Removing noise and spikes with the Profile Editor (G09)
Contents
1. Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Removing noise and spikes with the Profile Editor G09 7 Library Help Top 4 Back gt Select line 2742 4 Display the profile of line 2742 Use the Next Previous or Goto buttons to display line 2742 if it is not already showing Intrepid Profile Editor yo oo File Edit Layout Window Help ebagoola_S DIP E dit Profile raw_ mag Search Profile Line 2 742 Mouse Mode C Mowe Points OC Select Points C Query Points f Zoom Navigate By Line lt lt Previous lt lt Goto gt gt Display a copy 5 Opena second copy of the raw_mag field with a Naudy noise filter applied ae ai From the File menu choose Load Signal Field INTREPID displays the Select filter Signal Dataset dialog box Select raw_mag Choose OK INTREPID displays the Apply Signal Filter dialog box Select Naudy then choose OK INTREPID displays the Naudy Filter Parameters dialog box Set Tolerance to 0 1 and Wavelength to 5 The units here are 0 1 nT as the spike finder threshold and filter length of 5 data points in a moving window patiaa a Siena Naudy Filter Parameters Tolerance z Units 0 10 C 4th Difference Wavelengths Data Points 2 C Gradient _ _ _ _ _ OK Cancel OK __ Cancel Choose OK Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Libr2. This guided tour is intended for intermediate level users Its process is more complex than that of an introductory level tour and its instructions are less detailed If you are a beginner or wish only to have a brief overview of INTREPID s capabilities you can omit this guided tour Omitting this guided tour will not affect your understanding of later tours Examining time series profiles of your signal is often very helpful especially when you also do before and after comparisons Similarly noise and spike removal is an important step in processing geophysical data Gradiometry With the advent of support for FTG or full tensor gradiometry data an intersting application is the ability to inspect for correlations of the components with the terrain correction signal and then deciding what terrain denisty to use to minimize the correlations The tool has options for Falcon FTG Vector field data and a Quaternion or 3D rotations signal The linear vetorization of a 3D rotation matrix is becoming a lot more popular as a result of better instrumentaion systems being deployed upon aircraft Some of the geophysical signal can be ascribed to the wrong field gradient components when there are errors in measuring the Roll Pitch and Yaw of the aircraft The traditional compensation process to unscramble the signal using figures of merit and a 16 to 18 term polynomial embedded in a black box has done great service over the past 20 years but the
3. There are two traces in the Profile Editor window Select raw_mag Naudy for automatic editing This means that you will be searching the raw_mag field for noise as detected by the Naudy filter Choose Search Profile INTREPID displays the Select Search Profile dialog box with a list of profiles that are currently displayed Select click raw_mag Naudy r Select Search Profile 7 a raw_macq raw _magq NAUDY Ok Cancel Choose OK INTREPID displays the name of the profile against the Search Profile button and place a red frame around the profile in the display Specify the domain set of lines for automatic editing to include line 2742 only Choose Select Domain in the Condition dialog box INTREPID displays the Select Search Domain dialog box containing the list of loaded lines Select click line 2742 Choose gt gt to include line 2742 in the domain INTREPID will show it in the Selected lines list Choose OK in the Select Search Domain dialog box INTREPID will report the selected domain against the Search Domain button in the Condition dialog box Choose Apply in the Condition dialog box INTREPID displays the Confirm Action dialog box for every spike found You have to choose to either edit or ignore each spike In the top window the current spike has a red box drawn to mark its position in the profile f Select Search Domain E Loaded Lines Selected Lines CONDITION CONFIRM ACTION Eh me S
4. INTREPID User Manual Removing noise and spikes with the Profile Editor G09 1 Library Help Top q Back gt Removing noise and spikes with the Profile Editor G09 New survey data often contains errors that need to be removed for example e Noise small high frequency fluctuations in measurements due to extraneous factors or small shallow irrelevant data sources e Spikes a single point of noise In order to correct these errors and also for general viewing of line data it is helpful to be able to view a profile of the data collected along each line The Profile Editor enables you to do this In this guided tour you will examine the profiles of lines of a dataset You will then remove the noise and spikes using a variety of methods You can examine the results in a new grid This illustration shows a raw data line and the same line with noise and spikes removed Intrepid Pronita Teaia ii El Before noise and spike removal _ File Edit Search ZNoise Layout elp After noise and spike removal Select Points Overview The Profile Editor is one of the INTREPID editors Spreadsheet Flight Path auto clip line split cruise and Profile It provides a time and line based view of the data showing the profiles of individual lines one at a time Itcan calculate filters such as Naudy and 4th difference and display the results e You can use this tool to quickly and effectively identify
5. and edit noise It supports vector tensor and quaternion signal fields as well as the traditional scalars tis geared to work on a time series perhaps before the geolocation of your signal has been carried out It supports current next and previous overlays of profiles e Profile Editor enables you to e Select and change the values of data points using the mouse Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top Removing noise and spikes with the Profile Editor G09 2 4 Back gt Automatically filter an entire dataset Compare different fields from the same line of the same dataset Perform extensive range checks on the data Look at profiles of full tensor data and search for noise spikes Superimpose profiles of data components before and after noise filtering Profile Editing process This illustration on the first page of this guided tour shows a line profile of magnetic data before and after noise and spike removal The upper profile shows noise at regular intervals along the line and two spikes The lower profile shows the same line data with the noise and spikes removed Grids produced from data before and after use of Profile Editor This illustration shows grids produced from magnetic data before and after noise and spike removal The left grid produced from data still containing noise and spikes shows many small pin prick anomalies due
6. ary Help Top Configure search options Library Help Top Removing noise and spikes with the Profile Editor G09 4 Back gt INTREPID displays the profile showing Naudy noise levels Intrepid Frofile Editor File Edit Layout Window Help h ebagoola_3S DIR Edit Profile raw _ mag Search Profile Line 742 ii Navigate By lt lt Previous f Line Automatic noise removal C Fid in line lt lt Goto gt gt Next gt gt 6 Set the Find options to interpolate edited points From the Edit menu choose Find INTREPID displays the Condition dialog box Select Interpolate from the Action options E Intrepid Profile Editor File Layout Window Help Cut Interpolate Add Constant Add Slope Add Triangle Cut All Traces Interpolate All Traces Undo Find Supervised Range Clip Supervised Step Correction Spline Interpolation Mode Linear Interpolation Mode List Selected Points Mouse Mode C Mowe Points C Select Points f Query Points f Zoom p N FIND AND REPLACE CONDITION Search Profile Not Selected __Search Domain Not Selected Search Outside Range Min Ld Mex __ CONTROL Confirm C Apply All Apply Cancel 2012 Intrepid Geophysics 8 4 Back gt INTREPID User Manual Removing noise and spikes with the Profile Editor G09 9 Library Help Top Library Help Top q Back gt
7. ch one and place them side by side on the screen for best comparison See the first page of this chapter for an illustration of grids produced before and after a profile editing session 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Removing noise and spikes with the Profile Editor G09 15 Library Help Top 4 Back gt Exit 13 Exit from the Profile Editor without saving any of your editing From the File menu choose Quit INTREPID displays the Save Before Exit dialog box Please Choose Choose No The Profile Editor will exit Key points for this guided tour In this guided tour you have used the Profile Editor to Apply filters and perform range checks on the data Demonstrate automatic filtering that could be performed on an entire dataset Remove a spike by interpolating between points on either side of the spike Using the Profile Editor you can also Select and change values of data points by moving them with the mouse Frequently Asked Questions Q Can I superimpose profiles A Yes but in separate synchronised windows You can load as many different fields of the dataset as you wish The Profile Editor enables you to load and display as many field profiles as you wish Each profile displays in a separate window The Profile Editor synchronises all windows so that it always displays the same part of the same line in each window Q Can I also examine gradient rotational and tensor da
8. d_tours geosoft_datasets For example if INTREPID is installed in C Program Files Intrepid Intrepid4 5 nnn then you can find the INTREPID format sample data at C Program Files Intrepid Intrepid4 5 nnn sample_data guided_tours intrepid_ datasets This is the default location for the sample data If you have installed INTREPID normally the data resides there If you have installed INTREPID elsewhere the exercises will work just as well Just use the appropriate pathnames For more information about installing the sample data see Sample datasets installing locating naming in INTREPID Guided Tours Introduction G01 For a more detailed description of INTREPID datasets see Introduction to the INTREPID database G20 For even more detail see INTREPID database file and data structures R05 Location of sample data for CookBooks Right next to the Guided tours data is a rich set of more exotic geophysics datasets and grids already prepared for the cookbook training sessions A casual user might also gain some trial and error insights into the capbilities of the software just by testing the Project Manger s ability to preview and describe the attributes of each of the cookbook datasets 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Removing noise and spikes with the Profile Editor G09 4 Library Help Top lt 4 Back gt Should you complete this guided tour W Library Help Top
9. dit INTREPID will remove noise from the rest of the line Observe the effects of the noise removal in the top trace which shows the raw_mag data without noise filter Observe also that the automatic noise removal removed the low amplitude noise from the data but not the larger spikes B A Fl Intrepid Profile Editor oe File Edit Layout Window Help ebagoola_S DIP E dit Profile raw_mag S earch Profile raw_mag Line 2742 Information al EN Search Finished i Navigate By Line C Fid in line OK lt lt Previous lt lt Goto gt gt Next gt gt Manual spike removal by interpolating between points on either side The spikes have yet to be removed from this data You can remove them manually by e Moving individual data points to correct the spike or e Cutting out the spike and interpolating across the gap In this guided tour we will use the second option interpolate across the section of a line that contains a spike 8 Define a section of the profile enclosing a spike ready for interpolation Select Select Points mouse mode Mouse Mode C Mowe Points C Query Points C Zoom Move the mouse pointer to a point on the profile just to the left of the spike Hold down the mouse button and drag to a point just to the right of the spike A pair of blue lines will appear marking the region as you select it 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Removing nois
10. e and spikes with the Profile Editor G09 12 Library Help Top lt 4 Back gt Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Removing noise and spikes with the Profile Editor G09 13 Library Help Top 4 Back gt When you release the mouse button INTREPID displays red markers on the points selected RAHM To remove the spike choose Interpolate from the Edit menu E Intrepid Profile Editor J p aun eel a FE Intrepid Profile Editor P File Edit Layout Window _ Help File Edit Layout Window Help RAW Cut Interpolate Add Constant Add Slope Add Triangle Cut All Traces Interpolate All Traces Undo Find Supervised Range Clip Supervised Step Correction vV Spline Interpolation Mode Further practice and saving your results Repeat the 9 process Saving occurs 10 at this point If you require further practice repeat the process with the other spikes in line 2742 and with the noise and sptkes in lines 2751 2761 and or 2771 Normally you would save your edited Signal field at this stage This has been a brief demonstration of Profile Editing After completing the process you would normally save the edited Signal data Since you have only processed a small portion of the data we recommend that you do not save your work Tip We have provided a solution field smooth_mag which contains data with noise and spikes rem
11. earch Profile raw_mag NAUDY Point Found Search Domain Sia APPLY TO ACTION Search Outside Range cles Point Max C Line S e All ignore C None Confirm n C Cut C Apply All Close Interpolate Apply Cancel 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Removing noise and spikes with the Profile Editor G09 10 Library Help Top Apply automatic editing Library Help Top lt 4 Back gt Apply the automatic editing you have specified one by one to the first few instances of noise detected by the Naudy filter then automatically to the rest of the line Ensure that Point is selected from the Apply To options in the Confirm Action dialog box Choose Edit INTREPID will find and correct the first noise point in the line indicating the next instance of noise with a small red square RAW_MAG HAUDY Next noise point Choose Edit a few times Each time you choose Edit INTREPID will edit the next instance of noise RAWMAG HAUOT Next noise point 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Removing noise and spikes with the Profile Editor G09 11 Library Help Top Select line section containing a spike then remove the spike Library Help Top lt 4 Back gt Once you have observed the process working apply the automatic editing to the rest of the line Select Line from the Apply To options Choose E
12. ints C Select Points Query Points C Zoom Navigate By Line C Fid in line lt lt Previous lt lt Goto gt gt Next gt gt Display a 2 Opena dataset and display the raw_mag field preys From the File menu choose Load Signal Field INTREPID displays the Select Signal Dataset dialog box Open the ebagoola_S dataset directory install_path sample_data guided_tours intrepid datasets ebagoola_S Select raw_mag Choose OK INTREPID displays the Apply Signal Filter dialog box Select None then choose OK Select Database Daas Select Signal Field P o m Jasi J LocalDisk C gt Intrepid gt V45 gt sample data gt guded_tours gt mtrepid_datasets gt a Sn ee Organize New folder ri Intrepid Profile Editor Edit Layout Window Help Load Signal Field Pa Load Tensor Field BE Desktop i APPLY Signal FILTER Load Vector Field Boa Load Quaternion Field C Ath Difference C Gradient OK Cancel evy aaa o Close Documents Save ial Pictures Z ebsgocls A DIR Save As Load Options i 7 Save Options i Local Disk C Quit Filename ebagoola_5 DIR Examine 3 Examine the profiles of several lines profiles of i ee ee Choose Next and Previous to examine the next or previous line Note the noise patterns throughout all profiles and the larger spikes in lines 2742 2751 2761 and 2771 INTREPID displays the line number at the right of the screen
13. kes in this region of line 30138 See Deciding which line to clip in an overlap area in Editing with the Flight Path Editor G10 for an illustration and further discussion of this problem Examining the results in a grid This section is optional If you do not wish to create or examine a grid from the results of the profile editing process go to Step 12 You will create a grid using a Signal field from which noise and spikes have been removed and compare it with a grid that contains noise and spikes You can specify the input output and parameters for creating the grid in this stage of the guided tour using the job file ch10_1 Job If you wish start the Gridding tool and load the job file as described in Task specification job file short cuts in INTREPID Guided Tours Introduction G01 Choose Apply The Gridding tool will create the desired grid 12 Optional Create a grid dataset called smooth_grid1 from the smooth_mag field of the ebagoola_S dataset Recall the instructions in Creating grids G07 for creating grid datasets Optional Use the Windows Visualisation Tool to compare the grid created from a noise containing Signal field raw_grid with a grid created from a Signal field from which noise has been removed smooth_grid identical to smooth_grid1 you created Recall the instructions in Visualisation tools G05 for viewing these datasets Tip You can launch two copies of the tool load a different grid into ea
14. oved The following guided tours which demonstrate the next steps in the survey data refinement process will use this field rather than raw_mag Examining a section where two lines overlap This section is optional Go to Examining the results in a grid if you do not wish to KS complete it The ends of lines 3012 and 3013 overlap It is good practice to remove the end of one of the lines as part of dataset processing You can use the Profile Editor to examine the profiles of the lines in the overlap area and determine which line to trim The overlap area is between fiducial counts 528068 and 528192 in line 3012 and between 536052 and 536178 in line 3013 Examine a line 11 overlap region containing spikes Library Help Top Optional Open the smooth_mag field with no filter Turn on horizontal axis display View the profiles on lines 8012 and 3018 in the regions described above Open smooth_mag as described in Step 2 above but with no filter 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Removing noise and spikes with the Profile Editor G09 14 Library Help Top JOB Grid the filtered field and examine the grid Library Help Top q Back gt Choose HAxis from the Layout menu This will show the fiducial count as the horizontal axis scale Examine lines 3012 and 3013 in the fiducial ranges set out above Use the Goto button You will notice that there are spi
15. ta A Yes INTREPID uses a colour code system to allow you to show before and after traces in the same plot using the common scale option Q Can I compare fields with and without noise filters A Yes You can load several copies of a field and display each copy differently including versions of the data before and after processing Q What filter technology is used A All the filters are 1D convolution operators in this tool Library Help Top 2012 Intrepid Geophysics 4 Back gt
16. time has come to face up to the requirement for new and more rigourous treatments of the rotational attitude of the aircraft during acquisition and the deconvolution to tensor vector fields The tensor training course is the best place for detailed material on gradiometry The enhanced cookbook datasets and examples that are next to the guided tours includes some samples for you 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top What you will do Flowchart Summary Inputs Removing noise and spikes with the Profile Editor G09 5 Process Line dataset Library Help Top Select and ea E gt disply one or more fields y Visualise noise and spikes vy Edit noise and spikes 2012 Intrepid Geophysics Outputs Filtered line dataset lt 4 Back gt 4 Back gt INTREPID User Manual Removing noise and spikes with the Profile Editor G09 6 Library Help Top 4 Back gt Steps to follow Launch the 1 Start the Project Manager Navigate to the directory Profile Editor install_path sample_data guided_tours intrepid_ datasets Start the Profile Editor Choose Profile Editor from the Editors menu INTREPID displays the Profile Editor tool m c E Intrepid Profile Editor ee File Edit Layout Window Help Datas et Edit Profile Search Profile Line Zoom Mouse Mode C Move Po
17. to noise and several larger steep anomalies near the bottom due to spikes The right hand grid produced from data that has had noise and spikes removed does not have these anomalies File Edit Line Display PointDisplay Grid Display Window Help Intrepid Flight Path Editor 3 1d Intrepid Flight Path Editor 3 1d File Edit Line Display PointDisplay Grid Display Window Help Before noise and spike removal After noise and spike removal Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Removing noise and spikes with the Profile Editor G09 3 Library Help Top q Back gt Context of this guided tour Library Help Top In the context of your data processing cycle this tour represents an important first or second step in processing a set of newly imported data You should perform this process in conjunction with editing out unwanted sections of flight paths using the Flight Path Editor Location of sample data for Guided Tours We provide two complete sets of sample datasets one in INTREPID format and one in Geosoft format INTREPID works equally well with both formats When you want to open a dataset navigate to the directory containing the required data format Where install_pathis the path of your INTREPID installation the project directories for the Guided Tours sample data are install_path sample_data guided_tours intrepid_ datasets and install_path sample_data guide
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