Distortionless Data Hiding based on Slantlet Transform

In this paper we present a distortionless data hiding technique based on wavelet-like transform, known as Slantlet Transform (SLT). The proposed algorithm first encodes the original message using the encoder, T-codes. T-codes have shown to be more robust than the best known variable-length codes, Huffman codes. T-codes have a well-explained resyhchronization mechanism which leads to fast and reliable resynchronization. The secret data is then embedded in the high frequency sub-bands, viz., HH, HL and LH which are obtained by applying Slantlet transform to the cover-image. We use two steganography algorithms, viz., LSB algorithm and Thresholding algorithm for embedding data in the image. We show further that the original image can also be recovered from stego-image after the hidden data is extracted from it. It is known that SLT is a better candidate for signal compression compared to the DWT based scheme and it can provide better time localization. Experimental results have confirmed that the proposed algorithm yields better imperceptibility for the stego-images than the conventional DWT based scheme in case of low embedding rate and yields acceptable results for high embedding rate as well.