Difference between revisions of "Ambient vibration array"
| Line 23: | Line 23: | ||
== F-K Toolbox (conventional f-k) == | == F-K Toolbox (conventional f-k) == | ||
| − | links | + | The conventional frequency wavenumber technique as implemented in '''Geopsy''' is based |
| + | on the simple idea of [[Wikipedia:Delay_and_sum|''delay and sum'' (or ''shift and sum'')]]. | ||
| + | This technique may be effectuated equivalently in time domain or frequency domain. | ||
| + | In Geopsy we follow the frequency domain approach, as it is the most convenient and effective | ||
| + | way to use this approach for determination of frequency dependent apparent velocity estimation | ||
| + | (i.e dispersion curve estimation under the assumption of the wave field being composed of | ||
| + | surface waves only). | ||
| + | |||
| + | The simultaneous waveform recordings of a group of spatially distributed stations are analyzed | ||
| + | in many narrow (mostly overlapping) frequency bands for individual analysis windows cut from the | ||
| + | overall recordings. For each analysis window and frequency band, a grid search is performed | ||
| + | in the wavenumber domain to effectively find the propagation properties of the most coherent | ||
| + | and/or powerful plane wave arrival in the analysis window. Given the assumption of surface | ||
| + | waves dominating the wave field, the apparent velocity equals the phase velocity of the | ||
| + | surface wave at this particular frequency. | ||
| + | |||
| + | Details of the signal processing can be found in the [[General: Array signal processing|array signal processing]] | ||
| + | page of this wiki or following one of the links below in section [[#see also|see also]] | ||
| + | |||
| + | For learning about the detailed use of the f-k toolbox (geopsy plugin) in a tutorial like fashion [[FK|follow this link to FK]]. | ||
== High resolution frequency wavenumber Toolbox (Capon's method) == | == High resolution frequency wavenumber Toolbox (Capon's method) == | ||
Revision as of 08:07, 10 March 2010
Contents
Common pre-requisites for array processing - getting ready
For any array processing of ambient vibration data there are some common steps / pre-requisites regarding your signal recordings (selection of simultaneous recordings, coordinate insertion, signal grouping). Learn about all these options/preparatory steps in the following sub-chapters (linking to other parts of this wiki)
Loading and viewing signals (time series)
links to loading and viewing signals
Group signals
links to groups
Insert / edit station coordinates
links to set receivers
F-K Toolbox (conventional f-k)
The conventional frequency wavenumber technique as implemented in Geopsy is based on the simple idea of delay and sum (or shift and sum). This technique may be effectuated equivalently in time domain or frequency domain. In Geopsy we follow the frequency domain approach, as it is the most convenient and effective way to use this approach for determination of frequency dependent apparent velocity estimation (i.e dispersion curve estimation under the assumption of the wave field being composed of surface waves only).
The simultaneous waveform recordings of a group of spatially distributed stations are analyzed in many narrow (mostly overlapping) frequency bands for individual analysis windows cut from the overall recordings. For each analysis window and frequency band, a grid search is performed in the wavenumber domain to effectively find the propagation properties of the most coherent and/or powerful plane wave arrival in the analysis window. Given the assumption of surface waves dominating the wave field, the apparent velocity equals the phase velocity of the surface wave at this particular frequency.
Details of the signal processing can be found in the array signal processing page of this wiki or following one of the links below in section see also
For learning about the detailed use of the f-k toolbox (geopsy plugin) in a tutorial like fashion follow this link to FK.
High resolution frequency wavenumber Toolbox (Capon's method)
links to HRFK
Modified Spatial Autocorrelation (MSPAC) Toolbox
links to MSPAC
