`package be.tarsos.dsp.wavelet.lift;/*** * @author Ian Kaplan*/public class Daubechies4Wavelet extends LiftingSchemeBaseWavelet { final static float sqrt3 = (float) Math.sqrt(3); final static float sqrt2 = (float) Math.sqrt(2); protected void normalize(float[] S, int N, int direction) { int half = N >> 1; for (int n = 0; n < half; n++) { if (direction == forward) { S[n] = ((sqrt3 - 1.0f) / sqrt2) * S[n]; S[n + half] = ((sqrt3 + 1.0f) / sqrt2) * S[n + half]; } else if (direction == inverse) { S[n] = ((sqrt3 + 1.0f) / sqrt2) * S[n]; S[n + half] = ((sqrt3 - 1.0f) / sqrt2) * S[n + half]; } else { System.out .println("Daubechies4Wavelet::normalize: bad direction value"); break; } } } // normalize protected void predict(float[] S, int N, int direction) { int half = N >> 1; if (direction == forward) { S[half] = S[half] - (sqrt3 / 4.0f) * S[0] - (((sqrt3 - 2) / 4.0f) * S[half - 1]); } else if (direction == inverse) { S[half] = S[half] + (sqrt3 / 4.0f) * S[0] + (((sqrt3 - 2) / 4.0f) * S[half - 1]); } else { System.out .println("Daubechies4Wavelet::predict: bad direction value"); } // predict, forward for (int n = 1; n < half; n++) { if (direction == forward) { S[half + n] = S[half + n] - (sqrt3 / 4.0f) * S[n] - (((sqrt3 - 2) / 4.0f) * S[n - 1]); } else if (direction == inverse) { S[half + n] = S[half + n] + (sqrt3 / 4.0f) * S[n] + (((sqrt3 - 2) / 4.0f) * S[n - 1]); } else { break; } } } // predict protected void updateOne(float[] S, int N, int direction) { int half = N >> 1; for (int n = 0; n < half; n++) { float updateVal = sqrt3 * S[half + n]; if (direction == forward) { S[n] = S[n] + updateVal; } else if (direction == inverse) { S[n] = S[n] - updateVal; } else { System.out .println("Daubechies4Wavelet::updateOne: bad direction value"); break; } } } // updateOne protected void update(float[] S, int N, int direction) { int half = N >> 1; for (int n = 0; n < half - 1; n++) { if (direction == forward) { S[n] = S[n] - S[half + n + 1]; } else if (direction == inverse) { S[n] = S[n] + S[half + n + 1]; } else { System.out .println("Daubechies4Wavelet::update: bad direction value"); break; } } if (direction == forward) { S[half - 1] = S[half - 1] - S[half]; } else if (direction == inverse) { S[half - 1] = S[half - 1] + S[half]; } } // update public void forwardTrans(float[] vec) { final int N = vec.length; for (int n = N; n > 1; n = n >> 1) { split(vec, n); updateOne(vec, n, forward); // update 1 predict(vec, n, forward); update(vec, n, forward); // update 2 normalize(vec, n, forward); } } // forwardTrans /** * <p> * Default two step Lifting Scheme inverse wavelet transform * </p> * * <p> * inverseTrans is passed the result of an ordered wavelet transform, * consisting of an average and a set of wavelet coefficients. The inverse * transform is calculated in-place and the result is returned in the * argument array. * </p> */ public void inverseTrans(float[] vec) { final int N = vec.length; for (int n = 2; n <= N; n = n << 1) { normalize(vec, n, inverse); update(vec, n, inverse); predict(vec, n, inverse); updateOne(vec, n, inverse); merge(vec, n); } } // inverseTrans}`