Showing papers on "Image sensor published in 1970"

Perceptual Findings with the Vision-Substitution System

Abstract: The initial evaluation of a system for converting an optical image into a tactile display is reported. A 400-tactor array has proved capable of providing blind and sighted subjects with useful information about the disposition of objects in three dimensions. External localization of percepts was greatly facilitated by giving observers control of the sensing and imaging device, a television camera. There has been a surprising similarity between the blind and sighted observers in their manner and speed of gaining facility with the system. The system's limitations thus far appear to be due more to the low resolution of the display than to the skin's shortcomings as a receptor surface.

A monolithic image sensor for a reading aid for the blind

Abstract: A compact optical-tactile reading aid that allows a blind person immediate access to virtually all printed reading material used by sighted people has been developed. A singular feature of this instrument is a silicon monolithic image-sensing array that serves as the "retina" of the reading aid: signals from the retina are used to control an array of piezoelectric stimulators that form tactile images of printed characters. The image sensor consists of a 24×6 matrix of bipolar phototransistors integrated on a chip approximately 3×5 mm in size, and is designed on the basis of electrical, optical, psychological, and psychophysical considerations. The column-isolated structure incorporates a 2 to 1 aspect ratio to provide sufficient resolution and field of view for unambiguous letter-by-letter detection using a minimum number of sensor elements. A one-dimensional scanning technique minimizes fixed pattern noise and reduces the complexity of the total system. The individual 150×300 µm photosensing elements are optimized for maximum responsivity, uniformity, and dynamic range. The doping profile, featuring a 2 µm base depth and 12 µm epitaxial thickness, is based on spectral response and on a detailed electrical analysis of array operation. Output nonuniformity is minimized, and electrical crosstalk is virtually eliminated by designing for h FE ≥ 200 and C TC /C TE ≥ 5. Array performance correlates well with the predicted characteristics and has led to improved reading speeds greater than 50 words per minute.

Signal transfer system for panel type image sensor

Abstract: The image information producing photosensitive elements of the sensor, which are arranged in rows and columns, are addressed row-by-row and column group-by-column group to decode the information. The signal information from a group of elements in a row is impressed simultaneously upon a like group of signal processing circuits, with each of which is associated a pair of signal storage devices, each having an input gate and an output gate. The input gates for one set of corresponding storage devices are concurrently operated to impress a group of signals simultaneously upon these storage devices during a given time period while the output gates for the other set of corresponding storage devices are operated sequentially to transfer the signals stored in the other set of storage devices to the output circuit. The operation of the input and output gates is reversed in the succeeding time period and this alternating operation continues until the information from all of the sensor elements is transferred to the output circuit.

A self-scanned image sensor employing MOS structure

Abstract: Studies were carried out on a self-scanned image sensor comprising a linear integrated-circuit array of photodiodes and metal-oxide-semiconductor (MOS) transistors. It was found that the maximum scanning rate is about 2.5×105bits/s, and that the value is mainly restricted by the photo-induced current and the junction capacitance of the photodiode.

Self-scanned image sensors based upon bucket-brigade scanning

Abstract: Image sensors employing the charge-transfer principles of the bucket-brigade delay line for internal scanning offer potential advantages over the usual x-y addressed sensors in simplicity of fabrication. A design for a self-scanned bucket-brigade sensor that can be fabricated upon a monolithic silicon wafer with a single diffusion and one layer of metallization is proposed. An experimental array has been built comprising 15 rows of 32 series-connected MOS transistors whose sources and drains serve as photodiodes. These transistors are interconnected to adjacent horizontal buses so that each row can function independently as a shift register. In operation, each register remains inactive for a period of time during which an image charge pattern is built up on the photodiodes. The application of the horizontal clock pulses to that row causes the charge pattern to be transferred stepwise to the edge of the array where it is converted into a video signal. Although in the test sample the gating of the horizontal clock pulses to successive rows was accomplished by means of an external vertical scan generator, this could be replaced by an integrated vertical register formed on the same chip with the sensor.

Sensor Performance and the Vehicle

Abstract: : In this tutorial paper, remote imaging sensors such as airborne photography, infrared scanners, electro-optical sensors, television, and radar are discussed in terms of how their performance is affected by the aerospace vehicle in which they are carried. Imaging sensor performance is discussed in terms of such criteria as resolution, contrast rendition, dynamic range, signal- to-noise ratio, sensitivity, geometric fidelity, general appearance of results, reliability, and data usefulness. How the aerospace vehicle, carrying the sensor, affects the above criteria is discussed in terms of vehicle altitude (or distance from target), temperature at the sensor, moisture at the sensor, induced and natural air turbulence around the vehicle, sensor window, and the various motions of the vehicle.

Germanium imaging sensor

Abstract: The development and evaluation of a germanium imaging sensor is described. The sensor, comprised of an electron-beam-scanned photodiode array, was designed for air-glow operation. Surface- barrier photodiode arrays were developed for optimized imaging, and their processing provided a powerful technique for preserving the characteristic properties of high-resistivity germanium by limiting the maximum processing temperature to 540/spl deg/C. Photodiode-array processing was developed to a high degree of sophistication, but for satisfactory imaging using airglow illumination, additional development is required to improve the electron-beam characteristics of the tube, array cooling, and video amplifier. The best sensor had a quantum efficiency of /spl ges/67.4 percent at 1.55 /spl mu/m and 90/spl deg/K for an absolute sensitivity of 0.84 A/W.