{"title":"Arriving at an Optimum Value of Tolerance Factor for Compressing Medical Images","authors":"Sumathi Poobal, G. Ravindran","country":null,"institution":"","volume":24,"journal":"International Journal of Medical and Health Sciences","pagesStart":383,"pagesEnd":388,"ISSN":"1307-6892","URL":"https:\/\/publications.waset.org\/pdf\/3458","abstract":"Medical imaging uses the advantage of digital\r\ntechnology in imaging and teleradiology. In teleradiology systems\r\nlarge amount of data is acquired, stored and transmitted. A major\r\ntechnology that may help to solve the problems associated with the\r\nmassive data storage and data transfer capacity is data compression\r\nand decompression. There are many methods of image compression\r\navailable. They are classified as lossless and lossy compression\r\nmethods. In lossy compression method the decompressed image\r\ncontains some distortion. Fractal image compression (FIC) is a lossy\r\ncompression method. In fractal image compression an image is\r\ncoded as a set of contractive transformations in a complete metric\r\nspace. The set of contractive transformations is guaranteed to\r\nproduce an approximation to the original image. In this paper FIC is\r\nachieved by PIFS using quadtree partitioning. PIFS is applied on\r\ndifferent images like , Ultrasound, CT Scan, Angiogram, X-ray,\r\nMammograms. In each modality approximately twenty images are\r\nconsidered and the average values of compression ratio and PSNR\r\nvalues are arrived. In this method of fractal encoding, the\r\nparameter, tolerance factor Tmax, is varied from 1 to 10, keeping the\r\nother standard parameters constant. For all modalities of images the\r\ncompression ratio and Peak Signal to Noise Ratio (PSNR) are\r\ncomputed and studied. The quality of the decompressed image is\r\narrived by PSNR values. From the results it is observed that the\r\ncompression ratio increases with the tolerance factor and\r\nmammogram has the highest compression ratio. The quality of the\r\nimage is not degraded upto an optimum value of tolerance factor,\r\nTmax, equal to 8, because of the properties of fractal compression.","references":null,"publisher":"World Academy of Science, Engineering and Technology","index":"Open Science Index 24, 2008"}