Lensless cameras are a class of imaging devices that shrink the physical dimensions to the very close vicinity of the image sensor by replacing conventional compound lenses with integrated flat optics and computational algorithms. Here we report a diffractive lensless camera with spatially-coded Voronoi-Fresnel phase to achieve superior image quality. We propose a design principle of maximizing the acquired information in optics to facilitate the computational reconstruction. By introducing an easy-to-optimize Fourier domain metric, Modulation Transfer Function volume (MTFv), which is related to the Strehl ratio, we devise an optimization framework to guide the optimization of the diffractive optical element. The resulting Voronoi-Fresnel phase features an irregular array of quasi-Centroidal Voronoi cells containing a base first-order Fresnel phase function. We demonstrate and verify the imaging performance for photography applications with a prototype Voronoi-Fresnel lensless camera on a 1.6-megapixel image sensor in various illumination conditions. Results show that the proposed design outperforms existing lensless cameras, and could benefit the development of compact imaging systems that work in extreme physical conditions.

翻译：无镜头照相机是一种成像设备,通过以综合平板光学和计算算法取代常规复合镜片,将物理维度缩缩到图像传感器非常近的地方。 我们在此报告一个带有空间编码Voronoi- Frensonel 级的不显微镜照相机,以达到高图像质量。 我们提出了在光学中最大限度地增加所获信息以方便计算重建的设计原则。 通过采用与Strehl 比率有关的简单优化Fourier域度度度度度、 Modultult Translation 函数量(MTFv), 我们设计了一个优化框架, 以指导调相光学元素的优化。 由此产生的Vorononoi- Fresnele 级不显微细胞的不规则阵列, 其中包含一个基础一阶 Fresnelse 级功能功能。 我们演示并核实了在1.6- megaplix 图像传感器上原型Voronionoi- Frenel无镜头的摄影应用的成像性工作表现。 结果显示, 正在现有不光成型的摄影系统, 将有利于现有不相像系统。