{"paper":{"title":"ICDAR 2026 Competition on Writer Identification and Pen Classification from Hand-Drawn Circles","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Hand-drawn circles contain identifiable traces of both the writer and the pen used.","cross_cats":[],"primary_cat":"cs.CV","authors_text":"Fei Wu, Janne van der Loop, Linda-Sophie Schneider, Lukas H\\\"uttner, Mathias Seuret, Thomas Gorges, Vincent Christlein","submitted_at":"2026-05-08T14:48:57Z","abstract_excerpt":"This paper presents CircleID, a large-scale ICDAR 2026 competition on writer identification and pen classification from scanned hand-drawn circles. The primary objective is to investigate how biometric writer characteristics and physical pen features naturally entangle within minimal, static traces. CircleID comprises two distinct tasks: (1) open-set writer identification, requiring models to recognize known writers while explicitly rejecting unknown ones, and (2) cross-writer pen classification, evaluated across both seen and unseen writers. Participants were provided with a new, controlled d"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"In this large-scale competition, CircleID establishes a new baseline for minimal-trace analysis.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That biometric writer characteristics and physical pen features naturally entangle within minimal, static traces of hand-drawn circles in a way that permits meaningful disentanglement and generalization to unseen writers.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"A new dataset of hand-drawn circles from 66 writers and 8 pens yields competition results of 64.8% top-1 accuracy for open-set writer identification and 92.7% for pen classification.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Hand-drawn circles contain identifiable traces of both the writer and the pen used.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"d6eccd498817d58de687b3e35fcf04c419b6f95ead64caf0fe24dff4fc9b26bb"},"source":{"id":"2605.07816","kind":"arxiv","version":2},"verdict":{"id":"143bc19f-e061-4fad-b0fb-4646aa13824c","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-11T02:06:31.095546Z","strongest_claim":"In this large-scale competition, CircleID establishes a new baseline for minimal-trace analysis.","one_line_summary":"A new dataset of hand-drawn circles from 66 writers and 8 pens yields competition results of 64.8% top-1 accuracy for open-set writer identification and 92.7% for pen classification.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That biometric writer characteristics and physical pen features naturally entangle within minimal, static traces of hand-drawn circles in a way that permits meaningful disentanglement and generalization to unseen writers.","pith_extraction_headline":"Hand-drawn circles contain identifiable traces of both the writer and the pen used."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2605.07816/integrity.json","findings":[],"available":true,"detectors_run":[{"name":"claim_evidence","ran_at":"2026-05-20T10:02:13.994753Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"ai_meta_artifact","ran_at":"2026-05-20T04:49:44.591434Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"doi_title_agreement","ran_at":"2026-05-19T15:31:18.791026Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"doi_compliance","ran_at":"2026-05-19T11:31:15.194240Z","status":"completed","version":"1.0.0","findings_count":0}],"snapshot_sha256":"4727ae30467da089926cae87b4065bec2a09da33a393777d97ea8474c40977bd"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}