The Diffractive Achromat Full Spectrum Computational Imaging with Diffractive Optics
The Diffractive Achromat Full Spectrum Computational Imaging with Diffractive Optics
复制标题
DOI：
10.1145/2897824.2925941
复制
发表时间：
2016-07-01
影响因子：
6.2
通讯作者：
Heidrich, Wolfgang
中科院分区：
文献类型：
--
作者：
Peng, Yifan;Fu, Qiang;Heidrich, Wolfgang
衍射光学元件（DOEs）最近在计算成像中引起了极大的关注，因为它们可以大大减少成像器件的尺寸和重量。然而，固有的强色散是一个巨大的障碍，限制了在全光谱成像中使用do，导致不可接受的图像色彩保真度损失。特别地，同色异象引入了图像模糊中的数据依赖，这在计算成像方法中迄今为止一直被忽视。我们介绍了一种基于计算优化的衍射消色差，以及相应的残差校正算法。使用这种方法，我们展示了在全可见光谱上的高保真彩色衍射成像。在光学设计中，优化了衍射透镜的高度分布，以平衡不同波长对特定焦距的聚焦贡献。谱点扩展函数（psf）变得几乎相同，产生近似谱不变的模糊核。这种特性保证了捕获图像的良好颜色保存，并有助于在我们的快速两步反卷积中校正残余像差，而无需额外的颜色先验。利用光刻技术在0.5mm超薄衬底上展示了衍射消色差仪的设计。实验结果表明，该消色差衍射透镜在全可见光谱下具有较高的色彩保真度和较好的成像质量。
Diffractive optical elements (DOEs) have recently drawn great attention in computational imaging because they can drastically reduce the size and weight of imaging devices compared to their refractive counterparts. However, the inherent strong dispersion is a tremendous obstacle that limits the use of DOEs in full spectrum imaging, causing unacceptable loss of color fidelity in the images. In particular, metamerism introduces a data dependency in the image blur, which has been neglected in computational imaging methods so far. We introduce both a diffractive achromat based on computational optimization, as well as a corresponding algorithm for correction of residual aberrations. Using this approach, we demonstrate high fidelity color diffractive-only imaging over the full visible spectrum. In the optical design, the height profile of a diffractive lens is optimized to balance the focusing contributions of different wavelengths for a specific focal length. The spectral point spread functions (PSFs) become nearly identical to each other, creating approximately spectrally invariant blur kernels. This property guarantees good color preservation in the captured image and facilitates the correction of residual aberrations in our fast two-step deconvolution without additional color priors. We demonstrate our design of diffractive achromat on a 0.5mm ultrathin substrate by photolithography techniques. Experimental results show that our achromatic diffractive lens produces high color fidelity and better image quality in the full visible spectrum.