Showing papers on "Cardinal point published in 1990"
TL;DR: In this paper, the authors explore the potential of the homogeneous relaxation model (HRM) as a basis for the description of adiabatic, one-dimensional, two-phase flows.
Abstract: The paper explores the potential of the homogeneous relaxation model (HRM) as a basis for the description of adiabatic, one-dimensional, two-phase flows. To this end, a rigorous mathematical analysis highlights the similarities and differences between this and the homogeneous equilibrium model (HEM) emphasizing the physical and qualitative aspects of the problem. Special attention is placed on a study of dispersion, characteristics, choking and shock waves. The most essential features are discovered with reference to the appropriate and convenient phase space Ω for HRM, which consists of pressure P , enthalpy h , dryness fraction x , velocity w , and length coordinate z . The geometric properties of the phase space Ω enable us to sketch the topological pattern of all solutions of the model. The study of choking is intimately connected with the occurrence of singular points of the set of simultaneous first-order differential equations of the model. The very powerful centre manifold theorem allows us to reduce the study of singular points to a two-dimensional plane Π , which is tangent to the solutions at a singular point, and so to demonstrate that only three singular-point patterns can appear (excepting degenerate cases), namely saddle points, nodal points and spiral points. The analysis reveals the existence of two limiting velocities of wave propagation, the frozen velocity a f and the equilibrium velocity a e . The critical velocity of choking is the frozen speed of sound. The analysis proves unequivocally that transition from ω a f to w > a f can take place only via a singular point. Such a condition can also be attained at the end of a channel. The paper concludes with a short discussion of normal, fully dispersed and partly dispersed shock waves.
248 citations
1 Jan 1990
TL;DR: Confocal scanning microscopes are particularly attractive by virtue of their enhanced lateral resolution, purely coherent image formation and optical sectioning and it is probably the latter property which is most useful as it gives rise to the ability to image a thick specimen in three-dimensions.
Abstract: Confocal scanning microscopes are particularly attractive by virtue of their enhanced lateral resolution, purely coherent image formation and optical sectioning (Wilson and Sheppard, 1984). It is probably the latter property which is most useful as it gives rise to the ability to image a thick specimen in three-dimensions. This is possible because the optical system images information only from a thin region in the neighbourhood of the focal plane. This permits us to store many image slices in a computer to give a three dimensional data set which describes the object. There are now many sophisticated computer software systems available to display this data in various ways. Obvious examples include the extended focus technique (Wilson and Hamilton, 1982) in which we merely add up (integrate) the images from various depths to provide an image of greatly extended depth of field. We may also produce images where object height is coded as brightness or combine the whole data set to provide an isometric view of the object, Figure 1. It is ;also possible to use false color to label features of interest or, by simple processing, to obtain stereoscopic pairs (van der Voort, 1985). Other forms of image display are discussed in Chapter 10.
142 citations
Patent•
IBM1
TL;DR: In this paper, an optical system for classifying particles is described, which includes a first detector that responds to the beam's intensity along a first polarization axis to produce a first output and a second detector that reacts to the beams intensity along the second polarization axis for producing a second output.
Abstract: An apparatus is described for classifying particles and includes an optical system for transmitting to a focal plane which includes at least one particle, two substantially parallel optical beams, the beams being initially mutually coherent but of different polarizations. The beams are displaced and focused in the focal plane. A further optical system is positioned in the path which the beam takes after depating from the focal plane and combines the beams so that a particle-induced phase shift in one beam is manifest by a change in elliptical polarization of the combined beams. A first detector is responsive to the beam's intensity along a first polarization axis to produce a first output and a second detector is responsive to the beams intensity along a second polarization axis to produce a second output. The first and second outputs are added to provide an extinction signal and, in a separate device, are subtracted to provide to phase shift signal. The extinction signal and phase shift signal are both fed to a processor which classifies a particle in accordance therewith.
57 citations
Patent•
28 Dec 1990
TL;DR: In this paper, an image recording apparatus for converting a subject image to an image signal and storing the image signal in a memory was proposed, where an optical unit for focusing the subject image on a focal plane was fixed to obverse surface of a circuit board concentric to an opening formed as an optical path through the depth of the circuit board, and a sensing surface of the image sensor was directed to the optical unit and is coincident with the focal plane.
Abstract: An image recording apparatus for converting a subject image to an image signal and storing the image signal in a memory. An optical unit for focusing the subject image on a focal plane is fixed to obverse surface of a circuit board concentric to an opening of the circuit board that is formed as an optical path through the depth of the circuit board, and an image sensor is fixed to reverse surface of the circuit board concentric to the opening. A sensing surface of the image sensor is directed to the optical unit and is coincident with the focal plane of the optical unit.
49 citations
1 Feb 1990
TL;DR: An iterative algorithm is designed to estimate the 3D position of the camera assembly in space, a generalized version of the Church's method, and allows for multiple cameras with nonconvergent nodal points.
Abstract: In this paper, a new optical system for real-time, three-dimensional position tracking is described. This system adopts an "inside-out" tracking paradigm. The working environment is a room where the ceiling is lined with a regular pattern of infrared LEDs flashing under the system's control. Three cameras are mounted on a helmet which the user wears. Each camera uses a lateral effect photodiode as the recording surface. The 2D positions of the LED images inside the field of view of the cameras are detected and reported in real time. The measured 2D image positions and the known 3D positions of the LEDs are used to compute the position and orientation of the camera assembly in space.We have designed an iterative algorithm to estimate the 3D position of the camera assembly in space. The algorithm is a generalized version of the Church's method, and allows for multiple cameras with nonconvergent nodal points. Several equations are formulated to predict the system's error analytically. The requirements of accuracy, speed, adequate working volume, light weight and small size of the tracker are also addressed.A prototype was designed and built to demonstrate the integration and coordination of all essential components of the new tracker. This prototype uses off-the-shelf components and can be easily duplicated. Our results indicate that the new system significantly out-performs other existing systems. The new tracker provides more than 200 updates per second, registers 0.1-degree rotational movements and 2-millimeter translational movements, and processes a working volume about 1,000 ft3 (10 ft on each side).
44 citations
Patent•
12 Apr 1990TL;DR: In this paper, a correction system for a high resolution charged particle beam apparatus provided with two hexapoles (2,4) enclosing a telescopic round-lens system (7) with two lenses (8,10) which are arranged so that outer focal points (20,22) of the lenses are coincident with nodal points (16,18) which coincide with centre points of the Hexapoles was presented.
Abstract: A correction system for a high resolution charged particle beam apparatus provided with two hexapoles (2,4) enclosing a telescopic round-lens system (7) with two lenses (8,10) which are arranged so that outer focal points (20,22) of the lenses are coincident with nodal points (16,18) which coincide with centre points of the hexapoles. An additional coma-free round-lens doublet (30) is added for imaging a coma-free plane (50) of a lens (51) to be corrected into a centre plane (16') of a first hexapole (2) of the system. For both round-lens doublets the spacing between the two lenses preferably equals 2f, f being the focal length of each lens.
40 citations
TL;DR: Results for uniformly perfused tissues show that a single circular scan induces radially non-uniform temperature distributions at the focal depth and undesirable pre-focal high temperature regions, and a reasonable compromise of transducer choice is one with a low f-number and a frequency of about 1.0 MHz.
Abstract: A steady-state, three dimensional, bioheat transfer equation-based simulation program has been developed and used with single and multiple transducer arrangements to investigate the effects of spherical transducer characteristics (frequency and f-number) and scanning patterns on treatment temperature distributions. Results for uniformly perfused tissues show that: (1) a single circular scan induces radially non-uniform temperature distributions at the focal depth and undesirable pre-focal high temperature regions; and (2) multiple circular scans spaced by the focal diameter of the ultrasound beam and using feedback control can induce uniform temperature distributions in the focal plane, but still cause undesirable pre-focal plane high temperatures. These two results apply both to a single transducer scanned with its axis normal to the skin and to multiple tilted transducers with overlapping foci. The extent and magnitude of this pre-focal high-temperature region increases as frequency increases (from 0.5 to 2.0 MHz) and as the f-number increases (from 1.0 to 2.0). Finally, (3) when four tilted transducers with overlapping foci are used with multiple circular scans spaced by the focal diameter, if the transducer closest to the central axis of the scans is turned off (every transducer is turned off periodically) the pre-focal high-temperature region can be eliminated. From the results of this parametric study and practical considerations, a reasonable compromise of transducer choice for general use is one with a low f-number (about 1.0) and a frequency of about 1.0 MHz. For multiple tilted transducers with overlapping foci the choice of frequency is also 1.0 MHz and the f-number should be as low as possible.
40 citations
Patent•
2 Jul 1990
TL;DR: A catadioptric zoom relay telescope with an aspherical primary mirror and only three movable lens elements focuses all wavelengths in a broad infrared bandwidth onto a common focal plane with substantially diffraction-limited imagery throughout a changing focal ratio.
Abstract: A catadioptric zoom relay telescope with an aspherical primary mirror and only three movable lens elements focuses all wavelengths in a broad infrared bandwidth onto a common focal plane with substantially diffraction-limited imagery throughout a changing focal ratio (i.e., a zoom range) from less than f/1.5 to more than f/6.0.
32 citations
Patent•
12 Jun 1990TL;DR: An optical device for the spectral analysis of a light source which comprises a spectrograph assembly including a dispersive element, and a classical collimator is described in this article. But it is not suitable for both simultaneous and sequential spectroscopy.
Abstract: An optical device for the spectral analysis of a light source which comprises a spectrograph assembly including a dispersive element, and a classical collimator. The spectrograph assembly supplies a complete intermediate spectrum at the object focus of the classical collimator and the classical collimator reforms, at its image focus, an image of the dispersive element. The spectrograph assembly is preferably a Czerny-Turner or other type of spectrograph comprising an entry slit, two juxtaposed concave mirrors of the same focal length and a dispersive element placed strictly in the common focal plane of the two mirrors. Most preferably, the classical collimator is the first mirror of the second, similar spectrograph assembly. The device is most advantageous in that it is readily useable for both simultaneous and sequential spectroscopy.
28 citations
Patent•
13 Dec 1990TL;DR: In this paper, the Radon transform and angular correlation of input images using optical signal processing techniques is presented. But the authors focus the output light from the spatial light modulator onto a single photodetector using a spherical lens.
Abstract: A method and electro-optical apparatus for generating the Radon transform and angular correlation of input images using optical signal processing techniques is disclosed. In the preferred embodiment, video feedback of raster scanned images is utilized to perform the Radon transform and angular correlation separately or in combination. The basic video feedback architecture implements angular rotation of the input image via successive passes through a video feedback loop in which the feedback focal plane array is rotated by a fixed amount relative to the input/feedback miniature display unit. Subsequently, the Radon transform is derived by using anamorphic output optics, which image the Radon transform onto a linear self-scanned detector array. By projecting the rotated feedback image through a two-dimensional spatial light modulator, such as a liquid crystal television having a transmittance proportional to the intensity pattern of the unrotated input image, angular correlation is obtained by focusing the output light from the spatial light modulator onto a single photodetector using a spherical lens.
26 citations
Patent•
31 May 1990TL;DR: In this article, a beam focusing and positioning apparatus is proposed to focus and position the final waist of a gaussian beam at a desired location on a target such as an optical fiber, which includes a first lens, having a focal plane f 1, disposed in the path of an incoming beam, and a second lens, being spaced downstream from the first lens by a distance at least equal to f 1 + 10f 2.
Abstract: A beam focusing and positioning apparatus provides focusing and positioning the final waist of a gaussian beam at a desired location on a target such as an optical fiber The apparatus includes a first lens, having a focal plane f 1 , disposed in the path of an incoming beam and a second lens, having a focal plane f 2 and being spaced downstream from the first lens by a distance at least equal to f 1 +10f 2 , which cooperates with the first lens to focus the final waist of the beam on the target A rotatable optical device, disposed upstream of the first lens, adjusts the angular orientation of the final beam waist by a parallel displacement of the beam at said optical device The transverse position of the first lens relative to the axis of the beam is varied to control the transverse position of the final beam waist relative to the target while the relative axial positions of the lenses are varied to control the diameter of the final beam waist and to control the axial position of the final beam waist
TL;DR: In this paper, the dominant contribution to the focal region fields is found by transforming the physical-optics integral over the reflector surface into a plane-wave spectral integral, which is evaluated rapidly via the fast Fourier transform (FET) algorithm to furnish, in only a single computation, the field for every place in the focal plane (or any plane parallel to it) within the focal regions for a given direction of the incident wave.
Abstract: An efficient approach is described for calculating the field distribution in the focal region of an electrically large, symmetric or offset parabolic reflector antenna with an arbitrary rim contour, when the concave reflector surface is fully illuminated by an obliquely incident arbitrary electromagnetic plane wave. The dominant contribution to the focal-region fields is found by transforming the physical-optics integral over the reflector surface into a plane-wave spectral (PWS) integral. The PWS integral is evaluated rapidly via the fast Fourier transform (FET) algorithm to furnish, in only a single computation, the field for every place in the focal plane (or any plane parallel to it) within the focal region for a given direction of the incident wave. The correction to the physical-optics field is relatively small in the focal region and may therefore be neglected. Numerical results based on this PWS approach are presented, and their accuracy is established by comparison with results based on other approaches. >
Patent•
[...]
5 Jun 1990
TL;DR: In this article, an optical head device having a diffraction grating element divided into a plurality of diffraction gratings have a substantially equal diffraction angle and optical utilization efficiency, and different focal distances of first order diffracted lights.
Abstract: The invention discloses an optical head device having a diffraction grating element divided into a plurality of diffraction gratings have a substantially equal diffraction angle, a substantially equal optical utilization efficiency, and different focal distances of first order diffracted lights, each of the first order diffracted lights being produced from a reflected light from the recording medium, at the respective diffraction gratings and a photodetector positioned at a mid-position between two focal points produced when there occurs no focusing error, the photo-detecting means having a plurality of photo-detecting parts juxtaposed in a direction substantially orthogonal to an average diffracting direction of the diffraction grating element. The above arrangement enables to produce a small size optical head device and improve the detecting of focusing errors and tracking errors.
TL;DR: In this paper, the authors established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades, and showed that the number of nodal points equals the saddle points on the skinfriction line vector fields in each pitch range.
Abstract: Based on the working of Lighthill and Hunt et al., in the present paper the author has established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades. These rules are (1) for a rotor cascade without shroud band, the total number of nodal points equals that the saddle points on the skin-friction line vector fields in each pitch range; (2) for an annular or straight cascade with no clearances at blade ends, the total number of saddle points is two more than that of nodal points on the skin-friction line fields in a pitch; (3) the total number of saddles in the secondary flow fields on cross-sections in cascade is one less than that of nodes; (4) in the section streamline vector fields on a meridian surface penetrating a flow passage, and on leading and trailing edge sections, the total number of nodes is equal to that of saddles; (5) on the streamline vector fields of a blade-to-blade surface, the total number of nodes is one less than that of saddles.
1 Sep 1990
TL;DR: In this article, a monolithic focal plane array detector using PtSi Schottky barrier photodiodes was developed using 1.2-micron design rules to achieve a 54 percent fill factor with 25micron square pixels, using an interline CCD configuration with a progressive scan (noninterlaced) readout of the field, and two-phase clocking of both the vertical and horizontal registers.
Abstract: A 640 x 486 pixel monolithic focal plane array detector using PtSi Schottky barrier photodiodes was developed. This detector uses 1.2-micron design rules to achieve a 54-percent fill factor with 25-micron square pixels. The detector array used an interline CCD configuration with a progressive scan (noninterlaced) readout of the field, and two-phase clocking of both the vertical and horizontal registers.© (1990) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
1 Jul 1990
TL;DR: In this paper, a program based on the solution to the Poisson equation is applied in order to reconstruct the wavefront, using long-exposure CCD images of the beam cross-section on either side of the telescope focal plane.
Abstract: Results recently obtained for the use of the curvature-sensing method as a substitute for slope sensing in optical wavefront reconstruction, using long-exposure CCD images of the beam cross-section on either side of the telescope focal plane. A program based on the solution to the Poisson equation is then applied in order to reconstruct the wavefront. Relative to the existing Hartmann sensing methods, curvature-sensing yields sensitivity comparable to that of the Shack-Hartmann test. Additional optics and reference plane-based calibration are obviated. Tests of the new method on an 88-inch Ritchey-Chretien telescope have yielded a map of residual wavefront errors as a solution of the Poisson equation.© (1990) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: A lens made of a birefringent material shows two focal points and the polarization of incident light is switched periodically and a detector is placed between the two focal Points, which results in a compact optical pickup with reduced adjustment requirements.
Abstract: A lens made of a birefringent material shows two focal points. If the polarization of incident light is switched periodically and a detector is placed between the two focal points, this property can be utilized to detect a focus error signal equivalent to that of a dual detection optics. The proposed system offers the possibility to achieve amplitude detection for the focus error. It results in a compact optical pickup with reduced adjustment requirements. A second possible pickup uses a birefringent lens and a Wollaston prism. In this case, a compact dual detection method is achieved.
Patent•
23 Aug 1990
TL;DR: In this article, an apparatus for correcting a focal point according to a lens temperature includes an operation unit, to which data concerning a distance between a focusing lens and an object, data concerning the distance of the focusing lens between an object and a focusing screen, and data concerning changes in the focal point of a lens per temperature variation are inputted.
Abstract: An apparatus for correcting a focal point according to a lens temperature includes an operation unit, to which data concerning a distance between a focusing lens and an object, data concerning a distance of the focusing lens and a focusing screen, and data concerning a variation of a focal point of the focusing lens per temperature variation are inputted beforehand. When data on a desired magnification are inputted, the operation unit performs arithmetic operations on a focal point at a present temperature. According to the calculated data, adjusting means adjusts distance between the focusing lens and the object, and that between the focusing lens and the focusing screen. As the temperature of the focusing lens further changes, the operation unit continues calculating the variation of the focal point, and another adjusting means adjusts the focal points accordingly.
01 Jul 1990-Graphical Models \/graphical Models and Image Processing \/computer Vision, Graphics, and Image Processing
TL;DR: An algorithm for the calibration of a stereo system with small relative angles in an uncontrolled environment is presented and it is shown that the errors in the locations of principal points do not affect the computation of relative pan and roll angles appreciably, whereas the impact on the relative tilt angle is significant.
Abstract: Because of their relative ease in solving the correspondence problem, stereo systems without relative rotation are popular. However, in practice, mechanical difficulties will lead to a small, unknown relative rotation between stereo cameras. In this paper we present an algorithm for the calibration of a stereo system with small relative angles in an uncontrolled environment. This algorithm has two advantages: (a) It is more accurate than the existing algorithms in the computer vision and photogrammetry literatures (b) It provides useful insight into the problem of camera calibration and relative orientation. This is done by deriving explicit analytical solutions for the relative pan, tilt, and roll angles in terms of the world pan angle (gaze angle) and the coordinates of the feature points used in their computations. These solutions allow us a better understanding of the problem of calibration in general by providing us with insight as to how errors due to quantization and uncertainty in the location of image centers affect the computation of rotation angles. It is shown that as the distance of feature points from the center of the image decreases, the error due to quantization in the relative pan angle increases quadratically, that of the relative roll angle increases linearly, while that of the tilt angle does not change appreciably. Likewise, it is shown that the errors in the locations of principal points (image centers) do not affect the computation of relative pan and roll angles appreciably, whereas the impact on the relative tilt angle is significant. These findings are likely to be of use even when the relative rotation angles are not small. All of the analytical findings have been supported by extensive simulation.
Patent•
19 Dec 1990
TL;DR: In this article, the system comprises a focusing optics in the focal plane of which a linear array of photodetectors is disposed, and a double prism located opposite to said photodeter with respect to said focusing optics, is servo controlled in rotation relative to a support about its longitudinal axis perpendicular to the axis of said optics, said support being itself servo controlling in rotation about said optical axis in order to scan a space of about 2 π steradians.
Abstract: The system comprises a focusing optics in the focal plane of which a linear array of photodetectors is disposed. A double prism located opposite to said photodetectors with respect to said focusing optics, is servo controlled in rotation relative to a support about its longitudinal axis perpendicular to the axis of said optics, said support being itself servo controlled in rotation about said optical axis in order to scan a space of about 2 π steradians. A derotating prism aligned with said optical axis rotates about said optical axis at a speed half of that of said double prism, in order to hold the image of the target in a single direction in said focal plane, whatever the rotations of said support.
Patent•
26 Nov 1990TL;DR: In this article, a coded indicia is moved closer to the focusing lens, the intensity of the reflected light beams increases which is detected by a detector member whose output signals operate a drive member coupled to the slide member.
Abstract: A bar code scanning system having a focusing lens for focusing scanning light beams in a first focal plane includes a slide member supporting a transparent substrate which enables the focusing lens to focus the light beams in a first focal plane through which a coded indicia is moved. When a coded indicia is moved closer to the focusing lens, the intensity of the reflected light beams increases which is detected by a detector member whose output signals operate a drive member coupled to the slide member, moving the slide member to a position removing the substrate from the path of light beams enabling the focusing lens to focus the light beams in a second focal plane which is closer to the focusing lens than the first focal plane.
Patent•
8 Aug 1990
TL;DR: In this paper, an objective lens having chromatic aberration is disposed in an optical system for focusing recording and/or reproducing light beams upon a surface of an optical disc, and two detecting light beams having different wavelengths are passed through the lens.
Abstract: An objective lens having chromatic aberration is disposed in an optical system for focusing recording and/or reproducing light beams upon a surface of an optical disc, and two detecting light beams having different wavelengths are passed through the lens. When the surface of the optical disc is positioned at a focal point of one of the beams, the other beam is not focused on the optical disc. When the surface of the disc is positioned midway between the focal points of the two beams, two light spots formed on the optical disc by the two beams have equal intensity. The light intensity of the two spots is detected, so that focusing errors can be determined based on the difference between the detected intensities.
Patent•
[...]
TL;DR: An autofocus camera having a plurality of object distance measuring zones and a photographing lens system is deflected in the object distance measurement zones in accordance with object distances of the objects as discussed by the authors.
Abstract: An autofocus camera having a plurality of object distance measuring zones and a photographing lens system. A distribution pattern of objects is deflected in the object distance measuring zones in accordance with object distances of the objects. An axial position of at least a part of the photographing lens system is adjusted in the optical axis direction to detect the position of the focal plane so that the focal plane can be varied. The adjusting of the axial position of at least a part of the lens system and the varying of the focal plane are driven in accordance with the distribution pattern of the objects so that the focal point of the photographing lens meets the objects.
TL;DR: In this paper, diffractive Fresnel microlens arrays containing over six thousand F/0.9 lenslets are patterned in the surface of CdTe substrates by successive photolithographic and ion-beam-etching steps.
Abstract: Arrays of miniature focusing optics located at the focal plane can improve the performance of focal plane systems. By more completely collecting the light at the focal plane and concentrating it into a smaller spot size on the detector plane, the photodetector area can be substantially reduced. Increased gamma radiation hardening and noise reduction result from the decrease in photodetector surface area. Binary optics technology, a process for fabricating large arrays of diffractive optical elements, is especially attractive for infrared materials. In this paper, diffractive Fresnel microlens arrays containing over six thousand F/0.9 lenslets are patterned in the surface of CdTe substrates by successive photolithographic and Ar+ ion-beam-etching steps. Results on smaller arrays of monolithically integrated binary-optics lenslets with II-VI detectors, demonstrating enhanced photodetector responsivities, are presented for the first time.
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TL;DR: Astro-D as mentioned in this paper is a high-throughput imaging and spectroscopic X-ray observatory, scheduled for launch in early 1993, which utilizes multilayer conical Xray mirrors which provide a large effective area over a wide range energy range up to 12 keV.
TL;DR: In this article, a solid elastic sphere is placed on the focal point of a circular concave transducer and in the focal plane of the transducers, and the analysis is carried out in full for important practical cases.
Abstract: Analysis of an echo from a solid elastic sphere has been limited to the case of a plane incident wave so far. Plane‐wave theory is modified to the case of spherical incident wave first, and then it is modified to the case of an arbitrary ultrasonic transmitter and receiver by considering them as a set of point sources and point receivers, respectively. Using this relation, the general properties of the echo scattered from the sphere are analyzed first, and then the analysis is carried out in full for important practical cases; that is, the sphere is placed on the focal point of a circular concave transducer and in the focal plane of the transducer. It is applied to study the material dependence of the echo from the sphere placed at the focal point of the transducer as well as that of the sidelobe structure of the echo. These results are compared with those experimentally obtained using metal and plastic spheres of 3 mm in diameter, which show very good agreement.
Patent•
25 Jan 1990
TL;DR: In this article, a multispectral band imaging and detecting device for use with a catoptric (10,18) zoom optical device having a focal plane is presented. But the system is not suitable for the use of a single camera.
Abstract: A multispectral band imaging and detecting device for use with a catoptric (10,18) zoom optical device having a focal plane (21). A plurality of electromagnetic radiation detectors are provided that are sensitive to one or more portions of the electromagnetic spectrum. An optical bench has the plurality of electromagnetic radiation detectors disposed thereon. A torque motor or the like is operatively connected to move the optical bench relative to the focal plane to move a selected one of the detectors into coincidence with the focal plane.
Patent•
16 May 1990
TL;DR: In this paper, a drive control system automatically maintains the nozzle drive voltage within a proper range, independent of temperature, by monitoring the state of intermediate satellites positioned between ink drops used for printing.
Abstract: A drive control system automatically maintains nozzle drive voltage within a proper range. The control system monitors the state of the "intermediate satellites" positioned between ink drops used for printing. When these satellites are neither forwared nor backward merging, a first cardinal point designated C(L) is identified. A second cardinal point, C(H), is determined when the drop breakoff point stops decreasing, relative to said nozzle, with increasing nozzle drive voltage. From the two cardinal values, a desired operating range for a particular ink can be computed and the control system automatically set. The computed value is essentially independent of temperature.
1 Nov 1990
TL;DR: In this article, a compact focal plane assembly which consists of a linear array of 128 InSb photodiodes and two Si-MOSFET multiplexer IC chips has been developed.
Abstract: A compact focal plane assembly which consists of a linear array of 128 InSb photodiodes and two Si-MOSFET multiplexer IC chips has been developed. The design and fabrication of the photodiode array, the readout circuit on the focal plane, the hybrid packaging, and the operation of the focal plane assembly are described. A small InSb pixel size of 60 microns is used, and the total length of the array is 7.60 mm. A measured radiometric resolution of 0.04 K NE Delta T is obtained for a 300 K target with a simple circuit configuration under the TV-compatible operation.
Patent•
27 Feb 1990
TL;DR: In this paper, a focusing and tracking servo is executed using a light emitting/ receiving device, for which a light source, photodetector and arithmetic circuit are housed in one package, and element for which different diffraction gratings are provided on a part of a hologram element capable of the reproduction of a wave surface having two different focal points.
Abstract: PURPOSE:To safely execute focusing and tracking servo by using a light emitting/ receiving device, for which a light source, photodetector and arithmetic circuit are housed in one package, and element for which different diffraction gratings are provided on a part of a hologram element capable of the reproduction of a wave surface having two different focal points CONSTITUTION:A laser beam source 1 and a photodetector 5 are respectively provided on different type semiconductor substrates, arranged in a metallic block 41 and housed in a same package 2 The light receiving surface of the detector 5 is positioned in the hologram side out of the focal depth of the light source 1 and beam emitted from the light source is reflected by an optical disk 4 Then, diffracted rays of light 72-72 of a hologram 6 are received The detector 5 forms a slip-shaped one-dimensional array by constituting elements 51-54 and is connected to an automatic output control circuit in the package 2 The control circuit controls actuators 91 and 92 and stably executes the focusing and tracking servo with high reliability Then, a high frequency characteristics is improved by shortening the length of wiring and a device can be driven by a single power source Accordingly, the constitution of the device is simplified