Showing papers on "Image sensor published in 1973"

Sensors having charge transfer recycling means

Abstract: A sensor including an image sensor array having sensing elements arranged in rows and columns and vertical charge transfer registers integral to the array, said registers having input nodes equal in number to said elements Signals from the sensing element are transferred in parallel each to a different one of the nodes The sensor includes means for transferring the signal from each node and for recycling the signal from a given node back to said given node to permit addition or subtraction with a successive bit of information, within the sensor array The readout and recycling means may be used to remove spurious background signals from the output signal, for moving target detection or for the non-destructive read-out of stored images

A charge-coupled area image sensor and frame store

Abstract: A two-dimensional three-phase charge-coupled array with 128 × 106 elements, that can serve either as a solid-state image sensor or as an analog serial memory, has been built. As an image sensor the device has been operated successfully in the frame transfer mode to yield 120 frames/s with 64 × 106 resolution elements. By using the whole array as an image sensor, pictures with 128 × 106 resolution elements have been obtained at 15 frames/s with tolerable smearing. In the memory mode the device can store a whole analog frame as produced by a companion device, or 13 568 bits of digital information. But for the latter application defect-free devices are mandatory. The design of the device, the various modes of operation, the quality of the results, some typical defects, and some further applications are discussed.

The Aliasing Problems in Two-Dimensional Sampled Imagery

Abstract: Most electrooptical imaging devices involve sampling at both the camera and display. The electron beam scanning of television and the optical-mechanical scanning of infrared imaging devices are examples of one-dimensional sampling in the imaging sensor. The excitation of cathode ray tube phosphors by a scanned electron beam is an example of sampling in the displayed image. We are all familiar with the pictures produced by imaging devices with one-dimensional sampling but less familiar with pictures produced by electrooptical devices sampling in two dimensions. Recently two-dimensional arrays of photoconductive or photovoltaic detectors have been used to sense a scene, and two-dimensional arrays of photoemitting diodes, etc. have been used to display imagery.

Automatic focus control for facsimile cameras

Abstract: A movable stage contains two photodetectors for focusing, as well as an imaging sensor The imaging sensor produces the video data in the fashion standard to facsimile cameras The two photodetectors are placed with one closer to the lens of the facsimile camera than the imaging sensor and with the other farther away The movable stage is coupled to a linear motor which is driven from an error signal generated by the electronics The electronics consists of balanced ac amplifiers, two square law function generators, and a differential amplifier and power drive In order to insure that the electrical signals at the output of the two photodetectors and the imaging sensor are in phase, electrical delays are connected to the outputs of the two photodetectors The invention also includes means for maintaining the imaging sensor at the expected location of the focal plane as the facsimile camera scans a scene or terrain In a second embodiment of the invention, a 3-faced mirror is used to insure that all three of the detectors are detecting the same picture elements simultaneously thereby eliminating the need for the two electrical dalays at the outputs of the two photoconductors

Influence of the charge pumping effect on an integrated solid-state image sensor using MOST switches

Abstract: The charge pumping in image sensors with MOST switches is simulated experimentally and discussed. It is found that photodiode potential is changed with no illumination, that photoelectric characteristics are degraded, and that a storage mode operation cannot be achieved. A desirable treatment available to diminish this effect is proposed.

A transparent-electrode CCD image sensor

Abstract: Results of an investigation of the performance of a transparent polycrystalline silicon electrode CCD image sensor will be presented, citing the fundamental limits of the charge transfer efficiency of the sensors imposed by slow and fast surface states, and carrier drift and diffusion at low, medium and high transfer efficiencies.

The design and operation of charge-coupled image sensors

Abstract: A 45 × 60 element charge-coupled sensor incorporating an on-chip output amplifier and special signal-processing electrodes has been evaluated. Video recycling and optional summing of adjacent elements make possible useful new modes of operation.

A 24x6 interlaced-scan MOS image sensor

Abstract: A new 24/spl times/6 self-scanned MOS image sensor has been developed for the Optacon reading aid for the blind. This new image sensor has a unique circuit design that provides in a simple manner interlaced row scanning and low-light level detection. While a previous investigation (1969) showed that self-scanned MOS image sensors are capable of operating with illumination levels of 1 /spl mu/W/cm/SUP 2/, this report presents a working circuit to simply realize this performance in a device compatible with a reading aid application. The previous investigation also did not consider the noise at high-scanning frequencies (175 kHz) associated with package interconnection capacitances. This new circuit attempts to minimize this previously neglected switching noise.

An all-bipolar image sensor

Abstract: In this paper a monolithic image sensor consisting of a 16×16 phototransistor matrix and two scanners is described. For the extraction of the video signal a method is chosen which minimizes crosstalk. The scanners are designed to work at high frequencies (40 MHz) with low power consumption (40 mW). The power consumption of the scanners is independent of the number of stages.

Charge Coupled Devices - Phase I.

Abstract: : The discovery of the principle of charge coupling has completely revolutionized the field of solid state image sensors and promises for the first time the possibility of an all-solid-state, self-scanned, low-light-level, nonblooming imager. The objective of this 6-month contract was to design, build, and evaluate such a device using a surface channel technology. This report contains data and detailed information on all phases of this investigation. The design and performance, both electrical and optical, of 500 x 1 three-phase line scanners and 128 x 160 three-phase area arrays are discussed. Typical pictures taken with these devices are shown. The design and fabrication of a 100 x 100 two-phase area array is discussed. Other major topics include: experimental demonstration of various antiblooming CCD structures, experimental measurement of statistical CCD noise sources, analysis of the sensitivity and resolution of CCI's at low-light levels, experimental measurements involving the use of a CCI as an analog memory in frame-to-frame cancellation techniques, and a discussion of analog signal-processing applications of CCD's. (Author)

The use of a priori knowledge in image processing

Abstract: The processing of images on a digital computer is usually done for the purpose of extracting information from an image which the unaided human visual system cannot extract by itself. In nearly all image processing procedures a large amount of a priori knowledge related to the image must be utilized in order to extract the desired information. By a priori knowledge we mean knowledge about the image obtained from sources other than the image itself. This knowledge might include information about the object, the transmission media, the optical system, the sensor, the scanning and digitizing equipment, and the processing technique. Often a part of the a priori knowledge is contained in the mind of the observer as a result of accumulated experience.

Evaluation of ERTS-1 image sensor spatial resolution in photographic form. [microdensitometer correction of MSS data

Abstract: The author has identified the following significant results. The digital Optical Transfer Function (OTF) measurements showed the following: (1) there are no significant differences in optical performance, in terms of OTF, among all four bands of the multispectral scanner, (2) no substantial changes in the OTF's of bands 4, 5, and 6 during the period November 1972 to May 1973, and (3) comparison between the photographic and digital (CCT) two-dimensional OTF's indicated a strong asymmetry in the photographic product OTF between the MSS scan direction and across scan direction. The coherent light Fourier analysis program showed the following: (1) for agricultural areas, bands 5 and 7 of the MSS are superior in terms of image definition, and therefore mapping and acreage estimation, (2) amplitude modulation in imagery from MSS bands 4 and 5 is between 65 to 90 percent of that in corresponding bands of Apollo 9 imagery (SO65), and (3) MSS band 5 imagery has a ground resolution between 55 to 75 percent of that exhibited in the corresponding band of Apollo 9 imagery (SO65).

EOS mapping accuracy study

Abstract: Studies were performed to evaluate various image positioning methods for possible use in the earth observatory satellite (EOS) program and other earth resource imaging satellite programs. The primary goal is the generation of geometrically corrected and registered images, positioned with respect to the earth's surface. The EOS sensors which were considered were the thematic mapper, the return beam vidicon camera, and the high resolution pointable imager. The image positioning methods evaluated consisted of various combinations of satellite data and ground control points. It was concluded that EOS attitude control system design must be considered as a part of the image positioning problem for EOS, along with image sensor design and ground image processing system design. Study results show that, with suitable efficiency for ground control point selection and matching activities during data processing, extensive reliance should be placed on use of ground control points for positioning the images obtained from EOS and similar programs.

Evaluation of ERTS-1 image sensor spatial resolution in photographic form. [microdensitometer and radiometer calibration]

Abstract: The technique most widely used for detailed image evaluation of aerial and space photography has been edge analysis. Edges have been used because they appear more frequently in aerial scenes than do other simple objects such as points or lines. Methods for measurement and analysis of edges have been investigated extensively. One fundamental limitation of analysis employing naturally occurring edges is that the object must be assumed perfect; i.e., the edge appearing in the scene is assumed to be exactly a step function, uniform on both sides and with a perfect discontinuity at the edge. This is certainly not true of natural edges such as coast lines, field boundaries, etc., and it is not generally true of randomly occurring man-made edges, for example building roofs, pavement boundaries, etc. Even if there is a perfect edge object in the scene, its position and orientation are unique, and hence the analysis is limited. In addition, for sensors with low ground resolution, such as those on the Earth Resources Technology Satellite (ERTS), the size requirements on man-made edges are prohibitive. For these reasons we have investigated a technique that is largely independent of object scene. The approach is particularly applicable to evaluation of earth-orbiting multispectral sensors. In all programs employing such sensors, simultaneous underflight photography from aircraft is made during passes of the spacecraft. To evaluate the spacecraft imagery, the two sets of photographs are scanned and digitized with a microdensitometer, the same ground area being scanned in each case. The data are then Fourier analyzed, and the spatial frequency spectra is calculated. The spatial frequencies in the underflight 6 Ctrace are scaled to those in the spacecraft trace (by the ratio of altitudes if the two systems are of equal focal length), and the ratio of the spectra gives the in-flight OTF,T(f), for the orbiting sensor, T(f) = I(f)/0(f) In detail we must calibrate the spectroradiometric and distortion characteristics of the underflight sensor in the region of the image field that was scanned with the microdensitometer. Furthermore, the transfer function of this system must be known for the same region. However, because of the scale change for comparison of the images, we are interested only in very low spatial frequencies in the underflight image, thus relaxing the requirement on exact knowledge of the underflight sensor OTF. The method has been applied to an Apollo 9 (S065 experiment) frame, and the sensor OTF has been calculated. Image quality was also compared, using the same method, in second and fourth generation copies of the original film. The results are good enough to encourage use of the technique and to indicate the accuracies required of the various measurements involved in determining in-flight sensor OTF by this method. Results of investigations in progress will be presented. A technique for determining correct scan registration and scaling between the two sets of imagery will be dissussed and a promising approach to noise reduction, in the form of weighted averaging of OTF's from several scans, will be described.

Solid-State Photomultipliers

Abstract: The vacuum photomultiplier has had a dramatic impact on the field of sensors owing to its ability to detect single photons. The vacuum photomultiplier, however, is a single-picture-element device. The same principle of multiplication has been extended to large-area image sensors by the several forms of image multipliers discussed in Chapter 6. These image multipliers are beginning to service a wide range of applications where the supply of photons is limited.