Bianli Zhao | Searcharxiv

arXiv2026

High-fidelity tabletop nanoscopy enabled by non-linear spectral preconditioning

Ptychography is a powerful lensless imaging technique that overcomes conventional numerical aperture limits to achieve diffraction-limited resolution. While routine at high-brilliance synchrotron facilities, its application to laboratory-scale sources is primarily limited by low photon flux. Under these conditions, the wide dynamic range of diffraction signals presents a critical bottleneck where detector bit-depth limitations hinder the simultaneous recording of low-frequency intensity and high-frequency details. Currently, most high-dynamic-range (HDR) imaging methods enforce strict radiometric linearity, assuming the fused intensity must be linearly proportional to the squared modulus of the wavefront to satisfy Poisson likelihood models. In this paper, we introduce a multi-scale non-linear fusion approach into the ptychographic pipeline, demonstrating that strict linearity is not a prerequisite for accurate reconstruction. This method mitigates the traditional trade-off between noise suppression and physical fidelity, enables robust imaging under strong dispersion, and significantly broadens the effective spectral bandwidth.

cs.GR↗

arXiv2026

Breaking optoelectronic SNR limitations via physics-consistent computational diffractive imaging

Ptychography is a powerful lensless imaging technique capable of approaching the diffraction limit, yet its performance is increasingly constrained by non-ideal detection hardware. In photon-limited measurements, weak high-frequency diffraction signals often overlap with spatially heterogeneous detector noise, whereas most reconstruction algorithms still treat the detector as an ideal measurement plane. Here, we introduce detector-informed measurement consistency into ptychographic reconstruction. By calibrating the pixelwise sensor response, the method construct a spatially resolved confidence map and embed it into the iterative amplitude constraint, allowing unreliable detector residuals to be down-weighted while preserving physically meaningful diffraction information. Experiments across transmission, reflection, and weak biological phase imaging show improved diffraction-data quality, an approximately twofold signal-to-noise ratio (SNR) enhancement, and reconstruction approaching the Rayleigh limit with a measured (k)-factor of about 0.65. Compared with previous advanced denoising methods, the proposed framework achieves a better balance between suppressing detector-induced background and preserving structural diffraction information. These results show that detector reliability can be used as an in-loop physical constraint to extend the performance of ptychographic imaging with imperfect sensors.

cs.GR↗