Abstract: A polarimeter simultaneously measures the Stokes vectors of a light beam using an optics unit with a slit with a slit axis, a foreoptics that focuses the light beam from the point location through the slit, a collimator that receives the light beam from the slit and collimates the light beam, a cylinder lens that receives the light beam from the collimator, wherein the cylinder lens has a cylindrical axis parallel to the slit axis, a re-imaging lens that images the light beam from the cylinder lens onto a focal plane, and a set of polarizing filters including three polarization filters having three different polarizations. The polarization filters are adjacent to each other in a direction perpendicular to the slit axis and lie between the cylinder lens and the focal plane so that the light beam is directed onto the set of polarizing filters.

Abstract: An imaging polarimeter sensor includes an achromatic beam-splitting polarizer that receives a polychromatic image beam of a scene and simultaneously produces a first polarized polychromatic image beam and a second polarized polychromatic image beam. The second polarized polychromatic image beam is of a different polarization than the first polarized polychromatic image beam and is angularly separated from the first polarized polychromatic image beam. The achromatic beam-splitting polarizer preferably includes a Wollaston prism through which the polychromatic image beam passes, and at least one grating through which the polychromatic image beam passes either before or after it passes through the Wollaston prism. An imaging detector receives the first polarized polychromatic image beam and the second polarized polychromatic image beam and produces an output image signal responsive to the first polarized polychromatic image beam and the second polarized polychromatic image beam.

Abstract: An imaging polarimeter sensor includes an achromatic beam-splitting polarizer that receives a polychromatic image beam of a scene and simultaneously produces a first polarized polychromatic image beam and a second polarized polychromatic image beam. The second polarized polychromatic image beam is of a different polarization than the first polarized polychromatic image beam and is angularly separated from the first polarized polychromatic image beam. The achromatic beam-splitting polarizer preferably includes a Wollaston prism through which the polychromatic image beam passes, and at least one grating through which the polychromatic image beam passes either before or after it passes through the Wollaston prism. An imaging detector receives the first polarized polychromatic image beam and the second polarized polychromatic image beam and produces an output image signal responsive to the first polarized polychromatic image beam and the second polarized polychromatic image beam.

Abstract: An optical system has a light source of an optical beam, and a wavefront distortion generator that introduces a known wavefront distortion into at least one wavelength component of the optical beam prior to the formation of an intermediate image. A focusing device receives the optical beam, produces the intermediate image of the optical beam, and outputs the optical beam. A wavefront distortion corrector, after the formation of the intermediate image, introduces a wavefront distortion correction into each component of the optical beam into which the known wavefront distortion was introduced by the wavefront distortion generator. The wavefront distortion correction is the reverse of the known wavefront distortion introduced into the optical beam by the wavefront distortion generator.

Abstract: A scanning system (10) and a method permit scanning a desired field-of-view within a maximized field-of-regard at a constant speed without reversing the scan direction about a primary axis (38). The system includes a mirror (20) which rotates about the primary axis (38). The mirror (20) is supported for rotation about a flip axis (40) which is perpendicular to the primary axis (38). Rotation of the mirror (20) about the primary axis (38) is divided into a scan period during which the field-of-view is scanned by the mirror (20), and a flip period during which the mirror (20) rotates about the flip axis (40). The mirror (20) is mounted in a gimbal for independent rotation about a secondary axis (24) which is parallel to the primary axis (38).

Abstract: An optical system has a light source of an optical beam, and a wavefront distortion generator that introduces a known wavefront distortion into at least one wavelength component of the optical beam prior to the formation of an intermediate image. A focusing device receives the optical beam, produces the intermediate image of the optical beam, and outputs the optical beam. A wavefront distortion corrector, after the formation of the intermediate image, introduces a wavefront distortion correction into each component of the optical beam into which the known wavefront distortion was introduced by the wavefront distortion generator. The wavefront distortion correction is the reverse of the known wavefront distortion introduced into the optical beam by the wavefront distortion generator.

Abstract: A scanning system (10) and a method permit scanning a desired field-of-view within a maximized field-of-regard at a constant speed without reversing the scan direction about a primary axis (38). The system includes a mirror (20) which rotates about the primary axis (38). The mirror (20) is supported for rotation about a flip axis (40) which is perpendicular to the primary axis (38). Rotation of the mirror (20) about the primary axis (38) is divided into a scan period during which the field-of-view is scanned by the mirror (20), and a flip period during which the mirror (20) rotates about the flip axis (40). The mirror (20) is mounted in a gimbal for independent rotation about a secondary axis (24) which is parallel to the primary axis (38).

Abstract: A multi-slit spectrometer is combined with a two-dimensional detector array to enable simultaneous spectral analysis of several objects, improving the signal-to-noise ratio of multispectral imagery. The multi-slit spectrometer includes a multi-slit structure defining a plurality of parallel thin slits, and a first lens for directing object light onto the multi-slit structure. A second lens collimates and directs light which has passed through the slits of the multi-slit structure onto a light dispersing element such as a dispersing prism or a diffraction grating. A third lens focuses light which has passed through the light dispersing element onto the two-dimensional detector array at an image plane. A two dimensional detector array of detector elements is placed at the image plane. The slits are separated by a separation distance equal to an integral multiple of the detector width dimension, where the multiple is equal to (N times the number of slits) plus or minus one, where N is an integer.

Abstract: A calibration system and method for a display optical system including a projector and a projection screen. A calibration camera is inserted between the projector and the screen to receive the radiation directly from the projector. The image focused by the camera lens is captured by a charge-coupled device, and processed by a controller. The result is fed back to the image generator of the projector for further improvement in the image quality.

Abstract: A head mounted projector system with extremely high resolution. The system includes a retro-reflecting gain screen. The on-helmet apparatus of the system includes a truncated spherical mirror, a redirecting multi-faceted mirror and a small rotating polygon scanner. The system includes off-helmet apparatus including a background image source and an area-of-interest (AOI) image source. The background and AOI images are scanned into a linear ribbon array of fibers. To provide 20/20 visual acuity, one fiber per each 0.7 arc-minute field-of-view is used.

Abstract: A helmet/head mounted display including a display image source and a reflective visor for each eye. The image source includes a fiber optic cover plate with a planar input surface and a curved output surface which has curvature providing the correct curvature. The image source further includes a self-emitting device such as a field electrode display or electroluminescent device, or a polymer dispersed liquid crystal (PDLC) sandwiched between a thin, sharply tapered fiber optic plate and the fiber optic cover plate. For the PDLC image source, back light illumination is introduced through the tapered fiber optic plate, passes through or is scattered by the PDLC and then through the fiber optic face plate to the visor, for reflection to the observer's eye. The fiber optic face plate is constructed with a very low numerical aperture. The fibers of the cover plate are oriented toward the eye as seen in the reflection from the visor to reduce undesirable reflected light.

Abstract: A high efficiency, high performance full color projection system. The system includes a one-to-one relay and a refractive projection lens system. The one-to-one relay combines the outputs from two different spectral image sources, such as blue and red image sources. The refractive projection lens further combines the output from a third spectral image source, such as a green image source, with the combined images from the other two image sources relayed through the one-to-one relay to produce a single output. The one-to-one relay includes three modules, a spherical primary module, a spherical secondary module and a spectral combining module. The refractive projection lens system includes a beam combiner and a projection optics.

Abstract: A lighter weight helmet mountable display (HMD) that is easily adjustable to accommodate variable inter-pupillary distances includes substantially parallel left and right optical channels, and projects left and right images onto the helmet's visor. Each channel includes light sources that form a complete scan line of the image, and project luminance patterns for successive scan lines through a lens which reduces the light's divergence. A deflector is moved to deflect successive luminance patterns back through the lens so that the lens focuses the patterns onto successive scan lines on a back projection screen. The screen emits luminance patterns in response to the incident luminance patterns for each successive scan line to project the image onto the visor.

Abstract: Telecentric afocal microlens combinations are inserted between the liquid crystal cells of an active matrix liquid crystal subtractive color display to retain light within a projection of each liquid crystal pixel as the light propagates through the system. A resulting reduction in light losses at the edge of each pixel significantly improves the output brightness and resolution.

Abstract: In a display system suitable for high ambient light environments, a lamp is used simply as a light source to illuminate a rear projection display screen, which is a matrix of tiny cells that modulate the light at video rates. Each cell includes a polymer dispersed liquid crystal (PDLC), a focusing lens and a pinhole aperture. When the PDLC is electrically activated, light passing through the PDLC is scattered in many directions, and very little light passes through the pinhole aperture and is seen by the viewer. When the PDLC is not electrically activated, light passing through the PDLC is not scattered, the lens of each cell focuses the light through the pinhole aperture, and the viewer sees a bright spot of light.

Abstract: A lightweight fiber optic television display useful for front and rear projection systems. An array of pixels such as a fiber optic (FO) ribbon has an input end which receives input light illuminating the pixels so as to create a first dimension of the display. The output end of the FO ribbon is moved relative to the observer to create a second dimension. The FO ribbon is clamped by a clamp near the output end and vibrated by a driver so that the output end of the ribbon is moved to obtain the second dimension. A lens is disposed between the vibrating end of the FO ribbon and a projection screen, and images the two dimensional image formed by the vibrating output end of the ribbon onto the screen. The projection screen may be either a rear or front projection screen. The FO ribbon may include a single row of fibers, or multiple rows to improve the image quality.

Abstract: A uniform-brightness, high-gain projection screen is especially suited for reflecting radiation from a projector to a viewer who is spaced from the projector along a projection axis. The screen is formed with a plurality of reflective faces that each form at least a portion of a ring that is transverse to the projector axis, have different spacings from the projector and are axially tilted to set the projector-face angle equal to the viewer-face angle. The faces are preferably defined by a plurality of tiles that are bonded to the interior of a projection dome such as a flight simulator dome.

Abstract: A lightweight fiber optic television subminiature display for helmet mounted display systems. A one dimensional array of pixels such as a fiber optic (FO) ribbon (64) has an input end (62) which receives input light illuminating the pixels so as to create a first dimension of the display. The output end (64B) of the FO ribbon is moved relative to the observer to create a second dimension. At the helmet (66), the FO ribbon is clamped by a clamp (68) and vibrated by a driver (70) so that the output end of the ribbon is moved to obtain the second dimension. The dimensions of the FO ribbon are selected to provide a natural resonant frequency equal to the television field rate, and the driver vibrates the section (64A) of the ribbon between the clamp and the ribbon output end at the ribbon resonant frequency. The clamp and driver can be very lightweight, thereby reducing the weight of the display elements mounted on the helmet.

Abstract: A dynamic distortion correction apparatus 100 for use in an image projector 120. The invention includes a computer image generator 144 for generating a video image signal. A control circuit 102 processes the video image signal and regulates the clocking rate of a time-delayed video output signal. A modulator 104 is included for converting the video output signal to an optical image signal having a plurality of television raster lines. An optical device 148 is incorporated which orients each of the plurality of raster lines to compensate for distortion in the optical image signal at any viewing angle. A gimballed mirror 126 and a color projection optic device 178 are included to control the projection of the optical image signal onto a surface 110 to provide a display image 106. In a second embodiment, the optical device 148 is replaced by a correcting feature of the computer image generator which causes each of the raster lines to be parallel to every other raster line.

Abstract: An improved helmet mounted display. The inventive display includes a laser and a fiber optic cable having an array having two sets of rows of optical fibers and being mounted to receive input from said laser at a input end and to illuminate a screen with light from said laser via an output end thereof. A particularly novel aspect of the invention is the provision of a first mechanism at the input end of the fiber optic cable for illuminating a first set of rows of fibers in the array with light from the laser during a first scanning interval and for illuminating a second set of rows of fibers in the array with light from the laser during a second scanning interval. A second tilting mechanism is mounted at the output end of the fiber optic cable for directing illumination from the first set of rows of fibers in the array to a screen during the first scanning interval and for directing illumination from the second set of rows of fibers in the array to the screen during the second scanning interval.