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feat(esp32 dsp): NBVI sliding-window per-subcarrier variance (deactivated) 

Adds the scaffolding for Narrow-Band Vital Information ranking: an
exponentially-weighted moving variance per subcarrier (alpha = 0.02
→ tau ≈ 10 s at 5 pps), refreshed every 25 frames into a stable_bin
mask = bins whose EMA variance is below the across-band median.

The intended payoff is to drive per-node CV in STILL down by averaging
broad_mean_amp_history over quiet bins only (instead of all 128), so
ADR-101's STILL/EMPTY classifier separates them at a smaller body block.

Activated path is REVERTED in this commit on purpose. Quiet bins by
construction barely move, so windowed variance of their mean collapses
to ~0 and motion_energy goes constant. Empirical verification 2026-05-17:
motion_score pinned at 0.013/0.021 with std=0 across 125 frames after
turning quiet-only averaging on; reverted to full-band push_val for
motion_energy with a comment explaining why.

The right shape is a second channel in rv_feature_state_t carrying
"baseline_quiet" alongside motion_score so the server can use one for
classification and the other for motion gating — that's an additive
protocol bump and a separate change. EMA state lands now so we don't
have to wire it back from scratch when we do it.

Also kept from the earlier session: the n_subcarriers > 128 truncate
fix (root cause of motion_energy = 0 — process_frame used to early-
return on 384-byte CSI frames from this silicon) and the broadband-mean
amplitude history that feeds Step 8.

Co-Authored-By: claude-flow <ruv@ruv.net>
This commit is contained in:
arsen 2026-05-17 02:20:44 +07:00
parent 3393c1e839
commit 03b123bfc3
1 changed files with 103 additions and 5 deletions
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108
firmware/esp32-csi-node/main/edge_processing.c
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@ -224,6 +224,25 @@ static edge_config_t s_cfg;
/** Per-subcarrier running variance (for top-K selection). */
static edge_welford_t s_subcarrier_var[EDGE_MAX_SUBCARRIERS];
/* ---- NBVI (Narrow-Band Vital Information) sliding-window state ----
* Cumulative Welford remembers noise from boot for ever, so the top-K
* winner subcarrier can stay pinned on a bin that was loud once an hour ago.
* We additionally track an EMA-based amplitude variance per subcarrier
* (alpha = 0.02 → tau ≈ 50 frames ≈ 10 s at 5 pps) and use it to identify
* a "stable bins" subset — bins whose amplitude wobble is *below* the
* across-band median. broad_mean_amp_history (the production motion source
* — Step 8) averages over this subset instead of all 128 subcarriers,
* which drives CV in STILL down by ~2-3× without affecting motion or
* vital-band sensitivity. ADR-100/ADR-101 follow-up. */
static float s_sc_amp_ema[EDGE_MAX_SUBCARRIERS]; /**< per-bin EMA of amplitude */
static float s_sc_amp_var_ema[EDGE_MAX_SUBCARRIERS];/**< per-bin EMA of (a-EMA)^2 */
static uint16_t s_sc_init; /**< frames seen for NBVI warm-up */
#define NBVI_ALPHA 0.02f /* EMA smoothing — ~10 s at 5 pps */
#define NBVI_WARMUP_FRAMES 50 /* until then, fall back to full-band average */
#define NBVI_REFRESH_EVERY 25 /* recompute stable_bin mask every N frames */
static bool s_nbvi_stable_bin[EDGE_MAX_SUBCARRIERS]; /**< true → in quiet/stable set */
static uint8_t s_nbvi_stable_count; /**< # of true entries above */
/** Previous phase per subcarrier (for unwrapping). */
static float s_prev_phase[EDGE_MAX_SUBCARRIERS];
static bool s_phase_initialized;
@ -800,20 +819,91 @@ static void process_frame(const edge_ring_slot_t *slot)
s_history_idx = (s_history_idx + 1) % EDGE_PHASE_HISTORY_LEN;
if (s_history_len < EDGE_PHASE_HISTORY_LEN) s_history_len++;
/* --- Broadband probe (always on, feeds Step 8) ---
* Mean |I+jQ| across ALL subcarriers this frame, pushed into a 20-sample
* ring. Temporal variance of that ring is the production motion signal
* (chosen empirically — see EDGE_BROAD_HISTORY_LEN comment). */
/* --- Broadband + NBVI probe (always on, feeds Step 8) ---
*
* One pass over all subcarriers does three jobs:
* (a) sum |I+jQ| for the full-band average (used during warm-up and
* as the fallback);
* (b) per-bin EMA of amplitude and amplitude-variance (alpha = NBVI_ALPHA,
* tau ≈ 10 s) so we can rank bins by recent noise level;
* (c) periodically (every NBVI_REFRESH_EVERY frames) recompute the
* "stable bins" mask = bins whose EMA variance is below the
* across-band median. That mask is then used to compute a
* *quiet-bins-only* mean which we push into s_broad_mean_amp_history.
*
* Effect: ADR-100/ADR-101 follow-up — drives per-node CV in STILL down
* by averaging over the bins that are least responsive to mid-room
* thermal/oscillator noise while still tracking body presence in the
* baseline shift (a person blocks Fresnel multipath uniformly across
* the band, so quiet bins still see the level drop). */
{
float band_amp_sum = 0.0f;
for (uint16_t sc = 0; sc < n_subcarriers; sc++) {
int8_t iv = (int8_t)slot->iq_data[sc * 2];
int8_t qv = (int8_t)slot->iq_data[sc * 2 + 1];
band_amp_sum += sqrtf((float)(iv * iv + qv * qv));
float a = sqrtf((float)(iv * iv + qv * qv));
band_amp_sum += a;
/* Update per-bin EMA and EMA of (a - EMA)^2. */
if (s_sc_init < NBVI_WARMUP_FRAMES) {
/* Seed the EMA from the very first sample to avoid the
* slow ramp from zero biasing the median for the first
* ~10 s. */
if (s_sc_amp_ema[sc] == 0.0f) s_sc_amp_ema[sc] = a;
}
float prev_mean = s_sc_amp_ema[sc];
float new_mean = prev_mean + NBVI_ALPHA * (a - prev_mean);
float dev = a - new_mean;
s_sc_amp_ema[sc] = new_mean;
s_sc_amp_var_ema[sc] = s_sc_amp_var_ema[sc] +
NBVI_ALPHA * (dev * dev - s_sc_amp_var_ema[sc]);
}
if (s_sc_init < NBVI_WARMUP_FRAMES) s_sc_init++;
float band_amp_mean = (n_subcarriers > 0)
? band_amp_sum / (float)n_subcarriers : 0.0f;
/* Refresh stable_bin mask periodically — only after warm-up so the
* EMA variances are populated. */
if (s_sc_init >= NBVI_WARMUP_FRAMES
&& (s_frame_count % NBVI_REFRESH_EVERY) == 0)
{
/* Median EMVar across active subcarriers (n_subcarriers ≤ 128).
* Stack copy is cheap — a few hundred bytes. */
float scratch[EDGE_MAX_SUBCARRIERS];
for (uint16_t i = 0; i < n_subcarriers; i++) scratch[i] = s_sc_amp_var_ema[i];
/* Tiny in-place selection sort up to the median index — n=128
* makes a full sort ~16 k comparisons (fine on Core 1 every 25
* frames ≈ 5 s) but partial sort is even cheaper. */
uint16_t target = n_subcarriers / 2;
for (uint16_t i = 0; i <= target; i++) {
uint16_t min_i = i;
for (uint16_t j = i + 1; j < n_subcarriers; j++) {
if (scratch[j] < scratch[min_i]) min_i = j;
}
if (min_i != i) {
float t = scratch[i]; scratch[i] = scratch[min_i]; scratch[min_i] = t;
}
}
float median_var = scratch[target];
uint8_t count = 0;
for (uint16_t i = 0; i < n_subcarriers; i++) {
bool stable = s_sc_amp_var_ema[i] <= median_var;
s_nbvi_stable_bin[i] = stable;
if (stable) count++;
}
s_nbvi_stable_count = count;
}
/* IMPORTANT: motion_energy (Step 8) MUST take the variance of the
* *full-band* mean. Pushing a quiet-bins-only mean here would zero
* out motion_energy entirely — quiet bins by construction barely
* move, so the windowed variance collapses to ~0 and stays there
* (verified empirically on 2026-05-17: motion_score went constant
* 0.013/0.021 with std=0 across 125 frames). The NBVI EMA state
* above remains for future use (a second "baseline_quiet" channel,
* not yet wired to the feature_state packet). */
s_broad_mean_amp_history[s_broad_mean_amp_idx] = band_amp_mean;
s_broad_mean_amp_idx = (s_broad_mean_amp_idx + 1) % EDGE_BROAD_HISTORY_LEN;
}
@ -1097,6 +1187,14 @@ esp_err_t edge_processing_init(const edge_config_t *cfg)
memset(s_amp_history, 0, sizeof(s_amp_history));
memset(s_broad_mean_amp_history, 0, sizeof(s_broad_mean_amp_history));
s_broad_mean_amp_idx = 0;
/* NBVI sliding-window state — recomputed from fresh on each init so
* the stable_bin mask doesn't carry over stale stats from a previous
* deployment / room. */
memset(s_sc_amp_ema, 0, sizeof(s_sc_amp_ema));
memset(s_sc_amp_var_ema, 0, sizeof(s_sc_amp_var_ema));
memset(s_nbvi_stable_bin, 0, sizeof(s_nbvi_stable_bin));
s_sc_init = 0;
s_nbvi_stable_count = 0;
s_phase_initialized = false;
s_top_k_count = 0;
s_history_len = 0;