Target Conversion
This operator generates single targets data from a multibeam targets variable (created using the Multibeam target detection operator). Each resulting single target has a range and major-axis angle corresponding to the range and angle of a multibeam target. Target length data and other calculated target properties can also be displayed and exported from the resulting single targets variable.
You can filter targets for improved fish tracking on the Target conversion page of the Variable Properties dialog box.
Echoview accepts a multibeam targets variable as input.
Warning:
This operator is intended to make Echoview fish tracking feature available to multibeam users. When using it, you should take very careful note of the following in order to avoid any possible confusion:
- Multibeam targets are not single targets. The measurement of Target Strength or TS is currently restricted to single targets. The equivalent measure used in Echoview for multibeam targets is the Target strength source calculation for the detected object on a single multibeam ping. These are not interchangeable measures.
- The TS of targets in the resulting single targets echogram is not TS, it is the Target strength source calculation of the multibeam target which this single target represents. It will however be labeled as, and treated as, TS in Echoview from this point onwards.
- The depth of the targets in the resulting single targets echogram is not equal to the depth of the multibeam targets. The range of the single targets is equal to the range of the multibeam targets. See About single target depths for further information.
- Fish track regions may have an extremely thin part (the region looks like a tear-drop). The extreme thinness is a result of the region avoiding overlapping single targets. In effect, the single target from the extremely thin part is omitted from fish track analysis. Note: For single targets derived from multibeam targets, fish track region creation can be affected by "apparent" overlapping single targets which are really multibeam targets of similar range but they may be located in widely different beams.
- Single target display thickness or Data and Display thresholds may make the observation of overlapping targets difficult. Single target graphs or the 3D single target graph may be useful in characterizing overlapping single targets.
Settings
The Target Conversion Variable Properties dialog box pages include (common) Variable Properties pages and these operator pages:
Operands page
Target Conversion page
|
Setting |
Description |
|
Filter targets |
Select the checkbox to apply a filter to targets in the operand variable. If enabled targets that have a similar range, up to the valued entered under Minimum range difference, will be excluded. Note: This option is useful for improving fish tracking on the resulting single target variable. Without this enabled, most fish tracks created will be invalid, as for a particular ping the fish track may include multiple targets. See About fish track detection. |
|
Minimum range difference |
Enter a Minimum range difference in meters. |