Triton Isis - Manual (Page 226)

June 2004 Isis® Sonar User's Manual, Volume1 212
9. Once all settings are correct, click Start Logging to begin writing the
SPN file.
The Shadow Averaging Window can be used to smooth the response of
the shadow tracking gate, making the tracked position more stable.
However, setting this value too high may result in spans not being logged.
As shown in Figure 9-24, the various lines in the left-hand window of the left-
hand window of the Pipe Tracking Controls Dialog Box should be interpreted
as follows:
• A squiggly white line represents the raw, undecimated, sonar signal.
• A vertical green line shows the theoretical limit of the pipe’s shadow on a
flat seabed.
• A horizontal yellow line shows the pipe-tracking threshold level.
• A horizontal cyan line shows the Shadow Threshold Level.
• A vertical yellow line with a cap at the top shows the tracked pipe
position and the pipe search width.
• A vertical cyan line with a cap at the bottom shows the tracked position
of the shadow start and the width of the Shadow Averaging Window.
• A vertical red line, when present, would show the position of the bottom-
tracking gate (not visible in the example shown in Figure 9-24).
Chapter 9: Using the Tools Menu