Resolution Enhanced Transport of Intensity Phase Imaging Using Contrast Transfer Function Reformulation and SNR-Guided Deconvolution

The Transport of Intensity Equation (TIE) is a powerful phase imaging technique. However, its formulation fails to account for off-axial transfer function due to the paraxial approximation. To address the resulting image degradation, we analyze TIE phase retrieval using the contrast transfer function (CTF) framework. The attenuation of high-frequency components, leading to the loss of fine structural details, is assessed and restored through Wiener deconvolution. Simulations and experiment results demonstrate significant enhancements in sharpness, contrast, and structural clarity. We showcase enhanced phase imaging of cheek cells, revealing finer subcellular details and achieving diffraction-limited performance, contributing to advances in super-resolution phase imaging.