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Molecular AI & Methods / 2023

OCMR: A comprehensive framework for optical chemical molecular recognition

Recognizing chemical structures from images.

Computers in Biology and Medicine · 163, 107187

Major author · confirmed by Richard

Second listed author

01 / Research question

How can a chemical drawing become a machine-readable molecular graph without losing local chemical details?

02 / Innovation

Recover molecular topology and integrate local information, including noncanonical drawings and abbreviated atom groups. The public pipeline outputs a structured representation such as SMILES.

03 / Mechanism

OCMR recovers molecular topology and resolves local atom-group details, including abbreviations, from structure drawings. The public Docker implementation exposes image-to-SMILES inference alongside MolVec, OSRA and Imago.

Original Figure 1, published OCMR: KNet architecture (a), a demonstrative input molecule (b), and the atom-group output map (c).
Original Figure 1, published OCMR: KNet architecture (a), a demonstrative input molecule (b), and the atom-group output map (c). Figure source ↗ · Author-retained reuse rights; Elsevier copyright policy

04 / Experimental setup

Public benchmarks are CLEF, JPO, UOB and USPTO. SMI evaluates equality of canonical isomeric SMILES after retaining the longest disconnected fragment. The evaluator compares all four recognition systems; training-set size and held-out counts are unavailable in the README.

Public repository README · benchmark table · Source ↗

05 / Results

Repository SMI scores are 0.650202, 0.604444, 0.859930 and 0.746284 respectively. These are implementation-reported values, separate from the final journal tables.

Repository-reported SMI (0–1) · Public repository README · benchmark table · Data source ↗

Scale: 0 → 1

CLEF
0.650202
JPO
0.604444
UOB
0.85993
USPTO
0.746284
Repository-reported SMI (0–1)
ConditionMetric / seriesReported value
CLEFRepository-reported SMI (0–1)0.650202
JPORepository-reported SMI (0–1)0.604444
UOBRepository-reported SMI (0–1)0.85993
USPTORepository-reported SMI (0–1)0.746284

Values refer to the stated version and experimental conditions; different metrics do not form a common ranking.

Public image recognition benchmarks

SMI exact-match fraction, repository README; no internal PATENT cases included.

Swipe horizontally, or focus and use arrow keys to see all columns →

DatasetOCMR SMI
CLEF0.650202
JPO0.604444
UOB0.859930
USPTO0.746284

README benchmark table; evaluator_benchmarks.py lines 117–146 · Primary source ↗

06 / Ablation & limitations

Abbreviations, unusual drawing styles and stereochemistry remain important error modes. Fragment normalization can discard disconnected components. The README calls its second metric Tanimoto, but the evaluator computes Dice similarity on radius-3 Morgan fingerprints; that column is therefore not plotted here. A journal ablation table remains unavailable; the original Figure 1 is reproduced under the coauthor’s retained reuse rights.

High fingerprint similarity does not guarantee an identical decoded molecule. Chemical validity and structure identity need separate checks.

07 / My contribution

Second listed author on the published article.

08 / Paper & code

Cite this research

OCMR: A comprehensive framework for optical chemical molecular recognition. Computers in Biology and Medicine · 163, 107187, 2023. https://www.sciencedirect.com/science/article/pii/S0010482523006522