Abstract: A system for measuring deformation of at least one surface of an object including an interferometer for receiving illumination reflected from the surface of the object, and a surface treatment disposed on the surface of the object for providing a retro-reflective patina. The retro-reflective patina is configured to reflect the illumination from the surface of the object. The retro-reflective patina is attached to the surface of the object and may include a plurality of cube corners, or a plurality of dielectric spheres, or a combination of cube corners and dielectric spheres. Impinging light onto the object is provided by an optical source that may be separate from or integral to the interferometer. The impinging light may be directed toward the object through an objective lens, which is also used for receiving the illumination from the object. Alternatively, the impinging light may be directed toward the object by first bypassing the objective lens.

Abstract: An optical nulling apparatus for testing an optical surface includes an aspheric mirror having a reflecting surface for imaging light near or onto the optical surface under test, where the aspheric mirror is configured to reduce spherical aberration of the optical surface under test. The apparatus includes a light source for emitting light toward the aspheric mirror, the light source longitudinally aligned with the aspheric mirror and the optical surface under test. The aspheric mirror is disposed between the light source and the optical surface under test, and the emitted light is reflected off the reflecting surface of the aspheric mirror and imaged near or onto the optical surface under test. An optical measuring device is disposed between the light source and the aspheric mirror, where light reflected from the optical surface under test enters the optical measuring device.

Abstract: Apparatus for calibrating a linear image sensor, includes a fluorescent light source, at least as long as the image sensor; a fixture for holding the light source parallel to the image sensor and displaced from the image sensor by a fraction of the length of the image sensor; and a light level controller for producing a plurality of light levels from the lamp.

Abstract: Apparatus and method for radiometrically calibrating an imaging sensor array using the sun as a calibration light source in an optical system of the type having an accessible real conjugate of the entrance pupil, includes a flux concentrator for concentrating the sunlight. A flux modulator modulates the intensity of the concentrated sunlight and a flux relay for relaying the intensity modulated sunlight to the real conjugate of the entrance pupil of the optical system. A flux diffuser located at the real conjugate of the entrance pupil of the optical system illuminates the imaging sensor array with diffuse intensity modulated sunlight for calibrating the imaging sensor. A radiometric calibration assembly is proposed to calibrate an imaging sensor array of an earth imaging system. The calibration assembly comprises a flux concentrator, a flux modulator, a flux relay lens and a flux diffuser located within a conjugate pupil of the earth imaging system.

Abstract: A method of shaping surface on an optical element includes directing a stream of gas and particles at the surface at a velocity sufficient to controllably remove material from the surface to figure the surface to a desired optical profile.

Abstract: A focus detecting system for detecting focus state of an image forming optical system relative to an object, includes a beam splitter assembly for forming at least three coplanar two-dimensional images of a scene, each image having a different focus setting. An area array image sensor senses the images at the image forming plane. Signal processing electronics determine the sharpness of the three images and calculates an optimum focus setting for the optical system by deterring the variances of the three images and calculating a position of maximum variance corresponding to a best focus setting of the optical system.

Abstract: An assembly preferably utilized in cooperation with a method for determining a surface topology of a workpiece. The assembly includes a projectile; means for coupling the projectile to a surface of a workpiece, and for imparting an initial momentum to the projectile with respect to the surface; and, means for sensing a relative movement of the projectile with respect to the workpiece surface, for generating a locus of positional points over time of the projectile as a measure of the surface topology of the workpiece.

Abstract: A novel method for assessing a surface figure of an optical element. The method preferably comprises subjecting the optical element to a classical autocollimation testing procedure for ascertaining its surface figure relative to a predetermined ideal. The testing procedure is characterized by a step of modifying the classical optical testing procedure, so that the optical element under test simulates a paraboloid.

Abstract: A method for determining a surface topology of a workpiece preferably comprising a general symmetric asphere. The method includes the steps of coupling a projectile to a surface of a workpiece, and imparting a trajectory to the projectile with respect to the surface; sensing the trajectory of the projectile with respect to the workpiece surface, for assessing a locus of positional points over time of the projectile, the locus being a measure of the surface topology of the workpiece; and computing from the locus of positional points over time, the surface topology of the workpiece.

Abstract: A method for determining a vertex radius of curvature for an optical surface. The method comprises subjecting the optical surface to a classical collimation testing procedure, so that the optical surface simulates a paraboloid; and, subjecting the optical surface to a vertex focusing interferometric testing procedure, so that a vertex radius of the optical surface can be determined.

Abstract: The Foucault or knife-edge method may be employed for testing an optical surface defined by an imaging device, for example, a mirror surface, to ascertain its characteristics, for example, whether or not it is a source of optical aberrations. To this end, the traditional Foucault knife-edge method typically employs a knife-edge that comprises a metal razor blade. The present method, in contrast, provides an improved Foucault method, and features a novel optical element suitable for employment in the method. The optical element comprises a transparent substrate, and a coating material that can adhere to at least a portion of the transparent substrate, thereby forming at least one knife-edge pattern.

Abstract: An optical reticle projector which may be employed for astronomical data collection. The projector consists of a cylindrical housing having a radius from 0.5 to 4.0 inches; a source of radiation secured by the housing, the source of radiation capable of outputting a radiation beam along an optical axis defined with respect to the housing; an optical field element secured by the housing and positioned on the optical axis; a reticle having a predetermined geometry, and in operative association with the field element; and an imaging lens secured by the housing, positioned on the optical axis, and capable of imaging the reticle to infinity.

Abstract: A method suitable for determining large petal piston in a segmented imaging assembly. The assembly preferably comprises a polychromatic source of radiation that can output a polychromatic radiation beam; and, a segmented imaging system including petals comprising a reference component and a test component, which components can be used to form an imaged radiation beam. The method steps comprise intercepting preselected portions of the imaged radiation beam with a mask comprising two apertures, so that one aperture is dedicated to radiation imaged by the reference component, and the second aperture is dedicated to radiation imaged by the test component, thereby creating a real time masked image; and, interrogating an envelope and a fine structure spacing of the real time masked image, as a measure of the large petal piston of the segmented imaging system.

Abstract: A method for simultaneously determining coarse and fine petal piston in a segmented imaging assembly. The assembly preferably comprises a source of radiation that outputs a radiation beam; and, a segmented imaging system comprising a reference component and a test component, which components can be used to form an imaged radiation beam. The method comprises a first step of intercepting preselected portions of the imaged radiation beam with a novel composite mask. The composite mask comprises apertures which are dedicated to coarse petal alignment, and four phase retardation regions dedicated to fine petal alignment. The first step creates a real time masked image. A step of comparing the real time masked image against a family of off-line images generated for a sequence of known petal position errors, can provide the magnitude of the fine piston, while a step of interrogating an envelope and a fine structure spacing of the real time masked image, can provide the magnitude of the coarse piston.

Abstract: A novel composite imaging mask suitable for employment in a method for simultaneously determining coarse and fine petal piston in a segmented imaging assembly. The mask comprises a transparent substrate comprising two spaced-apart apertures, which apertures are dedicated to coarse petal alignment; a first overlay deposited on a face of the substrate, for defining four phase retardation regions dedicated to fine petal alignment; a second overlay comprising an opaque coating, the second overlay deposited on the face of the substrate and complementary to the four phase retardation regions and the apertures, and a means for spirally separating the coarse and fine alignment entities.

Abstract: A novel optical device, comprising, in one embodiment, a modified corner cube retroreflector. A conventional corner cube retroreflector may be modified so that a face plate comprises an enhanced reflectivity coating. The novel device functions such that at least five percent of the energy of a radiation beam incident to the device, may be reflected at the face plate in accordance with Snell's Law. It is disclosed that the novel device may be advantageously employed in a novel optical alignment assembly.

Abstract: An astronomical data collection method employing a novel optical reticle projector. Prior art ground-based optical systems for astronomical data collection typically comprise a main telescope, and a guide telescope comprising an internal reticle. The guide telescope presumably corrects nominal tracking errors, but may itself, by way of the internal reticle, develop supererogatory errors due to differential flexure. The method of the present invention addresses the problem due to differential flexure, and solves it, by minimizing a source of the supererogatory errors, while recreating an internal reticle function in the novel optical reticle projector.

Abstract: A method for monitoring an alignment of a workpiece with respect to a reference. The method includes a step of attaching to the workpiece a novel optical device comprising a modified corner cube retroreflector. The novel optical device can function such that a specified percentage of incident radiation reflects in accordance with Snell's Law, with a residual reflected beam reflecting retroreflectively. The method further includes a step of directing a radiation beam to the optical device, for generating an interference pattern induced by the Snell's Law and retroreflective beams. The interference pattern provides a measure of the alignment of the workpiece.

Abstract: A novel method that is suitable for uniquely aligning remote first and second objects. In one aspect, the method comprises pre-alignment and alignment stages. The pre-alignment stage comprises generating first and second geometric configurations on the first and second objects, respectively. The first configuration is, at least in part, characterized by randomness; and, the second configuration comprises a geometric complement of a projection of the first configuration. The alignment stage exploits variable geometries generated in the process of manipulating each of the two objects through six degrees of freedom, until a unique geometry, signifying alignment, is realized.

Abstract: A novel method that is suitable for uniquely aligning first and second objects. A pre-alignment stage of one aspect of the novel method comprises generating on a first object a first geometric configuration comprising dark and clear regions, and having at least one portion characterized by randomness; and generating on a second object, a geometric configuration which is a geometric complement of the first random geometric configuration. An alignment stage of the novel method comprises juxtaposing the first and second objects so that the first geometric configuration and its complement generate a unique dark spot; and, rotating the first and second objects about an axis normal to the first object and centered at the dark spot, until a transmissivity of the juxtaposed objects is at a minimum.