Abstract: A 1:1 Offner mirror system for imaging off-axis objects is modified by replacing a concave spherical primary mirror that is concentric with a convex secondary mirror with two concave spherical mirrors M1 and M2 of the same or different radii positioned with their respective distances d1 and d2 from a concentric convex spherical diffraction grating having its grooves parallel to the entrance slit of the spectrometer which replaces the convex secondary mirror. By adjusting their distances d1 and d2 and their respective angles of reflection α and β, defined as the respective angles between their incident and reflected rays, all aberrations are corrected without the need to increase the spectrometer size for a given entrance slit size to reduce astigmatism, thus allowing the imaging spectrometer volume to be less for a given application than would be possible with conventional imaging spectrometers and still give excellent spatial and spectral imaging of the slit image spectra over the focal plane.

Abstract: A focal plane scanner having a front objective lens, a spatial window for selectively passing a portion of the image therethrough, and a CCD array for receiving the passed portion of the image. All embodiments have a common feature whereby the spatial window and CCD array are mounted for simultaneous relative reciprocating movement with respect to the front objective lens, and the spatial window is mounted within the focal plane of the front objective. In a first embodiment, the spatial window is a slit and the CCD array is one-dimensional, and successive rows of the image in the focal plane of the front objective lens are passed to the CCD array by an image relay lens interposed between the slit and the CCD array. In a second embodiment, the spatial window is a slit, the CCD array is two-dimensional, and a prism-grating-prism optical spectrometer is interposed between the slit and the CCD array so as to cause the scanned row to be split into a plurality of spectral separations onto the CCD array. In a third embodiment, the CCD array is two-dimensional and the spatial window is a rectangular linear variable filter ("LVF") window, so as to cause the scanned rows impinging on the LVF to be bandpass filtered into spectral components onto the CCD array through an image relay lens interposed between the LVF and the CCD array.

Abstract: A focal plane processor, located on the focal plane of an imaging array, allows on-chip imaging and scaling. Computational functions normally achieved by a separate computer may be achieved through the imaging chip itself. This can result in an imager with advanced functionality. Also, additional processing bandwidth provided by the focal plane processor may assist a computer which may receive different image segments from different pixel arrays each having associated focal plane processors.

Abstract: The error and hence the residual nonuniformity in an IR focal plane array, after two-point linear nonuniformity correction, which results from measurement errors and nonlinearity, is calculated, yielding different results than have been obtained in the past.

Abstract: For exact (i.e., non-paraxial) waves ψ representing freely propagating Gaussian beams in two and three dimensions, the patterns of phase singularities, that is zeros of ψ, are studied in detail. The zeros (points in two dimensions, and rings in three) are phase dislocations (optical vortices). The waves depend on a single parameter L, representing the radius of the waist of the beam. As L increases, pairs of dislocations interact and depart from the focal plane. Each such interaction comprises three events where the phase topology of ψ changes; each event is a reaction between the dislocations and associated phase saddles, conserving two topological quantum numbers. The same behaviour was predicted and observed by Karman et al. for beams truncated by apertures. The geometrical sensitivity of the wave to L is astonishing: changes in phase topology can occur when the waist expands by a few thousandths of a wavelength. The integral representing ψ is evaluated asymptotically, leading to a global expl...

Abstract: A description is given of axicons obtained as a tandem of one diverging lens that has third-order spherical aberration and one perfect converging lens. The asymptotic representation obtained with the help of the nonuniform stationary phase method allows the determination of such principal features of the focal segment as the intensity distribution and the width of the central core along the optical axis. The obtained results are compared with the numerical evaluation of the corresponding diffraction integral. The analyzed system contains four special cases: the doublet of both lenses, the setup of the perfect converging lens placed in the front of the aberrated diverging lens, the setup of the aberrated diverging lens placed in the primary focal plane of the perfect converging lens, and the defocused Galilean telescope. A short discussion of the aberrated-lens bending factor as well as of choice of the most convenient system geometry is also included.

Abstract: An apparatus and method to determine the surface orientation of objects in a field of view is provided by utilizing an array of polarizers and a means for microscanning an image of the objects over the polarizer array. In the preferred embodiment, a sequence of three image frames is captured using a focal plane array of photodetectors. Between frames the image is displaced by a distance equal to a polarizer array element. By combining the signals recorded in the three image frames, the intensity, percent of linear polarization, and angle of the polarization plane can be determined for radiation from each point on the object. The intensity can be used to determine the temperature at a corresponding point on the object. The percent of linear polarization and angle of the polarization plane can be used to determine the surface orientation at a corresponding point on the object. Surface orientation data from different points on the object can be combined to determine the object's shape and pose. Images of the Stokes parameters can be captured and viewed at video frequency. In an alternative embodiment, multi-spectral images can be captured for objects with point source resolution. Potential applications are in robotic vision, machine vision, computer vision, remote sensing, and infrared missile seekers. Other applications are detection and recognition of objects, automatic object recognition, and surveillance. This method of sensing is potentially useful in autonomous navigation and obstacle avoidance systems in automobiles and automated manufacturing and quality control systems.

Abstract: A method and system providing single point high spatial and timing resolution for photoemission microscopy of an integrated circuit. A microscope having an objective lens forming a focal plane is arranged to view the integrated circuit, and an aperture element having an aperture is optically aligned in the back focal plane of the microscope. The aperture element is positioned for viewing a selected area of the integrated circuit. A photo-diode optically aligned with the aperture to detect photoemissions when test signals are applied to the integrated circuit.

Abstract: An in-situ imaging system suitable for analyzing particles or droplets contained in process reactor vessels or pipelines at full process concentrations is disclosed. The system includes a light source (45) capable of high peak power output operated in a pulsed mode that is located inside of a probe. The light from the light source (45) is coupled into an optical fiber (6). The light is carried by the optical fiber to a lens system (3) near the end of the probe which focuses the light through a window (11) to an area which coincides with the field of view in the focal plane of the imaging optics (7). The imaging optics collect the light which is backscattered from particles or droplets, magnifying the image and projecting it onto an image detector (52) such as a CCD array.

Abstract: The present invention provides a method and apparatus for high-speed autofocus and tilt of an inspection surface in a microscope system. The method and apparatus herein described projects an array of spots, lines, circles, grids or other shapes on the surface to be adjusted. The superposition of the array on the surface is imaged by a CCD camera and captured for subsequent analysis. Analysis of the captured image determines both the distance and angle through which the surface must be adjusted to bring it into the focal plane of the optical system. Focus and tilt error is estimated by comparing image dilation and distortion with calibrated data.

Abstract: Scanning method and apparatus for maintaining a desired position of an article are presented. The apparatus comprises an illumination unit, a focusing optics and a focus detection unit. The illumination unit generates an incident light beam for illuminating an elongated region of the article and producing light returned from the illuminated region. The focusing optics focuses the incident beam onto a focal plane and collects at least a portion of the returned light. The focus detection unit comprises an imaging optics and a detector having a sensing surface responsive to light impinging thereon for generating data representative thereof. The imaging optics is capable of forming first and second images on the sensing surface. The first and second images are formed by first and second spatially separated substantially identical light components of the collected returned light, respectively, which propagate symmetrically relative to an optical axis of the focusing optics. A position of the first image relative to the second image is indicative of the position of the article relative to the focal plane.

Abstract: A free-space optical lasercom system is disclosed which includes an optical subsystem for receiving an Rx signal and sending a Tx signal, wherein said optical subsystem establishes a focal plane. A first optical fiber with an end coupled to the optical subsystem for directing the Rx signal to an RX detector. A second optical fiber is also included with an end coupled to the optical subsystem for directing the Tx signal from a Tx laser source. A linear X-Y shifting apparatus is used for positioning the respective ends of the first and second optical fibers in the focal plane of the optical subsystem so as to maintain a desired coupling efficiency.

Abstract: A compound objective lens is composed of a hologram lens or transmitting a part of incident light without any diffraction to form a beam of transmitted light and diffracting a remaining part of the incident light to form a beam of first-order diffracted light, and an objective lens for converging the transmitted light to form a first converging spot on a front surface of a thin type of first information medium and converging the diffracted light to form a second converging spot on a front surface of a thick type of second information medium Because the hologram selectively functions as a concave lens for the diffracted light, a curvature of the transmitted light differs from that of the diffracted light Therefore, even though the first and second information mediums have different thicknesses, the transmitted light incident on rear surface of the first information medium is converged on the its front surface, and the diffracted light incident on a rear surface of the second information medium is converged on the its front surface That is, the compound objective lens has two focal points

Abstract: An optical head apparatus which records or reproduces signals stably on optical disks having different thicknesses. A correction hologram element or a correction filter is provided between a light source and a 2-focus lens in order to decrease optical intensity at a portion distant from the optical axis or to change the optical path length. The light which passes the correction hologram element or a correction filter is converged by the 2-focus lens as a micro-spot on an optical disk. The 2-focus lens comprises a hologram lens which diffracts a part of the light beam and an object lens.

Abstract: A penetrating radiation source (14) is disposed on one side of a object (10) which is on a object support (12). A flat panel radiation detector (18) is stationarily disposed on the opposite side of the object (10) than the source (14). A moving system (16, 50, 52) moves the source (14) with respect to the object (10). In each position (Xi, Yi, Zi) of the source (14) a center ray of the x-ray beam strikes the detector (18) at a corresponding location (xi, yi, 0). For each position (Xi, Yi, Zi) of the source (14), the image (xi, yi, 0) of an object located on a focal plane offsets by a vector displacement (Di) relative to a reference position (xo, yo, zo) of the image when the source is at (X0, Y0, Z0). A processor (28) shifts and interpolates each view by the different vector displacements corresponding to each of the focal planes (L1, L2, . . . ) and integrates the images to generate a series of slice image representations which are stored in a volume image memory (30). In this manner, by adjusting the view offset by an amount corresponding to each of the focal planes, (L1, L2, . . . ) the same data set is used to generate all of the slices of the resultant volume image.

Abstract: Developing maximum image performance in an infrared imaging system without exceeding physical design parameters, suchas size and weight, leads to system requirements for small and closely spaced detector pixels areas on the focal plane array.Small sensitive areas allow high resolution and close spacing that can result in high spatial sampling rates and the ability todiscern objects at long distances. The imaging resolution performance of compact two-dimensional Indium Antimonide(InSb) arrays can be limited by the fact that photo generated carriers can diffuse and be collected by junctions removed from the point of generation. Carrier diffusion can limit resolution in compact sensor packages. This paper quantitatively discusses the effect of carrier diffusion on resolution and the advantages of a reticulated pixel design. INTRODUCTION The image quality of infrared imaging sensors is typically characterized by the system thermal sensitivity and spatialresolution. Thermal sensitivity is a measure of the smallest detectable signal. Spatial resolution determines the finest detailthat can be observed. Although other factors, such as display brightness, image aberrations (optical, electrical or mechanical),or physical factors such as size and vibration can also influence the image quality, these factors can be minimized effectivelyby disciplined design techniques. The basic thermal sensitivity and spatial resolution of a system are the most criticalperformance factors in a typical system design. To achieve high quality images, the designer must begin system performancetrade-offs by selecting a high quality, highly responsive focal plane array detector.Indium Antimonide (InSb) provides some of the highest quality, highest reliability images available in infraredimaging systems. InSb has a high quantum efficiency (QE) in the mid-wavelength infrared (MWIR) region, providing highresponsivity and the opportunity for high sensitivity performance. As a consequence of this excellent QE, InSb focal planearray based imaging sensors can provide noise equivalent temperature differences (NETD) better than 0.020 K'. Thedetection/recognition ranges for staring array systems are typically resolution limited and not noise limited. Further, inresolution-limited system designs, a system operated in the 3 to 5

Abstract: The set of k points that optimally represent a distribution in terms of mean squared error have been called principal points (Flury 1990). Principal points are a special case of self-consistent points. Any given set of k distinct points in Rp induce a partition of Rp into Voronoi regions or domains of attraction according to minimal distance. A set of k points are called self-consistent for a distribution if each point equals the conditional mean of the distribution over its respective Voronoi region. For symmetric multivariate distributions, sets of self-consistent points typically form symmetric patterns. This paper investigates the optimality of different symmetric patterns of self-consistent points for symmetric multivariate distributions and in particular for the bivariate normal distribution. These results are applied to the problem of estimating principal points.

Abstract: Cone-beam (CB) collimators lead to higher sensitivity and resolution in SPECT brain images than parallel beam (PB) collimators. Point sources can be placed in the focal points of the CB collimators in order to obtain additional transmission CT projection data. In the design of a dual-head system with opposing detectors (Opposing Heads System, OHS), it is not possible to position the point sources in the focal points without truncating the patient's head in the projections, even when large crystals are used. Space for the point sources can be created by positioning the cameras at a right angle (Right Angle System, RAS), but such CB systems require collimators with long focal distances or strong offsets for the focal points. It is therefore important to study the effects of focal point positions on the emission image quality. To this end, the following cases were compared in a simulation study: half cone-beams (HCB) in OHS and RAS and quarter cone-beam (QCB) collimators in RAS, each CB with different focal distances (ED). Projections of a disc phantom and a brain phantom acquired with circular orbits were simulated. The size of the crystals was 51/spl times/38 cm. Images were reconstructed iteratively with an Ordered Subset Expectation Maximization algorithm. The disc phantom experiment showed slice-to-slice crosstalk in the CB reconstructions which decreases with increasing focal distance. The CB reconstructions of the brain phantom did not show these artifacts. This study indicates that (i) An OHS with large crystals and HCB collimators provides superior emission image quality compared to RAS with HCB collimators and RAS with QCB collimators. (ii) Dual head systems with large crystals have potential for very high resolution brain imaging.

Abstract: A device for the geometric calibration of a CCD camera, which includes a coherent light source and a synthetic hologram arranged relative to the coherent light source so that the hologram generates a real three-dimensional test structure f(x,y,z) around a focal plane of the CCD camera using coherent light. A method for geometric calibration of a CCD camera using a coherent light source and a synthetic hologram which includes the steps of calculating the synthetic hologram to provide a well-defined ideal three-dimensional test structure f(x,y,z) taking into account idealized camera optics of the CCD camera to be calibrated, illuminating the hologram using the coherent light source so that a real three-dimensional test structure f(x,y,z) is generated around a focal plane of the CCD camera, and evaluating in parallel a plurality of sensor pixels by determining a respective section plane through the real test structure f(x,y,z) from individual image information of each of the plural sensor pixels.

Abstract: An object (14) is positioned on an object support (16). A radiation source (10) projects a beam of radiation through a region of interest (12) of the object. A plurality of focal planes (F1, F2, . . . , Fn) mark the center of selected slice images through the region of interest. A gantry (20) rotates the radiation source (10) around a circular trajectory (22) as an encoder (26) monitors a radius (r) of the trajectory and an angular position (φ) of the radiation source (10) around the trajectory (22). A look-up table (40) is addressed with the selected focal plane(s) (F1, F2, . . . , Fn) and (r, φ) to generate a correction or shift value (S1, . . . , Sn.) for each selected focal plane (F1, F2, . . . , Fn). A flat panel detector (18) is read out a plurality of times to generate a plurality of electronic data views as the radiation source rotates. Each view is corrected with a corresponding correction or shift value and integrated in a summation circuit (50) with preceding views to generate an image representation of the slice(s) through the selected focal plane(s) (F1, F2, . . . , Fn) or a 3D volume. The slice image or 3D volume image representation is converted into a human-readable display (56) substantially in real-time, e.g., each time a preselected number of views has been summed.

Abstract: This invention is a one-dimensional optic flow sensor that operates in a small region of the two-dimensional visual field The heart of the sensor is an linear array of photoreceptors that generates a one-dimensional image representation of the visual field region of interest The linear photoreceptor array has an orientation in the two-dimensional image space Information in the two-dimensional image space parallel to the photoreceptor array's orientation is preserved while information in other directions is discarded The result is that a one-dimensional optic flow algorithm using the photoreceptor array output produces a measurement of the optic flow vector onto the sensor orientation vector In a preferred embodiment, the photoreceptor array circuitry is implemented on a focal plane chip on which an image is focused by a lens The focal plane chip is placed slightly off the lens's focal point to blur the image Each elongated photoreceptor has a long rectangular shaped active area, whose long dimension is perpendicular to the photoreceptor array's orientation An iris next to the lens controls the “shape” of the blurring by having a transmission function derived from a low-pass spatial filter The combination of the lens being out of focus and the shading from the iris blur the image in a controlled fashion that implements a low pass spatial filter This reduces high spatial frequency components in the image that could cause problems due to spatial aliasing from the photoreceptor array

Abstract: Sandia National Laboratories and several subsystem contractors are developing technologies applicable to multispectral remote sensing from space. A proof of concept multispectral sensor system is under development. The objective of building this sensor is to demonstrate and evaluate multispectral imaging technologies for various applications. The three major subsystems making up the sensor are the focal plane assembly (FPA), the cryocooler, and the telescope. This paper covers the focal plane assembly, which is the basis of the sensor system. The focal plane assembly includes sensor chip assemblies, optical filters, and a vacuum enclosure with cold shielding. Linear detector arrays provide spatial resolution in the cross-track direction for a pushbroom imager configuration. The optical filters define 15 spectral bands in a range from 0.45 /spl mu/m to 10.7 /spl mu/m. All the detector arrays are mounted on a single focal plane and are designed to operate at 75 K. No beam splitters are used. The four spectral bands covering the visible to near infrared have roughly 2400 pixels each, and the remaining 11 spectral bands have roughly 600 pixels each. The average total rate of multispectral data from the FPA is approximately 15.4 megapixels per second.

Abstract: An optical deflection angle measuring apparatus which does not require an operation for applying light to a position detecting element when a deflection angle is optically measured, and which can prevent the measurement results from being influenced by an external force, such as vibration, comprising a common lens (411) for condensing diffused light from light sources (41, 42) so as to optically measure a deflection angle ( PHI ) of two segments connecting together a cardinal point and points set at a distance therefrom on both sides thereof, position detecting elements (412-2, 412-1) adapted to receive the condensed light from the light sources (41, 42) and detect the position of reception of the light, and reflecting prisms (413-1, 413-2) adapted to transmit the diffusion light, which is to enter the lens (411), from the light sources (41, 42) and guide the light, which is to be condensed by the lens (411), from the light sources (42, 41) to the position detecting elements (412-1, 412-2), which are disposed in positions in which the condensation of the light by the lens (411) is not hindered, to form a detector (410), whereby the deflection angle ( PHI ) can be measured by computation on the basis of the results of detection by the position detecting elements.

Abstract: The optical analysis and design program RAYTRACE, which was developed at our institute, enables the simulation of micro-optical systems containing arrays of microlenses or other optical components. The most important features of the program are briefly described to show its broad application areas. A special simulation example showing the spot diagram and the intensity distribution in the focal plane of a simple Shack-Hartmann sensor with a diffractive microlens array for an incident aspherical wave is given. © 1998 Society of Photo-Optical Instrumentation Engi- neers. (S0091-3286(98)01906-0)

Abstract: Light reflected from a conical mirror produces an intensity gradient that can be used to focus atoms to a single spot. Within the Raman-Nath approximation the position of the focal plane, peak atomic density, and spot size have been determined for a range of field strengths. Theoretical estimates of the field strength needed to focus atoms using a conical lens are found to be three to four orders of magnitude lower than that needed for focusing atoms using standing-wave fields.

Abstract: A two-stage multi-spectral imaging system comprising a reflective objective and a reflective relay aligned on a common optical axis, the objective being arranged to form an intermediate image and the relay being arranged to deliver image-forming radiation emanating from the intermediate image to a focal plane, wherein the objective is formed by a large concave primary mirror which is apertured on-axis and a small secondary mirror generally disposed in the form of a “Cassegrain” objective, the relay is formed by a pair of confronting mirrors each being apertured on-axis to enable passage of radiation into and out of the relay, and the relay being positioned to provide space between the relay and the focal plane to accommodate waveband selective splitting optics if so desired.

Abstract: A scanning apparatus (100) providing separate fixed object focal planes for transmissive (2091) and reflective (2090) original documents to be scanned, wherein a scan carriage (220) containing illumination (6016), sensor (6014), and optical elements (6006, 6010) is moved together to scan an original document and to obtain a digitized representation thereof. The movable scan carriage has an illumination source disposed between the reflective (106) and transmissive (210) object focal planes, with the object focal plane to be used selected by changing the position of a single optical element (2002) within the scan carriage. The illumination source comprises a single lamp (2020) disposed for correct illumination of the selected object focal plane. Automatic resolution selection and focusing of the original image can occur using a converging device (2012) comprising a first (3004) and second (3004) focusing lens.