study(VR-013): cross-source identification probe over input resolution

Gallery from one recording, probes from another, sweeping the probe's
input resolution end to end. VR-005 asked the same question over gallery
mugshots but degraded an already-aligned 112x112 crop with alignment held
perfect, so it isolates the embedder. Here the whole frame is downscaled
before the detector, so detection and landmark regression degrade with
it — which is most of the difference.

Corpus is two 4096x2160 clips of one shoot, four people, hand-sorted.
Ground truth is sorted by hand and gated by verify_labels.py; labels
carried down the scales geometrically by box position, never by
embedding similarity, which would keep only the faces the embedder
already gets right and drop the ones the sweep exists to find.

Findings, all scored through the production gallery sigmoid at
prob_threshold 0.754 — never a raw cosine:

- Holding 90% of the plateau needs ~50 px end to end, against VR-005's
  ~22 px. min_face_px at 40 looks right; 32 would admit faces in the
  falling region.
- FPI is 0.0% at every scale. Resolution loss goes entirely to TBI.
- The ceiling is cross-view, not resolution: everyone matches themselves
  within a recording (0.55-0.85) and collapses across two (0.14-0.45,
  threshold 0.335). Only the subject with frontal *gallery* references
  identified reliably, whatever their probe pose — so the lever is
  gallery pose coverage, not a better landmark source.
- Averaging SCRFD's overlapping detections instead of discarding them at
  NMS lifts cross-recording TPI 41% -> 49%, for one forward pass and no
  extra model.

Four identities and one shoot, so the shape is the result and the
absolute rates are not. Both clips contain all four people, so there is
no out-of-gallery class and the 10x-weighted out-of-cast misID is
untested here.

Clips, frames, hand-sorted crops and results are gitignored and belong
in the artifact registry — the sorting is human ground truth and
expensive to redo.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

TRACES: VR-013 | AR-002, AR-005, AR-024
This commit is contained in:
2026-07-31 15:20:18 +02:00
co-authored by Claude Opus 5
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#!/usr/bin/env python3
"""Impact of input resolution on cross-source identification.
Gallery is built from one clip at NATIVE resolution. Probes come from the other
clip with the WHOLE FRAME downscaled before it reaches the detector, so
detection and landmark regression degrade together with the pixels. That is the
measurement VR-005 structurally could not make: it degraded an already-aligned
112x112 crop, holding alignment perfect, so it isolated the embedder's
resolution sensitivity and excluded everything upstream of it.
python3 resolution_sweep.py [--gallery-clip 5157339] [--detector scrfd_500m_bnkps.onnx]
Ground truth
------------
Hand-sorted person folders. Probe detections at reduced scale are tied back to
a labelled face GEOMETRICALLY — the box is mapped to native coordinates and
matched by IoU. Never by embedding similarity, which would be circular: it
would keep the faces the embedder still gets right and silently drop the ones
this sweep exists to find.
A probe whose label is only in the probe clip is OUT OF GALLERY. Naming it is a
true out-of-cast misID, the error the per-scene scorer weights 10x, so it is
counted separately from naming the wrong gallery member.
Metric
------
The calibrated probability from the PRODUCTION gallery sigmoid, never a raw
cosine (AR-024). Per-actor best-of-N similarity -> probability -> accept above
prob_threshold. This is identification, so the matcher's prior applies;
config.hpp has match_prior 0.5, i.e. log_prior_odds = 0.
Everything runs through the shipped C++ via sae_embed.
"""
import sys, glob, json, os, argparse
import numpy as np
import cv2
sys.path.insert(0, "/home/dtourolle/Development/Jray-project/scene-actor-extraction/build-ort")
import sae_embed
ROOT = "/home/dtourolle/Development/Jray-project/scene-actor-extraction/"
M = ROOT + "models/"
PROB_THRESHOLD = 0.754 # config.hpp:67
LOG_PRIOR_ODDS = 0.0 # config.hpp:61 match_prior=0.5
IOU_MIN = 0.3 # geometric label carry-down
SCALES = [1.0, 0.8, 0.6, 0.5, 0.4, 0.3, 0.25, 0.2, 0.15, 0.12, 0.09, 0.06]
ap = argparse.ArgumentParser()
ap.add_argument("--gallery-clip", default="5157339")
ap.add_argument("--probe-clip", default="5157344")
ap.add_argument("--detector", default="scrfd_500m_bnkps.onnx")
ap.add_argument("--embedder", default="LVFace-B_Glint360K.onnx")
ap.add_argument("--gallery-calibration", default=ROOT + "gallery_lvface.h5")
ap.add_argument("--out", default="results_resolution_sweep.json")
args = ap.parse_args()
eng = sae_embed.FaceEmbedder(detector_model=M + args.detector,
arcface_model=M + args.embedder,
conf=0.5, nms=0.4, max_side=0)
cal = sae_embed.gallery_calibration(args.gallery_calibration)
print(f"[calibration] global: {cal}", file=sys.stderr)
def labelled(clip):
"""{filename: person} from the hand-sorted folders, ignoring discard."""
out = {}
for path in glob.glob(f"labelling/{clip}/*/*.jpg"):
person = os.path.basename(os.path.dirname(path))
if person in ("discard", "unsorted"):
continue
out[os.path.basename(path)] = person
return out
def manifest(clip):
return {m["file"]: m for m in json.load(open(f"labelling/{clip}/manifest.json"))}
def iou(a, b):
ax, ay, aw, ah = a; bx, by, bw, bh = b
x0, y0 = max(ax, bx), max(ay, by)
x1, y1 = min(ax + aw, bx + bw), min(ay + ah, by + bh)
if x1 <= x0 or y1 <= y0:
return 0.0
inter = (x1 - x0) * (y1 - y0)
return inter / (aw * ah + bw * bh - inter)
# ── gallery: native resolution, labelled faces only ──────────────────────────
g_lab, g_man = labelled(args.gallery_clip), manifest(args.gallery_clip)
gal = {}
for frame in sorted({g_man[f]["frame"] for f in g_lab}):
img = cv2.imread(f"frames/d{args.gallery_clip}_{frame}.png")
dets = eng.detect(img)
for fname, person in g_lab.items():
m = g_man[fname]
if m["frame"] != frame or m["idx"] >= len(dets):
continue
lm = np.array(dets[m["idx"]].landmarks, dtype=np.float32).reshape(5, 2)
crop = sae_embed.align_face(img, lm)
if crop is None:
continue
gal.setdefault(person, []).append(np.asarray(eng.embed_crop(crop), dtype=np.float32))
gal = {p: np.stack(v) for p, v in gal.items() if v}
people = sorted(gal)
print(f"[gallery] {args.gallery_clip} @native: "
f"{ {p: len(v) for p, v in gal.items()} }", file=sys.stderr)
# ── probe ground truth at native resolution ──────────────────────────────────
p_lab, p_man = labelled(args.probe_clip), manifest(args.probe_clip)
truth = {} # frame -> [(bbox_native, person)]
for fname, person in p_lab.items():
m = p_man[fname]
truth.setdefault(m["frame"], []).append((m["bbox"], person))
n_out = sum(1 for p in set(p_lab.values()) if p not in people)
print(f"[probe] {args.probe_clip}: {len(p_lab)} labelled faces, "
f"{len(set(p_lab.values()))} people, {n_out} of them out-of-gallery",
file=sys.stderr)
# ── sweep ────────────────────────────────────────────────────────────────────
print(f"\n{'scale':>6}{'frame':>11}{'face px':>9}{'found':>7}{'matched':>9}"
f"{'TPI':>8}{'FPI-in':>8}{'FPI-out':>9}{'TBI':>8}")
results = []
for s in SCALES:
tpi = fpi_in = fpi_out = tbi = 0
n_found = n_matched = 0
pxs = []
for frame, gts in sorted(truth.items()):
img = cv2.imread(f"frames/d{args.probe_clip}_{frame}.png")
if s != 1.0:
img = cv2.resize(img, None, fx=s, fy=s, interpolation=cv2.INTER_AREA)
dets = eng.detect(img)
n_found += len(dets)
for d in dets:
x, y, w, h = d.bbox
native = (x / s, y / s, w / s, h / s) # geometric carry-down
best, best_iou = None, 0.0
for gt_box, person in gts:
v = iou(native, gt_box)
if v > best_iou:
best_iou, best = v, person
if best_iou < IOU_MIN:
continue # spurious / unlabelled
n_matched += 1
pxs.append(min(w, h))
lm = np.array(d.landmarks, dtype=np.float32).reshape(5, 2)
crop = sae_embed.align_face(img, lm)
if crop is None:
tbi += 1 # degenerate alignment
continue
emb = np.asarray(eng.embed_crop(crop), dtype=np.float32)
best_p, best_name = 0.0, None
for p in people: # per-actor best-of-N
prob = cal.probability(float((gal[p] @ emb).max()), LOG_PRIOR_ODDS)
if prob > best_p:
best_p, best_name = prob, p
if best_p <= PROB_THRESHOLD:
tbi += 1
elif best not in people:
fpi_out += 1 # named someone absent from the gallery
elif best_name == best:
tpi += 1
else:
fpi_in += 1
n = max(1, n_matched)
med_px = float(np.median(pxs)) if pxs else 0.0
print(f"{s:>6.2f}{f'{int(4096*s)}x{int(2160*s)}':>11}{med_px:>9.0f}"
f"{n_found:>7}{n_matched:>9}"
f"{100*tpi/n:>7.1f}%{100*fpi_in/n:>7.1f}%{100*fpi_out/n:>8.1f}%{100*tbi/n:>7.1f}%")
results.append({"scale": s, "median_face_px": med_px, "detections": n_found,
"matched_to_truth": n_matched, "tpi_pct": 100*tpi/n,
"fpi_in_gallery_pct": 100*fpi_in/n, "fpi_out_of_gallery_pct": 100*fpi_out/n,
"tbi_pct": 100*tbi/n})
json.dump({"gallery_clip": args.gallery_clip, "probe_clip": args.probe_clip,
"detector": args.detector, "embedder": args.embedder,
"prob_threshold": PROB_THRESHOLD, "log_prior_odds": LOG_PRIOR_ODDS,
"calibration": {"a": cal.a, "b": cal.b},
"gallery_people": people, "results": results},
open(args.out, "w"), indent=2)
print(f"\nwrote {args.out}", file=sys.stderr)