A Study on Image Denoising for Lung Ct Scan Images

Medical imaging is the technique and process used to create images of the human body for clinical purposes and diagnosis. Medical imaging is often perceived to designate the set of techniques that noninvasively produce images of the internal aspect of the body. The x-ray computed tomographic (CT) scanner has made it possible to detect the presence of lesions of very low contrast. The noise in the reconstructed CT images is significantly reduced through the use of efficient x-ray detectors and electronic processing. The CT reconstruction technique almost completely eliminates the superposition of anatomic structures, leading to a reduction of "structural" noise. It is the random noise in a CT image that ultimately limits the ability of the radiologist to discriminate between two regions of different density. Because of its unpredictable nature, such noise cannot be completely eliminated from the image and will always lead to some uncertainty in the interpretation of the image. The noise present in the images may appear as additive or multiplicative components and the main purpose of denoising is to remove these noisy components while preserving the important signal as much as possible. In this paper we analyzed the denoising filters such as Mean, Median, Midpoint, Wiener filters and the three more modified filter approaches for the Lung CT scan images to remove the noise present in the images and compared by the quality parameters.