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relativeEnergy.c
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Thu, May 30, 19:59

relativeEnergy.c
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#include "relativeEnergy.h"
#include "../adaptive_Rpeak_detection/adaptiveRpeakDetection.h"
#include "rt/rt_api.h"
//Previously-found short and long energies for RelEn signal generation
RT_L2_DATA uint32_t lastShortEnergy = 0;
RT_L2_DATA uint32_t lastLongEnergy = 0;
//circular ecg buffer and its pointers
RT_L2_DATA int16_t ecgBuffer_re[LONG_WINDOW + 1];
RT_L2_DATA uint16_t ecgBufferPointer = 0;
RT_L2_DATA uint16_t lastEcgBufferPointer = 0;
RT_L2_DATA uint16_t currentShortWindowPointer = 0;
RT_L2_DATA uint16_t lastShortWindowPointer = 0;
RT_L2_DATA uint16_t relEnBufferPointer = (LONG_WINDOW / 2);
RT_L2_DATA uint16_t multiplier = 10000;
void clearAndResetRelEn() {
//Previously-found short and long energies for RelEn signal generation
lastShortEnergy = 0;
lastLongEnergy = 0;
//circular ecg buffer and its pointers
ecgBufferPointer = 0;
lastEcgBufferPointer = 0;
currentShortWindowPointer = 0;
lastShortWindowPointer = 0;
relEnBufferPointer = (LONG_WINDOW / 2);
}
//This is the main function where rel-En coefficients are generated
uint16_t getRelEnCoefficients(uint8_t fillingBuffer, int16_t sample) {
//If this is the first window, start computing long and short energy sum
if (fillingBuffer == 1) {
if (ecgBufferPointer >= (LONG_WINDOW / 2 - SHORT_WINDOW_HALF) && ecgBufferPointer <= (LONG_WINDOW / 2 + SHORT_WINDOW_HALF)) {
lastShortEnergy += (sample) * (sample);
}
lastLongEnergy += (sample) * (sample);
if (ecgBufferPointer == LONG_WINDOW - 1) {
lastEcgBufferPointer = 0;
currentShortWindowPointer = LONG_WINDOW / 2 + SHORT_WINDOW_HALF + 1;
lastShortWindowPointer = LONG_WINDOW / 2 - SHORT_WINDOW_HALF;
}
return 0;
}
else { //If not, compute Rel-En coefficient c(n)
lastLongEnergy = lastLongEnergy + (ecgBuffer_re[ecgBufferPointer] * ecgBuffer_re[ecgBufferPointer]) - (ecgBuffer_re[lastEcgBufferPointer] * ecgBuffer_re[lastEcgBufferPointer]);
lastShortEnergy = lastShortEnergy + (ecgBuffer_re[currentShortWindowPointer]*ecgBuffer_re[currentShortWindowPointer]) - (ecgBuffer_re[lastShortWindowPointer]*ecgBuffer_re[lastShortWindowPointer]);
lastEcgBufferPointer++;
if (lastEcgBufferPointer > LONG_WINDOW) {
lastEcgBufferPointer = 0;
}
currentShortWindowPointer++;
if (currentShortWindowPointer > LONG_WINDOW) {
currentShortWindowPointer = 0;
}
lastShortWindowPointer++;
if (lastShortWindowPointer > LONG_WINDOW) {
lastShortWindowPointer = 0;
}
uint16_t result = 0;
if (lastLongEnergy > multiplier) {
result = lastShortEnergy / (lastLongEnergy / multiplier);
}
else {
result = (lastShortEnergy * multiplier) / lastLongEnergy;
}
return result;
}
}
void relEn_w(int32_t *arg[]){
int16_t *ecg_w = (int16_t*) arg[0];
int16_t *out = (int16_t*) arg[1];
int32_t *start = arg[2];
int32_t *bufferSize = arg[3];
int16_t rawRelEn = 0;
for(int32_t j = 0; j < *bufferSize; j++)
{
rawRelEn = 0;
if (*start == 0)
{
ecgBuffer_re[ecgBufferPointer] = ecg_w[j];
uint16_t relEnOutput = getRelEnCoefficients(*start, ecg_w[j]);
int16_t currentECG = ecgBuffer_re[relEnBufferPointer];
rawRelEn = (relEnOutput * currentECG) / multiplier;
ecgBufferPointer++;
relEnBufferPointer++;
} //The buffer is initially being filled
else {
ecgBuffer_re[ecgBufferPointer] = ecg_w[j];
uint16_t relEnOutput = getRelEnCoefficients(*start, ecg_w[j]);
if (ecgBufferPointer == LONG_WINDOW - 1) {
rawRelEn = (relEnOutput * ecgBuffer_re[relEnBufferPointer]) / multiplier;
*start = 0;
relEnBufferPointer++;
}
ecgBufferPointer++;
}
if (relEnBufferPointer > LONG_WINDOW) {
relEnBufferPointer = 0;
}
if (ecgBufferPointer > LONG_WINDOW) {
ecgBufferPointer = 0;
}
out[j] = rawRelEn;
}
}

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