System and method for calibrating ultra wide-angle lenses
AssigneeGeo Semiconductor Inc.
InventorsZorawar Singh Bassi, Ashkan Alavi-Harati
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Abstract
Systems and methods for obtaining mapping of Ultra Wide-Angle (UWA) lenses are disclosed. Captured image of a set of grid points on the inner surface of a precision made calibration dome is used as an input image. Image processing techniques are used to identify components of the image and compute the lens mapping. The lens mapping can be used to calibrate the lens against a standard or against other lenses. The mapping can further be used for perspective correction applications.
Claims22
A method for obtaining image mapping of an Ultra Wide-Angle (UWA) lens, having an optical axis and a field of view, said method comprising:
- installing a calibration dome, wherein said dome has an axis of symmetry, a ring shaped base, and an inner surface graded with a plurality of markers;
- placing the lens at the center of the base facing the calibration dome, such that the optical axis of the lens coincides with the axis of symmetry of the dome and the field of view of the lens is encompassed by the dome;
- capturing a picture of the inner surface of the calibration dome through the UWA lens;
- identifying image of each of the plurality of markers in the picture;
- computing centroid of the image of each of the plurality of markers;
- and
- fitting coordinates of the centroids to a functional basis.
A system for obtaining image mapping of an Ultra Wide-Angle (UWA) lens, having an optical axis and a field of view, said system comprising:
- a calibration dome having an axis of symmetry, a ring shaped base and an inner surface graded with a plurality of markers;
- a capture device comprising the UWA lens, an image sensor, and a unit coupled to the image sensor to acquire input image data;
- and
- a computing device equipped with means for identifying image of each of the plurality of the markers, computing their centroids and fitting coordinates of the centroids to a functional bases;
- wherein the capture device is placed in front of the dome such that the lens is at the center of the ring base, with its optical axis coinciding with the axis of symmetry of the dome and its field of view is encompassed by the dome.
Dependencies are inferred from the claim text.