Digital Processing Technology Research Articles

A new direction in space

From the very beginning of the Space Age, a fundamental issue has been whether space exploration should be conducted by manned missions or by unmanned missions. In a so-called unmanned mission, only inanimate systems are transported into space. In a manned mission, human beings are on board the spacecraft. A third option may now be available: an unmanned mission providing virtually the same subjective and objective effect as a manned mission, but with the much lower cost of an unmanned mission. The ongoing revolution in digital processing technology may now make it possible to develop the means for a human to be effectively there, without going there, over interplanetary distances. Unlike conventional robotic rover missions, this third option would be, both subjectively and objectively, virtually equivalent to a manned mission. The new (third) option for manned equivalent space exploration is based upon semi-autonomous control technology. Investment in this technology is likely to pay off with critically important industrial applications on Earth in the coming decades, no matter what may happen in space. Manned equivalent space exploration by this new approach will be much less expensive. and much more likely to prosper and to produce knowledge and commercial opportunities in space.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Direct on-line imaging and quantification of 8-12 bit digital image information for microscopy

In microscopy a digital pixel-accurate intensity processing (PAIP) technology for differential contrast enhancement became available for precise extraction and display of image information. Utilizing PC-based massively parallel processing at 1,600 million instructions per second (MIPS), the PAIP image enhancement can be performed on/off-line in near-real-time for objective image evaluation of 8-12 bit data.We used a PC-based workstation (PiXision PiX4: Visionary Systems Inc., New Haven, CT) on-line in combination with a JSM-890 FSEM (JEOL, Peabody, MA) as well as off-line with imported digital micrograph data and analyzed digital image contrast characteristics. The system provided automated intensity processing of any data independent of image content, size and depth. The images were first smoothed through averaging within a defined significant intensity range (IRs). Each pixel was provided with a variable automatically adjusting local averaging mask, generating a processing characteristic of non-linear point processing. Then, since the spacial processing was pixel-accurate (no spacial distortions of maintained intensity structures), all the contrast information eliminated by the smoothing could be recovered through subtraction of the smoothed from the original or previously smoothed data, followed by linear scaling to 8 bit.

The advantages of digital signal processors in PCN

Digital signal processors (DSPs) play a major role in personal communications networks (PCNs). The benefits of making DSPs the ideal processing element for digital PCN systems are considered. DSPs affect not only the new digital networks but also analog systems. This results from the advantages of digital integrated circuit process technology, of manipulating signals in the digital domain, and of programmable solutions over hard-wired solutions. These advantages are discussed, along with examples. >

A new concept of DATA/DAT system

Presents the DATA/DAT system, which is based on the high-density recording and reproducing technology and digital processing technology of the DAT (digital audio tape recorder) system. This system has various applications, such as replacement of the conventional magnetic tape and data streamer and data storage for image processing. To achieve data reliability, an adaptive decoding algorithm using C1, C2 decoding has been developed. As a result, even at an error rate of 10/sup -2/ after 5000 operations, an uncorrectable error probability of 10/sup -15/ has been attained. To implement the random access and update-in-place function, a group format using gap frames and after-recording technology has been developed. The system can be applied to home electronics and personal databases.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Minicomputer interface for magneto-optic spatial light modulator

Digital optical data storage and processing are rapidly increasing in technological importance. The magneto-optic spatial light modulator (MOSLM) is a relatively low-cost, small pixel optical parallel input device that is capable of binary amplitude or binary phase modulation of each pixel. Thus, it is well matched to digital optical coherent storage and processing technology. However, potential problems associated with its use include: lack of a design for a general minicomputer interface, lack of interactive data-page file generation software, lack of ability to switch single pixels in some cases, lack of remote-from-computer operation capability, spurious pixel switching, and catastrophic failure due to thermal effects. The hardware and software components of a versatile minicomputer interface that has been successful in overcoming all of these problems are described. This interface allows easy data entry of entire data pages or single pixels and minimizes cross talk and noise developed over long cable lengths. In tests, the designed interface has produced highly stable operating characteristics.

Advanced Seismic Techniques For Delineation of Petroleum Reservoirs

Introduction Seismic inversion yields synthetic sonic logs from seismic reflection data recorded at ground surface. Synthetic sonic logs are similar to, and have most of the properties of, long source-receiver borehole sonic logs. They provide a new area/or application of seismic digital process technology. The synthetics have been found to be particularly useful for the delineation of petroleum reservoirs, including the extent, thickness and porosity of the reservoir rocks. In a typical survey, field data, obtained from seismic line profiles across reservoirs, yield a sequence of synthetic sonic logs. Continuous vertical cross sections which display colour-coded transit time units can be interpreted in terms of lithology and porosity within the limits of interpretation of the single sonic curve and the resolution of the method. Sonic velocity changes are related to porosity and, by establishing the velocity of the matrix rock, the porosity within it can be estimated from synthetic sonic logs. Applications include optimizing development drilling patterns to obtain maximum production, the design of secondary recovery programs, the positioning of injection wells and the location of offshore drilling platforms to ensure maximum recovery. Introduction Delineation and definition of a known new petroleum reservoir is generally the responsibility of the production engineer or geologist, who must rely on a few well logs to make his determination. The advantages of the superb vertical resolution of the logs are offset by poor horizontal sampling; well logs can be obtained only by first drilling expensive boreholes, which are therefore usually spaced at rather wide intervals. The field was probably discovered with the reflection seismograph, which provides excellent horizontal sampling, but poor vertical resolution. Also, the conventional seismograph merely maps stratigraphic boundaries and pro- vides little or no confirmation about the actual rock units. Hence, it is of little help in determining reservoir properties. As a result, the development, geologist prefers to rely on samples and well logs, as they yield the desired degree of resolution and type of information. At the borehole location, both well logs and seismic traces sample the same geological column. In fact, a seismic reflection trace is merely a transform of the sonic and density information on borehole logs. For years, geophysicists have computed synthetic seismograms from sonic and density logs. A well constructed synthetic seismogram will match a field-recorded seismogram very closely, and aids in correlating seismograph information to borehole geology at the tie point. The reverse process, of computing a synthetic sonic log from a seismic trace, is also theoretically possible, but it has not worked well in the past, because of a difference "in quality of source signals. A sonic log is a relatively pure signal, recorded directly from the rock at the level of investigation. A seismic reflection signal, generated at the ground surface, must travel down through the· earth to the level of investigation and back again. In transit, it is often contaminated by external noise, distorted by wave pro" pagation phenomena, and part of it may be lost or attenuated in the transmission.

Synthetic Sonic Logs for Delineation of Petroleum Reservoirs: ABSTRACT

A recent development in digital process technology yields synthetic sonic logs from seismic reflection data recorded at the ground surface. Synthetic sonic logs are similar to, and have most of the properties of, long source-receiver borehole sonic logs. The synthetics have been found to be particularly useful for the delineation of petroleum reservoirs, including the extent, thickness, and porosity of the reservoir rocks. In a typical survey, field data, obtained from seismic line profiles across reservoirs, yield a sequence of synthetic sonic logs. Continuous vertical cross sections which display color-coded transit time units can be interpreted in terms of lithology, porosity, and related subsurface information, within the limits of interpretation of the single sonic curve and the resolution of the method. Applications include the optimization of development drilling patterns to obtain maximum production, the design of secondary recovery programs and the positioning of injection wells, and the location of offshore drilling platforms to ensure maximum recovery. End_of_Article - Last_Page 949------------

Simulation of dynamic environments for design verification

Surveys on verification techniques are updated in this report to include recent applications in nuclear facilities that use transient methods for dynamic excitation. Also covered are brief discussions of the theoretical considerations underlying this testing approach, as well as requirements for correlation of experimentally and analytically derived data. Within the context of the experimental approach, the application of the rapidly changing technology of digital signal capture and data processing portends shorter test times, lowered costs, and more comprehensive measurements and environmental simulations. The experimental data encompass the use of structural transfer functions. This type of data may be used to extract mode shapes, modal frequencies, and damping, and can also be used directly to calculate structural system response motions to a variety of dynamic forcing functions. Force pulse generators provide large input forces over short time periods for in-place testing of very large structures and massive equipments. The pulse generators are applied in two different ways. In one they are used to excite structures for measurement of transfer functions; in another, now being developed, multiple pulse generators are attached to large structures to create a response that will closely match that predicted for the structure when subjected to an earthquake or other dynamic loads. The discussions culminate in a projection of the design and development work that will be required to meet future needs in structural response of nuclear reactors to dynamic loads. It is envisioned that the technical community will be required to focus attention on nonlinear behavior with special emphasis on how structures can be tested to yield their structural response characteristics.

Speech and digital processing activities in Japan

Reports on the deployment and use of speech equipment and digital processing technologies in Japan.

Adaptive Delta Modulation for Companded PCM Coding and Decoding

An adaptive delta modulator and demodulator are used as the first and last stages in a system for coding and decoding telephone signals into μ = 255 companded pulse code modulation (PCM). The system objectives are to devise an economic coder and decoder that is reliable, free of potentiometer adjustments, and convenient for automated manufacturing for large quantity production. The strategy is a shift of circuit emphasis from analog to digital in order to take full advantage of low-cost, low-speed digital processing technology such as MOS/LSI to achieve the desired objectives. The system structure, digital signal processing, system implementation, and performance of the prototype are discussed in this paper.

Digital DPCM Codec for TV Signals Based on&amp;lt;tex&amp;gt;DeltaM/DPCM&amp;lt;/tex&amp;gt;Digital Conversions

A digital differential pulse-code modulation (DPCM) codec based on ΔM/DPCM and DPCM/ΔM digital conversions is presented as an equivalent replacement of a conventional DPCM codec for TV signals by using digital processing technology. A generalized model and equivalent circuit are shown for the digital DPCM codec, and transfer characteristics and quantizing noises are analyzed. The digital DPCM codec is designed for 1-MHz TV signals and the performance is verified by experiments. By the use of double integration ΔM and digital filter technology, it is shown that at the ΔM sampling rate of 16 MHz the overall SNR performance is sufficiently good for use as a conventional DPCM codec, and the digital code converters can be realized with commercially available transistor-transistor-logic (TTL) medium-scale-integrated (MSI) circuits and low-power emitter-coupled-logic (ECL) integrated circuits (IC's).

Digital DPCM codec for TV signals based on&amp;lt;tex&amp;gt;Delta&amp;lt;/tex&amp;gt;M/DPCM digital conversions

A digital differential pulse-code modulation (DPCM) codec based on AM/DPCM and DPCM/AM digital conversions is presented as an equivalent replacement of a conventional DPCM codec for TV signals by using digital processing technology. A generalized model and equivalent circuit are shown for the digital DPCM codec, and transfer characteristics and quantizing noises are analyzed. The digital DPCM codec is designed for I-MHz TV signals and the performance is verified by experiments. By the use of double integration AM and digital filter technology, it is shown that at the AM sampling rate of 16 MHz the overall SNR performance is sufficiently good for use as a conventional DPCM codec, and the digital code converters can be realized with commercially available transistor-transistor-logic (TTL) medium-scale-integrated (MSI) circuits and low-power emitter-coupled-logic (ECL) integrated circuits (IC's).