Showing papers on "Image sensor published in 1985"

Model of human visual-motion sensing

Abstract: We propose a model of how humans sense the velocity of moving images. The model exploits constraints provided by human psychophysics, notably that motion-sensing elements appear tuned for two-dimensional spatial frequency, and by the frequency spectrum of a moving image, namely, that its support lies in the plane in which the temporal frequency equals the dot product of the spatial frequency and the image velocity. The first stage of the model is a set of spatial-frequency-tuned, direction-selective linear sensors. The temporal frequency of the response of each sensor is shown to encode the component of the image velocity in the sensor direction. At the second stage, these components are resolved in order to measure the velocity of image motion at each of a number of spatial locations and spatial frequencies. The model has been applied to several illustrative examples, including apparent motion, coherent gratings, and natural image sequences. The model agrees qualitatively with human perception.

SNR and DQE analysis of broad spectrum X-ray imaging

Abstract: A general analysis of the signal to noise ratio SNR, of X-ray imaging with a broad spectrum is presented. The analysis indicates that the energy modulation of the signal together with its degree of matching by the energy response of the image receptor are significant determinants of the SNR for signal detection. This requires a generalisation of the interpretation of detective quantum efficiency, DQE, the transfer function appropriate from SNR, that will be dependent on the image detection or discrimination task. The generalised DQE is similar to the conventional DQE for the task of detecting radiation levels, but may differ substantially from it for the task of discriminating a lesion from its surround, particularly for signals of bone or iodine. The photon counter is shown to be inferior to the ideal detector for these tasks, but to be generally superior to the energy detecting scintillators used in conventional or digital radiography and computed tomography.

Dynamic Occlusion Analysis in Optical Flow Fields

Abstract: Optical flow can be used to locate dynamic occlusion boundaries in an image sequence. We derive an edge detection algorithm sensitive to changes in flow fields likely to be associated with occlusion. The algorithm is patterned after the Marr-Hildreth zero-crossing detectors currently used to locate boundaries in scalar fields. Zero-crossing detectors are extended to identify changes in direction and/or magnitude in a vector-valued flow field. As a result, the detector works for flow boundaries generated due to the relative motion of two overlapping surfaces, as well as the simpler case of motion parallax due to a sensor moving through an otherwise stationary environment. We then show how the approach can be extended to identify which side of a dynamic occlusion boundary corresponds to the occluding surface. The fundamental principal involved is that at an occlusion boundary, the image of the surface boundary moves with the image of the occluding surface. Such information is important in interpreting dynamic scenes. Results are demonstrated on optical flow fields automatically computed from real image sequences.

160 × 244 Element PtSi Schottky-barrier IR-CCD image sensor

Abstract: A 160 × 244 element IR-CCD image sensor was developed with PtSi Schottky-barrier detectors (SBD's) for thermal imaging in the 30-50-µm IR band This imager has 80 × 40 µm2pixels, a fill factor of 39 percent, and a chip size of 584 × 464 mil2 It produces excellent quality thermal imaging with noise-equivalent temperature (NEΔT) of less than 01 K for operation at 30 frames/s with standard-TV-interlace f/23 optics, and one-point offset-type uniformity corrector This paper describes the design, construction, and performance of 160 × 244 element IR-CCD imager and the characteristics of the PtSi Schottky-barrier detector elements

Dynamic microscope image processing scanner

Abstract: An image scanner for microscopic objects. The image scanner has a microscope with a high precision computer controlled motor driven stage to provide X,Y plane displacements in order to scan microscopic objects under the microscope. There is an image sensor and a digitizer in association with the microscope to sense a horizontal image line or a two dimensional image and provide a digital representation of the line or image. A digital signal processor processes digitized signals from the sensor. There is a computer to control the mechanical and electronic scanning and to store and display information from the digital signal processor. Methods of scanning a microscopic object are also described. The methods comprise positioning the object on a motorized stage of a microscope having an image sensor in a focal plane. The object is scanned and signals received from the sensor during scanning are digitized. The digitized signals are processed with a digital signal processor in order to automatically recognize objects while the sample is being scanned. The processed information contained in the signals and the location coordinates of objects are stored. The methods include automatical revisiting of recognized objects for further analysis.

Investigation of basic imaging properties in digital radiography. 6. MTFs of II-TV digital imaging systems

Abstract: We devised a new, simple technique for measuring the modulation transfer function (MTF) of a digital imaging system by using an image of an angulated slit. With this technique, the "presampling" analog MTF, which includes the geometric unsharpness, the detector unsharpness, and the unsharpness of the sampling aperture, can be measured even beyond the Nyquist frequency. A single-frame image of a slightly angulated slit was employed in order to obtain Fourier transforms of line spread functions at different alignments. The presampling MTF was determined by averaging the two Fourier transforms which we obtained from two extreme alignments (center and shifted) of the slit relative to the sampling coordinate. The presampling MTFs of our digital subtraction angiographic system were determined in two orthogonal directions for three different image-intensifier modes.

Z-axis height measurement system

Abstract: This invention concerns an optical system for use with a television camera for detecting the surface location of an object. A preferred optical image having a distinct, unique, recognizable pattern is projected on a surface along a defined path that ultimately falls on an imaging sensor associated with a television camera. The optical configuration causes a maximum light pattern energy to fall on the image sensor when the focal point coincides exactly with the surface of the object being detected. The system is not an automatic focussing system, since best focus is normally considered to be that condition which produces an image of maximum detail and sharpness, and the present invention does not rely on detail or sharpness of image for its operation. The invention can be used as an automatic focussing device if desired, since best focus can be derived as a useful by-product of accurate surface detection. In operation the camera moves in the Z direction through the point of maximum light pattern energy. The Z-axis position of the energy peak value is a function of the optical design. An output signal from the camera is filtered and processed and calculated to the Z-axis height of the camera as a measure of the distance to the object surface being detected.

Target acquisition system and method

Abstract: A system (20) for identifying and tracking targets in an image scene having a highly cluttered background. An imaging sensor and processing subsystem (21) provides a video image of the image scene. A size identification subsystem (23) removes background clutter from the image by filtering the image to pass objects whose sizes are within a predetermined size range. A feature analysis subsystem (24) analyzes the features of those objects which pass through the size identification subsystem and determines if a target is present in the image scene. A gated tracking subsystem (25) and scene correlation and tracking subsystem (26) track the target objects and image scene, respectively, until a target is identified. Thereafter, the tracking subsystems lock onto the target identified by the system (20). Several methods relating to target acquisition are also disclosed.

Method for calibrating photographic image information

Abstract: In a photographic image information detecting method of the type in which light transmitted from an original film is received by a two-dimensional image sensor and image information is detected with respect to the divided a plurality of picture elements of the original film, a photographic image information is calibrated by the steps of detecting information of the photographic image of a reference film with respect to the original film in use of the two-dimensional image sensor, storing the thus detected information as data for calibration, and subtracting the data for calibration from the detected data regarding the image information of the original film so as to thereby obtain accurately calibrated information regarding the photographic image of the original film.

Endoscope for displaying a normal image

Abstract: An endoscope used for observing the interior of a cavity in a human body. In the endoscope according to the present invention, an image sensor is provided in the forward end of an insertion section and an object of interest is displayed on a screen of a television set in response to a video signal obtained from the image sensor. According to the present invention, image information from the image sensor is provisionally stored in a memory, and the read-out from the memory is performed by horizontal scanning in accordance with read-out information by reversing the steps in the case of the write-in. With this arrangement, an image of the object of interest, which is inverted in an optical system in the forward end of the insertion section of the endoscope, can be displayed on the screen of the television as a normal image.

Optical system for endoscope

Abstract: An optical system is disclosed for an endoscope having a generally tubular distal end in which an objective lens assembly and an image sensor in the form of a solid-state video camera are internally housed so that an image formed by the lens assembly is focussed upon the input or pickup surface of the video camera. The video camera is disposed along or in proximity to the center axis of the distal end of the endoscope and in some instances is oblique with respect to the center axis. The video camera may be positioned in this way due to the provision of a reflecting surface which is angularly disposed in opposing relationship with an input surface of the video camera, and deflection means disposed in front of the lens assembly and within the objective lens assembly, or between the lens assembly and the reflecting surface so that an image formed by the lens assembly can be focussed on the input surface of the video camera.

Automatically guided vehicle control system

Abstract: A target member mounted on a stationary object, such as a pallet, includes at least three reflector elements. An identifying means, such as a high intensity light source, and an imaging sensor are carried by another, movable object, such as a forklift truck. The reflector elements are so configured as to form images of the identifying means with said images defining a plane oriented other than normal to align from the identifying means to that plane, the images also defining a circle that does not include the identifying means. The target member may be in the form of a vertically oriented planar support member on which are mounted a pair of convex mirrors and a concave mirror. The images of the identifying means in the mirrors are detected by an imaging sensor, such as a television camera, and the directions of each of the images at the camera are used to determine all six degrees of positional information of the sensor with respect to the target. That information may be used to guide the forklift truck into position relative to a pallet. The target support member includes retroreflector elements to aid in locating a pallet. Circuit means are provided to flash the light source and in response to the light returned by the retroreflectors to define an area on the image plane of the camera where reflections from the mirrors may be found. Ambient light images are then temporarily recorded, the light source again flashed, and the ambient images are electronically removed so that only those images due to reflections in the mirrors are finally recorded.

Portable scanning digital pupillometer and method of use thereof

Abstract: A portable, hand-held, dynamic, automatic scanning, measuring and recording device capable of inspecting holes and measuring gaps in any animate or inanimate object of up to about 10 millimeters in size (diameter, for example) such as a pupil of a vertebrate eye or a printed circuit board. The device comprises a light weight viewing optics/image sensor and a microprocessor controlled automatic scanning and data capture/storage system with a digital readout of pupil diameter measurements.

Surface flaw detecting method and apparatus

Abstract: A method for detecting flaws in a surface of an inspected object can moderate the requirements for inspection condition accuracy, particular for adjustment of spatial relationships among a laser unit, the surface and an laser detector unit. The method includes the step of transmitting a laser beam in a known configurationonto a specular surface of the inspected object, projecting the laser beam reflected by the surface onto a light-scattering screen and forming an image of the surface on the screen, and detecting the image of the surface in the known configuration in relation to a predetermined portion of the screen. An apparatus carrying out the method includes a sensor for detecting positional deviation of the image of the surface from a fixed monitored portion of the screen, a adjuster for adjusting the angle subtended by the axes of a transmitter of the laser slit beam and a flaw-detecting image sensor and an adjuster for adjusting the inclination of a plane defined by the axes of the transmitted and the flaw-detecting image sensor relative the surface, both adjusters operating in accordance with the output of the deviation detecting sensor.

Target member for use in a positioning system

Abstract: A target member mounted on a stationary object, such as a pallet, includes at least three reflector elements. An identifying means, such as a high intensity light source, and an imaging sensor are carried by another, movable object, such as a forklift truck. The reflector elements are so configured as to form images of the identifying means with said images defining a plane oriented other than normal to align from the identifying means to that plane, the images also defining a circle that does not include the identifying means. The target member may be in the form of a vertically oriented planar support member on which are mounted a pair of convex mirrors and a concave mirror. The images of the identifying means in the mirrors are detected by an imaging sensor, such as a television camera, and the directions of each of the images at the camera are used to determine all six degrees of positional information of the sensor with respect to the target. That information may be used to guide the forklift truck into position relative to a pallet. The target support member may also include retroreflector elements to aid in locating a pallet, and a bar code to distinguish one pallet from another.

Hybrid image recording and reproduction system

Abstract: A system utilizing aspects of both photography and electronic imaging is provided for recording and reproducing an image of scene in color. A camera component of the system photographically records the image on monochromatic film to provide a high resolution photograph from which electronic luminance signals are derived, and also utilizes an image sensor for providing lower resolution chrominance signals which are recorded on a medium, such as a magnetic stripe, that may be formed on the film unit. The photograph and chrominance signal recording are transferred to a reproduction component of the system which derives the luminance information signals from the photograph and combines it with the chrominance signals to provide three primary color signals which are utilized to drive a hard copy printer or an electronic image display device.

Displacement transducer which simultaneously extracts signals via sequential switching

Abstract: A displacement transducer comprising a code disk on which a plurality of light permeable slits arranged with a fixed pitch are formed, a light source which emits light to the code disk, and an image sensor which receives the light from the light source through the light permeable slits. High resolution and fast response performance are realized by measuring a displacement of the code disk from the amount of the phase shift of a fundamental wave component contained in the output obtained from the image sensor. There is a further advantage of suppressing zero point return operation to a minimum as well as improving linearity of an image sensor.

Image pick-up apparatus

Abstract: An image pick-up apparatus includes a laser light source (1) for emitting a laser beam, an acoustic-optical element (3) for deflecting the laser beam in a main-scanning direction at a horizontal scanning frequency, a vibrating mirror (8) for deflecting the laser beam deflected in the main-scanning direction in a sub-scanning direction perpendicular to the main-scanning direction at a vertical scanning frequency, and an objective lens (9) for projecting the laser beam deflected two-dimensionally onto a specimen (10) as a fine spot. A light flux reflected by the specimen (10) is collected and directed onto the vibrating mirror (8), and a linear image sensor (11) which receives the light beam reflected by the vibrating mirror (8) has a number of photoelectric converting elements aligned linearly in the main-scanning direction. The linear image sensor is read out at the horizontal scanning frequency to derive an image signal.

Multi-layered solid-state image sensor for three-dimensional picture image processing

Abstract: A multi-layered solid state image sensor senses a three-dimensional optical image introduced through a lens having a constant focal length and a constant focal depth. The image sensor has a plurality of transparent layers (24a, 24b, 24c, 24d) stacked together with reflection preventive coating films (26a, 26b, 26c, 26d) sandwiched therebetween. A cell matrix (C1, C2, C3, C4) is provided on each of the transparent layers (24a, 24b, 24c, 24d). Cells included in each cell matrix (C1, C2, C3, C4) are arranged so as not to overlap each other so that image light can effectively reach the lowermost layer. The cell matrices defining imaging surfaces on the stacked transparent layers (24a, 24b, 24c, 24d) become operative simultaneously for image sensing. Therefore, just-focused image planes at different focal points are formed on the cell matrices.

Endoscope having a plate-like image sensor for forming images

Abstract: An endoscope includes in the viewing head of its insertable section into a cavity of a living body an image sensor for generating a video signal which in turn is transmitted to a television display to be visualized thereon as a television picture. The image sensor with a shape such as a plate is located in a plane containing the longitudinal center line of the viewing head. The location permits to keep the shape of the viewing head unchanged. In addition, the image sensor thus located the interior of the viewing head into two spaces, one accommodating therein a forceps channel, and the other accommodating therein an objective lens assembly, resulting in a most efficient arrangement of essential elements for endoscope.

Light shielding construction for the forward end of an endoscope

Abstract: An endoscope includes in the viewing head of its insertable section into a cavity of a living body an image sensor for generating a video signal which in turn is transmitted to a television display to be visualized thereon as a television picture. The image sensor with a shape such as a plate is located in a plane containing the longitudinal center line of the viewing head. According to the present invention, a mask having an opening formed at a position opposed to an image area of the image sensor is provided, so that any light other than the light contributing to the image formation can be prevented from falling into the image sensor.

Completely integrated contact-type linear image sensor

Abstract: A new contact-type linear image sensor has been developed, which integrates a-Si:H photodiode and poly-Si TFT driving circuits on a quartz substrate. The C-MOS shift register of poly-Si TFT can operate in the frequency range from dc to 2 MHz. The sensor contains 848 bits with the density of 8 bits/mm on the substrate of 2 × 125 mm size. A readout time of less than 1 µs, a S/N ratio higher than 40 dB, and a saturation exposure of 0.89 lx . s are obtained.

Wobbling-swing driven image sensor

Abstract: A solid-state image sensing device (10), such as an interline-transfer type charge-coupled device (IT-CCD), produces signal carriers in response to incident light and generates an image pickup signal. One frame of the image signal is formed of two fields. The CCD chip (10) is coupled to fixed bimorph piezoelectric vibrators (12, 14) by which it is given a wobbling-swing drive during image pickup. This wobbling-swing drive is controlled by a vibration controller (28). This vibration controller (28) controls the vibration mode of the bimorph piezoelectric elements (12,14) to apply a first vibration (swing vibration) to the CCD (10) such that each pixel cell is displaced to a different sampling position in the plurality of field periods included in one frame period for image pickup, and applying a second vibration, i.e., a swing vibration with wobbling superposed, to the CCD (10) such that each pixel cell is wobbled while picking up an image in each sampling position, which is positioned in each field period.

Image sensing device

Abstract: An image sensing device comprises a stop to control the quantity of light coming from an object to be photographed; an image sensor; an automatic light quantity control system to control the stop according to a signal produced from the image sensor; a gain control circuit to control the gain of the signal produced from the image sensor; an operation member provided for manually operating the stop; and a memory to stabilize the gain of the gain control circuit in response to the operation member when the member is operated

Optical color document reading apparatus wherein an image is blurred on a color image sensor to minimize color moire phenomenon effects

Abstract: An optical document reading apparatus which minimizes color moire phenomenon effects including an optical imaging system, and a line image sensor having sensor elements arranged in a line and color filter elements disposed on the sensor elements. A plurality of sensor elements are assigned to one pixel of said document, and the line image sensor senses light reflected from the document through the optical imaging system. The apparatus has a magnification condition which is determined from a distance between the document and the optical imaging system and a distance between the optical imaging system and the image sensor. The magnification is selected to be such that the optical imaging system does not precisely image the document onto the image sensor.

Endoscope having a control for image stand still and photographing the image

Abstract: An endoscope used for observing the interior of a cavity and the like of a living human body. The endoscope according to the present invention is of such an arrangement that an image sensor is provided in the forward end of an insertion section and an object of interest can be displayed on a screen of a television set in response to a video signal obtained from the image sensor. According to the present invention, a control unit is provided therein with a circuit for producing an image standstill command and a shutter release command depending on a time or times of operation, or a step or steps in press-in value of a single push in switch provided a control section of the endoscope, so that the provision of a single control button makes it possible to make a monitored image stand still and to release a shutter of a camera.

Image acquisition technology

Abstract: This survey includes a description of all types of two-dimensional image sensors in current use in television. Television is loosely defined as the acquisition, transmission, and display of moving pictures by electronic means. The technology of image acquisition is greatly complicated by the requirement in many parts of the industry that the images be in natural color. Some imagers include the color analysis means as an inherent part of their makeup. However, many color cameras use two or more monochrome sensors and a substantial peripheral system of optical, control, and signal-processing functions. Both of these major classes of color imagining systems are described. An outline is included of major categories of camera users, their equipment, and numbers. Finally, a tabulation is presented, giving the physical and electrooptic properties of a variety of cameras.

New computed radiography using scanning laser stimulated luminescence.

Abstract: This short paper summarizes the basic concept and the technology of a new computed radiographic system which uses an energy-storage phosphorus panel called "Imaging Plate" as an image sensor. The "Imaging Plate" can be used to obtain radiographs in exactly the same way as the screen-film combination is used in conventional radiography. The system eliminates the drawbacks of conventional screen-film radiography by combining digital image processing and digitization of the x-ray energy pattern utilizing scanning laser stimulated luminescence.

Theoretical Bases And Measurement Of The Mtf For Integrated Image Sensors

Abstract: By analogy with optics, the spatial resolution of image sensors is generally characterized by the Modulation Transfer Function (MTF). This notion assumes the system being a linear filter, which is not the case in integrated image sensors, since they have a discrete photoelement structure. These sensors must in fact be considered as integral samplers. Their response to any irradiance distribution can thus be computed, knowing the pitch of photoelements and using a characteristic function. This function is more or less similar to the MTF. Once exact theoretical foundations have been defined, a computer simulation enables the various MTF measuring methods to be compared this makes it possible to rule out er-rors inherent to experiments. The most accurate and reliable method appears to be the knife edge method, applied with a relative displacement of the sensor and of the image. This avoids the occurence of aliasing phenomenon. Experimentation of this method for measurement of the CCD sensors characteristic function, which we call MTF as agreed, is described. This method also makes it possible to evaluate the transfer inefficiency of shift registers.

Film thickness measuring device and method

Abstract: Apparatus and a method are disclosed for measuring the thickness of a very thin transparent film formed, for example, on a photomask or wafer for an integrated circuit Diffracted reflected light from a film specimen is converted photoelectrically by use of a one dimensional image sensor array and then by an A/D converter having a resolution of more than 2 10 , which allows for discrimination into 1,000 graduations of output level Enhanced precision in determining film thickness is obtained by utilizing this high discrimination to first determine the variations among individual elements of the one dimensional sensor array and compensating for them, as well as by using known averaging and statistical techniques to generate output for comparison to reference data from film specimens of known thickness