Edge preserving smoothing and enhancement for electronic portal images

Portal images, acquired by Electronic Portal Imaging Devices (EPID), suffers from inherently poor visual quality in terms of spatial resolution and contrast. Edge-preserving smoothing is an image processing technique that smooths away the noisy textures while retaining sharp edges. Since portal images used for in-line treatment, patient setup verification, image processing could be applied to improve the visualization of anatomical details. To quantify the degree of enhancement we present an image enhancement technique particularly effective for sharpening major edges while eliminating a manageable degree of noise. To achieve this task guided filtering is proposed, which has better behavior at the edges. In this research, we firstly try to reduce the noise and then perform edge preservation on EPI.