Automatic Processing of Digital X-ray Medical Images by Bilateral Filtration Method
Serhiy V. Balovsyak, Mariana Borcha, Michal Greguš, Khrystyna S. Odaiska, Nataliya Serpak · 2021
The method of bilateral filtering of digital X-ray medical images has been improved by automatic selection of the filter kernel parameters, namely the standard deviations of the bilateral filter kernel in the spatial region and in the region of brightness. The parameters of the filter kernel are calculated using the noise level in the image and the average spatial period of the image. Its standard deviation is used as the noise level. The mean spatial period of an image is calculated by its Fourier spectrum. Bilateral filtering provided a reduction of Gaussian and pulsed noises while the image contours remained clear. To improve the visual quality of images, the local contrast increasing and gamma correction were also performed after bilateral filtering. The proposed methods of image processing are implemented as software in the Matlab system. The results of processing experimental X-ray medical images by the proposed method showed a significant increase of their signal-to-noise ratio and visual quality.