A new image compression method using noise bit removal

For communication and storage efficiency, image data should be substantially compressed. The compression ratio is limited by noise, which degrades the correlation between pixels. Due to the statistical nature of x-rays and the electromagnetic field, medical images are contaminated with random noise. Because of this effect, considerable effort has been devoted to remove noise from medical images. In this study we use standard deviation to evaluate the noise level and subsequently to estimate the number of noisy bits for each pixel. By discarding these noisy bits, the compression ratio can be improved. This method was verified using a synthetic digital image and tested in various radiological image modalities. This technique can increase the ratio up to 3.9 for MRI from 2.5 without significantly affecting the image quality. This process will have a great impact on storage reduction, transmission rate and the speed of image display and manipulation.