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InfiniTime/src/components/heartrate/Ppg.cpp

96 lines
2.1 KiB
C++

#include <vector>
#include <nrf_log.h>
#include "Ppg.h"
using namespace Pinetime::Controllers;
namespace {
// TODO no vector!
int Compare(int* d1, int* d2, size_t count) {
int e = 0;
for(int i = 0; i < count; i++) {
auto d = d1[i] - d2[i];
e += d * d;
}
return e;
}
int CompareShift(int* d, int shift, size_t count) {
return Compare(d +shift, d, count - shift);
}
int Trough(int* d, size_t size, float mn, float mx) {
auto z2 = CompareShift(d, mn-2, size);
auto z1 = CompareShift(d, mn-1, size);
for(int i = mn; i < mx + 1; i++) {
auto z = CompareShift(d, i, size);
if(z2 > z1 && z1 < z)
return i;
z2 = z1;
z1 = z;
}
return -1;
}
}
Ppg::Ppg(float spl) : offset{spl},
hpf{0.87033078, -1.74066156, 0.87033078,-1.72377617, 0.75754694},
agc{20, 0.971, 2},
lpf{0.11595249, 0.23190498, 0.11595249,-0.72168143, 0.18549138} {
}
int Ppg::Preprocess(float spl) {
spl -= offset;
spl = hpf.Step(spl);
spl = agc.Step(spl);
spl = lpf.Step(spl);
auto spl_int = static_cast<int>(spl);
if(dataIndex < 200)
data[dataIndex++] = spl_int;
return spl_int;
}
float Ppg::HeartRate() {
if(dataIndex < 200)
return 0;
NRF_LOG_INFO("PREPROCESS, offset = %d", offset);
auto hr = ProcessHeartRate();
dataIndex = 0;
return hr;
}
int cccount = 0;
float Ppg::ProcessHeartRate() {
if(cccount > 2)
asm("nop");
cccount ++;
auto t0 = Trough(data.data(), dataIndex, 7, 48);
if(t0 < 0)
return 0;
float t1 = t0 * 2;
t1 = Trough(data.data(), dataIndex, t1-5, t1+5);
if(t1 < 0)
return 0;
float t2 = static_cast<int>(t1 * 3) / 2;
t2 = Trough(data.data(), dataIndex, t2 - 5, t2 + 5);
if(t2 < 0)
return 0;
float t3 = static_cast<int>(t2 * 4) / 3;
t3 = Trough(data.data(), dataIndex, t3 - 4, t3 + 4);
if(t3 < 0)
return static_cast<int>(60 * 24 * 3) / static_cast<int>(t2);
return static_cast<int>(60 * 24 * 4) / static_cast<int>(t3);
}
void Ppg::SetOffset(uint16_t offset) {
this->offset = offset;
dataIndex = 0;
}