Efficient Secured Lossless Compression of Medical Images - Using Modified Runlength Coding for Character Representation

Lossless compression schemes with secure transmission play a key role in telemedicine applications that helps in accurate diagnosis and research. Traditional cryptographic algorithms for data security are not fast enough to process vast amount of data. Hence a novel Secured lossless compression approach proposed in this paper is based on reversible integer wavelet transform, SPIHT algorithm, new modified runlength coding for character representation and selective bit scrambling. The use of the lifting scheme allows to generate truly lossless integer-to-integer wavelet transforms. Images are compressed/decompressed by well-known SPIHT algorithm. The proposed modified runlength coding greatly improves the compression performance and also increases the security level. This work employs scrambling method which is fast, simple to implement and it provides security. Lossless compression ratios and distortion performance of this proposed method are found to be better than other lossless techniques.