Programmer Guide/Command Reference/EVAL/aseg1: Difference between revisions
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:;<var>x</var>: data vector (usally rms track in dB) | :;<var>x</var>: data vector (usally rms track in dB) | ||
:;<var>n</var>: minimum length of a signal segment in frames; 0 < n < <code>nrow(''x'')</code> | :;<var>n</var>: minimum length of a signal segment in frames; 0 < n < <code>nrow(''x'')</code> | ||
:;<var>m</var>: smoothing length; 0 | :;<var>m</var>: smoothing length; 0 ≤ m</code>; if ''m'' is greater than zero, the segmentation is performed on a smoothed data vector ''xs''. | ||
:::<code>''xs''[i] = avr(''x''[i-m], .., ''x''[i+m]); with: i=0..nrow(''x'')</code> | :::<code>''xs''[i] = avr(''x''[i-m], .., ''x''[i+m]); with: i=0..nrow(''x'')</code> | ||
:;<var>xmin</var>: segment threshhold | :;<var>xmin</var>: segment threshhold | ||
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::with: i=0..<code>nrow(''r'')</code> | ::with: i=0..<code>nrow(''r'')</code> | ||
---- | ---- | ||
;Usage 2:<code>aseg1(<var>x</var>, | ;Usage 2:<code>aseg1(<var>x</var>, 1, <var>n</var>, <var>m</var>, <var>xmax</var>, <var>xmin</var>)</code> | ||
:;<var>x</var>: data vector (usally rms track in dB) | :;<var>x</var>: data vector (usally rms track in dB) | ||
:;<var>n</var>: minimum length of a signal segment in frames; 0 < n < <code>nrow(''x'')</code> | :;<var>n</var>: minimum length of a signal segment in frames; 0 < n < <code>nrow(''x'')</code> | ||
:;<var>m</var>: smoothing length; 0 | :;<var>m</var>: smoothing length; 0 ≤ m</code>; if ''m'' is greater than zero, the segmentation is performed on a smoothed data vector ''xs''. | ||
:::<code>''xs''[i] = avr(''x''[i-m], .., ''x''[i+m]); with: i=0..nrow(''x'')</code> | :::<code>''xs''[i] = avr(''x''[i-m], .., ''x''[i+m]); with: i=0..nrow(''x'')</code> | ||
:;<var> | :;<var>xmax</var>: maximum threshold; the maximum value of a segment must be greater than ''xmax'' | ||
:;<var> | :;<var>xmin</var>: minimum threshold; all values of a segment must be greater than ''xmin'' | ||
;Description: segment detection: | ;Description: segment detection: | ||
:#find a position ''i'' with ''x''[i]>'' | :#find a position ''i'' with ''x''[i]>''xmax'' | ||
:#go backward while ''x''[i-j]>'' | :#go backward while ''x''[i-j]>''xmin; last index i-j is the segment begin | ||
:#go forward while ''x''[i+k]>'' | :#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''. | ;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''. | ||
::{|class="einrahmen" | ::{|class="einrahmen" | ||
|''r''[0,i] || beginning of the segment i | |''r''[0,i] || beginning of the segment i | ||
|- | |- | ||
|''r''[ | |''r''[1,i] || end of the segment i | ||
|} | |} | ||
::with: i=0..<code>nrow(''r'')</code> | ::with: i=0..<code>nrow(''r'')</code> | ||
---- | ---- | ||
[[ | [[../#Functions|<function list>]] | ||
Latest revision as of 08:05, 6 June 2013
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
-
- A segment is a continuous range of x, where all values are greater than xmin
- 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)
- with: i=0..
- Usage 2
aseg1(x, 1, 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:
- find a position i with x[i]>xmax
- go backward while x[i-j]>xmin; last index i-j is the segment begin
- 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[1,i] end of the segment i
- with: i=0..
nrow(r)
- with: i=0..
