Enhancing Fluorescence Microscopy Resolution Beyond the Diffraction Limit via Cascaded Up- and Down-Sampling Networks

Birla Institute of Technology Mesra, Patna Campus
International Conference on Computer Vision and Image Processing (CVIP-2025)

Model Architecture

Abstract

Fluorescence microscopy enables high-contrast visualization of subcellular structures through the use of synthetic fluorescent markers, though it is limited by lower spatial resolution and the risk of photobleaching. Super-resolution (SR) fluorescence microscopy overcomes the diffraction barrier to resolve finer details, but comes with trade-offs such as decreased temporal resolution, the need for sophisticated equipment, optical sectioning requirements, and constraints on the sample’s exposure tolerance.
In this study, we introduce a deep learning model that employs upsampling and downsampling to achieve super-resolution. By connecting up-projection and down-projection blocks in a cascaded arrangement, our model maintains the important relationships between the input low-resolution (LR) images and the target high-resolution (HR) labels. To extract dependencies across various depths, feature maps produced at intermediate upsampling stages are combined. Additionally, external self-attention blocks are integrated after these intermediate up-projection blocks to assess pixel-level affinities. Unlike traditional self-attention mechanisms that focus on correlations within a single sample, our approach uses external attention to capture inter-sample correlations across the entire dataset, offering the added benefit of reduced computational demands.

Dataset Description

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Row 1: Different samples obtained from structured illumination miscroscopy (SIM) (acting as groundtruth data) in increasing levels of structural complexity: clathrin-coated pits (CCP), endoplastic reticulum (ER), microtubules (MT) and F-actin fibers. Row 2: The corresponding gradient maps where structural complexity is measured in terms of grayscale mean gradient (MG) where \(\nabla_hx\) and \(\nabla_vx\) are the gradients across horizontal and vertical axes respectively. The representative widefield CCP images for two different excitation intensities serving as input samples during model training (last column).


Results

Super-resolution under High Fluorescence Excitation Level

(Row 1): Input and super-resolved images inferred from the trained models for different specimen types (clathrin coated pits (CCPs), endoplastic reticulum (ER), microtubules (MT) and F-actin fibers) under high-fluorescence excitation levels. (Row 2): The corresponding zoomed regions.

Super-resolution under Low Fluorescence Excitation Level

(Row 1): Input and super-resolved images inferred from the trained models for different specimen types (clathrin coated pits (CCPs), endoplastic reticulum (ER), microtubules (MT) and F-actin fibers) under low-fluorescence excitation levels. (Row 2): The corresponding zoomed regions.


Uncertainty Quantification

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Resolution Scaled Error Maps (RSM) and rolling Fourier Ring Correlation Maps (rFRC Maps) for different specimen types under the proposed methodology. Also provided are the corresponding metric values: resolution scaled error (RSE), Pearson correlation coefficient (RSP) and structural similarity index (RSSIM). Uncertainty quantification metrics: rFRC value (higher value indicates higher confidence in the reconstructed structures) and mean resolution (Res.) obtained for the given input LR image. Scalebar: \([0,~1]\) for RSM and \([0,~256]\) for rFRCMap from left to right.

Presentation

BibTeX


        @inproceedings{aetesam2025two,
        title={Enhancing Fluorescence Microscopy Resolution Beyond the Diffraction Limit via Cascaded Up-and Down-Sampling Networks},
        author={Aetesam, Hazique},
        booktitle={International Conference on Computer Vision and Image Processing},
        pages={179--190},
        year={2025},
        organization={Springer}
}