Wavelet filters analysis for speckle reduction in intravascular ultrasound images

Speckle noise is an inherent property of intravascular ultrasound imaging (IVUS) and it generally tends to deteriorate the image quality, thereby reducing the diagnostic value of this medical imaging modality. As a result, the speckle reduction filtering is considered to be an important and essential procedure to be used, whenever IVUS images are used for atherosclerotic lesions assessment. Wavelet-based methods have been found particularly for image enhancement and de-noising given that a suitable separation of signal and noise can be achieved in the transform domain based on their distinct localization and distribution in time and frequency domains. This paper presents a comparative study of various wavelet filter methods applied to intravascular ultrasound images. The comparative evaluation of the de-speckling performance is defined using image quality parameters such as the peak signal-to-noise ratio and the normalized mean square error. Furthermore, this performance has been compared with the Wiener filtering method. The results included a series of simulated and in vivo IVUS images.