Contents I. Introduction
Denoising Ultrasound (US) images is one of the most demanding fields in image processing. Different noises like Gaussian, impulse, speckle are intrinsically present in US images, which corrupts the content of the image [1]. Among these, removal of speckle noise is challenging due to its multiplicative nature and estimating the noise distribution unlike Gaussian noise. Denoised medical images helps in increasing the certainty of the disease diagnosis and easily detect the lesions. SAR images that give high resolution pictures of the earth are also contaminated by speckle noise [2]. Eliminating speckle noise increase the accuracy of successive segmentation and classification tasks in these images. Therefore, despeckling is a major task in pre-processing stages of US images before detailed analysis and decision making. Ultrasound is high frequency sound waves, inaudible for humans which operates in the range of 2 MHz to 18 MHz [3]. In medical imaging, ultrasound transducers or probes send ultrasound waves to the body, which penetrates through tissues, and the device constructs the image from the echoed waves. Ultrasound waves is a series of small mechanical pressure waves propagating through the body. Ultrasound medical imaging is an effective, noninvasive and inexpensive imaging modality for obtaining cross section of internal organs [4]. The aim of this paper is to analyze the major denoising filters applicable to ultrasound images and quantitative evaluation between these techniques.
