Speech recognition system and associated methods
First Claim
1. A method of building a filter for removing noise from a signal comprising the steps of:
- transforming the signal from a time domain to a frequency domain;
sorting the transformed signal into a plurality of energy-level sectors;
ordering the sectors by energy level;
selecting a threshold energy-level value, wherein the threshold energy-level value comprises the fifty-sixth energy-level value, comprising the steps of, summing the energy levels of all sectors to calculate a total energy content of the signal, determining a percentage retention value, sequentially summing energy levels starting from a highest energy level to form a running total until the running total divided by the total energy content reaches the percentage retention value, and assigning a last-added energy level from the sequentially summing step to the threshold value;
removing signal from all sectors below the threshold energy-level value; and
, reordering the sectors in frequency order.
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Abstract
A method and system for converting a sound signal containing a speech component and a noise component into recognizable language are disclosed, wherein the sound signal is transformed from a time domain into a frequency domain. Next the transformed signal is compared with a set of models of all possible sound signals to find a closest-matching known sound signal. A filter is then applied to the transformed signal. Here the filter corresponds to the model of the closest-matching known sound signal. Next a determination is made of an identity of the speech by searching a set of control data models to match a data model with the filtered transformed signal. Finally, a text stream representative of the determination is output, which enables a user not only to hear what may be a noisy voice message, but also to read the filtered message in some form, such as printed text or on a display screen.
91 Citations
1 Claim
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1. A method of building a filter for removing noise from a signal comprising the steps of:
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transforming the signal from a time domain to a frequency domain;
sorting the transformed signal into a plurality of energy-level sectors;
ordering the sectors by energy level;
selecting a threshold energy-level value, wherein the threshold energy-level value comprises the fifty-sixth energy-level value, comprising the steps of, summing the energy levels of all sectors to calculate a total energy content of the signal, determining a percentage retention value, sequentially summing energy levels starting from a highest energy level to form a running total until the running total divided by the total energy content reaches the percentage retention value, and assigning a last-added energy level from the sequentially summing step to the threshold value;
removing signal from all sectors below the threshold energy-level value; and
,reordering the sectors in frequency order.
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Specification
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- Resources
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Current AssigneeThe Government Of The United States Of America, As Represented By The Secretary Of The Navy
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Original Assigneethe united states of america as represented by the secretary of the navy
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InventorsBoemler, Stephen G., Cope, R. Bradley
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Primary Examiner(s)Banks-Harold, Marsha D.
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Assistant Examiner(s)Lerner, Martin
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Application NumberUS09/450,641Time in Patent Office1,196 DaysField of Search704/200.1, 704/205, 704/206, 704/226, 704/231, 704/233, 704/234, 704/235, 704/238, 704/255, 704/256, 704/203, 704/209, 381/94.1, 381/94.2, 381/94.3US Class Current704/205CPC Class CodesG10L 21/0208 Noise filteringG10L 21/0232 Processing in the frequency...G10L 25/18 the extracted parameters be...
