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| 1 | +#include "lulu.h" |
| 2 | + |
| 3 | +#include <stdbool.h> |
| 4 | +#include <stdint.h> |
| 5 | +#include <string.h> |
| 6 | +#include <math.h> |
| 7 | + |
| 8 | +#include "platform.h" |
| 9 | + |
| 10 | +#include "common/filter.h" |
| 11 | +#include "common/maths.h" |
| 12 | +#include "common/utils.h" |
| 13 | + |
| 14 | +#ifdef __ARM_ACLE |
| 15 | +#include <arm_acle.h> |
| 16 | +#endif /* __ARM_ACLE */ |
| 17 | +#include <fenv.h> |
| 18 | + |
| 19 | +void luluFilterInit(luluFilter_t *filter, int N) |
| 20 | +{ |
| 21 | + filter->N = constrain(N, 1, 15); |
| 22 | + filter->windowSize = filter->N * 2 + 1; |
| 23 | + filter->windowBufIndex = 0; |
| 24 | + |
| 25 | + memset(filter->luluInterim, 0, sizeof(float) * (filter->windowSize)); |
| 26 | + memset(filter->luluInterimB, 0, sizeof(float) * (filter->windowSize)); |
| 27 | +} |
| 28 | + |
| 29 | +FAST_CODE float fixRoad(float *series, float *seriesB, int index, int filterN, int windowSize) |
| 30 | +{ |
| 31 | + register float curVal = 0; |
| 32 | + register float curValB = 0; |
| 33 | + for (int N = 1; N <= filterN; N++) |
| 34 | + { |
| 35 | + int indexNeg = (index + windowSize - 2 * N) % windowSize; |
| 36 | + register int curIndex = (indexNeg + 1) % windowSize; |
| 37 | + register float prevVal = series[indexNeg]; |
| 38 | + register float prevValB = seriesB[indexNeg]; |
| 39 | + register int indexPos = (curIndex + N) % windowSize; |
| 40 | + for (int i = windowSize - 2 * N; i < windowSize - N; i++) |
| 41 | + { |
| 42 | + if (indexPos >= windowSize) |
| 43 | + { |
| 44 | + indexPos = 0; |
| 45 | + } |
| 46 | + if (curIndex >= windowSize) |
| 47 | + { |
| 48 | + curIndex = 0; |
| 49 | + } |
| 50 | + // curIndex = (2 - 1) % 3 = 1 |
| 51 | + curVal = series[curIndex]; |
| 52 | + curValB = seriesB[curIndex]; |
| 53 | + register float nextVal = series[indexPos]; |
| 54 | + register float nextValB = seriesB[indexPos]; |
| 55 | + // onbump (s, 1, 1, 3) |
| 56 | + // if(onBump(series, curIndex, N, windowSize)) |
| 57 | + if (prevVal < curVal && curVal > nextVal) |
| 58 | + { |
| 59 | + float maxValue = MAX(prevVal, nextVal); |
| 60 | + |
| 61 | + series[curIndex] = maxValue; |
| 62 | + register int k = curIndex; |
| 63 | + for (int j = 1; j < N; j++) |
| 64 | + { |
| 65 | + if (++k >= windowSize) |
| 66 | + { |
| 67 | + k = 0; |
| 68 | + } |
| 69 | + series[k] = maxValue; |
| 70 | + } |
| 71 | + } |
| 72 | + |
| 73 | + if (prevValB < curValB && curValB > nextValB) |
| 74 | + { |
| 75 | + float maxValue = MAX(prevValB, nextValB); |
| 76 | + |
| 77 | + curVal = maxValue; |
| 78 | + seriesB[curIndex] = maxValue; |
| 79 | + register int k = curIndex; |
| 80 | + for (int j = 1; j < N; j++) |
| 81 | + { |
| 82 | + if (++k >= windowSize) |
| 83 | + { |
| 84 | + k = 0; |
| 85 | + } |
| 86 | + seriesB[k] = maxValue; |
| 87 | + } |
| 88 | + } |
| 89 | + prevVal = curVal; |
| 90 | + prevValB = curValB; |
| 91 | + curIndex++; |
| 92 | + indexPos++; |
| 93 | + } |
| 94 | + |
| 95 | + curIndex = (indexNeg + 1) % windowSize; |
| 96 | + prevVal = series[indexNeg]; |
| 97 | + prevValB = seriesB[indexNeg]; |
| 98 | + indexPos = (curIndex + N) % windowSize; |
| 99 | + for (int i = windowSize - 2 * N; i < windowSize - N; i++) |
| 100 | + { |
| 101 | + if (indexPos >= windowSize) |
| 102 | + { |
| 103 | + indexPos = 0; |
| 104 | + } |
| 105 | + if (curIndex >= windowSize) |
| 106 | + { |
| 107 | + curIndex = 0; |
| 108 | + } |
| 109 | + // curIndex = (2 - 1) % 3 = 1 |
| 110 | + curVal = series[curIndex]; |
| 111 | + curValB = seriesB[curIndex]; |
| 112 | + register float nextVal = series[indexPos]; |
| 113 | + register float nextValB = seriesB[indexPos]; |
| 114 | + |
| 115 | + if (prevVal > curVal && curVal < nextVal) |
| 116 | + { |
| 117 | + float minValue = MIN(prevVal, nextVal); |
| 118 | + |
| 119 | + curVal = minValue; |
| 120 | + series[curIndex] = minValue; |
| 121 | + register int k = curIndex; |
| 122 | + for (int j = 1; j < N; j++) |
| 123 | + { |
| 124 | + if (++k >= windowSize) |
| 125 | + { |
| 126 | + k = 0; |
| 127 | + } |
| 128 | + series[k] = minValue; |
| 129 | + } |
| 130 | + } |
| 131 | + |
| 132 | + if (prevValB > curValB && curValB < nextValB) |
| 133 | + { |
| 134 | + float minValue = MIN(prevValB, nextValB); |
| 135 | + curValB = minValue; |
| 136 | + seriesB[curIndex] = minValue; |
| 137 | + register int k = curIndex; |
| 138 | + for (int j = 1; j < N; j++) |
| 139 | + { |
| 140 | + if (++k >= windowSize) |
| 141 | + { |
| 142 | + k = 0; |
| 143 | + } |
| 144 | + seriesB[k] = minValue; |
| 145 | + } |
| 146 | + } |
| 147 | + prevVal = curVal; |
| 148 | + prevValB = curValB; |
| 149 | + curIndex++; |
| 150 | + indexPos++; |
| 151 | + } |
| 152 | + } |
| 153 | + return (curVal - curValB) / 2; |
| 154 | +} |
| 155 | + |
| 156 | +FAST_CODE float luluFilterPartialApply(luluFilter_t *filter, float input) |
| 157 | +{ |
| 158 | + // This is the value N of the LULU filter. |
| 159 | + register int filterN = filter->N; |
| 160 | + // This is the total window size for the rolling buffer |
| 161 | + register int filterWindow = filter->windowSize; |
| 162 | + |
| 163 | + register int windowIndex = filter->windowBufIndex; |
| 164 | + register float inputVal = input; |
| 165 | + register int newIndex = (windowIndex + 1) % filterWindow; |
| 166 | + filter->windowBufIndex = newIndex; |
| 167 | + filter->luluInterim[windowIndex] = inputVal; |
| 168 | + filter->luluInterimB[windowIndex] = -inputVal; |
| 169 | + return fixRoad(filter->luluInterim, filter->luluInterimB, windowIndex, filterN, filterWindow); |
| 170 | +} |
| 171 | + |
| 172 | +FAST_CODE float luluFilterApply(luluFilter_t *filter, float input) |
| 173 | +{ |
| 174 | + // This is the UL filter |
| 175 | + float resultA = luluFilterPartialApply(filter, input); |
| 176 | + // We use the median interpretation of this filter to remove bias in the output |
| 177 | + return resultA; |
| 178 | +} |
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