aseg1

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This function implements a simple automatic signal segmentation based on the energy (rms) track of the signal.


Usage 1
aseg1(x, 0, n, m, xmin, omax)
x
data vector (usally rms track in dB)
n
minimum length of a signal segment in frames; 0 < n < nrow(x)
m
smoothing length; 0 <= m; if m is greater than zero, the segmentation is performed on a smoothed data vector xs.
xs[i] = avr(x[i-m], .., x[i+m]); with: i=0..nrow(x)
xmin
segment threshhold
omax
offset for segment center; 0 < omax
Description
  1. A segment is a continuous range of x, where all values are greater than xmin
  2. The center of a segment is a continuous range of values inside a segment, where all values are greater than xmax-omax (with: xmax is the maximum value inside the segment).
Result 1
A matrix r with 4 rows. Each column of r defines one segment. Note that all values of r are frame indices (or row indices) of the data vector x.
r[0,i] beginning of the segment i
r[1,i] beginning of the center of the segment i
r[2,i] end of the center of the segment i
r[3,i] end of the segment i
with: i=0..nrow(r)

Usage 2
aseg1(x, 0, n, m, xmax, xmin)
x
data vector (usally rms track in dB)
n
minimum length of a signal segment in frames; 0 < n < nrow(x)
m
smoothing length; 0 <= m; if m is greater than zero, the segmentation is performed on a smoothed data vector xs.
xs[i] = avr(x[i-m], .., x[i+m]); with: i=0..nrow(x)
xmax
maximum threshold; the maximum value of a segment must be greater than xmax
xmin
minimum threshold; all values of a segment must be greater than xmin
Description
segment detection:
  1. find a position i with x[i]>xmax
  2. go backward while x[i-j]>xmin; last index i-j is the segment begin
  3. go forward while x[i+k]>xmin; last index i+k is the segment end
Result 2
A matrix r with 2 rows. Each column of r defines one segment. Note that all values of r are frame indices (or row indices) of the data vector x.
r[0,i] beginning of the segment i
r[3,i] end of the segment i
with: i=0..nrow(r)

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