Automatic Picking Research Articles

Velocity field imaging with an anomaly recovery algorithm, incorporating later arrivals

We have developed a novel velocity‐field recovery algorithm incorporating later arrivals which is aimed at overcoming several drawbacks encountered with standard tomographic inversion schemes. The anomaly recovery algorithm (ARA) places a series of anomalies, each fully described by only a few parameters, into a given velocity‐field estimate, varying the parameters to minimize the residual errors in first‐arrival times and in reflection, refraction, and diffraction times, which are obtained by manual or automatic picks from seismograms. We successfully recover anomalies in synthetic variable velocity fields where standard conjugate gradient‐based tomographic inversion schemes fail, find the ARA to be very robust against errors in traveltimes of up to 8%, and obtain results that are economically more meaningful. A comparison of results of the ARA applied to a mineral field crosshole data set with that of a standard conjugate gradient least‐squares (CGLS) inversion scheme indicates the ARA is a viable option for real‐world applications. It recovers the major velocity features found in subsequent drilling. An examination of the solution space exhibits a generally smooth topography with few significant minima interspersed by a larger number of minor local minima, suggesting the applicability of several standard nonlinear inversion schemes. The central idea underlying the ARA, to represent the velocity‐field inversion problem as low dimensional rather than high dimensional, makes the method generic, highly flexible, and relatively easy to analyze in terms of stability and local minima.

Robust automatic P-phase picking: an on-line implementation in the analysis of broadband seismogram recordings

The onset of a seismic signal is determined through joint AR modeling of the noise and the seismic signal, and the application of the Akaike Information Criterion (AIC) using the onset time as parameter. This so-called AR-AIC phase picker has been tested successfully and implemented on the Z-component of the broadband station HGN to provide automatic P-phase picks for a rapid warning system. The AR-AIC picker is shown to provide accurate and robust automatic picks on a large experimental database. Out of 1109 P-phase onsets with signal-to-noise ratio (SNR) above 1 from local, regional and teleseismic earthquakes, our implementation detects 71% and gives a mean difference with manual picks of 0.1 s. An optimal version of the well-established picker of Baer and Kradolfer [Baer, M., Kradolfer, U., An automatic phase picker for local and teleseismic events, Bull. Seism. Soc. Am. 77 (1987) 1437–1445] detects less than 41% and gives a mean difference with manual picks of 0.3 s using the same dataset.

Automatic Picking System of Cigarette Logistics Center

Automatic Picking System of Cigarette Logistics Center

自動ピッキングシステムにおける商品の棚割付けと注文処理順序の効率化運用方式の提案

自動ピッキングシステムにおける商品の棚割付けと注文処理順序の効率化運用方式の提案

Automatic Picking and Attribute Mapping for a Quick Evaluation of the Potential of Turbiditic Sands and Stratigraphic Traps in Frontier Areas: An Example from the Deep Offshore of the Niger Delta: ABSTRACT

Most interpretation teams involved in the exploration of Nigeria's deep offshore have been faced with a major challenge: (1) how to scan through a large volume of 3D data in a drastically short time frame... (2) with the captive of understanding the depositional pattern of slope fan and basin floor fan turbidites to identify mostly stratigraphic traps... (3) in an environment almost devoid of reference wells and calibration. A traditional approach was likely to miss both the deadlines and the sensitivity required for the sedimentological aspects of the study. Elfs answer was to rely extensively on the advanced functionalities of the SISMAGE (TM) workstation, in order to quickly generate time and seismic attribute maps which could then be interpreted in terms of structure and sedimentology. Two critical aspects were particularly well handled by the workstation: (1) the reliability of the extrapolation process from a loose grid of manually picked lines, and (2) the generation of seismic attribute maps relative not only to surfaces (e.g. sequence boundaries), but also to whole intervals through statistical calculation. In a second stage, the interpreters were able to focus on the most prospective areas and to move on to prospect generation, with the help ofmore » AVO studies. This approach is illustrated through an example from the deep offshore of the Niger delta.« less

Accurate determination of phase arrival times using autoregressive likelihood estimation

We have investigated the potential automatic use of an onset picker based on autoregressive likelihood estimation. Both a single component version and a three component version of this method have been tested on data from events located in the Khibiny Massif of the Kola peninsula, recorded at the Apatity array, the Apatity three component station and the ARCESS array. Using this method, we have been able to estimate onset times to an accuracy (standard deviation) of about 0.05 s for P-phases and 0.15 0.20 s for S phases. These accuracies are as good as for analyst picks, and are considerably better than the accuracies of the current onset procedure used for processing of regional array data at NORSAR. In another application, we have developed a generic procedure to reestimate the onsets of all types of first arriving P phases. By again applying the autoregressive likelihood technique, we have obtained automatic onset times of a quality such that 70% of the automatic picks are within 0.1 s of the best manual pick. For the onset time procedure currently used at NORSAR, the corresponding number is 28%. Clearly, automatic reestimation of first arriving P onsets using the autoregressive likelihood technique has the potential of significantly reducing the retiming efforts of the analyst.

Characterization of global seismograms using an automatic-picking algorithm

AbstractAn automatic phase picker is useful for quickly identifying and timing phase arrivals in large seismic data bases. We have developed an automatic phase picker that is sensitive to small changes in amplitude and applied it to over 7 yr of global data distributed by the National Earthquake Information Center (NEIC). Our phase-picking algorithm is based on a short-term-average to long-term-average ratio (STA/LTA) taken along an envelope function generated from the seismogram. The algorithm returns arrival times and corresponding pick qualities. The procedure requires few input parameters and is easily adapted to various types of data. We produce global travel-time plots from both high-frequency (20- or 40-Hz sample rate) and low-frequency (1-Hz sample rate) data. These plots clearly image the predominant high- and low-frequency phases in the NEIC data base. Picks made from the long-period seismograms are less precise, but they reveal far more phase arrivals than the short-period picks. A number of phases resulting from reflections and phase conversions at upper mantle discontinuities can be identified in the low-frequency picks; however, a search of the short-period picks for upper mantle discontinuity phases, between P and PP and prior to P′P′, has so far been unsuccessful. In the long-period S and SS picks, we observe a discrepancy in SV and SH travel times, a possible result of upper mantle anisotropy. To check the accuracy and consistency of our algorithm, we present comparisons between hand-picked times and automatic-picked times for identical seismograms. Travel-time residuals from the short-period automatic picks and data reported to the International Seismological Centre (ISC) picks exhibit a comparable amount of scatter. Histograms of the ISC residuals and automatic-pick residuals are similar in shape and width for P and PcP. These observations suggest that human picking errors are not a major contributor to the scatter observed in ISC travel times, although direct comparisons between ISC reported picks and automatic picks on particular seismograms occasionally identify operator mispicks.

Flexible System for Automatic Order Picking

Abstract One of the areas in warehousing more open to be automated is the order picking. In different situations, as for shipment warehousing, mail ordering or movement of parts for just in time production, order picking takes up a lot of time and resources. This paper presents a complete system designed to perform the order-picking process in a flexible and automated way. The system includes automatic feeders for the general warehouse, picking systems to get parts from the general warehouse, a transport system and packing systems. The system uses robots, conveyors and special machines. A complete planning of the system, supported by a hierarchical hardware structure, is carried out in order to increase productivity. The system is now working on a parts shipment warehouse.

An automatic phase picker for local and teleseismic events

AbstractAn automatic detection algorithm has been developed which is capable of time P-phase arrivals of both local and teleseismic earthquakes, but rejects noise bursts and transient events. For each signal trace, the envelope function is calculated and passed through a nonlinear amplifier. The resulting signal is then subjected to a statistical analysis to yield arrival time, first motion, and a measure of reliability to be placed on the P-arrival pick. An incorporated dynamic threshold lets the algorithm become very sensitive; thus, even weak signals are timed precisely. During an extended performance evaluation on a data set comprising 789 P phases of local events and 1857 P phases of teleseismic events picked by an analyst, the automatic picker selected 66 per cent of the local phases and 90 per cent of the teleseismic phases. The accuracy of the automatic picks was “ideal” (i.e., could not be improved by the analyst) for 60 per cent of the local events and 63 per cent of the teleseismic events.

FIRST ARRIVAL PICKING ON COMMON‐OFFSET TRACE COLLECTIONS FOR AUTOMATIC ESTIMATION OF STATIC CORRECTIONS*

AbstractThe increase in the number of geophone groups in production records during recent years and the requirement for accurate basic static corrections for high resolution records have made it necessary to develop sufficiently accurate automatic techniques for the determination of static corrections.A fully automatic method is presented which makes use of the delay‐time method in order to compute static corrections at each shot position. Delay times, weathering and subweathering velocities are determined from automatic picks of the first arrivals on common‐offset trace collections.It is assumed that the weathering is a single layer and that the dip of the subweathering layer under the geophone groups is small.The picking routine is fully automatic and successful in most cases, provided the signal‐to‐noise ratio is sufficiently high.The subsequent filtering of erroneous values for picked times is performed by means of statistical techniques, using curves of picked times on common‐offset trace collections. If the distance between receivers and shot‐points on the profile is sufficiently short, one can expect only little change in the picked times of two contiguous traces.The method is well adapted to end‐on spreads with a great number of traces, where distances between geophone groups are short.Examples are presented showing the possibilities of the method for the determination of long wavelength as well as short wavelength components of static corrections.