DCFZA: a high-quality lensless imaging technique

Abstract

Applications such as mobile imaging, industrial testing, and biomedicine drive the demand for cost-effective and portable imaging systems. Lensless imaging offers advantages such as compact size and low cost, due to its independence from traditional imaging lenses. In this paper, building on Fresnel zone aperture (FZA) technology, we propose a dual compound FZA (DCFZA) for lensless imaging. The design incorporates the twin-image elimination concept from co-axial holography and optimizes the phase combinations of the constituent FZAs, each operating at different orders, to minimize reconstruction noise. Moreover, a high-order back-propagation (HBP) reconstruction method is employed to overcome the information throughput limitation imposed by the minimum aperture size, enabling rapid and sample-independent reconstruction. The DCFZA-based lensless imaging system achieves an 2-fold improvement in resolution over the FZA-based system with the same minimum aperture and a higher enhancement in reconstruction quality compared to BP reconstruction. While maintaining comparable imaging quality, it significantly reduces reconstruction time compared to traditional compressive sensing (CS) based algorithms. Experimental results demonstrate its capability for high-throughput imaging, edge-enhanced imaging, and text recognition. Relying on its rapid and high-throughput reconstruction algorithm, which utilizes direct backpropagation (BP) without iteration or sample-dependent training models, this technology has the potential to achieve real-time imaging with low cost and high compactness system.