Speckle Noise Reduction and Edge-Enhancement of Coronary Plaque Tissue in Intravascular Ultrasound Image by Using Anisotropic Diffusion Filter

This paper describes a novel edge-preserved smoothing method with special consideration to an intravascular ultrasound (IVUS) image. An IVUS image, which is commonly used for a diagnosis of acute coronary syndromes (ACS), is very grainy due to heavy speckle noise. The speckle noise prevents not only the medical doctors’ interpretation of the IVUS image, but also the processing of medical images for computer-aided diagnoses (CADs). In order to reduce the speckle noise, in this study, we propose a modification of anisotropic diffusion filter in which a diffusion strength is locally and adaptively controlled by a weighted separability of an IVUS image. The weighted separability is a modification of separability for an edge detection with special consideration to an IVUS image. Furthermore, the proposed method not only reduces a speckle noise but also effectively enhances an edge of plaque tissue in an IVUS image. The effectiveness of the proposed method is verified by the experiments using the real IVUS images.