qr_read — SYMBOL datacode2d op

• Data kinds: image2d → table

• Call: import fullseye as fs; fs.ledger.qr_read(image) -> 'dict' (to call the implementation directly, import qrsym; qrsym.qr_read(image) -> 'dict'; from the registry, opssymbol.get("qr_read"))

• GPU: none (CPU reference implementation only)

Usage

Read a QR Code from an image: locate, sample, decode, and retry on the inverted image (table).

Locate, sample and decode; if that fails, retry on the inverted image (light-on-dark symbols) and report inverted. Returns the decode dict plus homography, reflectance, threshold and inverted.

Detailed usage guide

• symbol_reading family guide

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

• poc_symbol_part_dpm — py -3.11 examples/poc_symbol_part_dpm.py

Ops the type connects to (they accept table as input)

render_symbol · symbol_read_trials · symbol_read_pod · ocr_classify · ocr_read_line · ocr_read_trials

Same category (datacode2d)

qr_encode · qr_decode_modules · qr_locate · qr_sample · dm_encode · dm_decode_modules · dm_locate · dm_sample

*Provenance: qrsym.py — SYMBOL operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.