Edinburgh Speech Tools 2.4-release
 
Loading...
Searching...
No Matches
delta.cc
1/*************************************************************************/
2/* */
3/* Centre for Speech Technology Research */
4/* University of Edinburgh, UK */
5/* Copyright (c) 1995,1996 */
6/* All Rights Reserved. */
7/* */
8/* Permission is hereby granted, free of charge, to use and distribute */
9/* this software and its documentation without restriction, including */
10/* without limitation the rights to use, copy, modify, merge, publish, */
11/* distribute, sublicense, and/or sell copies of this work, and to */
12/* permit persons to whom this work is furnished to do so, subject to */
13/* the following conditions: */
14/* 1. The code must retain the above copyright notice, this list of */
15/* conditions and the following disclaimer. */
16/* 2. Any modifications must be clearly marked as such. */
17/* 3. Original authors' names are not deleted. */
18/* 4. The authors' names are not used to endorse or promote products */
19/* derived from this software without specific prior written */
20/* permission. */
21/* */
22/* THE UNIVERSITY OF EDINBURGH AND THE CONTRIBUTORS TO THIS WORK */
23/* DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING */
24/* ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT */
25/* SHALL THE UNIVERSITY OF EDINBURGH NOR THE CONTRIBUTORS BE LIABLE */
26/* FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES */
27/* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN */
28/* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, */
29/* ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF */
30/* THIS SOFTWARE. */
31/* */
32/*************************************************************************/
33/* Author : Simon King */
34/* Date : July 1995 */
35/*-----------------------------------------------------------------------*/
36/* Compute delta coefficients for */
37/* Tracks and Tracks */
38/* */
39/*=======================================================================*/
40#include <cstdlib>
41#include "EST_Track.h"
42#include "EST_Wave.h"
43# define MAX_DELTA_ORDER 2
44/// max. number of points on which the delta co-eff is based
45# define MAX_REGRESSION_LENGTH 4
46
47static float compute_gradient(const EST_FVector &x, int num_points);
48
49void delta(EST_Track &tr, EST_Track &d, int regression_length)
50{
51 int reg_index, this_index;
52
53 // need at least two points to compute gradient
54 if ((regression_length < 2)||(regression_length > MAX_REGRESSION_LENGTH)){
55 cerr << "delta(EST_Track&, int) : ERROR : regression_length is "
56 << regression_length << endl;
57 exit(0);
58 }
59
60 // temp stores the points passed to compute_gradient
61 EST_FVector temp(regression_length);
62
63 for (int j = 0; j < tr.num_channels(); j++ )
64 for (int i = 0; i < tr.num_frames(); i++)
65 {
66 // copy values needed to compute gradient into temp[]
67 for (reg_index=0; reg_index<regression_length; reg_index++)
68 {
69 // gradient is computed from points to left of current time
70 // rather than points centred around the current time
71 this_index = i - reg_index;
72 if (this_index >= 0)
73 temp[reg_index] = tr.a(this_index, j);
74 }
75
76 // gradient at frame 0 is defined as 0
77 if (i < 1)
78 d.a(i, j) = 0.0;
79 else if (i < regression_length - 1)
80 // enough data, but would prefer more
81 // number of points available is only i+1
82 d.a(i, j) = compute_gradient(temp, i + 1);
83 else
84 // plenty of data, use the last regression_length points
85 d.a(i, j) = compute_gradient(temp, regression_length);
86 }
87}
88
89void delta(EST_Wave &tr, EST_Wave &d, int regression_length)
90{
91 int reg_index, this_index;
92
93 // need at least two points to compute gradient
94 if ((regression_length < 2)||(regression_length > MAX_REGRESSION_LENGTH)){
95 cerr << "delta(EST_Track&, int) : ERROR : regression_length is "
96 << regression_length << endl;
97 exit(0);
98 }
99
100 // temp stores the points passed to compute_gradient
101 EST_FVector temp(regression_length);
102
103 for (int j = 0; j < tr.num_channels(); j++ )
104 for (int i = 0; i < tr.num_samples(); i++)
105 {
106 // copy values needed to compute gradient into temp[]
107 for (reg_index=0; reg_index<regression_length; reg_index++)
108 {
109 // gradient is computed from points to left of current time
110 // rather than points centred around the current time
111 this_index = i - reg_index;
112 if (this_index >= 0)
113 temp.a_no_check(reg_index) = (float)tr.a(this_index, j);
114 }
115
116 // gradient at frame 0 is defined as 0
117 if (i < 1)
118 d.a(i, j) = 0;
119 else if (i < regression_length - 1)
120 // enough data, but would prefer more
121 // number of points available is only i+1
122 d.a(i, j) = (short)compute_gradient(temp, i + 1);
123 else
124 // plenty of data, use the last regression_length points
125 d.a(i, j) = (short)compute_gradient(temp, regression_length);
126 }
127}
128
129static float compute_gradient(const EST_FVector &x, int num_points)
130{
131 float gradient;
132
133 // NB x[0] is the point LATEST in time
134 // so x[1] is really x[t-1]
135
136 // time between points is assumed to be one unit
137
138 // These are solutions to least-squares fit of straight line
139 // to num_points points.
140 switch (num_points){
141
142 case 1:
143 gradient = 0.0;
144 break;
145
146 case 2:
147 gradient = x(0) - x(1);
148 break;
149
150 case 3:
151 gradient = (x(0) -x(2)) / 2.0;
152 break;
153
154 case 4:
155 gradient = ( (3.0*x(0)) + x(1) - x(2) - (3.0 * x(3)) ) / 10.0;
156 break;
157
158 default:
159
160 cerr << "compute_gradient(float*, int) : ERROR : num_points is"
161 << num_points << endl;
162
163 exit(0);
164 break;
165 }
166
167 return gradient;
168}
169
float & a(int i, int c=0)
int num_channels() const
return number of channels in track
Definition EST_Track.h:656
int num_frames() const
return number of frames in track
Definition EST_Track.h:650
short & a(int i, int channel=0)
Definition EST_Wave.cc:128
int num_channels() const
return the number of channels in the waveform
Definition EST_Wave.h:145
int num_samples() const
return the number of samples in the waveform
Definition EST_Wave.h:143