IP Library Granted Patent US 8,630,971
Granted Patent B2
US 8,630,971 · App. 12/652,608 · Granted Jan 14, 2014

System and method of using Multi Pattern Viterbi Algorithm for joint decoding of multiple patterns

Inventors: Nishanth Ulhas Nair (Bangalore, IN); Thippur Venkatanarasaiah Sreenivas (Bangalore, IN)
Assignee: Indian Institute of Science
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Quick Facts
Patent No.
US 8,630,971
App. No.
12/652,608
Granted
Jan 14, 2014
Kind
B2
Abstract

Systems, devices, and methods for using Multi-Pattern Viterbi Algorithm for joint decoding of multiple patterns are disclosed. An exemplary method may receive a plurality of sets of time-sequential signal observations for each of a number K of signal repetitions. Further, each set of signal observations is associated with a respective dimension of a K-dimensional time grid having time-indexed points. Moreover, at each of a plurality of the time-indexed points, a state cost metric is calculated with a processor for each state in a set of states of a hidden Markov model (HMM). In addition, each state in the set of states and for a given time-indexed point, the state cost metric calculation provides a most-likely predecessor state and a corresponding most-likely predecessor time-indexed point. The exemplary method may also determine a sequence of states using the calculated state cost metrics and determine a corresponding cumulative probability measure for the HMM.

Claims (63)

1. A method, comprising:

receiving a set of signal observations for a signal repetition, wherein the set of signal observations is associated with a dimension of a K-dimensional time grid having a plurality of time-indexed points;

calculating a state cost metric for a state in a plurality of states of a statistical model, for a given time-indexed point, wherein the state cost metric calculation provides a most-likely predecessor state and a corresponding most-likely predecessor time-indexed point;

determining a sequence of states using the state cost metric calculation;

determining a corresponding cumulative probability measure for the statistical model;

calculating a cost metric associated with a possible prior state at a possible predecessor time-indexed point;

selecting a lowest cost metric for the state to determine the state cost metric;

observing dimensions that are incremented when moving from a given predecessor time-index point to a given one of the plurality of time-indexed points; and

basing the state cost metric on at least the observing.

2. The method of claim 1 , further comprising:

repeating the calculating the state cost metric for the state for the plurality of time-indexed points and determining a most likely sequence and corresponding cumulative probability measure for a plurality of statistical models; and

identifying a most likely statistical model based on the corresponding cumulative probability measures for the plurality of statistical models.

3. The method of claim 1 , wherein the determining the sequence of states comprises identifying a lowest state cost metric at a final state at a terminal time-indexed point.

4. A method, comprising:

receiving a set of signal observations for a signal repetition, wherein the set of signal observations is associated with a dimension of a K-dimensional time grid having a plurality of time-indexed points;

calculating a state cost metric for a state in a plurality of states of a statistical model, for a given time-indexed point, wherein the state cost metric calculation provides a most-likely predecessor state and a corresponding most-likely predecessor time-indexed point;

determining a sequence of states using the state cost metric calculation; and

determining a corresponding cumulative probability measure for the statistical model;

wherein the set of signal observations includes feature vectors, and

wherein the feature vectors are selected from at least one of: Mel-Frequency Cepstral Coefficients feature vectors, Linear Predictive Coding Coefficients, spectral density, spectral energy, noise ratios, length of sounds, relative power, and filter matches.

5. A method, comprising:

receiving a set of signal observations for a signal repetition, wherein the set of signal observations is associated with a dimension of a K-dimensional time grid having a plurality of time-indexed points, wherein the plurality of time-indexed points are determined with respect to a predetermined distance from a diagonal line through the K-dimensional time grid;

calculating a state cost metric for a state in a plurality of states of a statistical model, for a given time-indexed point, wherein the state cost metric calculation provides a most-likely predecessor state and a corresponding most-likely predecessor time-indexed point;

determining a sequence of states using the state cost metric calculation; and

determining a corresponding cumulative probability measure for the statistical model.

6. The method of claim 5 , wherein the set of observations has a first time duration, and the predetermined distance is based on a difference of the first time duration and a second time duration of another set of signal observations.

7. The method of claim 1 , wherein the determining the sequence of states comprises backtracking through the plurality of time-indexed points based on the state cost metric.

8. A method, comprising:

receiving a set of signal observations for a signal repetition, wherein the set of signal observations is associated with a dimension of a K-dimensional time grid having a plurality of time-indexed points;

calculating a state cost metric for a state in a plurality of states of a statistical model, for a given time-indexed point, wherein the state cost metric calculation provides a most-likely predecessor state and a corresponding most-likely predecessor time-indexed point, wherein the calculating is based on:

state cost metrics for states associated with candidate predecessor time-indexed points,

a probability of transitioning from each state of each candidate predecessor time-indexed point to the given state,

a respective probability of transitioning from the respective candidate predecessor time-indexed point, and

a joint probability of the observations being emitted from the state in the plurality of states;

determining a sequence of states using the state cost metric calculation; and

determining a corresponding cumulative probability measure for the statistical model.

9. The method of claim 1 , wherein the determined sequence of states determines an alignment of the set of signal observations.

10. An article of manufacture including a non-transitory computer-readable medium having instructions stored thereon that, when executed by a computing device, cause the computing device to perform operations comprising:

retrieving from memory a set of signal observations for a signal repetition, wherein the set of signal observations is associated with a dimension of a K-dimensional time grid having a plurality of time-indexed points, wherein the plurality of time-indexed points are determined with respect to a predetermined distance from a diagonal line through the K-dimensional time grid;

retrieving from memory a set of parameters for a plurality of statistical models;

calculating a state cost metric for a state in a plurality of states of a statistical model at a time-indexed point, wherein the state cost metric calculation provides a most-likely predecessor state and a corresponding most-likely predecessor time-indexed point;

determining a cumulative probability measure for the statistical model; and

determining a most likely statistical model from the plurality of statistical models.

11. An apparatus, comprising:

a processor configured to execute software applications stored in memory, the software instructions including:

calculating a state cost metric for a state of a statistical model at a time-indexed point, wherein the state cost metric calculation provides a most-likely predecessor state and a corresponding most-likely predecessor time-indexed point;

determining a sequence of states using the state cost metric calculation;

determining a corresponding cumulative probability measure for the statistical model;

calculating a cost metric associated with a possible prior state at a possible predecessor time-indexed point;

selecting a lowest cost metric for the state to determine the state cost metric;

observing dimensions that are incremented when moving from a given predecessor time-index point to a given one of the plurality of time-indexed points; and

basing the state cost metric on at least the observing.

12. The apparatus of claim 11 , further comprising a memory configured to:

store a digital representation of a set of time-sequential signal observations for a signal repetition, wherein the set of time-sequential signal observations is associated with a dimension of a k-dimensional time grid having a plurality of time-indexed points; and

store a set of parameters for a plurality of statistical models.

13. The apparatus of claim 11 , further comprising an audio receiver configured to:

receive a set of audio signal observations for a signal repetition, wherein the set of audio signal observations is associated with a dimension of a k-dimensional time grid having a plurality of time-indexed points; and

convert the set of audio signal observations into a set of analog electrical signal observations for a signal repetition.

14. The apparatus of claim 11 , further comprising an analog-to-digital converter configured to convert a set of analog electrical signal observations into a set of digital electrical signal observations.

15. The apparatus of claim 11 , wherein the processor is further configured to compute a set of features vectors based on a digital representation of a set of signal observations for a signal repetition.

16. The apparatus of claim 11 , wherein the processor is further configured to transform the sequence of states using the state cost metric calculation into a digital representation of the sequence of states.

17. The apparatus of claim 16 , further comprising a digital-to-analog converter configured to transform the digital representation of the sequence of states into an output analog electrical signal.

18. The apparatus of claim 17 , further comprising a system output interface configured to transform the output analog electrical signal into an output audio signal.

Assignments (4)
RELEASE OF SECURITY INTEREST IN PATENTS, RECORDED ON JANUARY 29, 2019 AT REEL 048373 FRAME 0217 Recorded Sep 22, 2025
From: CRESTLINE DIRECT FINANCE, L.P., AS COLLATERAL AGENT
To: EMPIRE TECHNOLOGY DEVELOPMENT LLC
Reel/Frame 072936/0464 →
RELEASE OF SECURITY INTEREST Recorded Jul 31, 2019
From: CRESTLINE DIRECT FINANCE, L.P.
To: EMPIRE TECHNOLOGY DEVELOPMENT LLC
Reel/Frame 049924/0794 →
SECURITY INTEREST Recorded Jan 29, 2019
From: EMPIRE TECHNOLOGY DEVELOPMENT LLC
To: CRESTLINE DIRECT FINANCE, L.P.
Reel/Frame 048373/0217 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jan 6, 2010
From: NAIR, NISHANTH ULHAS; SREENIVAS, THIPPUR VENKATANARASAIAH
To: INDIAN INSTITUTE OF SCIENCE
Reel/Frame 023743/0232 →
Priority Claims (1)
IN 2870/CHE/2009 · Nov 20, 2009 · national
Continuity (1)
Related Publication 20110125701A1 · May 26, 2011