autoPitch Pitch_subtractLinearFit (Pitch me, int unit) {
try {
autoPitch thee = Pitch_interpolate (me);
/*
* Find the first and last voiced frame.
*/
long imin = thy nx + 1, imax = 0;
for (long i = 1; i <= my nx; i ++)
if (Pitch_isVoiced_i (thee.peek(), i)) { imin = i; break; }
for (long i = imin + 1; i <= my nx; i ++)
if (! Pitch_isVoiced_i (thee.peek(), i)) { imax = i - 1; break; }
long n = imax - imin + 1;
if (n < 3) return thee;
/*
* Compute average pitch and time.
*/
double sum = 0.0;
for (long i = imin; i <= imax; i ++) {
sum += Sampled_getValueAtSample (thee.peek(), i, Pitch_LEVEL_FREQUENCY, unit);
}
double fmean = sum / n;
double tmean = thy x1 + (0.5 * (imin + imax) - 1) * thy dx;
/*
* Compute slope.
*/
double numerator = 0.0, denominator = 0.0;
for (long i = imin; i <= imax; i ++) {
double t = thy x1 + (i - 1) * thy dx - tmean;
double f = Sampled_getValueAtSample (thee.peek(), i, Pitch_LEVEL_FREQUENCY, unit) - fmean;
numerator += f * t;
denominator += t * t;
}
double slope = numerator / denominator;
/*
* Modify frequencies.
*/
for (long i = imin; i <= imax; i ++) {
Pitch_Frame myFrame = & my frame [i], thyFrame = & thy frame [i];
double t = thy x1 + (i - 1) * thy dx - tmean, myFreq = FREQUENCY (myFrame);
double f = Sampled_getValueAtSample (thee.peek(), i, Pitch_LEVEL_FREQUENCY, unit);
f -= slope * t;
if (NOT_VOICED (myFreq))
FREQUENCY (thyFrame) = 0.0;
else
FREQUENCY (thyFrame) = Function_convertSpecialToStandardUnit (me, f, Pitch_LEVEL_FREQUENCY, unit);
}
return thee;
} catch (MelderError) {
Melder_throw (me, U": linear fit not subtracted.");
}
}
static void Pitch_line (Pitch me, Graphics g, double tmin, double fleft, double tmax, double fright,
int nonPeriodicLineType)
{
/*
* f = fleft + (t - tmin) * (fright - fleft) / (tmax - tmin);
*/
int lineType = Graphics_inqLineType (g);
double lineWidth = Graphics_inqLineWidth (g);
double slope = (fright - fleft) / (tmax - tmin);
long imin = Sampled_xToNearestIndex (me, tmin);
if (imin < 1) imin = 1;
long imax = Sampled_xToNearestIndex (me, tmax);
if (imax > my nx) imax = my nx;
for (long i = imin; i <= imax; i ++) {
double tleft, tright;
if (! Pitch_isVoiced_i (me, i)) {
if (nonPeriodicLineType == 2) continue;
Graphics_setLineType (g, Graphics_DOTTED);
Graphics_setLineWidth (g, 0.67 * lineWidth);
} else if (nonPeriodicLineType != 2) {
Graphics_setLineWidth (g, 2 * lineWidth);
}
tleft = Sampled_indexToX (me, i) - 0.5 * my dx, tright = tleft + my dx;
if (tleft < tmin) tleft = tmin;
if (tright > tmax) tright = tmax;
Graphics_line (g, tleft, fleft + (tleft - tmin) * slope,
tright, fleft + (tright - tmin) * slope);
Graphics_setLineType (g, lineType);
Graphics_setLineWidth (g, lineWidth);
}
}
static int Pitch_getVoicedIntervalAfter (Pitch me, double after, double *tleft, double *tright) {
long ileft = Sampled_xToHighIndex (me, after), iright;
if (ileft > my nx) return 0; /* Offright. */
if (ileft < 1) ileft = 1; /* Offleft. */
/* Search for first voiced frame. */
for (; ileft <= my nx; ileft ++)
if (Pitch_isVoiced_i (me, ileft)) break;
if (ileft > my nx) return 0; /* Offright. */
/* Search for last voiced frame. */
for (iright = ileft; iright <= my nx; iright ++)
if (! Pitch_isVoiced_i (me, iright)) break;
iright --;
*tleft = Sampled_indexToX (me, ileft) - 0.5 * my dx; /* The whole frame is considered voiced. */
*tright = Sampled_indexToX (me, iright) + 0.5 * my dx;
if (*tleft >= my xmax - 0.5 * my dx) return 0;
if (*tleft < my xmin) *tleft = my xmin;
if (*tright > my xmax) *tright = my xmax;
return 1;
}
