Abstract: An automatic system (CoSTEL) which permits the reconstruction of the instantaneous 3-dimensional position of target points (infra-red light emitting body markers) in a laboratory frame was designed. The 3-dimensional CoSTEL transducer is based on a suitable spatial arrangement of three one-dimensional transducers. Each transducer is made of a charge-coupled device linear array image sensor lying on the focal plane of a toroidal lens and appropriately aligned with it. The system was conceived for 3-dimensional whole body movement analysis and is able to track eight landmarks per subject side simultaneously. Its basic features are resolution of 1/4000, maximum sampling frequency 1·1 kHz (100 Hz is actually used), large insensitivity to background light and transducer output in digital form. These features provide a high level of accuracy, reliability and working stability.

Abstract: Method and apparatus for production of 3-D images (volume displays) from a set of 2-D images employing one or more multiple component holographic optical elements (mcHOEs) in combination with an off-axis array of a plurality of 2-D illuminated (or radiative) components of objects to be synthesized into 3-D images of the objects. An array of component regions is disposed in at least one plane generally normal to a defined optical axis. A mcHOE is disposed in a plane parallel to the plane of the array with the optical axis passing therethrough. The components are illuminated from behind, or are themselves radiative (as, for example, in the case of CRT screen(s)). The observer is positioned along the optical axis in front of the mcHOE. The mcHOEs are virtual image transmission or reflection holograms, but real images may be produced by using the appropriate mcHOE. The component region array is a set of 2-D representations of portions of an object (e.g., each member of the array being a section of the 3-D object to be reconstructed at a unique depth within the object). The component regions are successively illuminated, presented or turned on (in the case of a radiative region), by a light source having a narrow wavelength band substantially similar to that by which the mcHOEs were made. Diffuser screens and/or filters may be employed. When the rate of illumination of each number of array in sequence exceeds the flicker fusion threshold of the observer, the individually projected planes of the array fuse into a 3-D image. By a variety of techniques, the invention is adaptable to applications in various fields, including scientific, technical, medical, entertainment, educational, commercial and advertising. Specific examples shown include real image production, rotation or translation of reconstructed 3-D object images, 3-D holographic television, conjugate back focal plane hologram microscope, interactive 3-D holographic game devices, and the like.

Abstract: An analytical description for the field of a parametric focusing source is derived. It is valid for spherically concave sources with small aperture angle and high ka, under conditions of quasilinear interaction (strong shocks precluded). The solution furnishes computations on the phase and amplitude of difference frequency sound along the axis and in the focal plane, as well as on the width of the radiation lobe in the focal region. Underwater experiments conducted with an f/2 lens coupled to a dual, interleaved primary array are discussed. The results support the utility and validity of the analytical model for describing the distribution of sound along the acoustic axis and across the focal plane. The difference frequency radiation was found to be effectively focused, in that the width of the beam became quite narrow in the focal plane.

Abstract: Disclosed is an automatic focusing apparatus which comprises an objective disposed in opposition to a substrate with patterns formed thereon, a first line sensor disposed at a first focal point of the focal length of the objective, second and third line sensors which are disposed closer to and farther from the objective by a given distance with respect to second and third focal points of the focal length of the objective, first to third differential circuits for differentiating the output signals from the first to third line sensors, a detecting circuit for detecting a displacement of the substrate from a predetermined proper distance between the objective and the substrate on the basis of the output signals from the first to third differential circuits, and a correcting device for correcting the displacement on the basis of the output signal from the detecting circuit. Thus, a single optical system is used for automatically correcting focus and pattern inspection.

Abstract: An innovative nondestructive technique for mesuring the refractive index of a simple lens is described. The proposed method is superior to existing ones because the focusing error and the spherical aberrations are reduced. Apart from this, the strength parameters (i.e., r1 and r2) of a lens are not required at all since the derived lens-index formula is independent of the lens's physical parameters. The shearing interferometric technique is a sensitive aid for detecting the focal plane of the test lens. A modified criterion for determining the focal length has been used. In this case two miscible liquids or compounds are not necessary. The well-known liquid immersion method is the particular case of this technique. The Murty shearing interferometer has been used as an optical device to observe the defocusing defect in the form of fringes. The amount of defocusing is easily calculated. An equation for this error has been theoretically deduced and experimentally verified. The technique described is quick to perform and easy in handling. The various effects due to the lens's aperture and aberrations, thickness of the glass cell, liquid column, etc. are also discussed. For N liquids, there are N (N − 1)/2 ways of calculating the lens′s index. Owing to its nature this is termed the nondestructive nonmiscible-liquid immersion technique for index measurement of a lens.

Abstract: An automatic focusing apparatus for optical instruments, in particular for reflected light microscopes, wherein a measuring point is produced on the surface of an object by an eccentric measuring beam formed by blocking a portion of the path of a full beam. The measuring point is imaged onto a photoelectric device by reflecting the measuring beam along the blocked out path. When the object plane wanders from the focal plane, the photoelectric device actuates a control device which returns the object plane to the focal plane. The apparatus comprises a source of light to produce a, preferably pulsed, laser light for the full measuring beam, an optical structural element for geometrically blocking one-half of the full measuring beam to produce the eccentric measuring beam and simultaneously for geometrically blocking the reflected measuring beam from the path of the full measuring beam. A lens is positioned in the measuring beam and a photodetector device in the form of a differential photodiode pair is positioned to receive the reflected measuring beam. A divider mirror, preferably dichromatic, is provided for introducing the measuring beam into the path of the illuminating beam of the optical device and for reflecting the reflected measuring beam from the path of the illuminating beam of the optical instrument.

Abstract: A dual focus optical system for causing the images of two objects separate from each other on the optical axis to be formed on the same image plane comprises a diverging element for causing a second light ray to diverge relative to a first light ray, a converging element provided on the object side of the diverging element for converging the second light ray relative to the first light ray, and an objective lens provided on the object side of the two elements for converging both of the first light ray and the second light ray. The objective lens is disposed so that the point of intersection between the first light ray and the second light ray in the composite system comprising the diverging element and the converging element is coincident with the focal plane of the objective lens which is adjacent to the converging element.

Abstract: An interferometer which provides for the precise figure measure of optical surfaces through the interference of two pencil beams, reflected off the optical surface, comprises a laser for generating a laser beam which is split into two parallel beams by a beam splitter and a mirror, the two pencil beams are reflected off a second beam splitter, through an alignment invariant optical device and onto the optical surface to be measured. The two pencil beams are reflected and back-trace through the alignment invariant optical device, propagate through the second beam splitter and enter an optical lens which is capable of focusing two beams in its back focal plane where the interference of the two pencil beams takes place. This information is then relayed through optical spatial filter and optional micro objective into the readout section.

Abstract: An aberration theory is applied to spectrograph design. The initial system considered has a toroidal mirror in front of a concave grating spectrograph, giving spatial resolution perpendicular to the dispersion direction. The accuracy of the theory is shown by comparison of spot diagrams obtained from the aberrations with those produced by raytracing. The major aberrations affecting the vignetting at the intermediate slit and the spatial resolution are identified. A new system, using a holographic grating to give a flat focal plane, is then designed and optimized. It has increased spatial resolution over the wavelength range and is particularly suitable for microchannel array detectors.

Abstract: Disclosed is an automatic focusing apparatus for an optical imaging system which utilizes a focus detector which monitors the contrast of the image at the focal plane of the imaging system, the image being deemed to be in focus when the contrast of the image is maximized. The focus detector comprise a plurality of detector/converter elements arranged in an array in the focal plane. Each detector/converter senses the light intensity in a respective portion of the image at the focal plane and provides a pulse signal having a pulse-width which is approximately inversely proportional to the sensed light intensity. A detection circuit receives the pulses provided by the detector/converter elements and derives a digital quantity which is related to the difference between the maximum and minimum pulse-widths of the pulses. The digital quantity is received by a digital servosystem which appropriately adjusts the focusing of the imaging system to maximize the digital quantity provided by the detection circuit.

Abstract: The invention relates to a standing wave interferometer for measuring optical path differences in which a standing wave is produced between a monochromatic light source and a reflector. The displacement of the bulges and nodal points of the standing wave due to displacement of the reflector is sampled by a sampling normal inserted into the standing wave and having two photodetecting layers at a mutual space of k·λ/8, k being any desired odd integer. The sampling signals are fed into an electronic evaluation unit where these are processed. The measuring object, when having a well-reflecting surface can be the reflector itself, without the necessity of adjusting the same accurately to the incident light beam.

Abstract: A linear optical scanner adapted to receive light rays from object space, the light rays passing through the linear optical scanner in image forming relation, the linear optical scanner being adapted to periodically and reciprocally deflect the collimated light rays through a predetermined angle. The periodically and reciprocally deflected collimated light rays leave the linear optical scanner and passing through an objective lens system to an image plane. The objective lens system has an optical axis incident on the image plane and is adapted to focus the periodically and reciprocally deflected collimated light rays to form a periodically and reciprocally displaced image on the image plane. The linear optical scanner comprises: a first and second wedge prism, each wedge prism having: a first surface, an optical axis, and a second surface, each respective optical axis passing through a respective first and second surface, a pivot axis, means for pivoting each respective wedge prism on a respective pivot axis and for positioning each respective wedge prism optical axis to direct the collimated light rays passing through the linear optical scanner to the objective lens system, and means for periodically and reciprocally counter-rotating each respective wedge prism through a predetermined angle on each respective pivot axis. The wedge prisms have prescriptions adapted to produce reciprocal lateral displacement of the collimated light rays; whereby, the linear optical scanner and the objective lens cooperate to produce a focused image on the focal plane. The focused image is periodically, reciprocally and laterally displaced on the focal plane.

Abstract: It is pointed out that the development of two-dimensional infrared focal plane arrays (FPAs) offers new alternatives in imaging and remote sensing. Attention is given to an imaging spectrometer which represents a new concept exploiting two-dimensional arrays. This instrument is to be used for the remote sensing of the earth on the basis of a utilization of reflected sunlight in both the visible (VIS) and short wavelength infrared (SWIR). The imaging spectrometer concept is to make it possible to obtain contiguous spectral coverage at high resolution without having to use increasingly complex scanners. The concept utilizes a prism spectrometer to disperse the image of the slit across the area arrays in the focal plane. The focal plane consists of silicon CCDs for the VIS and near infrared portions of the spectrum and HgCdTe hybrid arrays for the SWIR.

Abstract: A lens-evaluation method based on the dynamic properties of laser-produced speckles is investigated and developed into a real-time modulation-transfer-function measuring system controlled by a microprocessor. One of the most important advantages of this method is the redundancy that permits rough adjustment of the lateral position of the light detecting point in the focal plane. Experimental results applied to a grin-rod lens as well as to an ordinary camera lens are obtained. For detection of the best focal position, the method of counting the zero-cross distribution along the optical axis is found to be effective.

Abstract: PURPOSE:To observe information clearly by interposing a translucent mirror between the transmission system and reflection system of an optical system and superimposing exterior information and information from an image display part upon each other CONSTITUTION:The image display part R and the optical system L of the transmission system are provided, and information is imageformed on a curved surface F shown by a chian line Further, the ceiling part of a steering room is provided with a spherical reflecting mirror in specific relation with the transmission system and the translucent mirror MH is provided so that the exit pupil P of the reflecting mirror M1 is symmetrical with the exit pupil of the transmission system L Consequently, information is projected on the image display part R at infinite distance, and when the exit pupil P is positioned on a surface containing the center C of curvature of the spherical mirror M, parallel luminous flux passing through the exit pupil P is free of coma and astigmatism at any angle of visual field and the image is formed on the focal plane F' of a spherical surface whose radius of curvature is a half as large as that of the spherical mirror M

Abstract: A sharpness-determining device is disclosed in which an object image generated on a prescribed focal plane of a photolens is once again projected by a second projecting optical system behind this focal plane into two object images which are not located one above another and are based on light bundle sections which are split up symmetrically relative to the optical axis of the photolens; light-sensitive elements are respectively arranged at the points at which these object images are once again projected by the second optical system; a sharpness state of the photolens is determined by using these light-sensitive elements to detect the relative spatial relationship of these object images projected once again. The sharpness-determining device comprises a beam-splitting device which is arranged in the second optical system and splits up a light bundle, coming from the exit pupil of the photolens, into a central section and an edge section. Using this arrangement, it is possible by means of the second optical system to obtain an object image which is required in accordance with the varying f-number of the exit pupil of the photolens, or an object image which simultaneously allows the use of a further determining process with this device.

Abstract: The optical imaging system comprises an optical field scanning device (4, 5) mounted on a dial frame fixed to the gyroscope of the missile and a detection system consisting of a linear detector array (6) arranged outside the gyroscope, stationary in relation to the structure of the missile and coupled to one end (12) of a flexible bundle (11) of optical fibres, of which the other end (13) arranged in the focal plane of the optical scanning device is fixed to this device. Coupling between the detectors and the optical fibres is carried out either directly or by means of an image transport device (10). The invention is used for detection and location of targets.

Abstract: An optical scanning system wherein a light beam from a laser source is reflected by a rotating polygonal mirror and focused by a scanning lens into a scanning beam spot on the drum surface. A cylindrical lens disposed between the scanning lens and the drum for correcting the unevenness of the scanning line pitch caused by the incline of the each facet of the polygonal mirror has a curvature in the scanning direction of the beam so that optimal focal points of the scanning beam spot align on a straight line.

Abstract: The system and method of the present invention minimizes artifacts caused by noncoplanarity between source and detector component in a computerized tomography system. The source component produces a beam of penetrating radiation which is rotatable about an axis and is incident on the detector component; and non-coplanarity is defined by the collection of the positions of the source component which defines a first plane, and by the collection of positions of the detector component which defines a second plane axially spaced from the first plane. Data obtained during a scan of a body located between the source and detector components are processed to form two images, one image being based on data related to one side of a focal plane interposed between the first and second planes, and another image being based on data related to the other side of the focal plane.

Abstract: In the measurement and characterization of the performance of infrared and visible focal plane arrays, the determination of the detailed spatial response of individual detectors as well as the entire array can be extremely important in many electro-optic sensor applica­ tions such as the detection of targets in the presence of clutter and passive acquisition and tracking. This paper describes a computer-controlled flying spot scanning technique for the measurement of detailed focal plane detector responses as well as detector-to-detector cross talk and spurious responses. The technique uses a computer-controlled flying spot scanner and online data processing. A simple deconvolution is used to remove the known temporal responses of the detector and electronics followed by a two-dimensional decorrela- tion of the blur spot from output signal to obtain focal plane spatial response. As a natural result of this process the individual detector MTFs can be obtained. This technique has been implemented in a low-background focal plane test facility, which is also described. Several examples of actual test data are shown to demonstrate the use of this spot-scanning facility and its utility as a diagnostic tool.IntroductionIn the design and development of sophisticated electro-optic sensors for infrared (IR) and visible applications, both detailed focal plane performance characterizations and end- to-end simulations using complex computer programs are essential to the design of the sen­ sor and the optimization of its performance for a given range of scenarios and operating conditions. In earlier papers we have described our computer-aided facilities for detailed testing and characterization of infrared and visible focal plane arrays1' 2' 3 and our low- background brassboard test facility designed specifically to evaluate the end-to-end per­ formance of both scanning and staring IR sensors over a wide range operating condi­ tions.4 The brassboard test facility presents a wide range of target and background sig­ nals and image scenes to infrared focal planes which are interfaced a dedicated online minicomputer. The minicomputer acts as a programmable realtime or near-realtime signal processor through which the sensor performance can be measured and signal processing algor­ ithms can be evaluated using real signals from the focal plane detectors. This paper describes a technique for measurement of the detailed spatial responses of individual detectors and detector arrays using these facilities.In the analysis and characterization of sensors, important assumptions are made about the spatial responsivity variation of the individual detectors. Often in performance analyses (such as tracking performance analysis), the detector responsivity is assumed to be flat over the area of detector and zero outside. For some detectors, however, actual responsivity deviates significantly from this hypothetical shape. The boundaries may com­ prise a significant portion of the detector real estate. The responsivity in central area of the detector may not be flat but may have significant nonuniformities. The actual shape of the detector responsivity functions may have significant effects on the results of performance analyses for both individual detectors and focal plane arrays.In many cases, such as a fine tracker, sensor performance requirements dictate that more accurate and detailed estimate of the detector responsivity function must be obtained and utilized in further signal processing. A powerful technique for obtaining the detailed spatial responsivity function of individual detectors and focal plane arrays uses a computer-controlled flying spot scanner. However, because the blur spot of a typical spot- scan system is of the same order magnitude as detector cell size, true respon­ sivity shape cannot be obtained by a simple point-by-point spatial measurement without accounting for and removing the effect of finite blur-spot size and shape. In order to do this we utilize a recently developed two-dimensional decorrelation technique^ to obtain the detector responsivity function from detector spot-scan data obtained in our test facil­ ities. Furthermore, the modulation transfer function (MTF) of individual detectors (the magnitude of the response function in the spatial frequency domain) is also obtained.41

Abstract: The present invention relates to an optical apparatus and a method for the enregisterment or instant viewing magnified and stereoscopic images of objects. The apparatus comprises an iris lens (1, 4) fixed, giving an object (2) an enlarged image, a first lens array (3) of which the elementary lenses are placed in the vicinity of said enlarged image, the angle field of the lens array (3) is substantially equal to the opening angle (4 ') of the exit pupil of the objective view of the lens array (3), so as to provide a sampled composite image, instant, at the focal plane of the first lens array. According to an alternative embodiment, for the instant observation, the apparatus further comprises a network (9) relief of rectifier, a network (10), observation and a network (11) beam spreader.

Abstract: A number of axes are recognized in the eye, such as optic axis, visual axis, pupillary axis, fixation axis, and line of sight [1,2], as shown in Fig. 1. It is well known that the visual axis is the most important for ophthalmic prescription, measurement of refraction and corneal configuration and so on [3] (Fig. 2). The visual axis is defined as the two lines, one from the fixation point to the first nodal point in object space, and other from the fovea to the second nodal point in image space [1]. However, objective measurement of the visual axis is extremely difficult because it is imaginary. In clinical viewpoint, the pupillary axis and line of sight are well in use because of the simplicity of measurement. Strictly speaking, these axes differ fairly from the visual axis, and do not pass through the fovea.

Abstract: The IRAS telescope is described in terms of its system configuration and physical characteristics, subsystem functions and descriptions, and performance characteristics. The mission and the configuration are reviewed briefly, and the major functional components of the telescope are described, including the focal plane assembly, the optics, the electronics, the cryogenics, and the thermal control. Exploded and cross-sectional views and block diagrams are presented for the telescope system configuration, focal plane assembly, infrared subarray module, optical subsystem, infrared channel data flow, and main cryogen dewar. The telescope physical characteristics are listed. The performance characteristics are listed and discussed, including the spectral response, sensitivity, optical quality, and photometric accuracy. Relative system spectral response curves for the infrared bands are shown.

Abstract: While streak cameras in particular, and strip cameras to an almost equal extent, are widely used in high speed photography, the level of sophistication achieved by these systems makes them appear much more complex than they really are. In this presentation the principles of slit shutter and scanning photographic techniques are related to ordinary focal plane shutter operation parameters. The commonalities and similarities between high speed and low speed systems are presented in very basic fashion. Photofinish, velocity recording, panoramic, peripheral and perspectiveless photography are among the applications explained and illustrated. Basic equipment suitable for experimentation is also described.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: A focus detection device is disclosed which has a light path splitting apparatus provided just in front of a diaphragm in the optical path of an image forming optical system and a different optical system from the aforesaid image forming optical system in the direction in which the split-off part of the light bundle by the aforesaid splitting apparatus goes. On an optical axis of the focus detecting optical system, the conjugate positions to a prescribed focal plane of the image forming optical system and at least two positions on its optical axis are occupied by respective photo-sensitive elements using their outputs for in-focus detection.

Abstract: A prism (2) with total internal reflection has a flexible membrane (5) fitted into a housing (7) in its large face. The membrane has a hole (5a) to permit balancing of the static pressure on both faces. The prism is mounted in a support (24) and has a protective grid (25) covered by the mouthpiece (22) screwed onto the handset (21). The handset has two housings (27a,b) in which collimating lenses (3a,b) are fitted with their focal points at the ends of optical fibres (4a,b) and adjacent to the small faces of the prism. One optical fibre (4a) permits coupling of the prism to an external light source while the other fibre is coupled to a photodetector. Movement of the membrane which has a light absorbing surface facing the prism causes part of the light energy to be subtracted from the transmitted energy.