text.