About single targets derived from multibeam data

Creating single targets from multibeam data

Using the Target Conversion operator to create a Single Targets echogram allows you to analyze these data as if they were single targets. An advantage of this method is the ability to export and then re-import the data into your EV file. This breaks the link for the chain of virtual variables, and increases the speed of processing time for the single target data. Use Synchronize To Target to synchronize a single target to the associated multibeam target.

Single target detection can be optimized using virtual variables to manipulate the data to remove background noise.

Step 1. Reduce the potential for missed single target detections by smoothing the echo intensity with a Convolution filter.

Step 2. Remove the background noise, for example, with the Sample statistic subtract operator.

Step 3. Identify single targets with the Multibeam target detection operator.

Step 4. Use the Threshold operator to remove unwanted targets.

Step 5. Use the Target conversion operator to create single targets.

Exporting single targets

1. On the Export page of the EV File properties dialog box, select Output empty single target pings.
2. Click on your Single Targets echogram to make it active.
3. On the Echogram menu, point to Export and select Single Targets.
4. Enter a name for your .target.csv file and click OK.

Importing single targets

1. Create a new fileset in the EV file that you want to import the single targets data to.
2. Open the Filesets window (F10).
3. On the Fileset menu, click New Fileset.
4. Enter a name for the new fileset in the Fileset Properties dialog box.
5. Click OK.
6. In the new Fileset, click Add to import your data.
7. Navigate to the exported .target.csv file and click Open.
8. The .targets.csv file is added, and a raw variable is created.
9. Open the new raw variable. Note: It may not appear similar to your original echogram at this stage.
10. Open the Echogram Display page of the Variable Properties dialog box.
11. Match the values to those on the original data.
12. Click on the Calibration page of the Variable Properties dialog box.
13. You will see that there is no calibration inheritance.
14. On the Dataflow window, select the raw variable.
15. Right-click, point to New and select Variable.
16. Show All operators and select the Copy operator.
17. Click OK.
18. In the Variable Properties dialog box of Copy 1.
19. Choose an appropriate name for your new variable on the Notes page.
20. Click on the Calibration page, and check that it now has inherited calibration.

See also

About single targets
About single target detection
About multibeam targets
Target properties from multibeam data