A new steganographic method using Contourlet Transform

The technique, digital steganography is a secret data hiding scheme which involves hiding data in multimedia files. Steganographic methods embed secret data in the cover media with minimum visual and statistical distortion. This paper introduces a new steganographic method in transform domain based on contourlet PDFB (pyramidal directional filter bank) based transform. Contourlet is a multiscale and multidirectional transform domain, which provides the both spatial and frequency domain information. This method also uses the wavelet based compression technique like that of JPEG2000 on the secret data for transferring more information with fewer data. The approximation sub-band is embedded in the contourlet coefficients of the cover image. Approximation subband is multiplied by a constant factor k, which is determined experimentally. Modified values of approximation sub-band are embedded in the contourlet subband of the cover image by replacing them directly. Experimental results give that the proposed method has a good imperceptibility and to show this, the method uses four different visual quality metrics.