Pan (Left click and drag mouse)The guide leads the user through the process of importing, displaying, processing, interpreting and exporting a set of sub bottom profiler data. However you may jump to specific chapters by following these links:
P4 3.0 GHz processor with 2GB RAM and 128MB Graphics card.
.NET 2.0 with Win2000 Service Pack 4 or Windows XP Service pack 2, and Intel's IPP5 libraries.
.NET 2.0 can be downloaded and installed from the Microsoft Website:
The IPP5 libraries are available here:
http://www.tritonimaginginc.com/site/content/public/downloads/Drivers/IPP5/IPP5_Installer.zip
The SEGY format has a number of different conventions for the file name extension, although internally the file may adhere to the SEGY format specification.
SB-I reads SEGY files with these extensions: *.SEG, *.SGY, *.SEGY
SB-I also reads .TRA files recorded by the DelphSeismic products. (Assuming that the .TRA files are SEGY format)
In addition SB-I will read and process a Triton .XTF file that has a Sub Bottom channel.
SB-Interpreter creates a Geo-referenced image, therefore data files must contain valid navigation data, either as Lat/Lon degrees or grid coordinates (meters)
SB_Interpreter has a number of different modes, these are selected from the toolbar: Pan/Zoom, Select, Pick etc
The cursor changes from the standard up/left arrow to these cursors when in the various modes:
Pan (Left click and drag mouse)
Select/Edit (Left Click to select, drag to move)
Zoom (Right Click and drag Window)
Measure (Left Click and drag)
Pick (Left click to create a new reflector point)
The first task is to process the navigation and start a project file.
Start SB-Interpreter and choose either Import File or Import Folder:
By default SB-Interpreter assumes that the navigation data are in Lat/Long related to the WGS84 datum, then SB-Interpreter will read the navigation, automatically selecting the correct UTM Grid Zone.
If you know that the navigation data are Lat/Long WGS84 you may skip the next section and follow from here.
If the navigation data are in some other coordinate system you will need to setup the correct parameters. There follows a description of three different scenarios where you will need to use the Geodesy dialogs in SB-I.
If the navigation coordinates in the data file are in degrees Lat/Long coordinates, but they are related to another datum not WGS84 click on View>Application settings, and select the Projections Tab:
Click Import Projection, the following dialogs will allow you to select a different Datum.
If the coordinates in the file you are reading are not Lat/Long degrees then SB-Interpreter will automatically open the projection dialogs so you can select the correct Zone in the case of UTMs, or the projection information that applies to your data.
In this example the data were logged in a Mercator projection with a Central Meridian 0E and a Standard Parallel 41.5N the False Northing was 2000000 meters:
After loading a line SB-I detects that the coordinates are not Lat/Long and opens the Import Projection Dialog:
Select the correct Projection and click Next:
Enter the correct parameters and click Next:
Select the correct datum and click Finish
SB-Interpreter will take some minutes while it searches the various projection information, if there is a problem with the information you entered the following message is displayed:
If all is well the navigation track-line is displayed. You would be well advised to do a sanity check on the cursor position, make sure that the Latitude and Longitude agree with the estimated position for your data:
Once again SB-I detects that the navigation coordinates are not Lat/Long degrees and opens the Import Projection dialog.
Select Universal Transverse Mercator:
And the correct Zone and North / South click Next
Click Finish the (Datum will be WGS84)
Save a project file at this point, click File>Save Project As to create an .SBI file.
You can then check that the projection information is correct by opening the .SBI file in the Project file reader:
If you choose a folder containing a number of files SB-I will spend a few moments scanning all of them and creating cache files for each, the creation of these cache files is an integral part of the processing and only occurs once, the next time you access these files they will load more quickly. A progress bar can be seen at the lower left side of the main window:
You may encounter a Warning message during this operation informing you that for some reason, there was no navigation found for some pings, in that case SB-I simply ignores those ping data:
Once all the files have been scanned, SB-I will display a plot of all the tracks in the map view, note that SB-I assigns a (P)rofile number to each line and displays P(n) alongside the track line:
To process the navigation in all lines RIGHT click on "Seismic Files" in the File View window:
To process the navigation in individual lines RIGHT click on the specific line name.
The Process Navigation dialog opens, click Filter Setup:
NOTE: Changes made to the navigation are only applied to the cache file for use by SB-I, the data in the original SEGY or XTF file are never changed.
Width - The navigation filter used is a "Boxcar" or Sliding Average filter. The basic parameter for this filter is the "Width" or number of points to be included, increasing the number of points increases the amount of smoothing that is applied to the position, 12 is the default.
Source - Sensor is the default, in an XTF file you may wish to choose the Ship position, in a SEGY file these positions will be the same. Smoothed - use the already smoothed position from the cache file, (that is smooth again)
Auto compute - If heading or speed are not available in the original file they can be calculated and saved in the cache file.
Speed - A basic speed filter to remove large jumps in navigation.
Layback - None - no layback applied, use the navigation found in the original data file. Computed - use the layback stored in the (XTF) file to compute the position. Manual - enter a value to be applied.
Method - Rigid body - use the heading computed or stored in the cache file (not usually a good idea except in special cases). Track walk - project the entered layback value back along the vessel track to compute the position (Default)
Offsets - Specify a offset in XY coordinates to apply to the position.
Click OK to continue:
Click Start - the navigation data data for each line are processed and saved in the cache file. When the processing is complete click Done to close and exit.
Note that by default that Check Intersections is enabled, after smoothing the track SB-I will compute all intersections, a progress bar will show how this is proceeding. If the area is large with complex lines and crossing points this may take a few minutes:
When all navigation processing is complete SB-I will display the smoothed navigation and the intersections:
The new cache files have a file extension of .SGC for SEGY file and .XTC for XTF files:
To change the thickness and/or color of the navigation track line, go to the View>Application Settings menu in the Main Map window:
After processing the navigation and computing the intersections it is recommended that you again save a project (.SBI) file. Click File>Save. You can quickly open this .SBI file by choosing File>Open Project from the main menu. The navigation in the cache files is already processed.
Note on project files
The .SBI file holds all of your project information, including information about projections, picked reflectors, lines processed, GeoTIFFs, intersections, profile display settings and much more. There is an option in the View>Application Settings dialog to have this file saved automatically at a user defined interval which can save losing recent changes in the event of a power outage, also when you close SB-I you will be asked if you want to save the current project file.
Warning
If for some reason the program encounters an error and you are forced to close and re-start do NOT save a project file; or if you do save it to a different name, under those conditions it is NOT advisable to overwrite your current project file until you have made sure that the new file is good.
Clicking the pan/zoom Icon allows the following functions:
Zoom Window - RIGHT click and drag to Zoom in on a point.
Pan - LEFT click and drag.
Zoom In - Page Down, + key or ToolBar Icon
Zoom Out - Page Up, - key or ToolBar Icon
Zoom Home - (Zoom Extents) - Home key or ToolBar Icon
Zoom 1m / pixel - ToolBar Icon
Measure Tool - Measure horizontal/vertical distances in the Map Window:
SB-Interpreter v1.5 can import and display background images, the GeoTIFF and .JPG formats are supported, also layer transparency, click File>Import GeoTIFF:
The GeoTIFF image must have either internal tags or an external .TFW (World File) if neither exists for the chosen image the following message is displayed:
The .JPG format is also supported, but in that case no internal tags will be available, an external .JGW file is needed. The format of the .JGW file is exactly the same as the corresponding .TFW file, (you can simply rename a .TFW to JGW)
The file is a simple text file, here is a typical .TFW or .JGW file:
20.17541308822119
0.000000000000000
0.000000000000000
-20.17541308822119
424178.11472601280548
4313415.90726399607956
And here’s what these six values represent (the values must be in this order in the file)
20.17541308822119 The dimension of a pixel in map units in the x direction (the x-scale)
0.000000000000000 Rotation term for a row. (rarely used )
0.000000000000000 Rotation term for a column (rarely used)
-20.17541308822119 The dimension of a pixel in map units in the y direction (the y-scale)
424178.11472601280548 The x coordinate of the center of the upper-left pixel in map units.
4313415.90726399607956 The y coordinate of the center of the upper-left pixel in map units.
Note that the y-scale is the negative value of the x-scale.
SB-I currently only supports geo referenced background images with coordinates in meters
If all is well, the image will appear in the correct place, (its worth checking!)
Multiple backgrounds can be imported and the transparency of both the image and its background controlled.
Here a side scan mosaic is overlaid, and the black background suppressed:
The Layer Alpha slider allows control the overall transparency of a layer:
To control the display order RIGHT click on the image in the tree view and choose Move Up or Move Down
RIGHT clicking on Seismic Profiles and choosing View All will open all profiles in the project. To open individual profiles RIGHT click on the profile name and choose View.
NOTE: If dual monitors are available, the profile window(s) will open on the second monitor, using the full width of that monitor,
Each profile window will display all available crossing points as red vertical lines annotated with the P)rofile number:
Initially the profile will display as raw (unprocessed) data:
Pan and Zoom Mode, RIGHT click and drag to create a zoom box, release the mouse button to Zoom the selected area:
LEFT click and drag in the window to PAN across the entire profile.
Zoom Tool +, Click to zoom in on the current window (<Page Up> and <+> keys)
Zoom Tool -, Click to zoom out on the current windows (<Page Down> and <-> keys)
Zoom Tool 1:1 - Display Image at maximum resolution. (<End> key)
Zoom Tool Home, Click to zoom extents of the whole profile (<Home> key)
Settings Mode
The settings button opens the settings Dialog which has 6 Tabs, the first is the Channel Tab which on multi-channel data allows the selection of which data channel to process 1-24, (only valid channels found in the data file will be available)
The LUT tab contains not only the LUT (look up table) selection but also the overall gain control, and is probably going to be the place to start with the image processing:
Moving the Flat Gain slider to the right increases the overall gain of the whole profile:
NOTE: At the bottom of each window in the Profile settings dialog you can select either All or individual lines to process by clicking the dropdown arrow. The default is All.
The Filter tab has a number of functions including the AGC, TVG and Bandpass filter settings:
In this example both the AGC and TVG processing is ON, the Bandpass filter is ON with the High Pass cut-off set to 100Hz, the Low Pass cut-off set to 1100Hz.
The Apodization functions are more fully described in the Help menu.
NOTE 1: The tools used here may not be appropriate for all types of data. The example shown is analog data containing both positive and negative signal components. This type of data is generally much improved by the use of the Bandpass filter. Other data types ("Chirp" or "FSSB" for example) may contain unipolar signals (positive only) and the use of the bandpass filter for this data is inappropriate. For that type of data only AGC, TVG and flat gain should be required.
NOTE 2: Use the Stacking tool with caution, it may help to remove some noise from the imagery it can obscure steeply dipping or undulating reflectors.
The LUT (Look Up Table) can also help the visualization. For analog data with both positive and negative signal components a bi-polar LUT may be useful:
When this Bi-Polar LUT is applied to analog data the positive signals display as Red, the negative signals as Blue:
You may also select which signal polarity to display by using the Signal Tab:
None: - Display both the positive and negative signals (Red and Blue)
Negative: - Display only the negative signals (Blue)
Postive: - Display only the positive signals (Red)
Rectified: - Rectify the signals and display as positive only (Red)
NOTE: For most "Chirp" data the rectified display is preferred because the signals are unipolar. (Under the LUT tab there are also unipolar LUTs)
Vertical and Horizontal downsampling - affects which parts of the signal are discarded when the data are downsampled for display on the PC monitor. In general using Max seems best; on a very long line with a high shot density choosing Max can improve the image considerably.
The Velocity tab allows you to select the default Velocity to use for both the water column and the sub seabed:
The Annotation tab controls the way various Grids, rulers etc. are shown in the profile window:
Bottom tracking should be done after any signal conditioning or filtering.
The first task is to track the bottom and assign that reflector as R0; to access the bottom tracking tools click the settings button;
And then select the Bottom Track tab:
Use the Method drop down to select Amplitude, note that the other controls Level, Holdoff, Delta and Delta Sensitivity become available.
Level. The percentage of the maximum signal level that will trigger the tracking gate
Holdoff: Bottom tracking will not start until after this time.
Delta: The maximum acceptable difference in milliseconds that the tracking gate will accept from ping to ping
Delta Sensitivity: This allows very small changes in the Delta value to be achieved, it has been found that very small chnages in the the Delta value can have a large effect on the bottom tracking quality.
ms/m: The default units are Milliseconds you may also choose meters (m)
1. Set the Level to around 10% -15%
2. Set the Holdoff to a value just above the shallowest part of the data.
3. Set the Delta to about 2mS (make sure its NOT zero!)
4. Delta Sensitivity to 15%
5. Hit Compute
A red line will appear on the section, depending on the comparative signal levels in the data it may look like this:
In this case the threshold has been set too low, increase it and hit Compute again:
Now the value is too high, the gate is looking for a higher signal level than it finds at the seabed, it should be possible to arrive at a threshold level that very nearly tracks the entire bottom:
There may still be areas where the gate has tracked on some noise in the water column. Use the Delta setting to constrain the gate so that it more closely follow the shape of the bottom, you may find that very small changes need to be made here. Reducing the Delta Sensitivity to 1% will allow you to adjust the Delta value by as little as 0.02mS:
Note that the amount of swell filtering to be applied set when you hit Compute however it is not applied at this time see Swell filtering.
NOTE: Be careful in areas where the seabed has large changes in depth, if you constrain the Delta too much here it will not follow the bottom contours accurately:
Tracking the bottom in areas like this when the water column is noisy can be difficult.
Once the bottom has been tracked the information is automatically stored in one of the cache files that SB-I creates for each SEGY file, any time the line is displayed the bottom track information is also displayed.
Bottom track Display options:
To turn off the display of the red bottom track line use the tool bar icon:
To change the thickness and/or color of the bottom track line go to the View>Application Settings menu in the Main Map window:
You may also use the tracked seabed as the origin for the TVG:
In this case the normal TVG curve starts from T0 (transmit) and additional TVG is applied from the seabed down.
Go to any open profile window and enter the digitize mode, by clicking the reflector Tab:
Once the Reflector Tab is active it is possible to switch between Digitise:
And Select/Edit
Initially there will be only one reflector visible in the table R0 - this is assumed to be Seabed, you may edit the name as required. If you have used the bottom tracking option to track the seabed you can simply assign the tracked seabed to R0:
And select Auto Generate Seabed:
SB-Interpreter superimposes the seabed reflector R0 over the bottom track. by default it does not use ever ping but only every 20th ping, this downsample can be changed from the Main Map view Window View>Application settings Misc tab:
Once the seabed reflector has been created in this way it becomes a normal reflector that can be edited by clicking and dragging, as described below.
To start a new reflector right click on Reflectors and then Add Reflector; the next reflector name defaults to R1:
Pick R1. Repeat as necessary for each reflector, if you make an error Undo is available; either Edit>Undo or CTRL+Z, you can undo back to the start of the currently selected reflector.
Click this icon and select either a single point or a selection of points using Right Click and drag:
A number of tools become available under the Edit menu and in the tool bar:
Cut, Copy and Paste allow you to Cut and Paste the selected points to a new or existing reflector in the current profile.
Delete will delete the selected point(s)
Break allows you to break the current reflector.
In this example we can move to the other side of an erosion surface:
R1 is not continuous, "jump across" the discontinuity and then enter Select Mode, select the point immediately before the start of the erosion surface:
Now click Edit>Break:
Later, when thickness R0 > R1 is exported this area will have no data.
You could also select the right hand set of points (right click>drag) and rename them to another reflector.
Join behaves in the reverse manner, allowing you to append points to a reflector - (only if the two reflectors have the same name).
Click the Measure tab to use the measure tool: left click and drag to make a measurement of Horizontal Distance, Thickness, (in meters or mS) and slope in degrees.
Click the Reverse Image button to swap the image L>R in the window. Note that this can be done after reflectors have been picked.
Click the Show/Hide Image Icon to show only the picked reflectors without the background:
Click the Next Channel Icon to display data from the other channels that may be stored for this section. Typically this might be the "real" and "imaginary" channels from an Edgetech Chirp system:
Once you have bottom tracked the data you may want to try and remove distortions in the image caused by swell motion:
To actually apply the filter to the image, return to the Bottom Track Tab:
Check the box Show swell correction and hit Apply
SB-Interpreter adjusts the image.
The amount of smoothing is determined when you hit compute during the bottom tracking procedure, if you need to change the amount of filtering applied you must return the bottom track area of this dialog box, change the Swell filter width value and hit compute again.
WARNING
SB-Interpreter cannot distinguish between swell motion and actual seabed topography, there is a danger that you may distort the data by applying swell correction in area where there may be regular features such as sand ripples, some knowledge of the local topography and geology is needed to use this tool correctly.
These are genuine sand ripples (mega ripples)...
Almost completely removed by inappropriate use of a heavy swell filter!
By default all crossing lines are displayed as a red line on the current profile, and all intersecting reflectors as R1 , R2 etc. with a dot where the intersection occurs:
The line intersections will draw as soon as the crossing profile is displayed. As the reflectors are added, the reflector intersections are also updated on the crossing line, allowing the user to check the validity of the information.
The profile folding feature attempts to reproduce the "folded paper record" method of checking reflector intersections across lines. It is a special mode accessed from the Folding Icon in the Map window toolbar:
With a set of lines loaded in the map window, clicking this Icon immediately opens a new window called "Profile Folding™". The Icon is not available until you have processed the navigation and computed intersections
Any adjacent section of a profile that has an intersection can be displayed as a part of this new "composite profile" by clicking in the main map window, in this example the box formed by Profile P1,P0,P2 and P4 has been displayed as a Folded Profile.
The new composite profile can be used in exactly the same way as any other profile window, reflectors can be selected, and edited. Also new reflectors can be created in this window, the relevant parts of the new reflectors being displayed back in the original profile window.
NOTE: The Settings Icon is disabled in the Folded Profile view.
Once all the reflectors have been picked there are four ways of exporting the information.
1. Individual or all profiles can be printed, with our without the picked reflectors,
2. The information can be exported as XYZ ascii text files either as thickness or as depth to a reflector.
3. A vertical TIFF image (image curtain) can be written
4. An Scientific Data file (.SD) can be saved and imported directly into Fledermaus from IVS 3D
Hitting Print from the map window opens a standard windows print dialog where the printer type, paper orientation can be selected.
The following dialog is then displayed allowing you to selected how many profiles per page and what you want to print, also the spacing (pixels) between profiles:
Clicking the Settings button allows you to choose the printer you want to use.
NOTE: if you have Adobe Acrobat installed than you can print directly to a .PDF file:
From either the Map window (all profiles) or from the individual profile windows you can select the export option:
Click the ... button to select the output folder, and select the Format. The units for the Z value can be Seconds, Milliseconds or Meters.
NOTE: for the Depth (meters) output you need to enter a suitable velocity,
both for the water column and sub seabed. This dialog is in under the
Settings 
button for each profile:
The X,Y coordinates can either be Lat/Lon (Decimal Degrees) or UTMs (meters) for the current grid zone, you may also choose to have the depth measured from the sea surface or from the picked seabed.
Hit Export to create the files, a progress indicator will show when the operation is complete.
Each reflector is saved in a separate folder which bears its name:
The ASCII file names will be:
<line name>_<reflector name>_XYZ.txt
Click on the the upper (left box) and lower (right box) reflector names for which you want to export a thickness value.
The remainder of procedure is the same as for the Reflector export. Again each ASCII file is saved to a folder that bears the name of the upper chosen reflector, in the example the thickness file will be saved to the [R2] folder.
The ASCII files have a name <line name>_<upper reflector>_<lower reflector>_XYZ.txt
Checking this box allows you to export the original SGY file but with the modified/smoothed navigation that was used for the reflector picking, (including layback, if that was selected)
Use the ... button to select the target folder, check the files you want to export and hit Export. A progress bar indicates when the operation is complete. The new files will have the same name as the original, but with _nav added before the .SGY extenstion.
NOTE: Since this operation is rewriting the whole SGY file it can take quite a while to complete.
Can be created with or without the picked reflectors and other details along with a .txt file describing the georeferencing information. Note this is NOT a GeoTIFF, because it is a vertical image.
The dialog box is self - explanatory. Turning on the Along Track Correction will correctly locate each shotpoint in the image, but will prevent the user from entering a horizontal dimension for the image (pixels) that is greater than the number of shotpoints on the line.
At present this is a "flat" mage and does not take into account variations in ships track from the mean line heading. (Start/End line coordinates)
An example of the TXT file associated with the Image Curtain output follows
# Triton SB-Interpreter Image Exporter
#
# File : 20040930THU_EW5.tif
# Along Track Distance : 2069.6 meters
# Vertical Depth : 149.0 meters
# Vertical Offset : 1.1 meters
# Vertical Depth : 99.3 milliseconds
# Vertical Offset : 0.8 milliseconds
# Vertical Exaggeration : 6x
#
# Right edge coordinates : 635309.900, 4901963.686
# Left edge coordinates : 636957.787, 4901776.334
The export routine supports either batch mode or single section export, and can be invoked either from the File>Export>IVS SD File menu or from any profile window:
or from the map map window:
The following dialog box is displayed:
Folder - the location where the .SD files will be created, you may choose or create a new folder, the default is to create the files in the same folder as the .SEGY files that are part of the current project.
1 Pixel/Shot - this option works well for normal length (up to about 5,000 pings) for very long lines you should specify a width in pixels
Vertical Exaggeration - set to 3 to match the Fledermaus default
Muting - normally choose to have the water column muted (Hidden) so that it becomes invisible in the IVS display, however you may wish to display the water column data and fill the sediment (Sub Bottom) with a single color, if you are mostly interested in imagery from matter in the water column.
Use R0 - force the muting to occur from R0 instead of the bottom track
Navigation - Set the navigation coordinate system. If you are intending to import the .SD fiel into and existing Fledermaus .scene file you must make sure the projection and coordinate type matches that of the .scene file.
Screenshot from IVS 3Ds Fledermaus showing 5 profiles.
