Zhang Benxuan, Sheng Bin, Li Ping, Lee Tong-Yee
IEEE Trans Vis Comput Graph. 2020 Aug;26(8):2546-2559. doi: 10.1109/TVCG.2019.2894627. Epub 2019 Jan 23.
Depth of field (DOF) is utilized widely to deliver artistic effects in photography. However, existing post-processing techniques for rendering DOF effects introduce visual artifacts such as color leakage, blurring discontinuity, and the partial occlusion problems which limit the application of DOF. Traditionally, occluded pixels are ignored or not well estimated although they might make key contributions to images. In this paper, we propose a new filtering approach which takes approximated occluded pixels into account to synthesize the DOF effects for images. In our approach, images are separated into different layers based on depth. Besides, we utilize adaptive PatchMatch method to estimate the intensities of occluded pixels, especially in the background region. We again propose a new multilayer-neighborhood optimization to estimate occluded pixels contributions and render the images. Finally, we apply gathering filter to achieve the rendered images with elite DOF effects. Multiple experiments have shown that our approach can handle color leakage, blurring discontinuity and partial occlusion problem while providing high-quality DOF rendering effects.
景深（DOF）在摄影中被广泛用于营造艺术效果。然而，现有的用于渲染景深效果的后处理技术会引入诸如颜色泄漏、模糊不连续以及局部遮挡问题等视觉伪像，这些问题限制了景深的应用。传统上，被遮挡的像素尽管可能对图像有重要贡献，但却被忽略或估计不准确。在本文中，我们提出了一种新的滤波方法，该方法考虑了近似的被遮挡像素，以合成图像的景深效果。在我们的方法中，图像基于深度被分离成不同的层。此外，我们利用自适应PatchMatch方法来估计被遮挡像素的强度，特别是在背景区域。我们还提出了一种新的多层邻域优化方法来估计被遮挡像素的贡献并渲染图像。最后，我们应用聚集滤波器来获得具有出色景深效果的渲染图像。多项实验表明，我们的方法能够处理颜色泄漏、模糊不连续和局部遮挡问题，同时提供高质量的景深渲染效果。
