Showing papers on "Image sensor published in 1981"

Solid-state image sensor with exposure controller

Abstract: A solid-state image sensor which detects the quantity of light incident on image sensor cells during exposure and performs exposure control in accordance with an exposure value thus obtained The solid-state image sensor is provided with a photoelectric converter having a plurality of non-destructive readout type image sensor cells arranged in a matrix form; an exposure detector for reading out stored information of predetermined ones of the image sensor cells during exposure, obtaining an added value of the stored information thus read out and detecting that the added value reaches a predetermined level; an exposure controller which is supplied with the detected signal from the exposure detector to control at least one of the charge storage time of each image sensor cell by an optical signal, the intensity of light incident on the image sensor cell and the photosensitivity of the image sensor cell; and a scanner for scanning the photoelectric converter to read out stored information of the image sensor cells during exposure

Real-Time Adaptive Contrast Enhancement

Abstract: A recursive filter approach is introduced to simplify real-time implementation of an adaptive contrast enhancement scheme for imaging sensors. With this scheme, even scenes possessing large global dynamic ranges (>40 dB) can be accommodated by the limited dynamic range (20 dB) of a display without losing the local contrast essential for image interpretation. This paper describes the recursive filter implementation of the local area contrast enhancement scheme using charge-coupled devices and the resultant real-time hardware capable of processing standard 525 and 875 line TV compatible video (from vidicons, videotape recorders, etc). Several examples from video imagery are included to demonstrate its effectiveness.

Method and apparatus for calibrating a linear array scanning system

Abstract: A linear image sensor and the video channel associated with the sensor are calibrated to maximize the video signal available. The sensor is limited in output by saturation of the CCD analog shift registers in the sensor. The channel is limited by the range of the analog-to-digital converter in the channel. The useable video signal is maximized by calibrating the sensor relative to its saturation condition and by adjusting the gain of the video channel relative to the range of the analog-to-digital converter. The sensor is calibrated by adjusting its exposure to illumination. The adjustment may be made by adjusting the illumination source or by changing the sampling interval for the sensor. The gain is adjusted by using a variable gain amplifier. A microprocessor monitors the digitized video signal and controls the exposure and gain to calibrate the sensor and channel.

Automatic focusing device

Abstract: An automatic focusing device by which the intensity distribution of an image of an object to be photographed is detected by a detecting section having an accumulation mode image sensor with a charge accumulation time in dependence upon the brightness of the object and develop a video signal corresponding to the intensity distribution. A signal processing circuit processes the video signal to determine whether the optical system of the photographing apparatus with which the focusing device is associated is focused or out of focus and when an out-of-focus condition is detected a drive direction signal is developed and applied to a drive to move the lens in a proper direction toward a focusing position. The drive direction signal is applied to the drive for only a predetermined time at each detection that the optical system is out of focus when the brightness of the object is low and when the brightness of the object is high the drive direction signal is applied without interruption until detection that the optical system is in focus irrespective of the charge accumulation time of the image sensor varying in response to the brightness of the object being photographed.

Passive ranging system especially for use with an electro-optical imaging system

Abstract: A passive ranging system functions in conjunction with an electro-optical imaging system to compute a range measurement based on determined changes of the image of a designated object or objects or image features representative thereof in the scene of an image sensor which is transported from one position to another with respect to the designated objects. In the present embodiment, the image sensor generates frames of image information corresponding to the one and another positions thereof while maintaining substantially a common image scene in its field of view. Image features representative of the designated image objects are extracted from at least a selected portion of the two frames for registration in accordance with a predetermined matching criteria. The variations in the geometric relationship of common image features of the registered selected portions of the two frames caused by the image sensor positioning are determined and used together with the one and another image sensor positions, measured with respect to the designated objects, for computing the range measurement in question.

Recognition method and apparatus

Abstract: A recognition apparatus comprising an image sensor sensing an image of a pad pattern on an IC chip pattern, a pre-treatment circuit for converting the outputs of the image sensor into binary-coded signals in accordance with at least two slice levels, and a pattern detecting section for detecting the position and inclination of the pad pattern based on the images of the pad and chip patterns corresponding to the data stored in a memory; that is, the binary-coded signals generated in accordance with two slice levels. Two image sensors may be used for sensing the chip and pad data respectively.

Image sensor sensitivity variation compensator

Abstract: A method and apparatus for compensating for sensitivity variations in image sensors. The sensing surface of an image sensor is arbitrarily divided into a plurality of detection elements. A field of uniform brightness is presented to the image sensor and the video signal from each detection element is multiplied by a corresponding correction value. The altered video signal is compared to a reference and the corresponding correction value is either incremented or decremented so that the altered video signal approaches the reference. During operation, the video data received from each detection element is multiplied by the corresponding correction value to produce corrected video data.

Position detecting method and apparatus

Abstract: There is provided a method of detecting any positional deviation of a workpiece from a reference position with the aid of an image sensor. First, a sample workpiece is put at the predetermined position, and is detected by the image sensor to provide reference image information. Likewise, a workpiece under inspection is detected by the image sensor to provide workpiece image information. The reference information is subjected to a parallel transformation and/or rotation and is compared with the workpiece image which remains in the original state, to detect the correlation degree between the two sets of information. The detection of the correlation degree is repeated for each incremental parallel transformation and/or rotation of the reference information. The maximum correlation degree is selected from among the accumulated correlation degrees, whereby the positional deviation of the workpiece, if any, from the reference position is represented by the amount and the direction of the parallel transformation and/or rotation which give the maximum correlation degree.

Image sensor using dynamic random access memory

Abstract: A new and improved solid-state image sensor uses a dynamic random access memory as the light sensitive element. The dynamic random access memory is mounted in a semiconductor package having a transparent lid, and one or more lenses focuses the light image onto the dynamic random access memory. A recording device or a display unit is provided. The new and improved solid-state sensor is particularly useful in low-cost applications, such as robots and toys.

All Solid State Color Camera With Single-Chip Mos Imager

Abstract: An all solid state color camera using a solid state image sensor has many advantages over the conven- tional tube type camera, such as light-weight, low power consumption, high reliability, elimination of lag and high picture quality.

Semiconductor image sensor

Abstract: A semiconductor image sensor which has photocells arranged in a matrix form is miniaturized and integrated with high density, thereby to increase its light amplification factor and operating speed. To this end, each photocell is formed by a static induction transistor which has a pair of main electrodes, a channel region formed between the main electrodes and a capacitor connected between a control region serving as a photocell and one of the row lines.

Image reading apparatus having a plurality of image sensors

Abstract: An image reading apparatus utilizing two one-dimensional image sensors arranged to have mutually overlapping sensing fields. A common fixed target provided in the overlapping portion of the sensing fields is viewed by two sensors and is utilized for automatically compensating for the signals from the overlapping portion.

A 2048-element contact-type linear image sensor for facsimile

Abstract: In order to realize more compact facsimile equipment, a contact type linear image sensor has been developed. The imager has the same length as the document width and does not require an optical lens system, as the imager virtually contacts the document. A new fabrication process, which combines CdS chemical bath deposition and CdSe vapor deposition, is adopted for photoconductive thin film. The process condition for CdS-CdSe mixing ratio is established to most suitably satisfy facsimile application characteristics, such as spectral response and photo response speed. By paying particular consideration to such structure design as the sensing aperture and scanning circuit, trial 2048-element, 256 mm long imager was successfully fabricated. Evaluation of the trially fabricated imager and its photo-electric conversion unit showed excellent operational properties and utilization for facsimile equipment.

Solid states image sensor array having circuit for suppressing image blooming and smear

Abstract: A solid-state image sensor in which a light signal charge transfer means comprising a metal oxide semiconductor (MOS) vertical shift register and switching elements is provided so that the light signal charge stored in the photoelectric transducer elements in one column in an (m×n) photoelectric transducer matrix array is simultaneously transferred to a vertical transmission line; and another charge transfer means comprising a transfer gate means and storage capacitor elements transfers the light signal charge transferred onto the vertical transmission line to a horizontal shift register from which the light signal charge is transferred to an output stage. The horizontal shift register comprises a charge-coupled device (CCD) type horizontal shift register. The solid-state image sensor can eliminate blooming caused by the incidence of light with a high intensity and smear caused by the incidence of light on the areas except predetermined light reception areas.

Semiconductor image sensor and the method of operating the same

Abstract: A semiconductor image sensor of wide dynamic range, high sensitivity, low noise and high image clarity, which is provided with a hook structure for detecting radiant energy input information, a readout transistor and means for refreshing stored optical information and which is capable of non-destructive readout of optical information, and a method of operating such a semiconductor image sensor. The impurity concentrations in the hook structure, their distribution profiles, materials of layers forming the hook structure and their thicknesses are so selected as to optimize the carrier storage function of the hook structure, thereby permitting the non-destructive readout of the optical information. The ratio between the junction capacitance and the earth capacitance of a floating pn junction establishing a potential barrier in the hook structure is selected so that a stored voltage in the floating pn junction and the readout sensitivity may become maximum. By repeating the non-destructive readout, as integrated value of the quantity of incident light is read out. The time interval to a first operation of the readout transistor after the operation of a refresh pulse signal is selected in accordance with the quantity of the incident light, by which an electric signal proportional to the quantity of the incident light can be read out. The refresh operation is performed by applying a pulse voltage in such a manner that a bias voltage may be provided to a substrate electrode or surface electrode in a light integration period alone and, in the refresh period, the pulse voltage is made zero or negative.

Rotating laminar emission camera with GE-detector: Experimental results

Abstract: Experimental results of a prototype rotating laminar emission camera (ROLEC) for nuclear medicine imaging are reported. A 11.5 mm thick, 45×45 mm high‐purity germaniumdetector is segmented into 30 1.47 mm wide parallel channels and collimated with 39 mm high parallel plates. Projection data acquired at multiple angular orientations as the detector‐collimator assembly is rotated about its center are mathematically reconstructed to image the activity distribution. The spatial resolution of the ROLEC is at least twice as good, at all distances, as that of gamma cameras with high resolution collimators. The better energy resolution of the germanium enhances the detection and resolution of the ROLEC in comparison to gamma cameras with NaI(T1) crystals, the relative superiority increasing with greater volumes and with greater depths. Adequate sensitivity is maintained while achieving these improvements in spatial resolution and in practice; ROLEC images are acquired in less time than pinhole collimatorimages with gamma cameras. Key words: emission camera, laminar camera,germaniumcamera

Charge-Coupled Device (CCD) Trackers For High-Accuracy Guidance Applications

Abstract: Recent advances in large area charge coupled device (CCD) imaging detectors and high speed microprocessors have prompted the development of a new class of electro-optical tracking instruments at the Jet Propulsion Laboratory (JPL). These instruments are designed for standardized NASA-wide usage and are characterized by their extremely high pointing accuracy and stability and performance capabilities which are largely software defined and thus easily adapted to a variety of mission requirements. This paper presents an examination of the methods by which CCD detectors are being incorporated in star tracker instruments and the performance capabilities that can be expected from currently available devices. The multi-function sensor concept, in which a single sensor can function in a variety of guidance applications, is described. Software algorithms designed to provide efficient extraction of guidance information from both point and extended images are also presented. CCD star tracker implementations currently underway at JPL are described, and performance data obtained during laboratory testing is presented and discussed.

Image Approximation by Variable Knot Bicubic Splines

Abstract: This paper presents a degree of freedom or information content analysis of images in the context of digital image processing. As such it represents an attempt to quantify the number of truly independent samples one gathers with imaging devices. The degrees of freedom of a sampled image itself are developed as an approximation problem. Here, bicubic splines with variable knots are employed in an attempt to answer the question as to what extent images are finitely representable in the context of digital sensors and computers. Relatively simple algorithms for good knot placement are given and result in spline approximations that achieve significant parameter reductions at acceptable error levels. The knots themselves are shown to be useful as an indicator of image activity and have potential as an image segmentation device, as well as easy implementation in CCD signal processing and focal plane smart sensor arrays. Both mathematical and experimental results are presented.

Electronic camera employing a solid-state image sensor.

Abstract: An electronic camera which focuses images of an object on the image plane by means of suitable lenses (14) such as those employed in 35 mm cameras. The optical system is held stationary while a self-scanning linear array (34), comprised of a row of light-sensitive devices, is moved a measured distance in the image plane. The linear array is continuously clocked as it is moved along the image plane. The resulting video signal output is a train of pulses, each proportional in magnitude to the light intensity falling on the corresponding light-sensitive device. An internal line-filament light source moves in synchronism with the linear array so that only the image slice being viewed by the array at any instant of time as it traverses the image field is being illuminated. The light source is directed onto the object plane through a beam splitter so that the light shines through the optical axis of the lens for maximum efficiency.

Digital scan converter for image scanning and display system

Abstract: A scan converter circuit for use in a imaging system that uses a sinusoidally oscillating scanning reflector for scanning an object and a constant rate scanned display monitor for displaying an image of the object The circuit enables a variable time rate of sampling of picture elements in the object field to match a desired constant display rate of picture elements in the CRT display monitor The circuit comprises a constant rate VCO clock and a sampling clock that produces periodically variable rate pulses, the periodicity of which being phase locked with zero crossings of the oscillating reflector and wherein the pulses are derived from the constant rate VCO clock The sampling clock enables an image sensor to sample the radiance levels at a rate which varies with the sinusoidal sweep speed of the oscillating reflector The circuit further includes a memory circuit for buffering and reversing the order of picture element information during at least one sweep direction, and a transfer control circuit for alternately supplying to the CRT display monitor picture element representations from the sensor and the temporary memory so that picture elements obtained during a right-to-left sweep and a succeeding left-to-right sweep are accurately aligned with each other and bear a one-to-one correspondence with picture elements in the image field

Photoelectric converter apparatus

Abstract: A photoelectric converter apparatus suitable for use as an optical pattern reader is disclosed. A CCD image sensor receives light reflected from a text having characters or graphic patterns marked thereon and stores charges proportional to the intensity of the reflected light. Unnecessary charges are transferred from the CCD image sensor to the shift register and are swept out during a time period other than a readout period for necessary data. The readout data which exactly reflects the data on the text is produced with a reduced sweep-out period.

Ccd image pickup device

Abstract: PURPOSE:To make it possible to obtain an electronic shutter function having an arbitrary shutter speed, by using the CCD having the self-scanning function and the photoelectric conversion function as the image sensor in the image pickup device and by varying the charge storage time. CONSTITUTION:Electric charge corresponding to the light quantity of the image pickup light is stored in respective light receiving elements of CCD1 while overflow drain gate clock signal OFDG and sensor gate clock signal SG are logical 0 and logical 1 respectively, and electric charge stored respective light receiving elements of CCD1 is abandoned to respective overflow drains of the CCD while overflow drain gate clock signal OFDG is logical 1. Since the duty ratio of overflow drain gate clock signal OFDG can be changed arbitrarily by adjusting the resistance of variable resistor 11 connected to clock signal generator 10, the charge storage time for light receiving part, namely, the shutter speed can be changed arbitrarily.

Solid-state image storage device

Abstract: A solid-state image storage device employing a recording system which permits easy reproduction of an excellent image even if a relatively low-grade recording medium and recording and reproducing device are used. The solid-state image storage device is provided with a photoelectric converter having a plurality of non-destructive readout image sensor cells arranged in a predetermined form; a scanner for scanning the photoelectric converter to read out image information of the image sensor cells; and a recorder having a recording medium for recording the image information read out by the scanner. An image formed on the photoelectric converter is read out by the scanner a plurality of times and each image information thus read out is recorded at one position on the recording medium of the recorder.

Two-dimensional solid-state image sensor

Abstract: A two-dimensional solid-state image sensor which is equipped with an image processing function and hence is able to directly output image information subjected to two-dimensional image processing. The two-dimensional solid-state image sensor is provided with a photoelectric converter having non-destructive readout type image sensor cells arranged in a matrix form; a scanner for scanning the photoelectric converter in such a manner that stored information of each image sensor cell is read out together with stored information of other image sensor cells bearing predetermined positional relationships to the image sensor cell to be read out; and an arithmetic unit for conducting predetermined operations for the plurality of stored information read out by the scanner to output an image signal subjected to two-dimensional image processing.

Texas Instruments (TI) 800X800 Charge-Coupled Device (CCD) Image Sensor

Abstract: Very-large area high-performance CCD image sensors with 800 x 800 pixel format have been successfully fabricated and operated on the basis of a three-level polysilicon gate technology. They are thinned to 8 microns over the entire 12.2 x 12.2 mm active area, and are used in the rear illumination mode. The light transfer characteristic has a gamma value of 1.000 + or - 0.002 over most of the dynamic range. Analysis of the noise behavior shows that the device SNR is shot-noise-limited over most of the dynamic range. Simple on-chip signal processing can be performed using an integration well to noiselessly collect signal charge from multiple pixels prior to reading out the charge. A UV-sensitive phosphor has been applied to the chip, yielding a device capable of imaging at wavelengths from the vacuum UV to the near IR.

A Color Television Camera Using a Single Interline Transfer Ccd Image Sensor With Color Filter Array

Abstract: A color television camera using a single interline transfer charge-coupled device (CCD) image sensor having 384(H) x 490(V) cells and a green dot checkerboard pattern color filter array was developed This paper describes a discussion on Bayer geometry as a color filter geometry and the facts that, using the present number of picture cells as a parameter, the Bayer geometry color filter array is clearly superior to the interline geometry color filter array (1) reported previously This color television camera has obtained satisfactory performance for home video tape recorder (VTR) use in regard to resolution, sensitivity and color rendition

Generator for video signal

Abstract: PURPOSE:To eliminate the picture distortion due to variance in the speed, by storing the video element information signal obtained at the location of lines orthogonal to the subscanning direction of two dimensional image sensor and obtaining the subscanning speed signal through the comparison with the signal after the read-in period of a given number, in a manual subscanning type read-in device CONSTITUTION:The optical image formed on a two dimensional image sensor IS is in photoelectric conversion and it is output as a video signal of m-bit per one line and n-lines The signal on specific lines among charges of each video element is read out with the pulse from a pulse generator PSG and stored in the 1st shift register SRa This signal is fed to an output terminal OUT as the video signal and stored in the 2nd shift register SRb simultaneously Further, the difference between the video information after a given number of read-in periods and the video element corresponding to a differentiating device DIC is obtained, the deviation of subscanning speed at a judging circuit JC is judged, and compensation is made by changing the read-in period

Range data entry techniques using a laser spot scanner and two linear solid-state image sensors

Abstract: A three-dimensional (3-D) range-finding technique, using a laser spot scanner and two linear solid-state image sensors is proposed. Both the solid-state nature of image sensors and the avoidance of correspondence problem make it possible to obtain the range data of 3-D objects with high accuracy.

A Proposed Novel Amorphous-Silicon Image Sensor

Abstract: A novel amorphous-silicon image sensor is proposed in this paper. The unit cell consists of an amorphous-silicon field-effect-transistor, an amorphous-silicon photo-conductor and an MOS capacitor. The fundamental properties of the unit cell are investigated and operation of a prototype integrated 8-bit linear array is described.

Image pickup device

Abstract: PURPOSE:To obtain an image pickup device, which has an excellent sensitivity and a superior spectral sensitivity characteristic and is manufactured easily, by fitting a solid image sensor, which is provided with an electron-impact inducing conductive effective layer and is used as a target, within an image tube producing an image electron current, reinforcing and accumulating the image electron current, and taking out the accumulated image electron current by means of the scanning function of the said solid image sensor. CONSTITUTION:An image tube 1 having a photoelectric screen 2 is fitted with a target 3 consisting of signal-charge accumulating diodes 18, EBIC layers 9 stacked over the diodes 18, signal-charge reading FETs 31, a vertical-signal-charge accumulation capacity 35, vertical signal lines 20a and the like. Signal charges reinforced by giving shocks to the EBIC layers 9 by accelerating an image electron current, which is produced from the photoelectric screen 2 by means of an input optical image, are accumulated in the diodes 18. Next, the FETs 31 and 33 are switched, in that order, by means of a vertical-scanning shift register 30 and a horizontal-scanning shift register 32 so as to make the signal of the position of an intersection to be obtained in an output terminal 26. In the same manner as above, output signals of time series are obtained by reading and scanning adjacent picture element, in order.