High-quality FZA lensless imaging via joint generation of original-twin images

Lensless imaging possesses the advantages of functional flexibility and high portability. The inherent twin-image problem in Fresnel zone aperture (FZA) lensless imaging cannot be eliminated using conventional image reconstruction methods based on spatial sparsity priors. A low-cost FZA encoder with orthogonal phases is used to construct a lensless imaging system, and high-quality FZA lensless imaging via joint generation of original-twin images (LOTI) is proposed. Image generation is performed in a high-dimensional solution space of original-twin images, separating the twin image from the reconstructed content and producing an artifact-free original image. LOTI demonstrates strong robustness to different mask fabrication methods, phase encoding schemes, target distances, and distance mismatch. Simulative and experimental validation demonstrate LOTI effectively suppresses twin-image artifacts in the reconstructed images while preserving textural details and color fidelity. Quantitative evaluations further confirm the superior performance, with an average peak signal-to-noise ratio (PSNR) of 24.37 dB and a structural similarity index measure (SSIM) of 0.92 within the regions of interest.