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Indoor/sensors/imu/StepDetection.h
FrankE d283d9b326 geometry changes/fixes/new features
new grid walkers + fixes
new test-cases
worked on step/and turn detection
android offline-data-reader
worked on vap-grouping
2016-09-07 10:16:51 +02:00

184 lines
3.8 KiB
C++

#ifndef STEPDETECTION_H
#define STEPDETECTION_H
#include "AccelerometerData.h"
#include "../../data/Timestamp.h"
#include <cmath>
#include <vector>
#include <KLib/misc/gnuplot/Gnuplot.h>
#include <KLib/misc/gnuplot/GnuplotSplot.h>
#include <KLib/misc/gnuplot/GnuplotSplotElementLines.h>
#include <KLib/misc/gnuplot/GnuplotPlot.h>
#include <KLib/misc/gnuplot/GnuplotPlotElementLines.h>
#include "../../Assertions.h"
#include "../../math/MovingAverageTS.h"
/**
* simple step detection based on accelerometer magnitude.
* magnitude > threshold? -> step!
* block for several msec until detecting the next one
*/
class StepDetection {
private:
MovingAverageTS<float> avgLong;
MovingAverageTS<float> avgShort;
Timestamp blockUntil;
bool waitForUp = false;
const Timestamp blockTime = Timestamp::fromMS(150); // 150-250 looks good
const float upperThreshold = +0.4f; // + is usually smaller than down (look at graphs)
const float lowerThreshold = -0.8f;
public:
/** ctor */
StepDetection() : avgLong(Timestamp::fromMS(500), 0), avgShort(Timestamp::fromMS(40), 0) {
;
}
/** does the given data indicate a step? */
bool add(const Timestamp ts, const AccelerometerData& acc) {
// update averages
avgLong.add(ts, acc.magnitude());
avgShort.add(ts, acc.magnitude());
// difference between long-term-average (gravity) and very-short-time average
const float delta = avgShort.get() - avgLong.get();
bool step = false;
if (blockUntil > ts) {return false;}
// wait for a rising edge
if (waitForUp && delta > upperThreshold) {
blockUntil = ts + blockTime; // block some time
waitForUp = false;
}
// wait for a falling edge
if (!waitForUp && delta < lowerThreshold) {
blockUntil = ts + blockTime; // block some time
waitForUp = true;
step = true;
}
// static K::Gnuplot gp;
// static K::GnuplotPlot plot;
// static K::GnuplotPlotElementLines lines1; plot.add(&lines1);
// static K::GnuplotPlotElementLines lines2; plot.add(&lines2); lines2.setColorHex("#0000ff");
// static Timestamp ref = ts;
// static int i = 0;
// //lines1.add( K::GnuplotPoint2((ts-ref).ms(), _delta) );
// lines2.add( K::GnuplotPoint2((ts-ref).ms(), delta) );
// if (++i % 100 == 0) {
// gp.draw(plot);
// gp.flush();
// usleep(1000*25);
// }
return step;
}
//private:
// /** low pass acc-magnitude */
// float avg1 = 0;
// /** even-more low-pass acc-magnitude */
// float avg2 = 0;
//private:
// class Stepper {
// private:
// /** block for 300 ms after every step */
// const Timestamp blockTime = Timestamp::fromMS(300);
// /** the threshold for detecting a spike as step */
// const float threshold = 0.30;
// /** block until the given timestamp before detecting additional steps */
// Timestamp blockUntil;
// public:
// /** is the given (relative!) magnitude (mag - ~9.81) a step? */
// bool isStep(const Timestamp ts, const float mag) {
// // still blocking
// if (ts < blockUntil) {
// return false;
// }
// // threshold reached? -> step!
// if (mag > threshold) {
// // block x milliseconds until detecting the next step
// blockUntil = ts + blockTime;
// // we have a step
// return true;
// }
// // no step
// return false;
// }
// };
// Stepper stepper;
//public:
// /** does the given data indicate a step? */
// bool add(const Timestamp ts, const AccelerometerData& acc) {
// avg1 = avg1 * 0.91 + acc.magnitude() * 0.09; // short-time average [filtered steps]
// avg2 = avg2 * 0.97 + acc.magnitude() * 0.03; // long-time average [gravity]
// // average maginitude must be > 9.0 to be stable enough to proceed
// if (avg2 > 9) {
// // gravity-free magnitude
// const float avg = avg1 - avg2;
// // detect steps
// return stepper.isStep(ts, avg);
// } else {
// return false;
// }
// }
};
#endif // STEPDETECTION_H