Abstract: An optical probe for splitting a beam of light into multiple beams. The optical probe may comprise a first polarizing beam splitter having a first polarization axis, a second polarizing beam splitter having a second polarization axis orthogonal to the first polarization axis, a first half wave plate and a second half wave plate, and optionally a first birefringent phase plate, and a second birefringent phase plate. The first half wave plate may be located before first polarizing beam splitter, and the second half wave plate may be located after the first polarizing beam splitter, relative to the propagation of the light beam. The optical probe may further include a lens for collimating the four light beams. A profilometer includes the optical probe for splitting a beam of light into four light beams, and a scanner for traversing the optical probe over a surface of an element to be measured.

Abstract: An optical probe for splitting a beam of light into multiple beams. The optical probe may comprise a first polarizing beam splitter having a first polarization axis, a second polarizing beam splitter having a second polarization axis orthogonal to the first polarization axis, a first half wave plate and a second half wave plate, and optionally a first birefringent phase plate, and a second birefringent phase plate. The first half wave plate may be located before first polarizing beam splitter, and the second half wave plate may be located after the first polarizing beam splitter, relative to the propagation of the light beam. The optical probe may further include a lens for collimating the four light beams. A profilometer includes the optical probe for splitting a beam of light into four light beams, and a scanner for traversing the optical probe over a surface of an element to be measured.

Abstract: A camera for aerial photography includes a reference projector that projects collimated beams of light into the optical system entrance aperture which are imaged by an image recording device. The beams produce fiducial images present in every image captured by the imaging recording device. The fiducial images can be used to characterize the performance of the optical system and derive distortion correction coefficients. The distortion correction coefficients can be applied to a portion of an image, such as a group of pixels, or to the entire image, to thereby compensate for distortions in the optical system. In some embodiments, e.g., airborne cameras, the projector is rigidly coupled to an inertial measurement unit. The ability of the airborne camera to perform object geolocation from imagery is improved.

Abstract: An optical system includes a reference projector that projects collimated beams of light into the optical system entrance aperture which are imaged by an image recording device. The beams produce fiducial images present in every image captured by the imaging recording device. The fiducial images can be used to characterize the performance of the optical system and derive distortion correction coefficients. The distortion correction coefficients can be applied to a portion of an image, such as a group of pixels, or to the entire image, to thereby compensate for distortions in the optical system. In some embodiments, e.g., airborne cameras, the projector is rigidly coupled to an inertial measurement unit. The ability of the airborne camera to perform object geolocation from imagery is improved. The fiducial images enable optical system performance to be characterized and distortion correction coefficients to be obtained and thereby improve the accuracy of a ray angle calculation to the object of interest.