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EP0227146A1
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Method of and device for segmenting an electric signal derived from an acoustic signal, for example a speech signal
Assignee: Koninklijke Philips NV
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Filing: 1986-11-25
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Granted: —
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Expires: 2006-11-25
Abstract
Abstract An accordance with the method a number of parameters, for example "log area" parameters, are derived as a function of time from the electric signal (block 2); for consecutive instants the signals of the parameters located within a time interval around each instant are taken up and transition functions (0i) are derived therefrom for each instant (block 3). Subsequently similarity factors (cij) are determined each between two transition functions (0i and 0j) associated with respective proximate instants (i and j) (block 4) and a replacing transition function (0ij<c>) is derived (block 6) from the transition functions of at least one group of two transition functions for which the associated similarity factor is larger than a reference value V, the said transition function (0ij<c>) replacing the aforementioned transition functions from which it is derived (block 7). <??>A combined transition function (0ij<c>) replacing one of these transition functions is preferably calculated from the aforementioned transition functions, while the other of these transition functions are omitted. <??>Furthermore the group of transition functions for which the similarity factor is largest is preferably taken (block 5). <??>The method is subsequently repeated (Fig. 1). <??>The transition functions obtained in accordance with the method are very suitable for use in the transmission or recognition of speech signals and for coding diphones.
Inventors
- 👤 Stephen Michael Marcus
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 19:55
CPC Classifications
G; G10; G10L; G10L15/00; G10L15/04
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
176 words
A method of segmenting an electric signal derived from an acoustic signal in which consecutively - a number of parameters is derived from the electric signal as a function of time, - the signals of the parameters located within a time interval around each instant are taken up for consecutive instants, - a transition function 0̸ is determined for each instant from the signals of the parameters located within the associated time interval, and - information relating to the segments from which the acoustic signal is built up is derived from the transition functions associated with the instants, characterized in that (a) similarity factors C ij are determined, each between two transition functions (0̸ i and 0̸ j ) associated with respective proximate instants i and j, and (b) a replacing transition function is derived from the transition functions of at least one group of two transition functions for which the associated similarity factor is larger than a reference value V, the said replacing transition function replacing the aforementioned transition functions from which it is derived.
Claim 2
Independent Claim
176 words
A method of segmenting an electric signal derived from an acoustic signal in which consecutively - a number of parameters is derived from the electric signal as a function of time, - the signals of the parameters located within a time interval around each instant are taken up for consecutive instants, - a transition function 0̸ is determined for each instant from the signals of the parameters located within the associated time interval, and - information relating to the segments from which the acoustic signal is built up is derived from the transition functions associated with the instants, characterized in that (a) similarity factors C ij are determined, each between two transition functions (0̸ i and 0̸ j ) associated with respective proximate instants i and j, and (b) a replacing transition function is derived from the transition functions of at least one group of two transition functions for which the associated similarity factor is larger than a reference value V, the said replacing transition function replacing the aforementioned transition functions from which it is derived.
Claim 3
Dependent Claim
29 words
A method as claimed in Claim 1, characterized in that the reference value V is a number between the largest similarity factor and the largest similarity factor but one.
Claim 4
Dependent Claim
145 words
A method as claimed in Claim 1 or 2, in which a step (b) the two transition functions of only one group are combined and a combined transition function replacing the aforementioned two transition functions is derived from these two transition functions, characterized in that (c) the combined transition function replaces one of the two transition functions from which the combined transition function is derived and the other of the two transition functions is omitted, (d) in that subsequently similarity factors are determined between the combined transition function and the transition functions associated with instants in the proximity of the instant with which the combined transition function is associated, and in that the similarity factors associated with those combinations of two transition functions of which at least one is one of the two transition functions from which the combined transition function is derived, are omitted.
Claim 5
Dependent Claim
147 words
A method as claimed in Claim 3, characterized in that (e) if there is subsequently at least one similarity factor which is larger than the aforementioned reference value, the transition functions associated with this similarity factor are combined and a combined transition function replacing the aforementioned two transition functions is derived from these two transition functions, whereafter the method is continued with step (c), (f) in that the reference value is decreased by a constant value, if there are no similarity factors which are larger than the aforementioned reference value, (g) in that it is subsequently determined whether the reference value thus obtained is larger than a given constant, (h) in that the method is continued with step (e) if the reference value is larger than the said constant, and (i) in that the method is ended if the reference value is smaller than the said constant.
Claim 6
Dependent Claim
97 words
A method as claimed in Claim 3, characterized in that it is determined whether the largest similarity factor is larger than a given constant, (e) in that, if the largest similarity factor is larger than this constant, a combined transition function is derived from the transition functions associated with this similarity factor, = the combined transition function replacing the aforementioned two transition functions from which it is derived whereafter the method is continued with step (c), and (f) in that the method is ended if the largest similarity factor is smaller than or equal to this constant.
Claim 7
Dependent Claim
82 words
A method as claimed in Claim 1 or 2, in which in step (b) the two transition functions of only one group are combined and a combined transition function replacing the aforementioned two transition functions is derived from these two transition functions, characterized in that in step (b) the combined transition function 0̸ ij c is calculated in the following manner from the two transition functions 0̸ i and 0̸ j , 0̸ ij c = (0̸ i + 0̸ j )/2
Claim 8
Dependent Claim
96 words
A method as claimed in Claim 4 or 5, characterized in that in step (e) the combined transition function 0̸ ij c is calculated from the two transition functions 0̸ i and 0̸ j in the following manner: 0̸ ij c = (n i 0̸ i + n j 0̸ j )/(n i +n j ) in which n i and n j indicate the numbers of the original transition functions from which the transition functions 0̸ i and 0̸ j respectively are obtained by combining two transition functions in one or more previous combination steps.
Claim 9
Dependent Claim
124 words
A method as claimed in Claim 7, characterized in that a number n c which is equal to n i +n j is appended to the combined transition function, which number n c indicates from how many original transition functions the combined transition function 0̸ ij c has been obtained by combining two transition functions in one or more previous combination steps, in that the number n c replaces the number (n i or n j ) associated with the transition function (0̸ i or 0̸ j ) which is replaced by the combined transition function, and in that the number (n j or n i ), which is associated with the one of the two transition functions that is omitted, is also omitted.
Claim 10
Independent Claim
65 words
A method as claimed in any one of the preceding Claims, characterized in that for calculating the similarity factor C ij between two transition functions 0̸ i and 0̸ j , the transition functions are considered to be vectors in a multidimensional space and in that the similarity factor is equal to the reciprocal value of the euclidic distance between the ends of these vectors.
Claim 11
Independent Claim
61 words
A method as claimed in any one of Claims 1 to 8, characterized in that for calculating the similarity factor C ij between two transition functions 0̸ i and 0̸ j the transition functions are considered to be vectors in a multi-dimensional space and in that the similarity factor is equal to the cosine of the angle between the two vectors.
Claim 12
Dependent Claim
28 words
A method as claimed in Claim 10, where appendant to Claim 4 or 5, characterized in that the said constant has a value of between 0.5 and 0.8.
Claim 13
Independent Claim
139 words
A device for performing a method as claimed in any one of the preceding Claims, comprising - first means for deriving a number of parameters from the electric signal as a function of time, and - second means for deriving a transition function for each instant from the signals of the parameters located within the associated time interval, characterized in that the device also comprises - a first memory for storing the transition functions, - third means for calculating a similarity factor between two transition functions associated with respective proximate instants i and j, - a second memory for storing the similarity factors, and - fourth means for deriving the replacing or combined transition function from the transition functions of at least one group of transition functions for which the associated similarity factor is larger than a reference value.
Claim 14
Dependent Claim
39 words
A device as claimed in Claim 12, characterized in that the device comprises a decision unit having an input coupled to an output of the second memory and an output coupled to an address input of the first memory.
Claim 15
Dependent Claim
40 words
A device as claimed in Claim 12 or 13, characterized in that an output of the first memory is coupled to an input of the fourth means an output of which is coupled to an input of the first memory.
Claim 16
Dependent Claim
76 words
A device as claimed in Claim 12, 13 or 14, for performing a method as claimed in Claim 7 or 8, characterized in that the device comprises a third memory for storing the numbers n i associated with the transition functions 0̸ i , and in that the output of the decision unit is coupled to an address input of the third memory, an output of which is coupled to another input of the fourth means.
Claim 17
Dependent Claim
62 words
A device as claimed in Claim 15, for performing a method as claimed in Claim 8, characterized in that the fourth means are also adapted to derive the number n c from the numbers n i and n j and to apply this number to a second output, and in that said output is coupled to an input of the third memory.
References Cited (Backward Citations)
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