Major-axis beam compensation graph

The Major-axis beam compensation graph is helpful when working with calibration sphere data. The graph takes its data from a single targets echogram and displays the single target major-axis angle versus uncompensated and compensated TS for single targets in a region or selection. The graph has no Graph Properties, graph linking updates automatically and graph export is unavailable.

Within the boundary conditions of the beam compensation model and close the beam axis while insonifying a calibration sphere, it is expected that:

• uncompensated TS data points approximate a parabola centered around beam axis (zero degrees), as dictated by the transducer beam pattern
• compensated TS data points approximate a constant corrected TS value, as predicted by the beam compensation model

When data are outside the boundary conditions of a beam compensation model, compensated TS data points may deviate with distance from the beam axis.

To display a major-axis beam compensation graph for a selection on a single targets echogram:

1. Make a selection.
2. On the Shortcut (right-click) menu, point to Graph selection, and then click Major-axis beam compensation.

To display a major-axis beam compensation graph for a region on a single targets echogram:

1. Select an existing region or define a new region.
   
   Note: If you wish to graph a bad data region, you must clear the Exclude bad regions option on the Analysis page of the Variable Properties dialog box.
    
2. On the Shortcut (right-click) menu, point to Graph region, and then click Major-axis beam compensation.

See About Beam Geometry for a brief description of beam angles in Echoview.

Note: Linking this graph to an extending selection, could cause performance problems.

Legend

• Uncompensated TS of single targets
• Compensated TS of single targets

See also

About graphs
About Linking Graphs
Minor-axis beam compensation graph
Off-axis beam compensation graph
Beam compensation
Example Minor-axis beam compensation graph