• 摘要: 边缘检测在自动驾驶、模式识别、生物医学影像等领域得到广泛应用,其中光学边缘检测具有速度快、可并行处理的优势而备受研究人员的青睐。超表面作为一种新兴的光场调制器件,能够在极微小的空间内对光场精确调控,被广泛应用于光学边缘检测系统。基于超表面的光学边缘检测的设计方法可分为两大类:空间傅里叶变换法和格林函数法。空间傅里叶变换法将超表面作为4f系统(f为焦距)中的滤波片,实现对光场频谱的精确调制。格林函数法利用单片超表面直接调制不同角度的入射光,实现特定的光学传递函数。本文综述了这两类方法的原理、特点,总结了国内外的相关研究进展,指出了当前面临的问题并提出了未来可能的发展方向。

       

      Abstract: Edge detection has been widely applied in autonomous driving, pattern recognition, biomedical imaging, and other fields. Among various approaches, optical edge detection has garnered significant attention from researchers due to its advantages of high speed and parallel processing capabilities. As an emerging optical field modulation device, metasurfaces enable precise manipulation of light fields within extremely compact spatial dimensions, and have been extensively employed in optical edge detection systems. Design methodologies for metasurface-based optical edge detection can be classified into two major categories: the spatial Fourier transform method and the Green's function method. The spatial Fourier transform method utilizes metasurfaces as filtering elements in 4F (f represents the focal length) systems to achieve precise modulation of the optical field spectrum. The Green's function method employs a single metasurface to directly modulate incident light at different angles, thereby realizing specific optical transfer functions. This review summarizes the principles and characteristics of these two methodologies, presents an overview of related research progress both domestically and internationally, identifies current challenges, and proposes potential directions for future development.