The developed digitization protocol successfully converts ECG report images into WFDB-compliant digital signals, enhancing interoperability for further analysis.
An automated digitization protocol enables the conversion of printed or PDF 12-lead ECGs into standardized WFDB-compliant digital signals for computational analysis.
Many clinics still archive 12-lead electrocardiograms (ECGs) as printed paper records or raster images embedded in PDF reports, which limits interoperability and downstream computational analysis. Here, we present a reproducible digitization protocol that converts ECG report images into WaveForm DataBase (WFDB)-compliant digital signals for standardized downstream use. The protocol consists of (i) grid detection and pixel-to-physical calibration, (ii) automated localization and labeling of the 12 lead regions using an object detection model, (iii) signal preprocessing and normalization, and (iv) waveform extraction using either a continuity-constrained path method (Viterbi) or an improved centerline-based approach. The workflow is designed to handle heterogeneous clinical layouts, variable grid visibility, and common imaging artifacts, and includes visual checkpoints for quality control at each stage. The protocol outputs time-aligned 12-lead WFDB records suitable for reproducible analysis in signal processing and machine-learning pipelines.
Nguyen et al. (2026) studied this question. The developed digitization protocol successfully converts ECG report images into WFDB-compliant digital signals, enhancing interoperability for further analysis.