Files
Behavision/behavision/gallery/index.py
Suriyakumarvijayanayagam dad04e8cda Behavision: face recognition for retail, edge to head office
Five components that ship as one product:

- behavision/  the recognition engine. RTSP ingest, YuNet detection, IoU
               tracking, ArcFace embeddings, a FAISS/SQLite gallery, and a
               FastAPI dashboard. Identity is decided once per TRACK from an
               average of at least three embeddings, never per frame.
- agent/       the Go edge agent: supervises the engine, holds a durable
               spool, and drains it to MQTT. Nothing is acked before the
               broker confirms.
- desktop/     the shop PC application (Wails + React + tray).
- server/      the cloud API, MQTT consumer, reports and assistant.
- web/         platform.loyaly.ai, the head-office app, embedded in the
               server binary.

The gallery stores 512-float embeddings and timestamps - no images unless
`app.store_faces` is switched on. Those embeddings are biometric personal
data under GDPR and India's DPDP: template inversion reconstructs a
recognisable face from an ArcFace vector, so data/behavision.db is treated
as a biometric database and DELETE /api/visitors/{id} is a real erasure.

CLAUDE.md carries the reasoning behind every non-obvious decision here,
including the ones that were measured and the ones that were wrong first.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HViLj9gYNRtSr7YVZmW5sn
2026-09-04 11:14:18 +05:30

84 lines
3.0 KiB
Python

"""Cosine-similarity vector index.
FAISS `IndexFlatIP` wrapped in `IndexIDMap2` when faiss is installed, plain
numpy otherwise — same interface, same results. Choices that fix the old
codebase's failure modes:
- Exact inner-product search (vectors are unit-norm, so IP == cosine).
No IVF: nothing to train, no wrong-metric trap, and exact search is
microseconds up to hundreds of thousands of vectors.
- `-1` ids from an empty index are filtered, never used as list indices.
- The index is rebuilt from SQLite at startup (SQLite is the source of
truth), so index and metadata can never drift apart.
"""
from __future__ import annotations
import logging
import numpy as np
log = logging.getLogger(__name__)
try:
import faiss # type: ignore
_HAVE_FAISS = True
except ImportError: # pragma: no cover - environment dependent
faiss = None
_HAVE_FAISS = False
class VectorIndex:
def __init__(self, dim: int):
self.dim = dim
if _HAVE_FAISS:
self._index = faiss.IndexIDMap2(faiss.IndexFlatIP(dim))
self._ids = None
self._vecs = None
else:
log.warning("faiss not installed - using exact numpy search "
"(identical results, slower at large scale)")
self._index = None
self._ids = np.empty((0,), dtype=np.int64)
self._vecs = np.empty((0, dim), dtype=np.float32)
def __len__(self) -> int:
if self._index is not None:
return self._index.ntotal
return len(self._ids)
def add(self, ids: "list[int]", vectors: np.ndarray) -> None:
if len(ids) == 0:
return
vectors = np.ascontiguousarray(vectors, dtype=np.float32).reshape(len(ids), self.dim)
id_arr = np.asarray(ids, dtype=np.int64)
if self._index is not None:
self._index.add_with_ids(vectors, id_arr)
else:
self._ids = np.concatenate([self._ids, id_arr])
self._vecs = np.vstack([self._vecs, vectors])
def remove(self, ids: "list[int]") -> None:
if len(ids) == 0:
return
id_arr = np.asarray(ids, dtype=np.int64)
if self._index is not None:
self._index.remove_ids(id_arr)
else:
keep = ~np.isin(self._ids, id_arr)
self._ids = self._ids[keep]
self._vecs = self._vecs[keep]
def search(self, vector: np.ndarray, k: int = 1) -> "list[tuple[int, float]]":
"""Top-k (embedding_id, cosine_similarity), best first."""
if len(self) == 0:
return []
q = np.ascontiguousarray(vector, dtype=np.float32).reshape(1, self.dim)
k = min(k, len(self))
if self._index is not None:
scores, ids = self._index.search(q, k)
return [(int(i), float(s))
for i, s in zip(ids[0], scores[0]) if i != -1]
sims = self._vecs @ q[0]
order = np.argsort(-sims)[:k]
return [(int(self._ids[i]), float(sims[i])) for i in order]