public void initialise(
double[] lowerCutOffsInHzIn, double[] upperCutOffsInHzIn, double overlapAround1000HzIn) {
normalizationFilterTransformedIR = null;
if (lowerCutOffsInHzIn != null && upperCutOffsInHzIn != null) {
assert lowerCutOffsInHzIn.length == upperCutOffsInHzIn.length;
lowerCutOffsInHz = new double[lowerCutOffsInHzIn.length];
upperCutOffsInHz = new double[upperCutOffsInHzIn.length];
System.arraycopy(lowerCutOffsInHzIn, 0, lowerCutOffsInHz, 0, lowerCutOffsInHzIn.length);
System.arraycopy(upperCutOffsInHzIn, 0, upperCutOffsInHz, 0, upperCutOffsInHzIn.length);
int i;
filters = new FIRFilter[lowerCutOffsInHz.length];
int filterOrder = SignalProcUtils.getFIRFilterOrder(samplingRateInHz);
double normalizedLowerCutoff;
double normalizedUpperCutoff;
overlapAround1000Hz = overlapAround1000HzIn;
for (i = 0; i < lowerCutOffsInHz.length; i++)
assert lowerCutOffsInHz[i] < upperCutOffsInHz[i];
for (i = 0; i < lowerCutOffsInHz.length; i++) {
if (lowerCutOffsInHz[i] <= 0.0) {
normalizedUpperCutoff = Math.min(upperCutOffsInHz[i] / samplingRateInHz, 0.5);
normalizedUpperCutoff = Math.max(normalizedUpperCutoff, 0.0);
filters[i] = new LowPassFilter(normalizedUpperCutoff, filterOrder);
} else if (upperCutOffsInHz[i] >= 0.5 * samplingRateInHz) {
normalizedLowerCutoff = Math.max(lowerCutOffsInHz[i] / samplingRateInHz, 0.0);
normalizedLowerCutoff = Math.min(normalizedLowerCutoff, 0.5);
filters[i] = new HighPassFilter(normalizedLowerCutoff, filterOrder);
} else {
normalizedLowerCutoff = Math.max(lowerCutOffsInHz[i] / samplingRateInHz, 0.0);
normalizedLowerCutoff = Math.min(normalizedLowerCutoff, 0.5);
normalizedUpperCutoff = Math.min(upperCutOffsInHz[i] / samplingRateInHz, 0.5);
normalizedUpperCutoff = Math.max(normalizedUpperCutoff, 0.0);
assert normalizedLowerCutoff < normalizedUpperCutoff;
filters[i] =
new BandPassFilter(normalizedLowerCutoff, normalizedUpperCutoff, filterOrder);
}
}
int maxFreq = filters[0].transformedIR.length / 2 + 1;
// Estimate a smooth gain normalization filter
normalizationFilterTransformedIR = new double[maxFreq];
Arrays.fill(normalizationFilterTransformedIR, 0.0);
int j;
for (i = 0; i < filters.length; i++) {
normalizationFilterTransformedIR[0] += Math.abs(filters[i].transformedIR[0]);
normalizationFilterTransformedIR[maxFreq - 1] += Math.abs(filters[i].transformedIR[1]);
for (j = 1; j < maxFreq - 1; j++)
normalizationFilterTransformedIR[j] +=
Math.sqrt(
filters[i].transformedIR[2 * j] * filters[i].transformedIR[2 * j]
+ filters[i].transformedIR[2 * j + 1] * filters[i].transformedIR[2 * j + 1]);
}
for (j = 0; j < maxFreq; j++)
normalizationFilterTransformedIR[j] = 1.0 / normalizationFilterTransformedIR[j];
// MaryUtils.plot(normalizationFilterTransformedIR, "Normalization filter");
//
}
}
