Digital Image Steganography Scheme for Speech Signals in the Discrete Wavelet Transform Domain

Abstract

In recent years, the evolution and expansion of the multimedia world has allowed digital images to be widely used as a carrier medium for facilitating the sending and receiving of confidential digital content such as text, audio and images. However, there are few steganographic schemes that hide digital speech signals into digital images; also, the state-of-the-art methods have some disadvantages such as low embedding capacity, low quality in the modified image, and/or low audible quality in the recovered speech signal. In this paper, a new steganographic scheme that hides a digital speech signal into a color image is presented, where the embedding process is performed in the HL and LH channels of the first decomposition level of the discrete wavelet transform (DWT) over the YCbCr color space; additionally, a chaotic map method is implemented to encrypt the speech signal and to spread it throughout the whole image. Experimental results have demonstrated that the proposed scheme results in better performance against other state-of-the-art methods, due to their ability to embed and recover speech signals with duration up to 16.384 seconds using color images of 512×512 pixels, obtaining 32 dB and 0.92 in PSNR and SSIM, respectively for the stego-image, and 41 dB in SNR for the recovered speech signal.