A Novel Trilateral Filter for Digital Subtraction Angiography
Purvi Tripathi, Richard Obler, Andreas Maier, Hendrik Janssen
Friedrich-Alexander Universität Erlangen-Nürnberg, Lehrstuhl für Mustererkennung
Abstract
In this paper, we formulate a novel Trilateral Filter (TF) for denoising digital subtracted angiography (DSA) without losing any vessel information. The harmful effect of X-rays limits the dose resulting in degraded signal-to-noise ratio (SNR). A bilateral filter (BF) is often applied for edge-preserving denoising. However, for a low SNR image, the filter needs to be iterated with smaller spatial window to avoid oversmoothing of low-contrast vessels. The proposed TF combines the BF of wider spatial window with the Frangi vessel enhancement filter to denoise the DSA and to improve the vessel visibility without the need for iteration. The experimental results shows that our method provides better vessel preservation and greater noise reduction than the BF.