PeakPicker.java (4772B)
1 /* 2 * _______ _____ _____ _____ 3 * |__ __| | __ \ / ____| __ \ 4 * | | __ _ _ __ ___ ___ ___| | | | (___ | |__) | 5 * | |/ _` | '__/ __|/ _ \/ __| | | |\___ \| ___/ 6 * | | (_| | | \__ \ (_) \__ \ |__| |____) | | 7 * |_|\__,_|_| |___/\___/|___/_____/|_____/|_| 8 * 9 * ------------------------------------------------------------- 10 * 11 * TarsosDSP is developed by Joren Six at IPEM, University Ghent 12 * 13 * ------------------------------------------------------------- 14 * 15 * Info: http://0110.be/tag/TarsosDSP 16 * Github: https://github.com/JorenSix/TarsosDSP 17 * Releases: http://0110.be/releases/TarsosDSP/ 18 * 19 * TarsosDSP includes modified source code by various authors, 20 * for credits and info, see README. 21 * 22 */ 23 24 package be.tarsos.dsp.util; 25 26 import java.util.Arrays; 27 28 /** 29 * Implements a moving mean adaptive threshold peak picker. 30 * 31 * The implementation is a translation of peakpicker.c from Aubio, Copyright (C) 32 * 2003-2009 Paul Brossier <piem@aubio.org> 33 * 34 * @author Joren Six 35 * @author Paul Brossiers 36 */ 37 public class PeakPicker { 38 /** thresh: offset threshold [0.033 or 0.01] */ 39 private double threshold; 40 /** win_post: median filter window length (causal part) [8] */ 41 private int win_post; 42 /** pre: median filter window (anti-causal part) [post-1] */ 43 private int win_pre; 44 45 /** biquad low pass filter */ 46 private BiQuadFilter biquad; 47 48 /** original onsets */ 49 private float[] onset_keep; 50 /** modified onsets */ 51 private float[] onset_proc; 52 /** peak picked window [3] */ 53 private float[] onset_peek; 54 /** scratch pad for biquad and median */ 55 private float[] scratch; 56 57 private float lastPeekValue; 58 59 /** 60 * Initializes a new moving mean adaptive threshold peak picker. 61 * 62 * @param threshold 63 * The threshold defines when a peak is selected. It should be 64 * between zero and one, 0.3 is a reasonable value. If too many 65 * peaks are detected go to 0.5 - 0.8. 66 */ 67 public PeakPicker(double threshold) { 68 /* Low-pass filter cutoff [0.34, 1] */ 69 biquad = new BiQuadFilter(0.1600,0.3200,0.1600,-0.5949,0.2348); 70 this.threshold = threshold; 71 win_post = 5; 72 win_pre = 1; 73 74 onset_keep = new float[win_post + win_pre +1]; 75 onset_proc = new float[win_post + win_pre +1]; 76 scratch = new float[win_post + win_pre +1]; 77 onset_peek = new float[3]; 78 } 79 80 /** 81 * Sets a new threshold. 82 * 83 * @param threshold 84 * The threshold defines when a peak is selected. It should be 85 * between zero and one, 0.3 is a reasonable value. If too many 86 * peaks are detected go to 0.5 - 0.8. 87 */ 88 public void setThreshold(double threshold) { 89 this.threshold = threshold; 90 } 91 92 /** 93 * Modified version for real time, moving mean adaptive threshold this 94 * method is slightly more permissive than the off-LineWavelet one, and yields to 95 * an increase of false positives. 96 * 97 * @param onset 98 * The new onset value. 99 * @return True if a peak is detected, false otherwise. 100 **/ 101 public boolean pickPeak(float onset) { 102 float mean = 0.f; 103 float median = 0.f; 104 105 int length = win_post + win_pre + 1; 106 107 108 /* store onset in onset_keep */ 109 /* shift all elements but last, then write last */ 110 /* for (i=0;i<channels;i++) { */ 111 for(int j=0;j<length-1;j++) { 112 onset_keep[j] = onset_keep[j+1]; 113 onset_proc[j] = onset_keep[j]; 114 } 115 onset_keep[length-1] = onset; 116 onset_proc[length-1] = onset; 117 118 /* filter onset_proc */ 119 /** \bug filtfilt calculated post+pre times, should be only once !? */ 120 biquad.doFiltering(onset_proc,scratch); 121 122 /* calculate mean and median for onset_proc */ 123 124 /* copy to scratch */ 125 float sum = 0.0f; 126 for (int j = 0; j < length; j++){ 127 scratch[j] = onset_proc[j]; 128 sum += scratch[j]; 129 } 130 Arrays.sort(scratch); 131 median = scratch[scratch.length/2]; 132 mean = sum/Float.valueOf(length); 133 134 /* shift peek array */ 135 for (int j=0;j<3-1;j++){ 136 onset_peek[j] = onset_peek[j+1]; 137 } 138 /* calculate new peek value */ 139 onset_peek[2] = (float) (onset_proc[win_post] - median - mean * threshold); 140 141 boolean isPeak = isPeak(1); 142 lastPeekValue = onset; 143 144 return isPeak; 145 } 146 147 /** 148 * 149 * @return The value of the last detected peak, or zero. 150 */ 151 public float getLastPeekValue() { 152 return lastPeekValue; 153 } 154 155 /** 156 * Returns true if the onset is a peak. 157 * 158 * @param index 159 * the index in onset_peak to check. 160 * @return True if the onset is a peak, false otherwise. 161 */ 162 private boolean isPeak(int index) { 163 return ( onset_peek[index] > onset_peek[index - 1] && 164 onset_peek[index] > onset_peek[index + 1] && 165 onset_peek[index] > 0.); 166 } 167 }