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| − | == Use == | + | = '''Use''' = |
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| − | This toolbox tab contains the parameters to select the part of the signal used for [[H/V_spectral_ratio|H/V]] or [[Spectral_amplitudes|Spectrum]] processing on which window selection is performed.
| + | [[Image:HV_SPEC_toolb_time.png|thumb|right|300px|''Time'' tab of the H/V and Spectrum toolboxes]] |
| − | The two series of paramaters are described in two sections:
| + | The toolbox '''Time''' tab is used to customize the parameters for selecting the signal windows used for processing. |
| | + | Two series of parameters are described in two sections: |
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| | * the global time range section | | * the global time range section |
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| | * the time windows section | | * the time windows section |
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| − | A third section gives information on the number of selected windows obtained after applying to the signal the parameters of the two precedent sections. | + | A third section gives information on the number of selected windows obtained after applying the parameters defined in the two precedent sections. |
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| − | At the very bottom two buttons indicate wether to [[Geopsy: Load_Toolbox_Parameters|load parameters]] from previouly processed data or to [[Geopsy: Load_Toolbox_Parameters|start signal processing]] signal processing.
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| − | [[Image:HV_SPEC_toolb_time.png|thumb|center|400px|''Time'' tab of the H/V and Spectrum toolboxes]]
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| | <br style="clear: both"/> | | <br style="clear: both"/> |
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| − | == Global time range section == | + | = '''Global time range section''' = |
| − | Used to select the portion of the signal that will be processed ([[Geopsy: Time_Limits|more informations]]).
| + | [[Image:HV_SPEC_toolb_time_global.png|thumb|right|300px|''Global time range'' section in the ''Time'' tab of he H/V and Spectrum toolboxes]]Used to select the portion of the signal that will be processed ([[Geopsy: Time_Limits|more informations]]). |
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| − | [[Image:HV_SPEC_toolb_time_global.png|thumb|left|300px|''Global time range'' section in the ''Time'' tab of he H/V and Spectrum tollboxes]] | |
| − | <br style="clear: both"/>
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| − | == Time windows section ==
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| − | Short-duration disturbances of the signal can be avoided during [[H/V_spectral_ratio|H/V]] or [[Spectral_amplitudes|Spectrum]] processing by using an anti-trigger window selection to remove the transients. The objective is to keep the most stationary parts of ambient vibrations, and to avoid the transients often associated with specific sources (footsteps, close traffic). This objective is exactly the opposite of the usual goal of seismologists who want to detect signals, and have developed specific trigger algorithm to track the unusual transients possibly indicating the satrt of an earthquake. Here an anti-trigger algorithm is used, which is exactly the opposite: it detects transients but it tries to avoid them. For more information on this topic it it suggested to consult the SESAME user guidelines <ref>Guidelines for the implementation of the H/V spectral ratio technique on ambient vibrations measurements, processing and interpretation, [http://SESAME-FP5.obs.ujf-grenoble.fr], 62 pages, April 2005</ref>. Windows are then processed indidualy to get individual window H/V or Spectrum, which are then averaged.
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| − | This section comprises four sub-tabs:
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| − | [[Image:Time_Windows_tabs.png|thumb|left|300px|The four sub-tabs of the ''Time windows'' section in the ''Time'' tab]]
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| − | * '''general''': window selection parameters
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| − | * '''raw signal''': STA/LTA crieria applied to the raw signal
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| − | * '''filter''': filtering criteria for applying STA/LTA on the filtered signal
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| − | * '''filtered signal''': STA/LTA crieria applied to the signal filtered uusing the criteria in the ''Filter'' sub-tab
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| | <br style="clear: both"/> | | <br style="clear: both"/> |
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| | + | = '''Time windows section''' = |
| | + | [[Image:HV_SPEC_toolb_time_windows.png|thumb|right|300px|''Time windows'' section in the ''Time'' tab of the toolboxes]] |
| | + | Short-duration disturbances of the signal can be avoided during [[H/V_spectral_ratio|H/V]] or [[Spectral_amplitudes|Spectrum]] processing by using an anti-trigger window selection to remove the transients. The objective is to keep the most stationary parts of ambient vibrations, and to avoid the transients often associated with specific sources (footsteps, close traffic). This objective is exactly the opposite of the usual goal of seismologists who want to detect signals, and have developed specific trigger algorithm to track the unusual transients possibly indicating the start of an earthquake. Here an anti-trigger algorithm is used, which is exactly the opposite: it detects transients and tries to avoid them. For more information on this topic, it it suggested to consult the SESAME user guidelines <ref>Guidelines for the implementation of the H/V spectral ratio technique on ambient vibrations measurements, processing and interpretation, [http://SESAME-FP5.obs.ujf-grenoble.fr], 62 pages, April 2005</ref>. Windows are then processed individually to get H/V or Spectrum curves in all selected windows, which are then averaged |
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| − | === General sub-tab ===
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| − | This sub-tab contains the parameters used to select stable signal windows.
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| − | [[Image: HV_SPEC_toolb_time_time_gen.png|thumb|left|300px|The ''General'' sub-tab in the ''Time windows'' section of the ''Time'' tab]]
| + | '''MAIN ARTICLE''': [[Geopsy: H/V and Spectrum Toolboxes: Time Tab: Time windows|Time windows]] |
| | <br style="clear: both"/> | | <br style="clear: both"/> |
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| − | ==== Window length ==== | + | = '''Number of windows section''' = |
| − | There are three ways to define window length (duration, in seconds) using the ''Length'' pop-up menu
| + | [[Image: View stations all.png|thumb|'right|300px|''Number of windows'' section]]In the '''Number of windows'' section, underneath the [[Geopsy: H/V and Spectrum Toolboxes: Time Tab: Time windows|Time windows]] tabs, a pop-up menu and a numerical display are used to show the number of selected windows. |
| − | [[Image: HV_SPEC_toolb_time_time_general_popup.png|thumb|left|''Window length'' pop-up menu]] | + | When '''all stations''' is displayed in the pop-up menu, the number of windows in the numerical display is the total number of windows selected over all the stations. It is also displayed when a single station is processed. |
| | <br style="clear: both"/> | | <br style="clear: both"/> |
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| − | * exactly: all selected windows will have the same exact duration.
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| − | Choose ''Exactly'' in the ''Length'' pop-up menu and enter the window length (in seconds) in the spin box to the right of the pop-up menu.
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| − | [[Image: Time-time_exactly.png|thumb|left|300px|]] | + | [[Image: View station pop-up.png|thumb|right|300px|Pop-up menu of the ''Number of windows'' section]] |
| | + | The number of windows selected in each station of a multiple processing may be displayed individually. |
| | <br style="clear: both"/> | | <br style="clear: both"/> |
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| − | * at least: selected windows will have a duration comprised between two values.
| + | [[Image: View station 1 Station.png|thumb|right|300px|Number of windows of the selected station]] |
| − | Choose ''At least'' in the ''Length'' pop-up menu and enter the window lengths (in seconds) in the two spin boxes to the right of the pop-up menu.
| + | The number of windows of the selected station appears in the numerical display, and simultaneously a zoom of the selected station appears in the signal Graphic Sheet. |
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| − | All windows with duration comprised between these two values will be selected, thus possibly resulting in windows with different sizes.
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| − | [[Image: Time-time_atleast.png|thumb|left|300px]] | |
| | <br style="clear: both"/> | | <br style="clear: both"/> |
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| − | This may be useful the most possible windows of very perturbated signal.
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| − | | + | = References = |
| − | ==== Window Overlaping ====
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| − | It is possible for succsive windows to be contiguous or to overlap, with the ''Overlap'' box and .
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| − | * When the ''Overlap'' box is not checked, contiguous selected signal windows will not overlap.
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| − | [[Image: Time-time_nooverlap_menu.png|thumb|left|300px]]
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| − | [[Image: Time-time_nooverlap.png|thumb|left|300px|Resulting windowing when ''Overlap'' box is not checked]]
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| − | <br style="clear: both"/>
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| − | * When the ''Overlap'' box is checked, contiguous selected signal windows will overlap by a chosen percentage entered in the neighboring spin box.
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| − | [[Image: Time-time_overlap_menu.png|thumb|left|300px|]]
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| − | [[Image: Time-time_overlap.png|thumb|left|300px|Resulting windowing when ''Overlap'' box is checked]]
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| − | <br style="clear: both"/>
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| − | ==== Bad Sample Definition and Use ====
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| − | It is possible to discard higher amplitudes when looking for stable windows, by defining a level of "bad" samples.
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| − | When a sample amplitude is above the defined "bad" sample threshold it is considered as being above the [[Geopsy: STA/LTA|STA/LTA]] threshold.
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| − | [[Image: Time-time_Bad_sample.png|300px]]
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| − | * '''Bad Sample Threshold box'''
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| − | It is possible to define a level above which a sample is considered as bad, i.e. that should rejected when defining stable windows.
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| − | To do so, check the ''Bad sample threshold'' box and enter the desired threshold, which is a percentage of the maximum amplitude over the entire signal.
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| − | * '''Bad Sample Tolerance box'''
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| − | A maximum number of bad samples may be accepted inside windows during the selection process.
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| − | Check the Bad sample tolerance button and enter the number of tolerated bad samples.
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| − | This option may only be used when the previous one is checked.
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| − | <br style="clear: both"/>
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| − | ==== Anti-triggering possibilities for window selection ====
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| − | The goal of the anti-triggering is to keep the most stationary parts of ambient vibrations, and to avoid the transients. Eventualy, user's defined bad sample are also considered as part of the non-stationary signal.
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| − | Two types of anti-trigger may be applied to he signal, both based on [[Geopsy: STA/LTA|STA/LTA]] detection.
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| − | [[Image: Time-time_antitriggering.png|300px]]
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| − | * Anti-triggering on raw signal
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| − | When the ''Anti-triggering on raw signal'' box is checked, the anti-trigger is applied sample per sample all along the entire signal, using the [[Geopsy: STA/LTA|STA/LTA]] parameters entered in the ''Raw signal'' sub-tab.
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| − | * Anti-triggering on filtered signal
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| − | When the ''Anti-triggering on filtered signal'' box is checked, the signal is first filtered using the parameters entered in the ''Filter'' sub-tab, and then the anti-trigger is applied sample per sample all along the entire signal, using the [[Geopsy: STA/LTA|STA/LTA]] parameters entered in the ''Filtered signal'' sub-tab.
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| − | All combinatins of checking the boxes are possible, including both boxes unchecked.
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| − | IMPORTANT NOTICE: when using the anti-triggering on the filtered signal, the signal is filtered ONLY to select stable windows.
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| − | The processing is then performed on the RAW signal.
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| − | In order to process filtered signal the raw signal should first be filtered with the [[Geopsy: Filter|''Filter'']] in the [[Geopsy: Waveform_Menu|''Waveform'']] menu.
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| − | === Raw Signal sub-tab ===
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| − | This sub-tab is divided into two sections.
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| − | [[Image: HV_SPEC_toolb_time_time_raw.png|300px]]
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| − | * STA/LTA parameters section (to the left), includes STA length, LTA length, as well as minimum and maximum STA/LTA thresholds [[Geopsy: STA/LTA|''(more information)'']].
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| − | * ''Apply to'' section (to the right), indicates to which tracks the anti-trigger is applied (top, above the … : e.g. Vertical, North, East) and to which file (bottom underneath the … : e.g."Strong Peak").
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| − | Simply check the boxes of the tracks and files that are to be processed.
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| − | === Filter sub-tab ===
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| − | [[Image: HV_SPEC_toolb_time_time_filter.png|300px]]
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| − | Contains the filtering parameters used in the ''Filtered Signal'' sub-tab [[Geopsy: Filter|''(more details)'']].
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| − | === Filtered Signal sub-tab ===
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| − | This sub-tab is divided into two sections.
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| − | [[Image: HV_SPEC_toolb_time_time_filtered.png|300px]]
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| − | * STA/LTA parameters section (to the left), includes STA length, LTA length, as well as minimum and maximum STA/LTA thresholds [[Geopsy: STA/LTA|''(more information)'']].
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| − | * ''Apply to'' section (to the right), indicates to which tracks the anti-trigger is applied (top, above the … : Vertical, North, East) and to which file (bottom underneath the … : "Strong Peak").
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| − | Simply check the boxes of the tracks and files that are to be processed.
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| − | === Widowing and data flow sub-section ===
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| − | Two boxes and one pop-up menu located at the bottom of the Time windows section are used to control windowing and real time data acquistion flow.
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| − | [[Image: Time-Time_select.png|300px]]
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| − | * ''Update'' box: should be checked when using geopsy for real time data acquisition. Checking the box when no data flow is entering as no effect on the processing.
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| − | * ''Common'' box: check this box to force selecting the same windows on all signal tracks, i.e. [[Geopsy: STA/LTA|STA/LTA]] threshold must be verified simultaneously on all tracks in order to keep a window. When the box is unchecked, [[Geopsy: STA/LTA|STA/LTA]] threshold must be verified on each track taken separately. There is no need to check this box in H/V processing, as in this case it is automatically applied.
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| − | [[Image: Common not checked.png|thumb|left|300px|Resulting windowing with the ''Common'' box unchecked]] [[Image: Common checked.png|thumb|left|300px|Resulting windowing with the ''Common'' box unchecked]]
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| − | <br style="clear: both"/>
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| − | * ''Select'' pop-up menu: used to determine which action is undertaken in the windowing process.
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| − | [[Image: HV_SPEC_toolb_time_popup.png|thumb|left|300px|Options in ''Select'' pop-up menu]]
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| − | '''Auto''': windows are selected automaticaly using the criteria of the ''General'' sub-tab of the ''Time'' section.
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| − | '''Add''': manualy add windows.
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| − | '''Remove''': manualy remove windows.
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| − | '''Inverse''': select the windows that were previously not selected. When no windowing has been performed, applying ''Inverse'' will select windows all long the signal without applying the criteria of the ''General'' sub-tab of the ''Time'' section.
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| − | '''Clear''': remove all windows.
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| − | '''Load''': load windows from previous processing stored in a [[Geopsy: Load Toolbox Parameters|name.log]] file.
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| − | <br style="clear: both"/>
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| − | [[Image: Windowing_Auto.png|thumb|left|300px|Resulting ''Auto'' windowing]]
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| − | <br style="clear: both"/>
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| − | [[Image: Windowing_Inverse.png|thumb|left|300px|Resulting ''Inverse'' windowing applied to the above ''Auto'' windowing]]
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| − | <br style="clear: both"/>
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| − | == References ==
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| | <references/> | | <references/> |
