Speech compression and encryption based on discrete wavelet transform and chaotic signals

摘要

To increase transfer and storage efficiencies of the information, data compression has emerged as a significant issue in the communication environments. This paper introduces compression and encryption of speech signals based on Discrete Wavelet Transform (DWT) and Chaotic signals. DWT sparsens and codes the speech signal to the wavelet coefficients. The less impactful coefficients are eliminated to reduce the amount of data. After that, a new coding process which utilizes the chaotic signals is proposed to encode, in encrypted form, the residual coefficients. A High strength to the encryption process is realized by using four linked Henon Chaotic Maps (HCM) in the proposed scheme. Multi HCM guarantees larger than 10(240) of key space to the encryption process. The proposed system obtains up to -41.449 dB of spectral segmental signal-to-noise ratio, which measures and proves the strength of encryption. Also, at 10% compression ratio, signal-to-noise ratio of 11.549 dB and perceptual evaluation speech quality of 3.02945 demonstrate that the proposed system has high quality and intelligibility of the reconstructed speech.