Abstract: A calibration device for a radiometer includes an integrating cavity and a honeycomb blackbody mounted to the integrating cavity. A plurality of emitters are mounted to the exterior rim of the integrating cavity for transmitting narrow band wavelengths of light into and out of the integrating cavity. A controller, selectively, activates one or more emitters to radiate a single narrow band wavelength of light during an ON period and turn OFF during another period. A plurality of reference detectors are also mounted to the exterior rim of the integrating cavity for measuring the intensity of each narrow band radiation outputted from the integrating cavity. The reference detectors are effective in determining changes in intensity output by each of the narrow band emitters from the integrating cavity. The measured changes in intensity outputted by the emitters are used to calibrate the radiometer with the changes traced back to a NIST standard.

Abstract: A technique for generating complementary signals for joint transmission involves generating a first signal having a first wavelength and a second signal having a second wavelength. The first signal is modulated with a first modulation to encode data, and the second signal is modulated with a second modulation, which is an inverted version of the first modulation, to encode the same data such that the first and second signals are complementary. The first and second signals are combined to produce a combined signal in which power attributable to the first signal is interleaved with and substantially non-overlapping temporally with power attributable to the second signal. The combined signal is amplified and then transmitted. The first and second signals can be optical signals at respective first and second optical wavelengths, where the first and second signals are on-off keying (OOK) modulated.

Abstract: A technique for simultaneously transmitting wide and narrow optical beacon signals includes generating a laser beam and splitting the laser beam into a first signal on a first path and a second signal on a second path via a wavelength-dependent beamsplitter. A wide beacon signal having a first beam divergence is generated from the first signal, and a narrow beacon signal having a second, lesser beam divergence is generated from the second signal. The wavelength of the laser beam determines an allocation of the laser energy between the wide and narrow beacon signals based on transmittance/reflectance characteristic of the beamsplitter at that wavelength. The wide and narrow beacon signals are simultaneously transmitted in a overlaid manner into free space to support acquisition and tracking in a free-space optical communication system. The beamsplitter can simultaneously transmit or reflect substantially all of a data signal at a different wavelength.

Abstract: A technique for simultaneously transmitting wide and narrow optical beacon signals includes generating a laser beam and splitting the laser beam into a first signal on a first path and a second signal on a second path via a wavelength-dependent beamsplitter. A wide beacon signal having a first beam divergence is generated from the first signal, and a narrow beacon signal having a second, lesser beam divergence is generated from the second signal. The wavelength of the laser beam determines an allocation of the laser energy between the wide and narrow beacon signals based on transmittance/reflectance characteristic of the beamsplitter at that wavelength. The wide and narrow beacon signals are simultaneously transmitted in a overlaid manner into free space to support acquisition and tracking in a free-space optical communication system. The beamsplitter can simultaneously transmit or reflect substantially all of a data signal at a different wavelength.

Abstract: A multiple field of view sensor lens assembly suitable for inclusion in an infrared imaging system. The lens assembly includes a rotatable telescope 10 for providing first and second fields of view for the sensor, the first field of view being along a first axis thereof L and the second field of view being along a separate second axis T. A servo mechanism 30 is included for rotating the telescope 10 from a first orientation at which the first axis is aligned with the optical axis to a second orientation at which the second axis is aligned with the optical axis. In a preferred embodiment the inventive lens assembly is disposed to provide fields of view in opposing directions along the first axis L, and a third field along the second axis T.

Abstract: A camera (40) is mounted on a gimbal (44) inside a missile (30) and views forwardly through a transparent, generally conical front dome or ogive (70). An optically refractive corrector (72) is mounted in front of the camera lens (42) for integral movement therewith. The corrector (72) has a least one conical surface segment (74a,74b) which is dimensioned to reverse optical conical deformation created by the dome (70). The conical deformation includes little or no refractive power in a plane defined by the axis (38) of the dome (70) and the look axis (46) of the camera (40) and gimbal (44), and progressively varying one-dimensional refraction perpendicular to this plane. Variables including the apex angles (.alpha.1,.alpha.2) of cones (76,78) which define the surfaces (74a,74b), the angle (.alpha.3) between the axes (76b,78b) of the cones (76,78), the distances (D1,D2) between the apices (76 a,78a) of the cones (76,78) and the center (74c) of the corrector (72), the tilt angle (.alpha.

Abstract: A multiple field of view sensor lens assembly suitable for inclusion in an infrared imaging system. The lens assembly includes a rotatable telescope 10 for providing first and second fields of view for the sensor, the first field of view being along a first axis thereof L and the second field of view being along a separate second axis T. A servo mechanism 30 is included for rotating the telescope 10 from a first orientation at which the first axis is aligned with the optical axis to a second orientation at which the second axis is aligned with the optical axis. In a preferred embodiment the inventive lens assembly is disposed to provide fields of view in opposing directions along the first axis L, and a third field along the second axis T.

Abstract: A monocular inspection system (10) having a substantial eye relief (62), a large exit pupil, and a line of sight viewing of an object under observation (14). The inspection system (10) includes an objective lens assembly (20) which forms an image of the object (14) and which has an axis coincident with an optical path (66). A prism (16) redirects the optical path (66) to coincide with a viewing axis (64) such that the image is formed in a focal plane intersected by the viewing axis (64). A monocle assembly (40) having an axis coincident with the viewing axis (64) forms an exit pupil for the image.

Abstract: Optical systems with very long eye relief and large working distances (10) and (110) with four lenses (12), (14), (16), (18) and (20) and three lenses (112), (114) and (116), respectively, have lens surfaces shaped to focus upon an object such that a high resolution image is formed at infinity substantially over the entire field of view. High resolution and low distortion are substantially maintained independent of the user's eye location.

Abstract: A stereomicroscopic inspection system having low eyestrain features is disclosed. The system (10) includes an objective lens assembly (12) for forming an image of a viewed object (22). A prism mechanism (14) is positioned adjacent to the objective lens assembly (12) for orienting the image along a heads-up axis. A telephoto objective assembly (16) is positioned adjacent to the prism mechanism (16) for focusing the image transmitted through the prism mechanism (14). A reticle (18) is positioned adjacent to the telephoto objective assembly, and the image is focused (16) onto the reticle (18). An assembly (20) is positioned adjacent to the reticle (18) for enabling heads-up viewing of the object by the viewer, (22) said system projecting a virtual image at a predetermined distance from the viewer. This distance may be substantially equal to the eye's natural focusing distance to minimize eyestrain.

Abstract: A six element optical magnifying system (10) is disclosed. The primary lens (12), secondary lens (14), tertiary lens (16), quaternary lens (18), quinary lens (20), and sextiary lens (22) form an optical system (10), having surfaces shaped to focus upon an object such that a high resolution image is formed at infinity at 10.times. magnification substantially over the entire field of view.

Abstract: A four element optical magnifying system (10) is disclosed. The primary lens (12), secondary lens (14), tertiary lens (16), and quaternary lens (18) form an optical system (10) have surfaces shaped to focus upon an object such that a high resolution image is formed at infinity at 4.times. magnification substantially over the entire field of view.