Showing papers on "Data acquisition published in 1993"

Model-based object recognition in dense-range images—a review

Abstract: The goal in computer vision systems is to analyze data collected from the environment and derive an interpretation to complete a specified task. Vision system tasks may be divided into data acquisition, low-level processing, representation, model construction, and matching subtasks. This paper presents a comprehensive survey of model-based vision systems using dense-range images. A comprehensive survey of the recent publications in each subtask pertaining to dense-range image object recognition is presented.

Fast imaging using subencoding data sets from multiple detectors

Abstract: A new fast imaging method using a subencoding data acquisition scheme and a multiple coil receiver system is proposed and demonstrated. In this method, a set of aliased images are produced from receiver coils by using the subencoded data without sacrificing the desired resolution, and resolved to an aliasing-free image by using the distance-dependent sensitivity information of each coil. The reduction rate of data acquisition time is proportional to the number of receiver coils. This method can be easily adapted to conventional imaging methods including fast imaging to further reduce the scan time.

Biomedical Digital Signal Processing: C Language Examples and Laboratory Experiments for the IBM PC

Abstract: Introduction to computers in medicine electrocardiography signal conversion basics of digital filtering finite impulse response filters infinite impulse response filters integers filters adaptive filters signal averaging data reduction techniques other time and frequency domain techniques QRS filters ECG monitoring systems VLSI in digital signal processing configuring the PC for UW digiscope data acquisition and control routines data acquisition and control - some hints UW digiscope user's manual signal generation finite length register effects commercial DSP systems.

Imaging time reduction through multiple receiver coil data acquisition and image reconstruction

Abstract: A technique is described for the simultaneous acquisition of MRI data using two independent receiver coils surrounding the same region of tissue, which enables the collection of data necessary for image reconstruction in a reduced number of phase-encoded acquisitions This results in a 50% reduction in minimum scan time and may be useful in time-critical procedures The algorithm and imaging procedures are described, and example images are shown that illustrate the reconstruction Signal to noise is decreased by the square root of the time savings, making this technique applicable to cases in which the need to decrease minimum scan time outweighs the signal to noise penalty

The Fundamentals of FFT-Based Signal Analysis and Measurement in LabVIEW and LabWindows

Abstract: The Fast Fourier Transform (FFT) and the power spectrum in LabVIEW® and LabWindows® are powerful tools for analyzing and measuring signals from plug-in data acquisition (DAQ) boards. For example, you can effectively acquire time-domain signals, measure the frequency content, and convert the results to real-world units and displays as shown on traditional bench-top spectrum and network analyzers. By using plug-in DAQ boards, you can build a lower cost measurement system as well as avoid the communication overhead of working with a stand-alone instrument. Plus, you have the flexibility of configuring your measurement processing to meet your needs.

Substation load distribution monitor system

Abstract: The monitoring and control system of the present invention provides a distributed intelligence, data acquisition and control system which collects and analyzes large amounts of data representing power usage from a power distribution substation. Using a Discrete Fourier Transform, the system provides accurate tracking of the primary frequency of the voltage and current waveforms in the power equipment, and determines the relative phase between the voltage and current waveforms. The system provides real time monitoring of power usage and real time control of various functions in the substation.

The application of satellite time references to HVDC fault location

Abstract: An HVDC fault location scheme is described. It relies on very precise detection of the time of arrival of fault-created surges at both ends of the line. Such detection is achieved by a very accurate data acquisition and processing system combined with the time reference signals provided by a Global Positioning System receiver. Extensive digital simulation is carried out to determine the voltage and current waveforms, to identify the main sources of error, and to suggest possible compensation techniques. >

Airborne multiband imaging spectrometer

Abstract: A multichannel imaging spectrometer for airborne geological, geophysical and environmental surveys in a moving vehicle An optical scanner (123) employs a rotating polygon (20) allowing reduced scan optics with increased data acquisition efficiency Multiple spectrometers (122) integrally registered allow channelization of the received signal to optimize noise performance in the range from ultraviolet through infrared Output data is in a form for recording and real time display A staring mode configuration provides enhanced sensitivity by using a two-dimensional detector array (320, 330) and adjustable mirror orientation A scanning mode embodiment employs a two-dimensional detector array with time delay integration and three-dimensional storage of temporal spatial data and spectral wavelength and intensity Thus, all channels are acquired simultaneously, resulting in perfect band-to-band registration with continuous spectral curves over the field of view

Pressure data acquisition device for a patient monitoring system

Abstract: A data acquisition device is disclosed for use in a patient monitoring system which includes a display device. The system also includes a pressure transducer which produces patient blood pressure signals. The data acquisition device includes terminals for receiving signals representing blood pressure from the pressure transducer. Circuitry in the data acquisition device, including multiplexers and a digital to analog converter conditions the signals representing blood pressure. The pressure transducer and the circuitry are collocated. The device also includes circuit paths for electrically coupling the pressure transducer and the conditioning circuitry. The conditioning circuitry is selectably coupled to the display to provide the conditioned signals to the display. The data acquisition device may be positioned independently of the display device.

High speed data acquisition system and method

Abstract: A high speed data acquisition system which acquires an analog signal, converts it to digital data, and compresses the large volume of accumulated data into a format that can be handled in a microcomputer environment. The data acquisition system of the present invention can rapidly and continuously acquire and process large volumes of data. Included is an averaging circuit which allows the present invention to efficiently process and store large amounts of data uninterruptedly. The present invention is thus well suited for applications that require uninterrupted high-speed sampling over long periods of time.

Seismic transmission method and system using concentration units

Abstract: Seismic data acquisition devices (BA) distributed in an exploration zone are divided into n groups (GA1 to GAn) and, therein, into sub-groups having each a specific frequency for communicating with a concentration unit (Ck) which is connected to a central station (1) through Hertzian channels or cables or optical fibers. Acquisition devices in the various subgroups communicate simultaneously with the corresponding concentration unit (Ck) during predetermined emission windows. The concentration unit collects the signals received from the acquisition devices to transmit them in series to station (1). The acquisition devices are adapted for delaying their own emission window according to the rank which has been previously assigned thereto within the respective subgroups thereof.

ARIES—a system for concurrent physical, biological and chemical sampling at sea

Abstract: A multi-function sampling device is described that provides high resolution concurrent sampling of physical, chemical and biological parameters throughout the water column from a moving ship. The device is modular, being composed of a water sampling unit, a plankton sampling unit and an oceanographic sensor unit, each of which can stand alone or be used in combination with the others. System management, data acquisition and storage are controlled by microprocessor units, with programming and integration from a personal computer. Specimen data collected with the system are presented.

A simple data loss model for positron camera systems

Abstract: A simple model to describe data losses in PET cameras is presented. The model is not intended to be used primarily for dead time corrections in existing scanners, even if this may be possible. Instead the model is intended to be used for data simulations in order to determine the figures of merits of future camera systems based on data handling state-of-art solutions. The model assumes the data loss to be factorized into two components, one describing the detector or block-detector performance and the other the remaining data handling such as coincidence determinations, data transfer and data storage. Two modern positron camera systems have been investigated in terms of this model. These are the new Siemens-CTI systems, Ecat Exact and Ecat Exact HR, both with an axial field-of-view (FOV) covering around 15 cm. They both have retractable septa and can acquire data from the whole volume within the FOV and can reconstruct volume image data. An example is given how to use the model for live time calculations in a futuristic large axial FOV cylindrical system. >

The SIMON project: model-based signal acquisition, analysis, and interpretation in intelligent patient monitoring

Abstract: The authors describe SIMON (signal interpretation and monitoring), an approach which combines static domain-specific information, which relates variables and alarm events, with dynamic information provided by a model. It is currently being tested for the monitoring of neonates in the intensive care unit. The model component is responsible for estimating the state of the monitored system, predicting the evolution of the system's variables and parameters, and establishing a monitoring contest. This information is then used by the DA (data abstraction) and the data acquisition modules to plan a monitoring strategy to filter, rank, and abstract incoming data. Faults and artifact models included in the DA permit the low-level detection of noise-contaminated episodes. The adaptation of the monitoring strategy to these changes in the environment effectively shields the model from untrustworthy information and thus increases the reliability and robustness of the system. The scheduling mechanism included in the DA permits a continuous evaluation of the system load as well as an ability to process all its tasks. >

A VAX and PC-based data acquisition system for MCA, scanning and list-mode analysis

Abstract: The design of the data acquisition system for the National Accelerator Centre's nuclear microprobe is described. The system consists of an intelligent PC scanner and imaging terminal, interfaced to a VAX-11/750 running a general purpose data acquisition package XSYS. In this way, the user friendliness of a dedicated, intelligent scanner has been combined with the flexibility of a general purpose data acquisition package. It is illustrated how simple tasks such as beam focussing, area of interest localization, and quantitative single spot PIXE or RBS analysis can be performed with minimal complexity, whereas requirements of a more complex nature can be implemented routinely using the general purpose acquisition package with standard command files. Even unique studies can be performed by means of minor software modifications.

Beam transformation techinques for ultrasonic medical imaging

Abstract: Data acquisition rates in pulsed ultrasound scanners are limited by the speed of sound in the human body. This poses severe limitations to the design of future ultrasound equipment, such as 3-D imaging scanners. The authors describe a technique for higher data acquisition rates based on the simultaneous transmission of multiple beams. By using a linear combination of the received beams, interbeam interference due to the sidelobe energy of the transmitting beams can be significantly reduced. The transformation coefficients are found by using a least squares minimization criterion. A simulation environment used for the evaluation of the authors' methodologies and various simulation results are presented. >

Software methods for system address tracing

Abstract: This paper discusses the use of software methods to collect system trace for DEC Ultrix and 3.0 Mach on a DECstation 5000/200. We assert that software methods are a valuable tool for collecting system trace and understanding operating system and memory system behavior for modern workstation workloads. Software methods have some well documented shortcomings. We discuss how their impact was minimized in our system. We further support the validity of the software approach by comparing behavior predicted by our tracing/simulation system to measurements made with less intrusive methods. >

Portable multiband imaging spectrometer

Abstract: A light-weight, portable spectroradiometer provides a real-time data acquisition capability from 0.3 νm to 3.0 νm with selectable integration periods, and operates through a Centronics parallel port of a personal computer to program the spectrometer, store data, and to provide real time graphic output. Equipped with two spectrometers operating from a common optical input, high detector efficiency is obtained by structuring the detector elements for maximum energy gathering capability, matched to slit aperture size and orientation. No filters or mechanically driven mirrors are required, thereby permitting a compact, easily portable instrument. If desired, the detector array is readily adaptable to thermoelectric cooling.

Bioenergy assessing method and system for diagnosing and providing therapy

Abstract: A system and method are provided for diagnosing, therapy, and/or prevention of a plurality of diseases. The method is based on an assessment of data, reflecting the level of inner bioenergy produced by a human body. The system performs a multichannel data acquisition, processes the data, generates a diagnosis, and provides a prescription for the therapy. The system exists in several embodiments and generally includes a set of diagnostic and therapy electrodes, an input demultiplexer, analog-to-digital converter, output demultiplexer, a computer, power and control units, and a portable data acquisition unit.

Method and apparatus for determining mis-registration

Abstract: An image processing apparatus includes a data acquisition stage for acquiring data representative of several spatially separated regions of a sample. The apparatus also includes data storage means for storing reference data corresponding to the sample data. The two sets of data are compiled and analyzed to determine if the sample is shifted from a nominal position.

A data acquisition system for flat-panel imaging arrays

Abstract: An electronic data acquisition system for pixelated, two-dimensional, amorphous silicon x-ray imaging arrays has been developed. The system was designed in a modular fashion with digital control provided by field-programmable logic devices. This approach allows sections of the design to be upgraded with little impact an other aspects of the system. Good analog noise performance was obtained by matching the preamplifier design to the characteristics of the array outputs. The design of this system is presented and its performance quantified. >

Simultaneous vibroseis recording1

Abstract: An experiment was undertaken at BP's Fulbeck Geophysical test site to compare the viability of various simultaneous vibroseis recording techniques, which are often recommended as a means of improving data acquisition production rates for 3D seismic surveys. Of particular interest were: (a) the ability to separate the signals from each source during processing, (b) the generation and suppression of harmonics and (c) the effects of any source interaction. Two vibrators were deployed with a baseplate separation of 10 m, about a borehole containing a vertical array of geophones. Our analysis concentrated on the groundforce signals measured at each vibrator and the far-field signatures measured using a vertical geo-phone at a depth of 204 m. By comparing single vibrator records with similar but separated records from a simultaneous recording sequence, signal separability, harmonic suppression and vibrator interaction could be fully studied. Separated far-field signatures from simultaneous vibroseis methods using combinations of up and downsweeps exhibited unsuppressed harmonics and substantial energy from the undesired source which leaked through the correlation process. The ‘up/down’ method was capable of separating the signal from each source by only 12.7 dB, and is therefore unsuitable as a field technique. The variphase simultaneous vibroseis methods studied afforded some harmonic suppression and gave signal separations of about 30.0 dB. Use of variphase simultaneous vibroseis methods will compromise the quality of the data recorded, when compared with single-source acquisition methods. None of the simultaneous vibroseis methods tested provided adequate signal separation and, therefore, cannot be recommended as data acquisition techniques. The ‘alternate sweeping’ method coupled with multispread recording will give the desired improvement in data acquisition rates, while preserving the necessary quality of our seismic data.

The E791 parallel architecture data acquisition system

Abstract: To collect data for the study of charm particle decays, we built a high speed data acquisition system for use with the E791 magnetic spectrometer at Fermilab. The DA system read out 24000 channels in 50 μs. Events were accepted at the rate of 9000 per second. Eight large FIFOs were used to buffer event segments, which were then compressed and formatted by 54 processors housed in six VME crates. Data was written continuously to 42 Exabyte tape drives at the rate of 9.6 Mb/s. During the 1991 fixed target run at Fermilab, 20 billion physics events were recorded on 24000 8 mm tapes; this 50 Tb (Terabyte) data set is now being analyzed.

On-line expert system for power system diagnosis and restoration

Abstract: The authors have implemented a real-time expert system as part of a supervisory and data acquisition system for the Public Utilities Board of Singapore, controlling its 22 kV distribution network. It works as an operator support tool by diagnosing network disturbances and device malfunctions, and by presenting a switching sequence which can be executed immediately to restore supply. The authors describe how the expert system is integrated into a large supervisory control and data acquisition system for power distribution networks. The necessary techniques to cover online processing of real-time data, intelligent alarm processing and network reconfiguration/restoration are discussed. The expert system is based on a hierarchic multilevel problem-solving architecture, integrating model-based, heuristic and algorithmic techniques acting on an object-oriented data structure. Techniques such as the automatic creation and update of the knowledge base, event filtering, online event processing, and structural and temporal focusing have been implemented to enable the system to perform its task online and in real time.

Data acquisition system having selective communication capability

Abstract: A data acquisition system having selective communication capability to enable the data acquisition system to communicate with other data acquisition systems. The probe of the present invention initiates communication with a data acquisition unit located in an appliance. The data acquisition unit maintains a collection record which indicates the current setup and counts of the appliance. When the probe communicates with the data unit, it identifies itself and based upon this identification, the data unit responds with a particular collection record which is compatible with the probe communicating with the data unit. In addition, if the probe is used to setup a data unit, the probe decides what type of setup record to send based upon the collection record received from the data unit.

Rapid Inspection of Composites Using Laser-Based Ultrasound

Abstract: Current techniques for automated ultrasonic inspection of airframe structures can only be used to examine limited areas which have large radii of curvature. Manual inspection techniques are required in areas having small radii. Laser-based ultrasound (LBU) offers the potential to rapidly inspect large-area composite structures having contoured geometries, without restriction to large radii of curvature [1–4]. The key components that comprise an LBU rapid inspection system are the generation and detection lasers, a 2D scanner and a suitably fast data acquisition system. These must be integrated to provide an areal scan rate of at least 100 ft2/hr based on a 0.5″ × 0.5″ pixel size. In this paper results are presented of an investigation of the relative merits of using a CO2 laser versus a Nd:YAG laser for thermo-elastic ultrasonic generation in composite materials. In our previous studies, ultrasonic C-scan images of components were acquired with the LBU system by mechanically translating the test specimen in front of the stationary generation and detection laser beams [2–4]. If the scan is to be done rapidly, this technique becomes increasingly difficult and more expensive as the mass of the part increases. To fully realize the high speed scanning potential of a same side laser-in/laser-out inspection system, it is necessary to deflect the laser beams across the part surface. An implementation of angular scanning of the generation and probe laser beams across the part surface is described. A data acquisition scheme that has been used to demonstrate data acquisition rates of 33 waveforms/sec (for 200 point waveforms) is also described.

Design of a high-order FIR digital filtering and variable gain ranging seismic data acquisition system

Abstract: A new approach to designing an embedded microcomputer seismic data acquisition system to record high-quality seismic data is discussed. The seismic signal is sampled at a rate 10 times higher than the desired rate to avoid aliasing. The noise in the digitized seismic signal is filtered by a high-order finite impulse response (FIR) digital filter implemented in the microcomputer system. During filtering, excess samples are decimated to yield the required sampling rate. To avoid saturation, variable gain amplifiers (VGAs) were deployed in the design. A 16-b high-resolution analog-to-digital (A/D) converter helps to achieve a large dynamic range (120 dB) of the system and reduce the number of VGA gain ranges. Both computer simulation and experimental results confirm the validity of the design. >