TWO-DIMENSIONAL DISCRETE GABOR TRANSFORMATIONAND ITS APPLICATION TO NOISE SUPPRESSIONIN DIGITAL IMAGES
Hardware and software processing of digital images is a complex technological process consisting of several stages. One of the main stages is noise suppression and this process is necessary not only in digital image processing but also in many other important fields of modern computer science. Noise suppression allows you to improve the quality of visual information, to reduce the influence of artifacts in digital images, to increase the possibilities of pattern recognition and interpretation of the measurements as well as simply to increase the number of useful properties of the images obtained from the registered devices. In addition to these areas noise modulation in digital images is used to reduce the volume of digital images in order to optimize their storage and transmission over communication lines including Internet. At the same time in applied problems as a rule a certain level of quality loss is allowed which is compensated by the benefits of such optimization for example due to the possibility of operating large arrays of digital images. A whole class of areas in modern computer science cannot be considered in isolation from such approach. First it is space image processing, medical image processing and almost any task of cartography. Thus that it is very important to develop and apply highly effective noise suppression algorithms for digital image processing. The article is devoted to the synthesis of noise suppression algorithm in digital image processing based on the design of a special spatial linear filter. The filter is based on the two-dimensional discrete Gabor transformation which is applied to numerical matrices modeling digital photographs. For completeness the article includes the description of the two-dimensional continuous Gabor transformation, its two-dimensional discrete version and general noise reduction scheme based on it. The article has a practical orientation. The scheme of linear filtering presented in the article allows to make effective noise suppression for digital images. The proposed algorithm is not tied to any specific standard of digital images and can be successfully applied both for the widespread JPEG standard, which includes most of the images in the Internet, and for more complex and advanced formats ICER and JPEG 2000 focused mainly on images for space, medical as well as scientific, technical and technological photographs of large volume.