ESA-FPM High-Throughput Imaging Technology for Digital Pathology | KFBIO

Introduction: Solving the Challenge of Faster and Higher-Quality Imaging

Digital pathology requires both high resolution and large imaging areas.

However, traditional imaging methods often face a difficult balance between image quality, scanning speed and field of view (FOV).

Whole slide imaging (WSI) scanners provide excellent image quality. However, mechanical scanning processes can increase system complexity and acquisition time.

At the same time, Fourier Ptychographic Microscopy (FPM) offers a promising solution for high-resolution imaging.

By combining multiple images captured under different illumination angles, FPM can create a larger synthetic aperture and improve resolution.

However, conventional FPM requires hundreds of raw images.

As a result, the large amount of image data and long acquisition time limit its practical use in high-throughput applications.

To overcome this challenge, KFBIO collaborated with the Smart Computational Imaging (SCI) Laboratory at Nanjing University of Science and Technology to develop Efficient Synthetic Aperture for FPM (ESA-FPM).

This innovative imaging technology significantly improves acquisition efficiency.

Therefore, ESA-FPM makes faster and high-quality digital pathology imaging more practical for clinical and research applications.

The Challenge: Improving Efficiency in High-Throughput Imaging

Conventional FPM improves resolution by combining many low-resolution images.

During imaging, the system captures multiple images under different illumination conditions.

This process provides enough data for accurate image reconstruction.

However, it also creates several challenges:

• Long acquisition time
• Large image datasets
• Complex hardware requirements

For applications such as intraoperative pathology and large-scale screening, speed is critical.

Therefore, improving imaging efficiency has become an important challenge in digital pathology.

ESA-FPM Innovation: A More Efficient Imaging Approach

The key innovation of ESA-FPM is its hybrid coherent and incoherent illumination strategy.

This approach improves how the system collects and uses image information.

Instead of capturing hundreds of images, ESA-FPM extracts more useful information from each acquisition.

As a result, it reduces the amount of required raw data while maintaining high-resolution imaging performance.

Single-Shot Bright-Field Imaging

First, ESA-FPM captures a single incoherent bright-field image.

Unlike traditional methods that use sequential LED illumination, ESA-FPM activates all bright-field LEDs at the same time.

This single image collects important sample information efficiently.

Furthermore, it provides imaging information beyond the conventional diffraction limit of the objective lens.

Efficient Dark-Field Image Acquisition

For high-resolution details, ESA-FPM uses a simplified dark-field illumination pattern.

The system activates opposite LED pairs simultaneously.

This symmetric design improves data efficiency during image reconstruction.

As a result, each dark-field image contributes more information to the final synthetic aperture.

Compared with traditional FPM methods, ESA-FPM achieves higher imaging efficiency with fewer raw images.

Reducing Data Requirements While Maintaining Resolution

Through detailed optimization and data analysis, the ESA-FPM team developed a more efficient acquisition strategy.

The result is significant:

ESA-FPM can achieve a synthetic aperture of 3× the objective lens numerical aperture (NA) using only 7 raw images.

These images include:

• 1 bright-field image
• 6 dark-field images

Compared with conventional FPM methods, this approach greatly reduces image acquisition requirements.

Therefore, ESA-FPM provides a practical solution for high-throughput imaging applications.

Experimental Validation: Faster Imaging with Less Data

The advantages of ESA-FPM are not only theoretical.

Experimental results have confirmed its strong performance in high-resolution imaging.

Compared with conventional FPM, ESA-FPM achieves similar image quality with significantly fewer acquisitions.

The results demonstrate its potential for high-throughput digital pathology applications.

98.4% Less Data While Maintaining Resolution

To evaluate imaging performance, researchers used a standard USAF resolution target.

The results showed that ESA-FPM achieved a full-pitch resolution of 776 nm.

This performance was comparable to conventional FPM.

However, ESA-FPM required only 7 images.

In comparison, traditional FPM required 441 images.

Therefore, ESA-FPM reduced data acquisition requirements by 98.4% while maintaining similar resolution performance.

This improvement provides important advantages for practical applications.

Less data means:

• Faster image acquisition
• Lower data storage requirements
• Reduced computational workload

More efficient digital pathology workflows

Faster Acquisition for Real-World Applications

In addition to reducing data volume, ESA-FPM significantly improves imaging speed.

Traditional FPM acquisition may take several minutes.

However, ESA-FPM reduces the total acquisition time from approximately 3 minutes to only 1.5 seconds.

As a result, the technology enables near-real-time imaging performance.

This advantage is especially valuable for applications that require rapid image analysis, such as:

• Intraoperative pathology
• High-volume screening
• Research imaging

High-Throughput Pathological Imaging with Large Field of View

To demonstrate clinical potential, researchers developed a customized ESA-FPM system for pathology imaging.

The system used:

• A specialized 6× / 0.35 NA objective
• A high-brightness LED illumination array

Using an H&E-stained lymph node metastasis slide, ESA-FPM generated high-resolution images across a large field of view.

The imaging area reached 2.19 × 1.46 mm².

Furthermore, the system clearly captured important cellular details, including lymphocyte nuclei.

Although it used a lower magnification objective, ESA-FPM achieved image quality comparable to a traditional 40× / 0.65 NA objective.

At the same time, it covered an imaging area 44.5 times larger.

This capability demonstrates the potential of ESA-FPM for large-scale pathology imaging.

Why ESA-FPM Matters for Digital Pathology

The collaboration between KFBIO and SCI Lab addresses several important challenges in modern pathology imaging.

ESA-FPM provides four major advantages:

1. Faster Imaging Speed

ESA-FPM enables near-real-time image acquisition.

Therefore, it can support faster diagnosis and large-scale screening workflows.

2. Simpler System Design

Traditional high-resolution imaging systems often require complex mechanical scanning and control processes.

However, ESA-FPM reduces system complexity by improving illumination efficiency and reducing acquisition requirements.

As a result, imaging systems can become more compact and easier to operate.

3. Large Field of View with High Resolution

Digital pathology requires both detailed cellular information and large tissue coverage.

ESA-FPM provides both advantages.

It combines:

• High-resolution imaging
• Large field of view
• Efficient data acquisition

Therefore, it is suitable for creating comprehensive digital pathology images.

4. Reliable Image Reconstruction

ESA-FPM uses an optimized acquisition strategy and computational reconstruction method.

This approach helps maintain image quality with fewer raw images.

As a result, the system provides stable and efficient imaging performance.

From Research Innovation to KFBIO Digital Pathology Products

The value of ESA-FPM extends beyond laboratory research.

KFBIO is transforming this technology into practical digital pathology solutions.

The ESA-FPM technology serves as the core imaging technology behind KFBIO’s high-magnification oil-immersion-free scanner.

By applying ESA-FPM to commercial scanners, KFBIO brings advanced computational imaging into real pathology workflows.

Faster Whole Slide Digitization

Traditional high-resolution microscopy often requires large numbers of images.

However, ESA-FPM achieves high-resolution reconstruction with only a small number of acquisitions.

Therefore, KFBIO scanners can significantly improve scanning efficiency.

This enables faster whole slide digitization for high-volume pathology laboratories.

Oil-Immersion-Free High-Resolution Imaging

Traditional 100× microscopy often relies on oil-immersion objectives.

Although this method provides high resolution, it also creates operational challenges.

For example:

• Additional preparation steps
• Oil cleaning procedures
• Increased maintenance requirements

ESA-FPM provides a different approach.

It uses a low-magnification, high-NA dry objective and computational reconstruction technology.

As a result, KFBIO scanners can achieve oil-immersion-level resolution without using immersion oil.

This simplifies operation, reduces maintenance and improves workflow reliability.

Conclusion: Building the Future of High-Throughput Digital Pathology Imaging

ESA-FPM represents an important advancement in computational imaging.

By improving illumination strategies and reducing acquisition requirements, KFBIO and SCI Lab have developed a practical solution for biomedical and pathology applications.

The technology enables:

• Faster imaging
• Higher efficiency
• Large field-of-view imaging
• Simplified system operation

Furthermore, its integration into KFBIO scanners demonstrates how research innovation can become a practical clinical solution.

Looking ahead, ESA-FPM will continue to support the development of faster, smarter and more accessible digital pathology imaging systems.

Ultimately, this technology can help laboratories accelerate diagnosis, research and the future of precision medicine.

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Research Foundation
This article presents applications of the ESA-FPM technology, a breakthrough developed jointly by KFBIO and Nanjing University of Science and Technology’s SCI Lab. The foundational research is published in:
Fan et al., Laser & Photonics Rev. 2022, 2200201. https://doi.org/10.1002/lpor.202200201