Showing papers on "Data acquisition published in 1994"

The Marmousi experience; velocity model determination on a synthetic complex data set

Abstract: The motivation behind seismic data acquisition and processing is simple—to obtain a depth image of the earth—but performing this process correctly is extremely difficult. A number of well known processing tasks (such as static corrections, deconvolution, multiple elimination, velocity estimation, and migration) have to be executed, and each directly influences the final result. However, the success of the velocity estimation is paramount and critical, and large amounts of man/CPU hours are devoted to it.

The L3 silicon microvertex detector

Abstract: The design and construction of the silicon strip microvertex detector (SMD) of the L3 experiment at LEP are described. We present the sensors, readout electronics, data acquisition system, mechanical assembly and support, displacement monitoring systems and radiation monitoring system of the recently installed double-sided, double-layered SMD. This detector utilizes novel and sophisticated techniques for its readout.

Electronic processor for pulse oximeters

Abstract: An apparatus for measuring the concentration of blood constituents in which the architecture of the electronic processor reduces the amount of controller processing time required for tasks such as data acquisition and generation of system control signals. A demodulator is coupled to a probe for converting a first electrical signal to digital data. An interface is coupled to the demodulator for receiving the digital data and generating interrupts when a first amount of the digital data has been received. A buffer memory is coupled to the interface for storing the digital data. A controller having a controller memory (in specific embodiments, a CPU having a CPU memory) is also coupled to the buffer memory. The controller transfers the digital data from the buffer memory to the controller memory in response to the interrupts. The controller then processes the digital data to calculate the arterial oxygen concentration.

System and method for collecting data used to form a geographic information system database

Abstract: A portable data acquisition device, including a position-determining device and data collector, determines and stores positional data associated with objects positioned in a geographical area within sight of the device. Data representative of attributes associated with the objects are also stored in the device. The data stored in the device can be transferred to processing circuitry of a computer and absolute positional coordinates of the objects are determined. The absolute positional coordinates and the data representative of the attributes associated with the objects are placed in files accessible by geographic information system (GIS) software which utilizes the data to form a geographic information system (GIS) database from which GIS maps may be formed.

Distributed trace data acquisition system

Abstract: A dedicated debugging facility for tracing hardware and software faults in a distributed digital system. An event data capture circuit is integrated into each processing node in a distributed multinode system for capturing event data within each node under software control. The captured event data is stored in one of a plurality of variable-length trace data buffers in the node processor memory space for analysis or transfer. These dedicated trace data acquisition circuits provide continuously available trace data for the hardware and software functions within each node. Each variable-length trace data entry is stored in the trace data buffers according to a format of this invention that permits collection and assembly of trace data entries from throughout the distributed multinode system to debug local hardware or software and to debug internodal interconnection hardware and software.

A PC-based data acquisition package for nuclear microbeam systems

Abstract: This paper describes a hardware and software package that enables nuclear microprobe data to he collected with a minimum of complexity using a standard Personal Computer. The package comprises an external module containing ADCs for pulse height and x and y position together with pulse sealers for recording accumulated charge and dead time. Up to 8 detector signals are multiplexed into the ADC using peak detecting front-end modules so that no additional timing signals are required. The controlling software runs under Windows and allows the collection and display of spectra and 2D maps generated by setting energy windows on the spectra. Saving and playback of event-by-event (listmode) data is also possible. Using a DAC card in the PC, the system will control the beam position, allowing the generation of irregular scan patterns or the positioning of the beam using the mouse. Using a high performance PC, data throughput of up to 50 kHz is possible.

Phase shifting interferometer and method for surface topography measurement

Abstract: A system for measuring surface topography with notably decreased sensitivity to errors in phase and phase interval calibration and to the presence of low-frequency vibration during data acquisition includes an optical interferometer for developing interference data from the surface to be profiled, an electronic imaging system or camera for receiving the interference data, an arrangement for variably adjusting the reference phase of the interferometer illumination, and a digital signal processing device or computer for determining surface height from the interference data. A sequence of seven intensity images are detected by the imaging system and stored electronically. The intensity images correspond to interference patterns for seven different reference phase values spaced at intervals of approximately π/2. The images are processed by the computer so as to recover the surface topography. The invention differs substantially from the prior art in that the phase shifts need not be perfectly exact or repeatable, and neither is it necessary to completely eliminate low-frequency mechanical vibrations from the optical system during data acquisition. An alternative embodiment of the invention includes a laser diode-based illumination source that is operatively tuned in wavelength to effect the required phase shifts.

Data acquisition and scan control system for nuclear microprobe and other multiparameter experiments

Abstract: A multipurpose data acquisition and beam control system was developed for use on a personal computer (PC) in an MS Windows graphical environment. Data acquisition is performed via a FAST MPA/PC adapter card and MPA/LBB large bus-box by a host computer. Beam and sample positioning are controlled from another computer connected to the host. Applications in the nuclear microprobe and experimental nuclear physics are presented.

Seismic data acquisition

Abstract: A system for acquiring and processing seismic data comprises source-means for generating sound waves and receiver-means for recording as data those waves as reflected from sub-surface interfaces, and means for processing the recorded data operable to generate sets of actual data each individually associated with specific sub-surface reflection points, order the data-sets in accordance with receiver and source-means separation, process each data-set to generate additional data intermediate the recorded data, and re-order each data-set and additional data in accordance with receiver and source-means separation for further processing. Each data-set is applied to a filter to generate said additional data intermediate of the recorded actual data. The filter is selected from the group comprising linear, quadratic or spline interpolation filters, frequency space (f-x) filters, tau-p filters, smart filters artificially intelligent filters, neural network filters and (preferably) sinc filters. The recorded actual data are also subject to traveltime correction (for example NMO). Data collection may be by use of a single shot source and a plurality of receivers which are equi-spaced, linked in a linear array, and movable above a surface to be surveyed. The data-sets may comprise common receiver or common shot gathers and the described techniques are applicable to other forms of seismic data gathers.

Development of a real-time adaptive current tomograph

Abstract: Following the successful development of a multiple-drive electrical impedance tomography system OXPACT-II featuring a voltage-driven current method for in vitro studies, research work currently being undertaken at the EIT research group in Oxford is aimed at developing a real-time multiple-drive adaptive system, called the Oxford Brookes Adaptive Current Tomograph Mark-III (OXBACT-III) which will operate at several frequencies in between 10-160 kHz. The objective of this system development is to enable EIT clinical studies to be undertaken based on the adaptive current method. One of the most important issues addressed in the new system design is to achieve high data acquisition speed while maintaining sufficient system accuracy. This paper will describe the overall data acquisition system structure and relevant system performance specifications.

An image analysis system for automatic data acquisition from colored scanned maps

Abstract: Many maps [an important source of information for efficient spatial data evaluation using a Geographic Information System (GIS)] must still be digitized manually, a time-consuming and error-prone process. Therefore, we developed the processing of maps (PROMAP) system, which incorporates adequate image analysis. The system can generate a symbolic description of the map that can be imported into a GIS. A color scanner generates a multicolor raster image of the map. This image is split into layers of predefined map colors. Each layer is vectorized and methods like neural network-based symbol and object recognition for the extraction of attributed structure primitives and knowledge-directed image interpretation are applied. The map scene is structured hierarchically. The interface to the GIS is represented by the map objects at the upper levels of hierarchy. These investigations described are part of the interdisciplinary projectEnvironmental Planning System. The scope of this project is the combination of data acquisition, the development of an evaluation scheme, and GIS in an integrated concept.

Synchronized digital signal processor for MRI reception

Abstract: A multi-rate sample MRI (magnetic resonance imaging) digital receiver maintains synchronization of digitally processed signals. This multi-rate sample data system is used to demodulate and filter a digitized MRI RF signal. A phase/timing relationship is established between the signal received and processed by the digital receiver, and the physical nuclear magnetic resonance (NMR) process the body being imaged is undergoing. Once established, the phase/timing relationship is maintained for the duration of the particular NMR experiment being performed. Special logic in the digital system ensures that the data output is synchronized with an external synchronous signal controlling data acquisition within the MRI system. Optimum signal processing is performed to minimize the time between the end of the acquisition control signal and the last output from the digital signal processing system.

Self-calibration/compensation technique for microcontroller-based sensor arrays

Abstract: Described is a generalized technique for real-time gain and thermal compensation of embedded microcontroller-based sensor arrays By incorporating a single or multiple low-cost, uncalibrated thermal sensor(s) into a software feedback loop, a self-normalized calibration/compensation table for each sensor can be generated and stored in EEPROM for later use in real-time signal acquisition The compensation is accomplished by executing a one-time initialization software routine as the sensor array is cycled through the expected temperature range To achieve compensation to within the system resolution, the required correction loop bit width will be different from that of the system bit width In addition to temperature compensation, the technique also includes correction for gain and voltage offset errors introduced by the analog signal conditioning as well as A/D conversion errors An example of the technique is presented using a 68HC711E9 microcontroller for real-time acquisition and compensation of a four-element strain gage array >

Instantaneous data acquisition and processing system for internal-combustion engine control

Abstract: The control system of the invention is associated with an engine provided with means for measuring one or several parameters including pressures (in the cylinder, induction pressure, exhaust pressure) for each cylinder, acceleration, injection needle lift, knock detection, engine torque, etc., and with means for the angular coding of the crankshaft position. The control system includes a synchronization set (7) co-operating with angular discrimination means so as to readjust automatically at any time the angular coding data with respect to the combustion cycles. An acquisition set digitizes at a high frequency the various data measured, and notably the pressure values taken during each cycle, simultaneously in all the cylinders. A processing set (18) including notably a fast digital processor suited for determining in real time complex physical parameters such as the man indicated pressure (PMI) at each cycle or each engine revolution, stability factors of these parameters in time, etc. The results obtained are applied to a control computer (19) suited for determining and optimizing various engine parameters such as fuel injection, advanced ignition, etc.

Component maintenance system

Abstract: A component maintenance system having a network linked to a data acquisition system, a data analysis system, a historical file of component design and inspection information, and a diagnostic system having the capability to perform structural analysis of discontinuities identified by the data acquisition system. The network nodes may be located apart from each other; for example in the maintenance of a nuclear power plant steam generator, the data acquisition system may be located in a high radiation area while the data analysis system is safely located away from the radiation areas. Furthermore, the diagnostic system and the file of component design and inspection history information may be centrally located and shared to support component evaluations being conducted in numerous geographic locations. Network communication facilitates the rapid evaluation of discontinuities, thereby permitting the inspection plan to be modified as the inspection results are obtained.

360-deg profilometry: new techniques for display and acquisition

Abstract: Two optical methods are proposed for shape measurement and defect detection of curved surfaces in the form of a complete 360-deg profile of the object. The first one is the standard structured light approach. Display of the resulting data is the emphasis of this section. The second approach uses modulated structured light with a scanning digital camera for faster and simpler data acquisition. Quantitative processing is done off-line while real-time moire produces enhanced display of the defects for qualitative analysis.

An inductive scanning system for two-dimensional imaging of reinforcing components in concrete structures

Abstract: A novel form of imaging steel reinforcing components in concrete is described which employs a scanning inductive sensor. A host computer, linked to the scanning and data acquisition system, generates grey-scale images whose intensities are proportional to the signal strengths produced by the sensor. Simple signal subtraction algorithms have been employed to achieve considerable improvements in image contrast, spatial resolution and the extraction of dimensional information. Models of the sensor response suggest that with further signal manipulation, detailed quantitative measurements on image features will also be possible.

Airborne hyperspectral sensor systems

Abstract: This paper presents brief profiles of 19 airborne hyperspectral sensor systems currently or nearly available for data acquisition. These systems represent various design concepts and innovations in hyperspectral information collection technology. A number of companies now have the ability to acquire data from these systems. As the scientific and commercial communities become aware of hyperspectral imaging data acquisition opportunities, more applications for this type of data will be investigated and implemented. >

Data acquisition and storage system for telecommunication equipment to facilitate alignment and realignment of the telecommunications equipment

Abstract: A data acquisition and transceiver module is used to acquire data from diagnostic equipment, such as a portable sampling spectrum analyzer. This data is then transmitted to a slave transceiver and storage module where it is stored in memory. The slave transceiver and storage module is typically housed remotely from the diagnostic equipment in the telecommunications electronic equipment and serves as an archival resource for set-up and maintenance parameters.

Airborne hyperspectral sensor systems

Abstract: This paper presents brief profiles of 19 airborne hyperspectral sensor systems currently or nearly available for data acquisition. These systems represent various design concepts and innovations in hyperspectral information collection technology. A number of companies now have the ability to acquire data from these systems. As the scientific and commercial communities become aware of hyperspectral imaging data acquisition opportunities, more applications for this type of data will be investigated and implemented. >

Lasercom system architecture with reduced complexity

Abstract: Spatial acquisition and precision beam pointing functions are critical to spaceborne laser communication systems. In the present invention a single high bandwidth CCD detector is used to perform both spatial acquisition and tracking functions. Compared to previous lasercom hardware design, the array tracking concept offers reduced system complexity by reducing the number of optical elements in the design. Specifically, the design requires only one detector and one beam steering mechanism. It also provides means to optically close the point-ahead control loop. The technology required for high bandwidth array tracking was examined and shown to be consistent with current state of the art. The single detector design can lead to a significantly reduced system complexity and a lower system cost.

Intrinsically safe data acquisition system and apparatus

Abstract: An intrinsically safe data acquisition system is disclosed for use in hazardous locations. The system includes a driller's console that itself is intrinsically safe and includes a large LCD monitor, keypad and local CPU. The system further includes satellite data acquisition and processing boxes that are also intrinsically safe and that are located within the hazardous area. Each satellite box includes its own CPU and acquires and locally processes signals received from a number of field sensors. The satellite box converts the signals into digital form, and transmits the data via a fiber optic communication channel to a master CPU box located in an unclassified area. A high current intrinsically safe barrier distributes power from the master CPU box to the satellite box for powering all the sensors supported by that satellite box. Another such barrier distributes all the power required by the driller's console.

Resolution degradation parameters of ionospheric tomography

Abstract: Tomographie reconstruction of the electron density structure in the ionosphere has generated much interest due to the possibility of high-resolution two-dimensional image reconstruction using total electron content (TEC) data. An algorithm based upon the filtered backprojection algorithm of X ray tomography that provides such two-dimensional reconstructions has been developed; however, the resolving capability is limited by the nature of the ionospheric system. In ionospheric tomography, each piece of data contains information similar to a sample on a projection in X ray tomography. Collectively, however, the information content of ionospheric data sets is significantly different from a set of tomographic projections. These differences are the result of characteristics of the data acquisition system and are directly related to the resolution limits of the reconstructed images. In this paper the data acquisition system is analyzed to determine the sources of this degradation. Two key parameters of nonuniform sample spacing and angular reindexing error are analyzed to determine their effect upon the reconstruction process. A method of evaluating sampling schemes to measure the information content of the resulting projections is presented. Finally, a relationship between the angular reindexing error and the point spread function of the imaging system is derived.

Optimization of phase-locked loop performance in data recovery systems

Abstract: Optimized design conditions are presented for a phase-locked loop (PLL) used as a functional block in data recovery systems with the primary function of timing recovery. A mathematical model is presented which takes into account the nonlinear and discrete-time nature of the PLL when used in data recovery applications. Performance attributes for these systems such as acquisition, tracking, and noise are considered. A systematic design procedure is presented which permits quantitative trade-offs among these performance attributes. The validation of the mathematical model and the systematic design procedure on a practical circuit implementation in CMOS technology is described. >