Showing papers on "Real image published in 1974"

Method of and apparatus for target tracking

Abstract: The invention relates to optical target tracking. A target image, particularly based on reflected laser light, is projected by an optical system onto a light-sensitive detector, control signals for directing purposes being generated depending on the position of the target image on the detector surface. At least when a clear target image on the detector surface would be small in comparison with the detector surface, the area of the target image is increased by blurring the target image, for instance by displacing the detector plane from the image plane of the optical system.

Rear-screen wide-angle on-axis projection system

Abstract: A wide-angle on-axis projecting and viewing display system in which the image rays of a wide-angle lens are directed by a reflector means to the rear convex side of a rear projection screen means to be viewed from a point adjacent the front concave side of the screen means, and in which the relative curvatures of the reflector and screen means are selected in relation to each other and to the screen viewing point to cause the image rays to pass through a common point which is the mirror image of the screen viewing point, and hence to provide on-axis viewing of the projected image.

Holography of the Eye: A Critical Review

Abstract: Holography is a technique producing a three-dimensional picture of a real physical object. A hologram is a recorded interference pattern between light coming from an object (the object field) and light coming from a suitable reference source (the reference field).

Optical projection apparatus

Abstract: An optical projection apparatus including a projection screen on which a microimage is projected on an enlarged scale and adapted to be connected with an information processing system comprising; Microfilm feeding means which feeds and stops a microfilm on which a plurality of images are recorded, each image of the microfilm comprising an image frame portion and a code pattern portion recorded adjacent the image frame, each code in the code pattern portion representing information concerning a part of the image of the image frame portion positioned at a position corresponding to the code, An optical projection system for projecting an image of the image frame portion onto a transmission type projection screen and projecting an image of the code pattern portion onto a reflection type projection screen provided in a side by side relation with the transmission type projection screen, A light source device for illuminating a part of the image projected on the transmission type projection screen selectively from the opposite side of the screen to the optical projection system, Means for taking a view of the screen from the side of the projection system and putting out an image signal representing the view taken thereby, Signal conversion means for receiving the output image signal and converting the signal into a computer input signal representing the information concerning a part of the image of the image frame portion illuminated by the light source means, and Control means for controlling the microfilm feeding means according to an output signal of the computer.

Device for detecting focussing in optical instruments

Abstract: A device for detecting focussing in an optical instrument such as a camera which has an objective lens and a plane, at which light sensitive film may be disposed, upon which a real image of an object is intended to be focussed. The device comprises a window to which the eye of the operator is held, and means for projecting light to the operator's eye which looks at the real image of the object formed by the objective lens. The light projected on the retina of the operator's eye is reflected back into the camera and is directed to focus-judging means in the nature of a light sensitive member which detects when the retina of the operator's eye is optically conjugate with an imaginary reference plane located in a position optically equal to a plane on which a real image of the object formed by the objective lens is intended to be focussed, thus also detecting when the position of the real image coincides with said reference plane so that the selected object is properly focussed.

Optical image reproducing system for a hologram using a linear white light source

Abstract: An optical image reproducing system for a hologram comprising a white-light linear light source for radiating a white light beam in a line shape, an image hologram of a non-diffuse type having optical information of an object stored therein by means of a coherent light beam for producing, when irradiated by the white light beam of linear light source, an optical image of the object without any substantial scatter, a screen of the scattering type, which is positioned substantially in parallel with the image hologram and at the opposite side to the linear light source for scattering an incident light beam to such an extent as to reproduce a visual optical image which is viewable at different points, and a projecting lens interposed between the image hologram and the scattering type screen for projecting the optical image of the hologram on the screen. The projected optical image can desirably be colored with the use of a color image hologram and by interposing between the image hologram and the projecting lens a shielding plate, which is formed with a slit which extends in the lengthwise direction of the linear light source.

Beam-index color television displays

Abstract: Beam-index line-screen television display systems are disclosed for generating multi-color images throughout the size range from small direct view cathode ray tubes to projection type wall screen configurations. The image in the small screen display is generated by a scanning electron beam whereas the image generated in the large screen configuration is developed bY a scanning optical beam. In both cases the excitation of the image producing target screen is synchronized by beam-indexing features which utilize optical index signals transmitted across the target screen.

Complex On-Axis Holograms and Reconstruction without Conjugate Images

Abstract: Holograms representing both real and imaginary parts have been obtained with an on-axis reference from an experimental acoustical underwater viewing system and digitally reconstructed to yield only the real image. The absence of both the conjugate imagery and dc and autoconvolution terms allows maximum efficiency in utilizing the relatively limited amount of sampling often available for microwave and acoustic radiation and reduces conjugate image noise. Improved imagery of underwater targets which has been obtained in this way with relatively light sampling (20 × 20) is presented.

Method for producing three-dimensional real image using radiographic perspective views of an object

Abstract: A sequence of separate radiographs are made by indexing a radiation source along a known path relative to the object under study. Thus, each radiograph contains information from a different perspective. A holographically-recorded image is then made from each radiographic perspective by exact re-tracing of the rays through each radiographic perspective such that the re-tracing duplicates the geometry under which it was originally prepared. The holographically-stored images are simultaneously illuminated with the conjugate of the reference beam used in the original recordings. The result is the generation of a three-dimensional real image of the object such that a light-sensitive device can be moved to view the real image along any desired surface with the optical information in all other surfaces greatly suppressed.

Luminance distribution photometer

Abstract: An optical system with a first lens system which produces at a first image plane a real image of an object and a second lens system for producing a real image of the exit pupil of the first lens system at a second image plane. A stop arrangement is provided for controlling the region of the image of the object surface from which light can travel to the second plane. Conveniently the luminance of the object is detected at the second image plane by suitable luminance detection means.

Spatial Pulse Modulation for Coherent Optical Densitometry

Abstract: Purely optical methods of spatial pulse width coding for coherent optical densitometry are described. The proposed coding scheme correlates the image intensity with the orientation of one edge of triangular or trapezoidal pulses. One encoding technique employs a contact screen similar to those used for half-tone printing. The image to be coded is copied through this contact screen onto hard-limiting film. This method is limited to the encoding of images with density distributions varying only slowly across the area of one pulse. A holographic encoding technique overcomes these drawbacks, utilizing the storage redundancy of holograms recorded with diffuse object beams. An array of identical holograms is reconstructed with a beam spatially modulated by the image transparency to be encoded. The array of reconstructed real images is recorded on hard-limiting film and renders a pulse-modulated version of the original image. The limiting conditions for the pulse size and the size of details in the image imposed...

Image Evaluation Of Image Intensifiers

Abstract: Image Intensifiers are used to detect, recognize, and identify objects of, or in, radiation of low intensity. The type of radiation for which image intensification can be used, ranges from x-rays into the near infrared region. In this review, x-ray intensifiers will not be considered. A review of the various types of image inten-sifiers has been given recently (Ref 1).