The head is now part of a store rather than a script: `finetune_identity.py --stock
stock-lopia` trains on that store's enrolled views (27 views over 7 products, 12
augmented copies each) and writes `<stock>/identity_head.pt`, which ProductGallery
loads automatically.
The first attempt exposed a trap worth recording. A discriminative head has no "none
of the above": trained with an angular margin to separate seven products, it maps
everything confidently onto those seven, including cartons it has never seen.
raw features, threshold 0.55 home shelf 78% accepted foreign shelves 5% accepted
trained head, threshold 0.40 home shelf 58% accepted foreign shelves 44% accepted
Rejection - the gallery's whole point - disappears. The fix needs no retraining: the
two mechanisms fail in opposite directions, so raw features decide *whether* to answer
(they generalise) and the head decides *what* to answer (it discriminates). Measured:
47% accepted on the home shelf, 5% on foreign ones. Lower coverage than raw-only,
which is the honest trade.
The head also needs its own threshold (0.40 against the raw 0.55): a trained head's
similarity scale is its own, and reusing the raw line rejected almost everything it
said.
175 tests pass.
Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Part 2 ended on the number that matters: enrolling a real shelf from itself leaves
off-the-shelf DINOv2 at ~25% top-1, because real milk cartons differ by small text
and a colour band. This trains a small projection head on frozen features - 384 -> 128,
cosine classifier, angular margin - with augmentation standing in for the second visit
we do not have, and measures it on 72 held-out facings over 8 products.
raw DINOv2 cosine top-1 2/72 (2%) balanced 1%
raw, rejecting below 0.55 top-1 2/72 (2%) balanced 1% (5% of answered right)
fine-tuned + margin top-1 28/72 (38%) balanced 73%
fine-tuned, rejecting below 0.4 top-1 17/72 (23%) balanced 58% (94% of answered right)
So fine-tuning is the difference between working and not (balanced 1% -> 73%), and
with a rejection threshold the model becomes precise - it answers 18 of 72 facings and
is right on 94% of them, which is the operating point a store wants. The raw model
cannot do that at any threshold.
Where it fails is where my labels are coarse: MEGMILK, which the contact sheet shows
is probably several products under one brand, scores 1/32 because the class is
internally inconsistent and the model correctly refuses most of it.
Honest limit, stated in the doc: enrolment and held-out facings come from one
photograph, so these are upper bounds; only a recorded second visit settles the real
number. What is settled is the mechanism - a head trained on labels the pipeline can
produce itself moves fine-grained identity from useless to usable.
175 tests pass.
Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
The external evaluation showed the matcher cannot say "unknown": on 20 shelves whose
products are absent it claimed 47.8% of facings as recognised, and its raw inlier
score cannot be thresholded (foreign shelves' median 6.0 overlaps the real shelf's
5.2 p10, and the worst offenders score 50-190). So the gallery becomes a selectable
identity backend:
--identity gallery (or DORAYAKI_IDENTITY=gallery)
Measured on the same 20 foreign shelves: false accepts fall from 47.8% to 13.8% at
the default threshold and to **5%** at 0.60, with a smooth curve to pick an operating
point from. Detection is unchanged (the gallery only names boxes).
What it does NOT fix, measured on a milk shelf where 14 of 107 facings really are
明治 おいしい牛乳 (labelled by eye): precision is 28-45%, no better than the matcher's
39%, and enrolling the shelf from itself (1-3 views per product) is flat at ~25%
top-1. Off-the-shelf DINOv2 is not discriminative enough for fine-grained SKUs - the
same conclusion the literature reaches, now measured here.
The packaging's own text is a real channel and resolution-bound: 51% recall
single-scale, 60% with the tag reader's multi-scale + red-channel trick, 85% where
the text is large (MEGMILK) and 28% where it is small vertical Japanese.
docs/EXTERNAL-EVAL.md records all of it, including the identity architecture it
implies: reject by default, name from the tag when readable, from the packaging text
when legible, from a fine-tuned embedding otherwise, and hand the rest to the
operator.
175 tests pass.
Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Everything else here is measured on two photographs. This collects real store
shelves from Wikimedia Commons (scriptable API, explicit licences: CC0, CC BY,
CC BY-SA, public domain, each recorded in a manifest) and evaluates the pipeline on
them. 46 of 54 images carry a shelf; the rest are book scans and a shop front.
What it found, and it is not what I expected:
- **Detection transfers.** 2,258 detections across dairy cases, soy-sauce shelves,
spice racks, a confectionery aisle, an Okinawan supermarket and a Hong Kong
grocery - tight boxes on images the model has never seen, and correctly nothing on
the book scans.
- **Identity transfers when the product is genuinely there.** On a 2011 milk-case
photo it labelled six facings of 明治 おいしい牛乳 correctly, and 野菜生活100 and
R-1 elsewhere. The matcher does reach new photographs of products it has templates
for.
- **Precision is the failure, and rejection is missing.** In that same photograph it
labelled 低脂肪殺菌牛乳, 有機豆乳, 特濃4.5, 無調整豆乳 and 北海道牛乳 as おいしい牛乳 -
they are all white milk cartons. Across 24 shelves whose products are not in the
catalog it accepted 451 identities, and the score cannot be thresholded to fix it:
the real shelf's median is 18.2 with a p10 of 5.2, while the foreign shelves' median
is 6.0 and the worst offenders score 50.5 (a bento), 80.6 (a shop interior) and
189.9 (deer cookies). A threshold that catches the foreigners also throws away the
real matches.
That confirms on real data what the literature and the review predicted: the
matcher's raw inlier score is not a confidence, and fine-grained look-alikes are the
failure mode. Step 4 of the plan - shortlist, local re-rank, calibrated rejection -
is the fix, not a refinement.
docs/EXTERNAL-EVAL.md records the numbers, the method and the attribution; the
images themselves are not redistributed. 175 tests pass.
Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
