Showing papers on "Image sensor published in 1990"

The unifying role of the coarray in aperture synthesis for coherent and incoherent imaging

Abstract: Systems of two-dimensional (2-D) imaging arrays and apertures are considered from the point of view of their performance in the imaging of spatially incoherent as well as coherent source distributions. Such systems find applications in radar, sonar, and ultrasound imaging, as well as in applications such as seismology and radio astronomy. For linear imaging techniques related to beamforming and based on the Fourier transform relationship between the source distribution and the aperture plane measurements, the point spread function of the system completely characterizes its performance. This function is determined by the geometry of the physical aperture or array as well as the weighting that can be applied to measurements. It is shown that the introduction of the concept of coarray, both for receive apertures in incoherent imaging and for transmit/receive systems in reflection-mode coherent imaging, provides a convenient and elegant framework within which many apparently isolated techniques for point-spread function or aperture synthesis can be understood. In addition to this unifying role, coarray concept gives new insight into the aperture synthesis process, which allows interesting new imaging techniques to be developed, especially in coherent imaging. >

Electronic still camera utilizing image compression and digital storage.

Abstract: An electronic still camera employs digital processing of image signals corresponding to a still image and storage of the processed image signals in a removable static random access memory card (24). An image sensor (12) is exposed to image light and the resultant analog image information is converted to digital image signals. A control processor (20) controls the exposure section (10) and an A/D converter (16), delivering digital signals to a multi-image buffer (18) at a rate commensurate with normal operation of the camera. A digital processor (22) operates on the stored digital signals, transforming blocks of the digital signals and encoding the signals into a compressed stream of processed image signals, which are downloaded to the memory card. The digital processor (22) operates at a throughput rate different than the input rate for better image capture and optimum utilization of the camera.

Ink jet recording apparatus

Abstract: PURPOSE:To reduce the nonuniformity in density by adjusting an electric signal impressed on a liquid droplet forming means in accordance with a printing career CONSTITUTION:To digital image signal is corrected by a shading correcting element 104 so as to correct the characteristic of an image sensor 101 and an optical system, and it is sent to an image processing element 109 A grey chart having a prescribed density is read by the image sensor 101 and printing is made A head characteristic table 108 varies a pulse width of a pulse width modulator 110 so as to cancel an increased part of an image When the width of a drive pulse given to an ink jet head becomes large, the density of the image after printing increases, and when the width of the drive pulse becomes small, to the contrary, the density of the image after printing decreases

Electronic imaging apparatus with interchangeable pickup units

Abstract: Electronic Imaging Apparatus is partitioned into separable modular units including an image pickup unit (4a) attachable to an image recording unit (2) The pickup unit (4a) is selected from a plurality of pickup units (4a, 4b), each producing image signals from an image sensor (6, 70, 71) uniquely devoted to the acquisition of a particular type of image (eg, high resolution vs low resolution, colors vs monochrome, NTSC motion vs PAL motion) By providing an identifying signal in connection with the pickup unit, the characteristics of the sensor (6) are specified to the recording unit More specifically, the recording unit includes a buffer (36) for storing the image signals, a processor (40) for controlling the operation of the recording unit, including the buffer, and interface circuitry (10, 32) for responding to the identifying signal and enabling operation of the processor (40) according to the characteristics of the attached image pickup unit (4a)

Automatic focusing apparatus

Abstract: An automatic focusing apparatus comprises a photographic optical system for forming an optical image of an object, an optical system driving circuit for moving the photographic optical system in a direction of its optical axis, a storage circuit for prestoring a plurality of MTF ratios corresponding to a plurality of focusing states of the photographic optical system, an image sensor for detecting the optical image, a spatial frequency component extracting circuit for extracting a plurality of spatial frequency components from image signals output from the image sensor, a calculating circuit for calculating a ratio between spatial frequency components representing different focusing states at every common frequency from the spatial frequency components extracted by the spatial frequency extracting circuit, a defocus detecting circuit for detecting a defocus amount and a focusing direction from the spatial frequency component ratios calculated by the calculating circuit and the MTF ratios stored in the storage circuit, and a driving control circuit for calculating an amount and a direction of movement of the photographic optical system from the detection result from the defocus circuit, and outputting the calculating result to the optical system driving circuit.

Review of image-blur models in a photographic system using the principles of optics

Abstract: When a photographic imaging system has a focus error or a motion blur, it is not possible to correct the error by conventional optical printing. Digital image processing offers a chance to restore the blurred images by reversing the blurring processes under certain constraints. Although restoration algorithms vary in detail, they all need a model of the image-blurring process. This paper reviews image-blur models of each individual component in an image chain consisting of camera, film, and scanner. The models include image blur caused by focus error, camera shutter, object motion, light scattering in the film emulsion, film interimage effect, scanner optics, and scanner aperture. The emphasis is on mathematical simplicity and practical usefulness.

Video camera unit having an airtight mounting arrangement for an image sensor chip

Abstract: A video camera unit is separated into a holder for receiving lenses and a base on which a solid-state image pickup chip is mounted. The holder and the base are assembled together with the distance between them made variable so that it is possible to adjust the back focus of the lens. Further, a video camera unit has a holder which is separated into a first holder for receiving lenses and a second holder for receiving a solid-state image pickup device so that both holders can be assembled together with the distance between them made variable. Therefore, it is also possible to adjust the back focus of the lens.

Image forming apparatus for forming image corresponding to subject, by dividing optical image corresponding to the subject into plural adjacent optical image parts

Abstract: An image forming apparatus for forming an image corresponding to a subject is provided, which image forming apparatus includes a taking lens for making an optical image corresponding to the subject, and a dividing portion for dividing the optical image transmitted via said taking lens into several adjacent optical image parts. The image forming apparatus further includes several solid-state image sensors corresponding to the number of the optical image parts, each of said solid-state image sensors receiving a corresponding optical image part from among the several optical image parts from the dividing portion and outputting an image signal corresponding to the optical image part, the optical image parts received by said solid-state image sensors being adjacent to each other. Finally, the image forming apparatus includes an image forming portion, coupled to said solid-state image sensors, for forming an image part corresponding to the respective optical image part based on the image signal transmitted from one of said solid-state image sensors, and for composing each image part to form the image corresponding to the subject by arranging the image parts to be adjacent to each other like the optical image parts.

Electronic camera for line-by-line imaging of documents

Abstract: An electronic camera comprises an illumination unit (30) for line-by-line imaging of large-size documents (50) or the like on an elongate solid-state image sensor, in particular a CCD line sensor (22). The illumination unit is provided with optical elements for producing a light strip (37) on the document (50). The illumination unit (30) is arranged within the camera housing (10) for pivotal movement in the direction of the arrows "A" or "B". The CCD line sensor (22) is movable, in response to the pivotal movement of the illumination unit (30), in the vertical direction within the image plane of the camera lens (42) in the direction of the arrows "A" or "B" so that the light strip (37) guided across the document (50) can be imaged on the CCD line sensor (22).

ASIC image sensors

Abstract: Two image array sensors designed and fabricated using a standard two-level metal ASIC CMOS process are described. The results show that good quality grey-level images can be formed, and that CMOS sensors arrays can be successfully integrated with efficient analogue sense amplifiers and with digital control/image-processing logic. The first sensor is a prototype 128*128 pixel test array. The second is a 312*287 pixel image sensor chip which includes all the necessary circuitry to produce full PAL format video output, as well as automatic electronic exposure control and built-in test circuits. Test results characterizing the devices are given, covering dynamic range, spectral response, sensitivity, resistance to blooming, etc. Some potential applications for such devices are mentioned. >

Charge-coupled device image sensor as a demodulator in a 2-D polarimeter with a piezoelastic modulator

Abstract: It is shown how demodulation of rapidly modulated light beams can be achieved within a single charge-coupled device (CCD). Two interlaced image planes are created by optically masking every second CCD row and transferring the charges back and forth between the two image planes in synchrony with the modulation. The method has been successfully tested for modulation frequencies of 50 and 100 kHz, using integration times up to 1 s. No significant accumulated charge transfer losses are seen for integration times as long as 10(5) modulation cycles (1 s). This demonstrates the feasibility of a CCD polarimeter using piezoelastic modulation of the state of polarization.

Automatic sensor and light source positioning for machine vision

Abstract: The authors discuss an optimization approach to automatic sensor and light source positioning for a machine vision task where geometric measurement and/or object verification is important. The goal of the vision task is assumed to be specified in terms of edge visibility. There are two types of edge visibility: geometric edge visibility tells how much of the given edge is not occluded, and photometric visibility tells how much of the given edge has enough contrast to be detected in the image. A heuristic optimality criterion for the optimal sensor and light source position is defined in terms of these two edge visibilities. A preliminary experiment has been conducted to demonstrate the feasibility of the optimization approach. The result shows that the optimization problem formulated can be solved by mathematical programming techniques. >

Single-exposure dual-energy computed radiography.

Abstract: This paper focuses on analysis and development of a single-exposure dual-energy digital radiographic method using computed radiography (Fuji FCR-101 storage phosphor system). A detector sandwich consisting of storage phosphor imaging plates and an interdetector filter is used. The goal of this process is to provide a simple dual-energy method using typical plane-projection radiographic equipment and techniques. This approach exploits the transparency of the storage phosphor plates, using radiographic information that would be otherwise lost, to provide energy selective information essentially as a by-product of the radiographic examination. In order to effectively make use of the large dynamic range of the storage phosphor imaging plates (10,000:1), a computed radiography image reading mode of fixed analog-to-digital converter gain and variable photomultiplier sensitivity provides image data which can be related to relative incident exposure for export to the decomposition algorithm. Scatter rejection requirements necessitated crossed 12:1 grids for a field size of 36 x 36 cm. Optimal technique parameters obtained from computer simulation through minimization of the aluminum and Plexiglas equivalent image uncertainty under conditions of constant absorbed does resulted as: 100 kVp using a 0.15-mm-thick tin (Sn) interdetector filter for the lung field. This yields a surface exposure of 23 mR and a surface absorbed dose of 0.26 mGy for a 23-cm-thick chest. Clinical application in evaluation of the solitary pulmonary nodule is discussed, along with an image set demonstrating this application.

A 250000-pixel image sensor with FET amplification at each pixel for high-speed television cameras

Abstract: An amplified MOS imager (AMI) for use in each pixel in a high-speed TV camera is discussed. The AMI performs such functions as amplification, readout, and resetting independently and completely. Thus the AMI is easier to operate and completely free from image lag, and has relatively little smear (2*10/sup -5/) compared with other devices. The AMI can also handle both hole and electron signals when a photoconductive layer is laminated on its surface. The image area dimensions are 8.8 mm (H)*6.6 mm (V) with 510 (H)*490 (V) pixels. Each pixel has an FET amplifier that enhances signal current 100*immediately after receiving the incident light. A source-follower is used for output signal linearity. The AMI is equipped with three horizontally aligned output lines, each operated at a horizontal clock rate of 30 MHz. The total sampling frequency can be 90 MHz, but the device in this television camera application operates at a sampling frequency of 57 MHz. >

Method and apparatus for controlling exposure of video camera

Abstract: An exposure control apparatus receives a video signal from a scene pick-up image sensor and performs a divided brightness measuring for an image free. In accordance with the brightness distribution or a change amount of a scene obtained by the divided brightness measuring, the adjustment speed for a diaphragm is switched. In another embodiment, a scene brightness value for use as the exposure control is corrected to thereby obtain a smooth exposure control for continuous scenes. Scene pick-up by panning is detected by a built-in acceleration sensor in a video camera. Therefore, if the video camera is moved abruptly, then the exposure control is made slowly.

Camera with camera-shake detection apparatus

Abstract: A camera wherein the light emitted by a subject, which has passed through a photographic optical system, is formed as an image on an area sensor, and which includes an electronic viewfinder that indicates the image of the subject based on the output from the area sensor and an apparatus that detects image shaking caused by camera shake, based on the output from the area sensor.

Automatic target detection process

Abstract: A novel data processing technique is provided for detecting, locating and identifying targets from a plurality of images generated by an imaging sensor such as an imaging lidar system. The present invention employs physical models of signals produced by target objects of interest. Such a model based detection system globally processes frames of data to determine the existence and location of component elements that characterize the target being modeled.

Development of hydrogenated amorphous silicon sensors for high energy photon radiotherapy imaging

Abstract: Measurements with a-Si:H n-i-p photodiodes with sensitive areas of approximately 0.6 mm/sup 2/ exposed to a 6 MV radiation therapy treatment beam have been performed. Such photodiodes can be configured into large two-dimensional arrays of addressable sensors suitable for real-time imaging of megavoltage treatment beams as well as other applications such as diagnostic X-ray imaging. Signal sizes per radiation pulse up to 3.9*10/sup 6/ and 69*10/sup 6/ electrons are observed when the sensors are used with cronex (CaWO/sub 4/) and lanex (gadolinium-oxysulfide) intensifying screens, respectively. For the cronex and lanex screens the size of the measured signals can be enhanced by reducing the thickness of the top p-layer, thereby reducing the attenuation of the incident light. However, this is a smaller effect for the lanex screen, which provides substantially more light signal. The variation in cronex signal size with p-layer thickness is consistent with calculations based on known attenuation coefficients. >

Sensor fusion in image reconstruction

Abstract: A Bayesian method for ECT (emission computed tomography) image reconstruction has been developed to incorporate a priori information derived from the spatially correlated CT and MR (magnetic resonance) images. These anatomic maps, showing boundaries between regions that exhibit distinctly different characteristics, can be incorporated into the Bayesian method, thus improving the spatial resolution and noise properties. The correlated structural information can also be used as templates for deriving correcting factors for the effect of photon attenuation, thus improving the quantitative accuracy and noise properties. This novel image reconstruction method using the concept of sensor fusion has been validated by computer simulation studies. Results from these studies indicate that significant improvements in image quality can be achieved. >

Compact recording apparatus with functional components mounted on a substrate

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.

Imaging system having a blurring optical element for minimizing moire phenomenon

Abstract: An image pickup device using a solid-state image sensor adapted to provide an optical component having a multiple curved surface, polyhedral surface, symmetric cylindrical surface, axially symmetric aspherical surface or asymmetric refracting surface in an objective lens system, or lengthen a shape of an image formed on an exit end face of an illuminating optical system in a direction parallel to a scanning direction of the solid-state image sensor, or select an angle made by a line segment connecting between the centers of individual exit end faces of two illuminating optical systems with the scanning direction of the solid-state image sensor to ±40° or less, or extend a shape of an aperture of a stop in a direction parallel to the scanning direction of the solid-state image sensor, in order to make it possible to fabricate the device in a small size and at a low cost and eliminate moire and false color without reducing resolving power.

A 2 million pixel FIT-CCD image sensor for HDTV camera system

Abstract: The image area of the frame FIT (frame-interline-transfer)-CCD (charge-coupled-device) image sensor is 140 mm (H)*79 mm (V), the effective number of pixels is 1920 (H)*1036 (V) and the unit cell size of a pixel is 73 mu m (H)*76 mu m (V) These specifications are for the high-definition-television (HDTV) format The horizontal shift register consists of dual-channel, two-phase CCDs driven by a 37125-MHz clock pulse The readout phase of each channel is the same, which allows the reset gate of each channel to be connected together To adapt to the 7425-MHz readout frequency, one of the output signals is delayed by 1347 ns through a sample-hold circuit To reduce the voltage drop of the vertical shift register (V-CCD) drive pulse along the poly-Si transfer gate, an Al wire is put onto the transfer gate and interconnected to decrease the resistance This Al wire works also as a photoshield In addition, another poly-Si layer placed between the Al wire and the transfer gate prevents potential shift by separating the poly-Si contact of the transfer gate/poly-Si layer, from the Al contact of the poly-Si layer/Al wire >

Electronic still camera with lessened power consumption

Abstract: In an electronic still camera of the kind having a detachably mounted photo-taking optical system, an image sensor which converts into an electrical video signal an object image formed by the photo-taking optical system, a recording circuit which records the video signal and an electronic viewfinder which displays an image represented by the video signal obtained by the image sensor when the camera is in a shootable state, a confirmation member is arranged to confirm a mounted or detached state of the photo-taking optical system, and a driving-suspending and displaying-off control circuit is arranged to suspend a driving action on the image sensor and to turn off the electronic viewfinder when the detachment of the photo-taking optical system from the camera body is confirmed by the confirming member.

ASIC vision

Abstract: Advances in VLSI vision sensor design that enable high-quality, analog images to be formed through devices fabricated using standard 5 V CMOS ASIC processes are reported. The potential for integrating mixed sensor-processor systems, using an integrated VLSI camera system as an example, is reported. The feasibility of the techniques is confirmed by results obtained from working prototype CMOS sensor arrays. It is believed that the methods and results demonstrated can form the basis of a first generation of cost-effective ASIC vision products. >

Inertial navigation sensor integrated motion analysis for obstacle detection

Abstract: A maximally passive approach to obstacle detection is described, and the details of an inertial sensor integrated optical flow analysis technique are discussed. The optical flow algorithm has been used to generate range samples using both synthetic data and real data (imagery and inertial navigation system information) obtained from a moving vehicle. The conditions under which the data were created/collected are described, and images illustrating the results of the major steps in the optical flow algorithm are provided. >

A retinal CCD Sensor for fast 2D shape recognition and tracking

Abstract: A human-retina-like image sensor has been developed for applications in robotics. The CCD imager has a circular pixel organization and the resolution is a decreasing function of the radius. Detailed software modeling resulted in an imager design consisting of four main parts: a circular CCD, a radial CCD, a coupler and an output structure. In order to avoid a blind spot in the center, a central fovea with a rectangular interline transfer imager is included. This paper outlines in detail the design concepts and reports on the electrical performance and functionality of the first prototypes.

A 310 K pixel bipolar imager (BASIS)

Abstract: The BASIS (base-stored image sensor) bipolar imaging device, which consists of a bipolar phototransistor in a capacitor-loaded emitter-follower circuit, is discussed. The device is used in an imager with 310 K pixels (640 H*490 V) in a 2/3-in optical format. The imager exhibits excellent performance characteristics, such as a high aperture ratio of 60%, an image lag less than 0.1%, and good linearity with a dynamic range of 76 dB. The read out and reset operation, antiblooming capability, and total system circuit and FPN cancellation are discussed. >

Imaging system for providing separate simultaneous real time images from a single image sensor

Abstract: A system is disclosed for providing separate simultaneous real time images from a single image sensor. The invention 10 is adapted for use with an image sensor 12 which provides a first set of electrical signals in response to electromagnetic energy received thereby from a scene and includes a processor 16 for processing the first set of electrical signals to provide a second set of electrical signals and at least one display 14 for providing first and second separate simultaneous real time images in response to the first and second sets of electrical signals respectively. In a preferred embodiment, the processor 16 includes circuitry for increasing the sampling rate of the image sensor 12 and a deconvolver 30 for processing the highly sampled signals to generate a second set of electrical signals which, when displayed contemporaneously with said first electrical signals, provide an enhanced magnified portion of the sensed scene.

Image sensor array using two stage transfer having improved uniformity

Abstract: A linear image sensor array and process having a two stage transfer circuit where in order to reduce non-uniformities between the photosite cells of the array resulting from difference transistor thresholds, the bias charge is injected between the first and second transistors of the two stage transfer circuit, with the first transistor function as a metering gate for bias charge injection.