Speech encryption using discrete orthogonal transforms
Sridha Sridharan, Ed Dawson, B. Goldburg · International Conference on Acoustics, Speech, and Signal Processing · 2002
The performances of five discrete orthogonal transforms in speech encryption systems are compared. The transforms considered are the discrete Fourier transform, discrete cosine transform, Walsh-Hadamard transform, Karhunen-Loeve transform, and discrete prolate spheroidal transform. Four objective measures are used to grade the encryption systems with respect to residual intelligibility and recovered voice quality. A figure of merit based on all the four objective measures is formed. It gives good correlation to the subjective results of residual intelligibility and recovered speech quality.>