High-speed extended depth-of-field microscopy for whole slide digital pathology

Whole-slide imaging (WSI), as a foundational technology in digital pathology, enables high-resolution digitization of entire tissue sections, providing critical support for accurate diagnosis, detailed prognostic analysis, and therapeutic decision-making. However, conventional WSI systems face inherent trade-offs among resolution, depth of field (DOF), and imaging speed, posing significant challenges for analyzing thick pathological specimens. To address this issue, this study proposes a high-speed extended-depth-of-field whole-slide imaging method (HSEDOF-WSI). By integrating an electrically tunable lens (ETL) with an optimized annular illumination scheme, the developed system achieves non-coherent diffraction-limited resolution (approximately 500 nm using a 20×/0.8 NA objective) while maintaining a large DOF. Experimental validation on liquid-based cytology slides demonstrated significant improvements in image contrast and signal-to-noise ratio (SNR), along with a six-fold improvement in single-axis scanning speed. This technology offers an effective solution for high-resolution rapid pathological imaging, with strong potential to advance its widespread adoption in advanced digital pathology and precision clinical applications.