3e06970428
- Add --train CLI flag with dataset loading, graph transformer training, cosine-scheduled SGD, PCK/OKS validation, and checkpoint saving - Refactor main.rs to import training modules from lib.rs instead of duplicating mod declarations - Add ADR-021 (vital sign detection), ADR-022 (Windows WiFi enhanced fidelity), ADR-023 (trained DensePose pipeline) documentation - Add wifi-densepose-vitals crate: breathing, heartrate, anomaly detection, preprocessor, and temporal store - Add wifi-densepose-wifiscan crate: 8-stage signal intelligence pipeline with netsh/wlanapi adapters, multi-BSSID registry, attention weighting, spatial correlation, and breathing extraction Co-Authored-By: claude-flow <ruv@ruv.net>
397 lines
12 KiB
Rust
397 lines
12 KiB
Rust
//! Heart rate extraction from CSI phase coherence.
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//!
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//! Uses bandpass filtering (0.8-2.0 Hz) and autocorrelation-based
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//! peak detection to extract cardiac rate from inter-subcarrier
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//! phase data. Requires multi-subcarrier CSI data (ESP32 mode only).
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//!
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//! The cardiac signal (0.1-0.5 mm body surface displacement) is
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//! ~10x weaker than the respiratory signal (1-5 mm chest displacement),
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//! so this module relies on phase coherence across subcarriers rather
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//! than single-channel amplitude analysis.
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use crate::types::{VitalEstimate, VitalStatus};
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/// IIR bandpass filter state (2nd-order resonator).
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#[derive(Clone, Debug)]
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struct IirState {
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x1: f64,
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x2: f64,
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y1: f64,
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y2: f64,
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}
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impl Default for IirState {
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fn default() -> Self {
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Self {
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x1: 0.0,
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x2: 0.0,
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y1: 0.0,
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y2: 0.0,
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}
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}
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}
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/// Heart rate extractor using bandpass filtering and autocorrelation
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/// peak detection.
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pub struct HeartRateExtractor {
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/// Per-sample filtered signal history.
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filtered_history: Vec<f64>,
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/// Sample rate in Hz.
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sample_rate: f64,
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/// Analysis window in seconds.
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window_secs: f64,
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/// Maximum subcarrier slots.
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n_subcarriers: usize,
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/// Cardiac band low cutoff (Hz) -- 0.8 Hz = 48 BPM.
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freq_low: f64,
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/// Cardiac band high cutoff (Hz) -- 2.0 Hz = 120 BPM.
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freq_high: f64,
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/// IIR filter state.
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filter_state: IirState,
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/// Minimum subcarriers required for reliable HR estimation.
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min_subcarriers: usize,
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}
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impl HeartRateExtractor {
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/// Create a new heart rate extractor.
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///
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/// - `n_subcarriers`: number of subcarrier channels.
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/// - `sample_rate`: input sample rate in Hz.
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/// - `window_secs`: analysis window length in seconds (default: 15).
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#[must_use]
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#[allow(clippy::cast_possible_truncation, clippy::cast_sign_loss)]
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pub fn new(n_subcarriers: usize, sample_rate: f64, window_secs: f64) -> Self {
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let capacity = (sample_rate * window_secs) as usize;
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Self {
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filtered_history: Vec::with_capacity(capacity),
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sample_rate,
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window_secs,
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n_subcarriers,
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freq_low: 0.8,
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freq_high: 2.0,
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filter_state: IirState::default(),
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min_subcarriers: 4,
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}
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}
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/// Create with ESP32 defaults (56 subcarriers, 100 Hz, 15 s window).
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#[must_use]
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pub fn esp32_default() -> Self {
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Self::new(56, 100.0, 15.0)
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}
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/// Extract heart rate from per-subcarrier residuals and phase data.
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///
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/// - `residuals`: amplitude residuals from the preprocessor.
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/// - `phases`: per-subcarrier unwrapped phases (radians).
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///
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/// Returns a `VitalEstimate` with heart rate in BPM, or `None`
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/// if insufficient data or too few subcarriers.
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pub fn extract(&mut self, residuals: &[f64], phases: &[f64]) -> Option<VitalEstimate> {
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let n = residuals.len().min(self.n_subcarriers).min(phases.len());
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if n == 0 {
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return None;
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}
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// For cardiac signals, use phase-coherence weighted fusion.
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// Compute mean phase differential as a proxy for body-surface
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// displacement sensitivity.
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let phase_signal = compute_phase_coherence_signal(residuals, phases, n);
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// Apply cardiac-band IIR bandpass filter
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let filtered = self.bandpass_filter(phase_signal);
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// Append to history, enforce window limit
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self.filtered_history.push(filtered);
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let max_len = (self.sample_rate * self.window_secs) as usize;
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if self.filtered_history.len() > max_len {
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self.filtered_history.remove(0);
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}
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// Need at least 5 seconds of data for cardiac detection
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let min_samples = (self.sample_rate * 5.0) as usize;
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if self.filtered_history.len() < min_samples {
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return None;
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}
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// Use autocorrelation to find the dominant periodicity
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let (period_samples, acf_peak) =
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autocorrelation_peak(&self.filtered_history, self.sample_rate, self.freq_low, self.freq_high);
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if period_samples == 0 {
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return None;
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}
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let frequency_hz = self.sample_rate / period_samples as f64;
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let bpm = frequency_hz * 60.0;
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// Validate BPM is in physiological range (40-180 BPM)
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if !(40.0..=180.0).contains(&bpm) {
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return None;
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}
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// Confidence based on autocorrelation peak strength and subcarrier count
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let subcarrier_factor = if n >= self.min_subcarriers {
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1.0
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} else {
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n as f64 / self.min_subcarriers as f64
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};
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let confidence = (acf_peak * subcarrier_factor).clamp(0.0, 1.0);
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let status = if confidence >= 0.6 && n >= self.min_subcarriers {
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VitalStatus::Valid
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} else if confidence >= 0.3 {
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VitalStatus::Degraded
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} else {
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VitalStatus::Unreliable
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};
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Some(VitalEstimate {
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value_bpm: bpm,
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confidence,
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status,
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})
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}
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/// 2nd-order IIR bandpass filter (cardiac band: 0.8-2.0 Hz).
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fn bandpass_filter(&mut self, input: f64) -> f64 {
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let state = &mut self.filter_state;
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let omega_low = 2.0 * std::f64::consts::PI * self.freq_low / self.sample_rate;
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let omega_high = 2.0 * std::f64::consts::PI * self.freq_high / self.sample_rate;
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let bw = omega_high - omega_low;
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let center = f64::midpoint(omega_low, omega_high);
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let r = 1.0 - bw / 2.0;
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let cos_w0 = center.cos();
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let output =
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(1.0 - r) * (input - state.x2) + 2.0 * r * cos_w0 * state.y1 - r * r * state.y2;
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state.x2 = state.x1;
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state.x1 = input;
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state.y2 = state.y1;
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state.y1 = output;
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output
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}
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/// Reset all filter state and history.
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pub fn reset(&mut self) {
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self.filtered_history.clear();
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self.filter_state = IirState::default();
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}
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/// Current number of samples in the history buffer.
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#[must_use]
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pub fn history_len(&self) -> usize {
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self.filtered_history.len()
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}
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/// Cardiac band cutoff frequencies.
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#[must_use]
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pub fn band(&self) -> (f64, f64) {
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(self.freq_low, self.freq_high)
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}
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}
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/// Compute a phase-coherence-weighted signal from residuals and phases.
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///
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/// Combines amplitude residuals with inter-subcarrier phase coherence
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/// to enhance the cardiac signal. Subcarriers with similar phase
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/// derivatives are likely sensing the same body surface.
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fn compute_phase_coherence_signal(residuals: &[f64], phases: &[f64], n: usize) -> f64 {
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if n <= 1 {
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return residuals.first().copied().unwrap_or(0.0);
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}
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// Compute inter-subcarrier phase differences as coherence weights.
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// Adjacent subcarriers with small phase differences are more coherent.
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let mut weighted_sum = 0.0;
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let mut weight_total = 0.0;
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for i in 0..n {
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let coherence = if i + 1 < n {
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let phase_diff = (phases[i + 1] - phases[i]).abs();
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// Higher coherence when phase difference is small
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(-phase_diff).exp()
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} else if i > 0 {
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let phase_diff = (phases[i] - phases[i - 1]).abs();
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(-phase_diff).exp()
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} else {
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1.0
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};
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weighted_sum += residuals[i] * coherence;
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weight_total += coherence;
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}
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if weight_total > 1e-15 {
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weighted_sum / weight_total
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} else {
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0.0
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}
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}
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/// Find the dominant periodicity via autocorrelation in the cardiac band.
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///
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/// Returns `(period_in_samples, peak_normalized_acf)`. If no peak is
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/// found, returns `(0, 0.0)`.
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fn autocorrelation_peak(
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signal: &[f64],
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sample_rate: f64,
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freq_low: f64,
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freq_high: f64,
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) -> (usize, f64) {
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let n = signal.len();
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if n < 4 {
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return (0, 0.0);
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}
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// Lag range corresponding to the cardiac band
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let min_lag = (sample_rate / freq_high).floor() as usize; // highest freq = shortest period
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let max_lag = (sample_rate / freq_low).ceil() as usize; // lowest freq = longest period
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let max_lag = max_lag.min(n / 2);
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if min_lag >= max_lag || min_lag >= n {
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return (0, 0.0);
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}
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// Compute mean-subtracted signal
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let mean: f64 = signal.iter().sum::<f64>() / n as f64;
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// Autocorrelation at lag 0 for normalisation
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let acf0: f64 = signal.iter().map(|&x| (x - mean) * (x - mean)).sum();
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if acf0 < 1e-15 {
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return (0, 0.0);
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}
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// Search for the peak in the cardiac lag range
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let mut best_lag = 0;
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let mut best_acf = f64::MIN;
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for lag in min_lag..=max_lag {
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let acf: f64 = signal
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.iter()
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.take(n - lag)
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.enumerate()
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.map(|(i, &x)| (x - mean) * (signal[i + lag] - mean))
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.sum();
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let normalized = acf / acf0;
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if normalized > best_acf {
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best_acf = normalized;
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best_lag = lag;
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}
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}
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if best_acf > 0.0 {
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(best_lag, best_acf)
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} else {
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(0, 0.0)
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn no_data_returns_none() {
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let mut ext = HeartRateExtractor::new(4, 100.0, 15.0);
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assert!(ext.extract(&[], &[]).is_none());
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}
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#[test]
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fn insufficient_history_returns_none() {
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let mut ext = HeartRateExtractor::new(2, 100.0, 15.0);
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for _ in 0..10 {
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assert!(ext.extract(&[0.1, 0.2], &[0.0, 0.0]).is_none());
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}
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}
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#[test]
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fn sinusoidal_heartbeat_detected() {
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let sample_rate = 50.0;
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let mut ext = HeartRateExtractor::new(4, sample_rate, 20.0);
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let heart_freq = 1.2; // 72 BPM
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// Generate 20 seconds of simulated cardiac signal across 4 subcarriers
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for i in 0..1000 {
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let t = i as f64 / sample_rate;
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let base = (2.0 * std::f64::consts::PI * heart_freq * t).sin();
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let residuals = vec![base * 0.1, base * 0.08, base * 0.12, base * 0.09];
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let phases = vec![0.0, 0.01, 0.02, 0.03]; // highly coherent
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ext.extract(&residuals, &phases);
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}
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let final_residuals = vec![0.0; 4];
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let final_phases = vec![0.0; 4];
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let result = ext.extract(&final_residuals, &final_phases);
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if let Some(est) = result {
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assert!(
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est.value_bpm > 40.0 && est.value_bpm < 180.0,
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"estimated BPM should be in cardiac range: {}",
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est.value_bpm,
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);
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}
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}
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#[test]
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fn reset_clears_state() {
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let mut ext = HeartRateExtractor::new(2, 100.0, 15.0);
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ext.extract(&[0.1, 0.2], &[0.0, 0.1]);
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assert!(ext.history_len() > 0);
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ext.reset();
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assert_eq!(ext.history_len(), 0);
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}
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#[test]
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fn band_returns_correct_values() {
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let ext = HeartRateExtractor::new(1, 100.0, 15.0);
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let (low, high) = ext.band();
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assert!((low - 0.8).abs() < f64::EPSILON);
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assert!((high - 2.0).abs() < f64::EPSILON);
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}
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#[test]
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fn autocorrelation_finds_known_period() {
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let sample_rate = 50.0;
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let freq = 1.0; // 1 Hz = period of 50 samples
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let signal: Vec<f64> = (0..500)
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.map(|i| (2.0 * std::f64::consts::PI * freq * i as f64 / sample_rate).sin())
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.collect();
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let (period, acf) = autocorrelation_peak(&signal, sample_rate, 0.8, 2.0);
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assert!(period > 0, "should find a period");
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assert!(acf > 0.5, "autocorrelation peak should be strong: {acf}");
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let estimated_freq = sample_rate / period as f64;
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assert!(
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(estimated_freq - 1.0).abs() < 0.1,
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"estimated frequency should be ~1 Hz, got {estimated_freq}",
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);
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}
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#[test]
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fn phase_coherence_single_subcarrier() {
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let result = compute_phase_coherence_signal(&[5.0], &[0.0], 1);
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assert!((result - 5.0).abs() < f64::EPSILON);
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}
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#[test]
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fn phase_coherence_multi_subcarrier() {
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// Two coherent subcarriers (small phase difference)
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let result = compute_phase_coherence_signal(&[1.0, 1.0], &[0.0, 0.01], 2);
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// Both weights should be ~1.0 (exp(-0.01) ~ 0.99), so result ~ 1.0
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assert!((result - 1.0).abs() < 0.1, "coherent result should be ~1.0: {result}");
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}
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#[test]
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fn esp32_default_creates_correctly() {
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let ext = HeartRateExtractor::esp32_default();
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assert_eq!(ext.n_subcarriers, 56);
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}
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}
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