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US 4,833,711 AGranted
Speech recognition system with generation of logarithmic values of feature parameters
AssigneeComputer Basic Technology Research Assoc.
InventorsToru Ueda, Yoshiki Nishioka
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Abstract
In a speech recognition system, logarithmic amplifiers avoid low level signal or noise problems by clamping all signals below an input threshold to a constant output level.
Claims7
In a speech recognition system utilizing a generator of feature parameters, the improvement comprising:
- extractor means for producing a feature parameter signal from a signal containing speech information;
- and
- converter means for transforming said feature parameter signal into a logarithmic signal wherein said converter means produces a first constant value when said feature parameter signal has a value less than a specific threshold value, and a second value corresponding to a logarithm of said feature parameter signal, when said feature parameter signal is at least as great as said specific threshold value.
In a speech recognition system, the improvement comprising:
- extractor means for producing a feature parameter signal from a signal containing speech information;
- and
- converter means for transforming an input signal into a logarithmic signal, said input signal including said feature parameter signal, wherein said converter means produces said logarithmic signal in accordance with the following formula,
- W=K when Pi<K
- W=AlogPi+B;
- Pi.gtoreq.K
- where W equals the logarithmic signal, A and B are specified constants, Pi is said input signal and K is a specified threshold value.
4 more elements
A speech recognition system, comprising
- speech input means for detecting speech signals and producing a speech sector signal;
- feature extractor means for producing a feature parameter signal from said speech sector signal;
- logarithmic converter means for transforming said feature parameter signal into a logarithmic signal wherein said logarithmic converter means produces a first constant value as said logarithmic signal when said feature parameter signal has a value less than a specific threshold value, and produces a second value as said logarithmic signal, said second value being a logarithm of said feature parameter signal, when said feature parameter signal is at least as great as said specific threshold value;
- and
- means for normalizing said logarithmic signal.
2 more elements
Dependencies are inferred from the claim text.