agc.h

CMU大名鼎鼎的SPHINX－3大词汇量连续语音识别系统

/* ====================================================================
 * Copyright (c) 1999-2004 Carnegie Mellon University.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * This work was supported in part by funding from the Defense Advanced 
 * Research Projects Agency and the National Science Foundation of the 
 * United States of America, and the CMU Sphinx Speech Consortium.
 *
 * THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND 
 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY
 * NOR ITS EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ====================================================================
 *
 */
/*
 * agc.h -- Various forms of automatic gain control (AGC)
 * 
 * **********************************************
 * CMU ARPA Speech Project
 *
 * Copyright (c) 1999 Carnegie Mellon University.
 * ALL RIGHTS RESERVED.
 * **********************************************
 * 
 * HISTORY
 * 
 * 28-Apr-1999	M K Ravishankar ([e-mail]) at Carnegie Mellon University
 * 		Copied from previous version.
 */


#ifndef _S3_AGC_H_
#define _S3_AGC_H_

#include <s3types.h>

/** \file agc.h
 *  \brief routine that implements automatic gain control
 *  
 *  \warning This function may not be fully compatible with
 *  SphinxTrain's family of AGC. 
 *
 *  This implements AGC. 
 */
#ifdef __cplusplus
extern "C" {
#endif

  /**
 * Apply AGC to the given mfc vectors (normalize all C0 mfc coefficients in the given
 * input such that the max C0 value is 0, by subtracting the input max C0 from all).
 * This function operates on an entire utterance at a time.  Hence, the entire utterance
 * must be available beforehand (batchmode).
 */
void agc_max (float32 **mfc,	/* In/Out: mfc[f] = cepstrum vector in frame f */
	      int32 n_frame);	/* In: #frames of cepstrum vectors supplied */

#ifdef __cplusplus
}
#endif

#endif