added IIR stuff
worked on StepDetection
This commit is contained in:
33
math/DelayBuffer.h
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33
math/DelayBuffer.h
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@@ -0,0 +1,33 @@
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#ifndef DELAYBUFFER_H
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#define DELAYBUFFER_H
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#include <vector>
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/** efficient delay using a ring-buffer */
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template <typename Scalar> class DelayBuffer {
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size_t head = 0;
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std::vector<Scalar> vec;
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public:
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/** ctor */
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DelayBuffer(int size) {
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vec.resize(size);
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}
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/** set all elements to the same value */
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void setAll(const Scalar s) {
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std::fill(vec.begin(), vec.end(), s);
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}
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/** append a new element, get the delayed output */
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Scalar add(Scalar s) {
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vec[head] = s;
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head = (head + 1) % vec.size(); // next to-be-overwritten element = oldest element = tail
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return vec[head];
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}
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};
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#endif // DELAYBUFFER_H
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@@ -3,7 +3,7 @@
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#include <vector>
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#include <complex>
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#include "../../Assertions.h"
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#include "../../../Assertions.h"
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/**
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* FIR filter using complex convolution
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322
math/dsp/iir/BiQuad.h
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322
math/dsp/iir/BiQuad.h
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@@ -0,0 +1,322 @@
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#ifndef IIR_BIQUAD
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#define IIR_BIQUAD
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#include <string.h>
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#include "../../../Assertions.h"
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namespace IIR {
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/** frequency limits */
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#define BFG_MIN 0.0001
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#define BFG_MAX 0.4999
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/**
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* a simple biquad filter that can be used
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* for low- or high-pass filtering
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* http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt
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*/
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template <typename Scalar> class BiQuad {
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public:
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/** ctor */
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BiQuad() : in(), out() {
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reset();
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}
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/** filter the given amplitude of the given channel (history) */
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Scalar filter( const Scalar aIn ) {
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Scalar aOut = 0;
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aOut += aIn *(b0a0);
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aOut += in[0] *(b1a0);
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aOut += in[1] *(b2a0);
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aOut -= out[0]*(a1a0);
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aOut -= out[1]*(a2a0);
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in[1] = in[0];
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in[0] = aIn;
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out[1] = out[0];
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out[0] = aOut;
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return aOut;
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}
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void preFill(const Scalar s) {
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for (int i = 0; i < 100; ++i) {
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filter(s);
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}
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}
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/** reset (disable) the filter */
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void reset() {
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b0a0 = 1.0;
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b1a0 = 0.0;
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b2a0 = 0.0;
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a1a0 = 0.0;
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a2a0 = 0.0;
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memset(in, 0, sizeof(in));
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memset(out, 0, sizeof(out));
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}
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/** configure the filter as low-pass. freqFact between ]0;0.5[ */
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void setLowPass( double freqFact, const float octaves ) {
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sanityCheck(freqFact);
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double w0 = 2.0 * M_PI * freqFact;
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double alpha = sin(w0)*sinh( log(2)/2 * octaves * w0/sin(w0) );
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double b0 = (1.0 - cos(w0))/2.0;
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double b1 = 1.0 - cos(w0);
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double b2 = (1.0 - cos(w0))/2.0;
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double a0 = 1.0 + alpha;
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double a1 = -2.0*cos(w0);
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double a2 = 1.0 - alpha;
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setValues(a0, a1, a2, b0, b1, b2);
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}
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/** configure the filter as low-pass */
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void setLowPass( const float freq, const float octaves, const float sRate ) {
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double freqFact = double(freq) / double(sRate);
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setLowPass(freqFact, octaves);
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}
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//http://dspwiki.com/index.php?title=Lowpass_Resonant_Biquad_Filter
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//http://www.opensource.apple.com/source/WebCore/WebCore-7536.26.14/platform/audio/Biquad.cpp
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/**
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* configure as low-pass filter with resonance
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* @param freqFact the frequency factor between ]0;0.5[
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* @param res
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*/
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void setLowPassResonance( double freqFact, float res ) {
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sanityCheck(freqFact);
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res *= 10;
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double g = pow(10.0, 0.05 * res);
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double d = sqrt((4 - sqrt(16 - 16 / (g * g))) / 2);
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double theta = M_PI * freqFact;
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double sn = 0.5 * d * sin(theta);
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double beta = 0.5 * (1 - sn) / (1 + sn);
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double gamma = (0.5 + beta) * cos(theta);
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double alpha = 0.25 * (0.5 + beta - gamma);
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double a0 = 1.0;
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double b0 = 2.0 * alpha;
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double b1 = 2.0 * 2.0 * alpha;
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double b2 = 2.0 * alpha;
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double a1 = 2.0 * -gamma;
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double a2 = 2.0 * beta;
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setValues(a0, a1, a2, b0, b1, b2);
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}
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/** configure the filter as high-pass. freqFact between ]0;0.5[ */
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void setHighPass( double freqFact, const float octaves ) {
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sanityCheck(freqFact);
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double w0 = 2.0 * M_PI * freqFact;
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double alpha = sin(w0)*sinh( log(2)/2 * octaves * w0/sin(w0) );
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double b0 = (1.0 + cos(w0))/2.0;
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double b1 = -(1.0 + cos(w0));
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double b2 = (1.0 + cos(w0))/2.0;
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double a0 = 1.0 + alpha;
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double a1 = -2.0*cos(w0);
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double a2 = 1.0 - alpha;
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setValues(a0, a1, a2, b0, b1, b2);
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}
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/** configure the filter as high-pass */
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void setHighPass( const float freq, const float octaves, const float sRate ) {
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double freqFact = double(freq) / double(sRate);
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setHighPass(freqFact, octaves);
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}
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/** configure the filter as band-pass. freqFact between ]0;0.5[ */
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void setBandPass( double freqFact, const float octaves ) {
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sanityCheck(freqFact);
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//double w0 = 2 * K_PI * / 2 / freqFact;
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double w0 = 2.0 * M_PI * freqFact;
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double alpha = sin(w0)*sinh( log(2)/2 * octaves * w0/sin(w0) );
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double b0 = sin(w0)/2.0;
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double b1 = 0.0;
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double b2 = -sin(w0)/2.0;
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double a0 = 1.0 + alpha;
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double a1 = -2.0*cos(w0);
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double a2 = 1.0 - alpha;
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setValues(a0, a1, a2, b0, b1, b2);
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}
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/** configure the filter as band-pass */
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void setBandPass( const float freq, const float octaves, float sRate ) {
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double freqFact = double(freq) / double(sRate);
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setBandPass(freqFact, octaves);
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}
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/** configure the filter as all-pass. freqFact between ]0;0.5[ */
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void setAllPass( double freqFact, const float octaves ) {
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sanityCheck(freqFact);
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double w0 = 2.0 * M_PI * freqFact;
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double alpha = sin(w0)*sinh( log(2)/2 * octaves * w0/sin(w0) );
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double b0 = 1 - alpha;
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double b1 = -2*cos(w0);
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double b2 = 1 + alpha;
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double a0 = 1 + alpha;
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double a1 = -2*cos(w0);
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double a2 = 1 - alpha;
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setValues(a0, a1, a2, b0, b1, b2);
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}
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/** configure the filter as all-pass */
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void setAllPass( const float freq, const float octaves, const float sRate ) {
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double freqFact = double(freq) / double(sRate);
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setAllPass(freqFact, octaves);
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}
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/** configure as notch filter. freqFact between ]0;0.5[ */
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void setNotch( double freqFact, const float octaves ) {
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sanityCheck(freqFact);
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double w0 = 2.0 * M_PI * freqFact;
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double alpha = sin(w0)*sinh( log(2)/2 * octaves * w0/sin(w0) );
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double b0 = 1.0;
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double b1 = -2.0*cos(w0);
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double b2 = 1.0;
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double a0 = 1.0 + alpha;
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double a1 = -2.0*cos(w0);
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double a2 = 1.0 - alpha;
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setValues(a0, a1, a2, b0, b1, b2);
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}
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/** configure as notch filter */
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void setNotch( const float freq, const float octaves, const float sRate ) {
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double freqFact = double(freq) / double(sRate);
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setNotch(freqFact, octaves);
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}
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/** configure the filter as low-shelf. increase all aplitudes below freq? freqFact between ]0;0.5[ */
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void setLowShelf( double freqFact, const float octaves, const float gain ) {
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sanityCheck(freqFact);
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double A = sqrt( pow(10, (gain/20.0)) );
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double w0 = 2.0 * M_PI * freqFact;
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double alpha = sin(w0)*sinh( log(2)/2 * octaves * w0/sin(w0) );
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double b0 = A*( (A+1.0) - (A-1.0)*cos(w0) + 2.0*sqrt(A)*alpha );
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double b1 = 2.0*A*( (A-1.0) - (A+1.0)*cos(w0) );
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double b2 = A*( (A+1.0) - (A-1.0)*cos(w0) - 2.0*sqrt(A)*alpha );
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double a0 = (A+1.0) + (A-1.0)*cos(w0) + 2.0*sqrt(A)*alpha;
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double a1 = -2.0*( (A-1.0) + (A+1.0)*cos(w0) );
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double a2 = (A+1.0) + (A-1.0)*cos(w0) - 2.0*sqrt(A)*alpha;
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setValues(a0, a1, a2, b0, b1, b2);
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}
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/** configure the filter as low-shelf. increase all aplitudes below freq? */
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void setLowShelf( const float freq, const float octaves, const float gain, const float sRate ) {
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double freqFact = double(freq) / double(sRate);
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setLowShelf(freqFact, octaves, gain);
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}
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/** configure the filter as high-shelf. increase all amplitues above freq? freqFact between ]0;0.5[ */
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void setHighShelf( double freqFact, const float octaves, const float gain ) {
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sanityCheck(freqFact);
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double A = sqrt( pow(10, (gain/20.0)) );
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double w0 = 2.0 * M_PI * freqFact;
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double alpha = sin(w0)*sinh( log(2)/2 * octaves * w0/sin(w0) );
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double b0 = A*( (A+1.0) + (A-1.0)*cos(w0) + 2.0*sqrt(A)*alpha );
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double b1 = -2.0*A*( (A-1.0) + (A+1.0)*cos(w0) );
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double b2 = A*( (A+1.0) + (A-1.0)*cos(w0) - 2.0*sqrt(A)*alpha );
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double a0 = (A+1.0) - (A-1.0)*cos(w0) + 2.0*sqrt(A)*alpha;
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double a1 = 2.0*( (A-1.0) - (A+1.0)*cos(w0) );
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double a2 = (A+1.0) - (A-1.0)*cos(w0) - 2.0*sqrt(A)*alpha;
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setValues(a0, a1, a2, b0, b1, b2);
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}
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/** configure the filter as high-shelf. increase all amplitues above freq? */
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void setHighShelf( const float freq, const float octaves, const float gain, const float sRate ) {
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double freqFact = double(freq) / double(sRate);
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setHighShelf(freqFact, octaves, gain);
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}
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protected:
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/** pre-calculate the quotients for the filtering */
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void setValues(double a0, double a1, double a2, double b0, double b1, double b2) {
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b0a0 = float(b0/a0);
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b1a0 = float(b1/a0);
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b2a0 = float(b2/a0);
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a2a0 = float(a2/a0);
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a1a0 = float(a1/a0);
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}
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/** the bi-quad filter params */
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float b0a0;
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float b1a0;
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float b2a0;
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float a1a0;
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float a2a0;
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/** history for input values, per channel */
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Scalar in[2];
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/** history for ouput values, per channel */
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Scalar out[2];
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void sanityCheck(const float freqFact) const {
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Assert::isTrue(freqFact >= BFG_MIN, "frequency out of bounds");
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Assert::isTrue(freqFact <= BFG_MAX, "frequency out of bounds");
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}
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};
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}
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#endif // IIR_BIQUAD
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176
sensors/imu/StepDetection3.h
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176
sensors/imu/StepDetection3.h
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@@ -0,0 +1,176 @@
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#ifndef STEPDETECTION3_H
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#define STEPDETECTION3_H
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#include "AccelerometerData.h"
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#include "../../data/Timestamp.h"
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#include <cmath>
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#include <vector>
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#ifdef WITH_DEBUG_PLOT
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#include <KLib/misc/gnuplot/Gnuplot.h>
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#include <KLib/misc/gnuplot/GnuplotSplot.h>
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#include <KLib/misc/gnuplot/GnuplotSplotElementLines.h>
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#include <KLib/misc/gnuplot/GnuplotPlot.h>
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#include <KLib/misc/gnuplot/GnuplotPlotElementLines.h>
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#include <KLib/misc/gnuplot/GnuplotPlotElementPoints.h>
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#endif
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#ifdef WITH_DEBUG_OUTPUT
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#include <fstream>
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#endif
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#include "../../Assertions.h"
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#include "../../math/dsp/iir/BiQuad.h"
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#include "../../math/FixedFrequencyInterpolator.h"
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#include "../../math/DelayBuffer.h"
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/**
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* simple step detection based on accelerometer magnitude.
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* magnitude > threshold? -> step!
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* block for several msec until detecting the next one
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*/
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class StepDetection3 {
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static constexpr float gravity = 9.81;
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static constexpr float stepRate_hz = 2.0;
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static constexpr int sRate_hz = 100;
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static constexpr int every_ms = 1000 / sRate_hz;
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static constexpr float threshold = 1.0;
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float max = 0;
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Timestamp maxTS;
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private:
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FixedFrequencyInterpolator<AccelerometerData> interpol;
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IIR::BiQuad<float> biquad;
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DelayBuffer<float> delay;
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#ifdef WITH_DEBUG_PLOT
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K::Gnuplot gp;
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K::GnuplotPlot plot;
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K::GnuplotPlotElementLines lineRaw;
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K::GnuplotPlotElementLines lineFiltered;
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K::GnuplotPlotElementPoints pointDet;
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Timestamp plotRef;
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Timestamp lastPlot;
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#endif
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#ifdef WITH_DEBUG_OUTPUT
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std::ofstream outFiltered;
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std::ofstream outSteps;
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#endif
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public:
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/** ctor */
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StepDetection3() : interpol(Timestamp::fromMS(every_ms)), delay(10) {
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biquad.setBandPass(stepRate_hz, 1.0, sRate_hz);
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biquad.preFill(gravity);
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#ifdef WITH_DEBUG_PLOT
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gp << "set autoscale xfix\n";
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plot.setTitle("Step Detection");
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plot.add(&lineRaw); lineRaw.getStroke().getColor().setHexStr("#0000FF");
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plot.add(&lineFiltered); lineFiltered.getStroke().getColor().setHexStr("#000000");
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plot.add(&pointDet); pointDet.setPointSize(2); pointDet.setPointType(7);
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#endif
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#ifdef WITH_DEBUG_OUTPUT
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outFiltered = std::ofstream("/tmp/sd2_filtered.dat");
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outSteps = std::ofstream("/tmp/sd2_steps.dat");
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#endif
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}
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/** does the given data indicate a step? */
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bool add(const Timestamp ts, const AccelerometerData& acc) {
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bool gotStep = false;
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// accel-data incoming on a fixed sampling rate (needed for FIR to work)
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// NOTE!!!! MIGHT TRIGGER MORE THAN ONCE PER add() !!!
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auto onResample = [&] (const Timestamp ts, const AccelerometerData data) {
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bool step = false;
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const float mag = data.magnitude();
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// apply filter
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const float fMag = biquad.filter(mag);
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// history buffer
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float fMagOld = delay.add(fMag);
|
||||
|
||||
// zero crossing?
|
||||
float tmp = max;
|
||||
if (fMagOld > 0 && fMag < 0) {
|
||||
if (max > threshold) {
|
||||
step = true;
|
||||
gotStep = true;
|
||||
}
|
||||
delay.setAll(0);
|
||||
max = 0;
|
||||
}
|
||||
|
||||
// track maximum value
|
||||
if (fMag > max) {max = fMag; maxTS = ts;}
|
||||
|
||||
#ifdef WITH_DEBUG_OUTPUT
|
||||
if (step) {
|
||||
std::cout << ts.ms() << std::endl;
|
||||
outSteps << maxTS.ms() << " " << tmp << "\n";
|
||||
outSteps.flush();
|
||||
}
|
||||
outFiltered << ts.ms() << " " << fMag << "\n";
|
||||
#endif
|
||||
|
||||
#ifdef WITH_DEBUG_PLOT
|
||||
|
||||
if (plotRef.isZero()) {plotRef = ts;}
|
||||
const Timestamp tsPlot = (ts-plotRef);
|
||||
const Timestamp tsOldest = tsPlot - Timestamp::fromMS(5000);
|
||||
|
||||
lineRaw.add( K::GnuplotPoint2(tsPlot.ms(), mag) );
|
||||
lineFiltered.add( K::GnuplotPoint2(tsPlot.ms(), fMag) );
|
||||
|
||||
if (step) {
|
||||
pointDet.add( K::GnuplotPoint2((maxTS-plotRef).ms(), tmp) );
|
||||
}
|
||||
|
||||
if (lastPlot + Timestamp::fromMS(50) < tsPlot) {
|
||||
|
||||
lastPlot = tsPlot;
|
||||
auto remove = [tsOldest] (const K::GnuplotPoint2 pt) {return pt.x < tsOldest.ms();};
|
||||
lineRaw.removeIf(remove);
|
||||
lineFiltered.removeIf(remove);
|
||||
pointDet.removeIf(remove);
|
||||
|
||||
gp.draw(plot);
|
||||
gp.flush();
|
||||
usleep(100);
|
||||
|
||||
}
|
||||
|
||||
#endif
|
||||
|
||||
};
|
||||
|
||||
// ensure fixed sampling rate for FIR freq filters to work!
|
||||
interpol.add(ts, acc, onResample);
|
||||
|
||||
return gotStep;
|
||||
|
||||
|
||||
}
|
||||
|
||||
};
|
||||
|
||||
|
||||
#endif // STEPDETECTION3_H
|
||||
Reference in New Issue
Block a user