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7: Baseline Correction
The following are brief descriptions of the numbered items from Figure 7-1.
1. Select Baseline From pop-up menu. Specifies the source for the baseline interval.
Depending on the option that you select, different controls appear in the Baseline
Correction specification editor.
• Portion of Segment: uses a portion of the segment as the baseline interval.
Figure 7-1 shows the Baseline Correction specification editor, with Portion of
Segment selected. With this option, the Select Baseline With Respect To pop-up
menu (2) appears, which allows you to select the baseline with respect to either
Segment Time = 0 (the segment’s zero point; see page 131 for more information)
or Start of Segment. You specify the beginning of the baseline interval and its
length, in samples or milliseconds.
• Entire Segment: defines the baseline interval as the length of the entire segment.
With this choice, there is no need for other controls (see Figure 7-2).
Figure 7-2. Baseline Correction specification editor, with Entire Segment selected
• Event: uses an event as the point of reference for the baseline interval. When
you select this option, additional controls appear. This option is discussed in
the "Select Baseline From Event" section on page 75.
2. Select Baseline with Respect to. Specifies the start and duration of the baseline
interval. The pop-up menu offers two items:
• Start of Segment: the baseline interval begins a specified time or sample count
after the segment start.
• Segment Time = 0: the baseline interval begins a specified time or sample count
before or after the first sample that occurs after the event on which
segmentation is based + the offset.
74 Net Station Waveform Tools Technical Manual S-MAN-200-WFTR-001 • December 21, 2006