The Ultrasound Image Compression Based On Directional Wavelet Transform

With the developing of medical information network,the transmission of medical images in network become very necessary to remote medical education and the share of patients' information.There are high requirements of medical images and transfer speed in the process of transmission,so it is the only choice in the environment of scarcity bandwidth resource to transfer compressed images.The purpose of the image code is to express image with less bits,at the same time retain the quality of reconstructed image satisfying the special use.Aiming at the existent and related redundancy information in the images,adopting a certain method to do away with the surplus composition,can carry out the compression of the image.Though the saving technique of data develops continuously,the letter way delivers the bandwidth to widen continuously,people for the compression image data with economical data saving the space and exaltations believe the need of an utilization to increase still.Wavelet transform inherits and develops Fourier transform.The wavelet analysis have many advantages of time-frequency analysis,many differences analysis etc.,and wavelet transform is suitable to detect the stochastic signal that is feeble and submerged in strong noise.It also is adapted to analyze the unstable signal sources such as the medical images,so the method of a wavelet transformation is high among the people value.The paper introduces not only the necessity and possibility of image compression but also the basic principle and method of image compression.Then introduce the wavelet transform simply and analyze the method of image compressing and the two-dimension wavelet decomposition.Then the paper develops a new algorithm which is based on the lifting scheme to get the conclusion of 2D dimensional discrete wavelet transform which contains spin.The mathematical model of the new algorithm is like Mallat algorithm but much more strict in the choosing of wavelet's type.And by using this algorithm,an experiment has been done.By the result of the experiment,the paper finds out the advantages of two 2D dimensional discrete wavelet transform which contains spin,even be compared with the JPEG2000' base wavelet. Experimental results showed that it had better quality of reconsteucted images and faster speed. From the subjective appraisal which is make by the doctors come from Tokai University's affiliated hospital," much of time the new methods' results is better than the JPEG2000' base wavelet' results." is be sure.At last,the paper shows the deficiency of this paper and the aspects that need to be improved.