Super-resolution lensless imaging system based on a fast anti-diffraction algorithm

Conventional lens imaging systems modulate incident rays with a set of lenses and focus these rays on their imaging planes. A lensless imaging system uses a single mask instead of lenses to project incident rays onto the imaging plane. These rays pass through or are blocked off according to the binary mask pattern. These systems are thin, lightweight, and inexpensive. However, they do not converge the rays, causing the local images corresponding to individual light transmission units to heavily overlap in a global scene, requiring a specific algorithm for decoding. Additionally, diffraction is unavoidable when the holes on the mask are extremely small, which can degrade the imaging quality. To address these difficulties, we propose a decoding algorithm called Fourier-ADMM algorithm to unwrap the overlapped images rapidly. In addition to providing high decoding speed, the proposed technique can suppress the diffraction from the tiny holes, owing to its conjugated structure. Based on this novel decoding algorithm, a lensless imaging system is proposed, which can handle overlapped and diffracted images with a single random mask. The camera can work beyond the theoretical diffraction limit and tremendously enhance the resolution. In summary, the super-resolution lensless camera provides users with additional options to suit different situations. It can facilitate robust, high-resolution, fast decoding without sophisticated calibration.

Automated summary

Conventional lens imaging systems use lenses to focus incident rays, while a lensless imaging system uses a mask to project the rays. Lensless systems are thin, lightweight, and inexpensive, but they require specific decoding algorithms for the heavily overlapped images. We propose a decoding algorithm called Fourier-ADMM to rapidly unwrap the overlapped images and suppress diffraction from tiny holes. Based on this algorithm, a lensless imaging system is proposed, achieving super-resolution and providing users with additional options for robust, high-resolution, fast decoding without complicated calibration.