WBCBENCH 2026: A Challenge for Robust White Blood Cell Classification Under Class Imbalance

We present WBCBench 202611https://www.kaggle.com/competitions/wbc-bench-2026/overview,22https://xudong-ma.github.io/WBCBench2026-Robust-White-Blood-Cell-Classification/, an ISBI challenge and benchmark for automated WBC classification designed to stress-test algorithms under three key difficulties: (i) severe class imbalance across 13 morphologically fine-grained WBC classes, (ii) strict patient-level separation between training, validation and test sets, and (iii) synthetic scanner- and setting-induced domain shift via controlled noise, blur and illumination perturbations. All images are single-site microscopic blood smear acquisitions with standardised staining and expert hematopathologist annotations. This…