ST-FPM: suppressor tunable FPM for high-quality and highly robust full-field reconstruction

Fourier ptychographic microscopy (FPM) offers an effective approach for high-resolution (HR) and large field-of-view (FOV) imaging, with significant applications in digital pathology. However, the full-field reconstruction is limited by the vignetting effect, so it needs to be processed by blocks and stitching, which will lead to stitching artifacts and reduce the reconstruction quality. Although the reconstruction algorithm based on the feature domain avoids vignetting artifacts, due to the fact that the loss function of the feature domain and the spatial gradient operation are only based on the amplitude (or intensity) of the image, the improper utilization (excessive or insufficient) of image features, the reconstruction details become blurred or distorted, limiting the performance of the algorithm. In this work, we propose a suppressor tunable FPM (ST-FPM) to achieve high-quality and robust full-field reconstruction by modulating the loss in the feature domain. This algorithm introduces a weighted term with a tunable suppressor in the gradient of the loss function, efficiently utilizes the image feature information to guide the reconstruction, and makes the gradient update more conducive to detail recovery. Compared with the existing full-field reconstruction algorithms, ST-FPM can flexibly adjust the feature utilization degree of different samples to obtain full-field reconstruction with clear and reliable details and excellent quality. Extensive simulations and system experiments show that ST-FPM has significant advantages in reconstruction details and robustness, providing a promising direction for the development of full-field reconstruction methods.