Toni: moved Programmer Guide/SPU Reference/ASEG1 - automatic segmentation to Programmer Guide/SPU Reference/ASEG1

2011-04-28T09:23:02Z

moved Programmer Guide/SPU Reference/ASEG1 - automatic segmentation to Programmer Guide/SPU Reference/ASEG1

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Admin: 1 revision: Initial import

2010-11-18T16:31:53Z

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2010-05-17T13:05:27Z

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{{DISPLAYTITLE:{{SUBPAGENAME}}}}
====ASEG1 - automatic segmentation====

=====Usage:=====

<code>ASEG1 <var>DT TABP TABC TABS TABM TABO P0 P1 P2 P3</var></code>

=====Inputs:=====

{|
|-
|DT
|time step
|-
|TABP
|name of parameter definition table. Note: all tables are extended shell<nowiki>-</nowiki>table
|-
|TABC
|name of channel definition table
|-
|TABS
|name of segment definition table
|-
|TABM
|name of channel<nowiki>-</nowiki>to-segment mapping table
|-
|TABO
|name of output table
|-
|P0..<var>P3</var>
|segmentation parameter inputs (numbers or vectors)
|}

=====Outputs:=====

none, the output data (segment names and addresses) are stored in (appended to) the output table

=====Function:=====

The segmentation parameters P0-<var>P3</var> can be any type of parameters (e.g.: RMS, band-RMS, F0) but must be extracted time-synchronous from the signal. It is assumed, that the parameters processed in the evaluation cycle t (t=0,1,....) are extracted from the signal time-interval [t.<var>DT</var>, (t+1).<var>DT</var>]. Each parameter value (each number and each vector element) must be defined by an entry of the table <var>TABP</var>. E.g. if <var>P0</var> is a vector of three band-RMS values and <var>P1</var> is the F0 value, the table <var>TABP</var> must consist of four entries (entry 0..2 for <var>P0</var>[0,1,2] and entry 3 for <var>P1</var>).

Table 1: <var>TABP</var>: parameter definitions (2 fields, 1 entry / parameter track){|
|-
|Field
|Content / Description
|-
|0
|defines the parameter track type (0 or 1):0: the parameter track is a continuous function (e.g. RMS); for each frame a value is computed1: the parameter track is not a continuous function (e.g. F0, Formants); for some frames no parameter value can be computed (missing values)
|-
|1
|missing value indicator (any number):for not<nowiki>-</nowiki>continuous parameters this field defines the number that is used to indicate a missing parameter value in a frame (e.g. for F0 tracks the missing value indicator is set to 0)
|}

The first segmentation step is implemented by a simple feature detection. For this purpose each parameter is assigned to one or more segmentation channel(s). A channel is used to detect a signal/segment feature based on the values of the assigned parameter. Two detection modes are defined:

{|
|-
|p(t)
|value of assigned parameter in the frame t
|-
|s(t)
|status of the channel in the frame t
|}

Interval method:

{|
|-
|s(t) = 'on'
|if minimum <= p(t) <= maximum
|-
|s(t) = 'off'
|otherwise
|}

Threshold method:

{|
|-
|s(t) = 'on'
|if s(t<nowiki>-</nowiki>1) = 'off' and p(t) >= on-threshold
|-
|s(t) = 'off'
|if s(t<nowiki>-</nowiki>1) = 'on' and p(t) <= off-threshold
|-
|s(t) = s(t<nowiki>-</nowiki>1)
|otherwise
|}

Table 2: TABC: channel definitions (5 fields, 1 entry / channel, multiple channels / parameters are possible){|
|-
|Field
|Content / Description
|-
|0
|index of the assigned parameter (0 to number_of_parameters<nowiki>-</nowiki>1)
|-
|1
|selects the type of condition (0 or 1)
0: detect/filter an interval of parameter values
1: split parameter values using a threshold
|-
|2
|lower interval boundary (minimum) or on<nowiki>-</nowiki>threshold
|-
|3
|upper interval boundary (maximum) or off<nowiki>-</nowiki>threshold
|-
|4
|selects the processing used for frames with missing values (0, 1 or 2)
0: set channel to 'off'
1: set channel to 'on'
2: do not change channel (stay)
|}

In the second segmentation step the channels (features) are combined. A mapping (mask) is used to define the feature configuration of a segment.

{|
|-
|
|
|
|-
|mi,j
|mapping (mask) for segment i to channel j
|-
|mi,j =
|0
|channel j must be 'off'
|-
|
|1
|channel j must be 'on'
|-
|
|2
|channel j is ignored
|}

If a channel configuration <c0(t)..cn<nowiki>-</nowiki>1(t)> (n = number of channels) matches the conditions defined by the mapping <mi,0..mi,n-1>, the segment status si(t) is set to 'on', otherwise it is set to 'off'. If multiple mappings are defined for a channel, the results of the matches are logically ORed (only one mapping must match).

Table 3: <var>TABS</var>: segment definitions (5 fields, 1 segment / entry){|
|-
|Field
|Content / Description
|-
|0
|minimum segment 'on' duration (>0)
|-
|1
|maximum segment 'off' (pause) duration inside the segment (>=0)
|-
|2
|pre<nowiki>-</nowiki>offset = time subtracted from the detected beginning (>=0)
|-
|3
|post<nowiki>-</nowiki>offset = time added to the detected end (>=0)
|-
|4
|number of channel/segment mappings used for the segment (>0)
|}

The mappings for all segments are stored in the mapping table TABM. This table consists of only one field and table entry for each mapping of a segment. E.g. if the 1st segment uses 3 mappings and the 2nd segment uses 1 mapping, the entries 0, 1 and 2 of <var>TABM</var> are the mappings for the 1st segment and the entry 3 is the mapping for the 2nd segment.

In the third step some decisions/processing based on the durations and offsets defined for a segment are performed:

If the stream of 'off' frames (pause) between two streams of 'on' frames (signal) is shorter than the defined maximum segment 'off' duration inside a segment, the two 'on' streams are connected.

If the duration of the 'on'-stream is shorter than the minimum segment 'on' duration, the 'on'-stream is ignored (not saved)

Before the segment is saved, the begin- and end-time are corrected to 'detected-begin-time – pre-offset' and end-time = detected-end-time + post-offset

The checked and corrected segment definitions are saved into the output table <var>TABO</var>. For each segment the index of the segment definition entry (for identification) and the begin- and end-time is saved.

Table 4: <var>TABO</var>: output table (3 fields, 1 field / segment){|
|-
|Field
|Content / Description
|-
|0
|identification = index of segment definition entry
|-
|1
|begin time
|-
|2
|end time
|}

Programmer Guide/SPU Reference/ASEG1 - Revision history

Toni: moved Programmer Guide/SPU Reference/ASEG1 - automatic segmentation to Programmer Guide/SPU Reference/ASEG1

Admin: 1 revision: Initial import

193.171.195.8: initial import