A survey on noise reduction techniques in medical images

An image is a visual representation of the real world, represented in the form of two dimensional matrix consisting of x and y coordinates. Any image usually has a component of noise present in it. Image noise is an unwanted component due to random variation of brightness or colour information in images. Noise can be of various types including Gaussian noise and speckle noise. Rapid and unchecked cell growth in tissues of the lung is the primary cause of lung cancer. Computed Tomography (CT) scan images provide the detailed imaging of tumour growth inside the lungs and are widely used. However various noise types like those mentioned above can be encountered during a CT scan. Removal of these noises is critical for medical diagnoses and is done using filters. Filtering is a method by which we can enhance and denoise the image. This paper presents an overview of lung cancer and a survey on various noises and their removal techniques, including the usage of various filters.