Semi‐guided bilateral filter
Ba Thai, Mukhalad Al‐nasrawi, Guang Yi Deng, Zhuo Su · IET Image Processing · 2017
The bilateral filter (BF) is a non‐linear filter that spatially smooths images with awareness of large structures such as edges. The level of smoothness applied to a pixel is constrained by a photometric weight, which can be obtained from the same image to be filtered (in case of the original BF) or from a guided image (in case of the joint/cross BF). In this study, the authors propose a new filter called the semi‐guided BF which is derived from solving a non‐linear constraint least square problem. The proposed filter's photometric weight incorporates information from the image to be filtered and the guided image. They propose a fast implementation of the filter based on layer approximation. They also study the iterative application of the proposed filter and show that the filter can preserve large structures while smoothing out small structures. This makes the proposed filter an efficient and effective tool for structure‐aware image smoothing. Experimental results have demonstrated that performance of the proposed filter is comparable to those of the state‐of‐the‐art algorithms.