Frame erasure concealment technique for a bitstream-based feature extractor
First Claim
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1. A method of generating speech coding parameters of an erased frame in a bitstream-based front end of a speech recognition system, the method comprising the steps of:
- detecting an erased frame;
measuring the Euclidean distance between the line spectrum pairs (LSPs) of adjacent frames (n−
1) and n;
defining a steady-state threshold T associated with an acceptable difference between the LSPs of the adjacent frames;
deleting the LSPs of the nth frame in an observation sequence if the measured distance is less than or equal to T; and
generating the speech coding parameters with a standard hidden Markov model process.
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Abstract
A frame erasure concealment technique for a bitstream-based feature extractor in a speech recognition system particularly suited for use in a wireless communication system operates to “delete” each frame in which an erasure is declared. The deletions thus reduce the length of the observation sequence, but have been found to provide for sufficient speech recognition based on both single word and “string” tests of the deletion technique.
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3 Claims
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1. A method of generating speech coding parameters of an erased frame in a bitstream-based front end of a speech recognition system, the method comprising the steps of:
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detecting an erased frame; measuring the Euclidean distance between the line spectrum pairs (LSPs) of adjacent frames (n−
1) and n;defining a steady-state threshold T associated with an acceptable difference between the LSPs of the adjacent frames; deleting the LSPs of the nth frame in an observation sequence if the measured distance is less than or equal to T; and generating the speech coding parameters with a standard hidden Markov model process. - View Dependent Claims (2, 3)
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Specification