LOSSY TO LOSSLESS IMAGE CODING USING A COMPLEX ALLPASS FILTER

Since wavelet filters composed of a single complex allpass filter satisfy both of the conditions of orthonormality and symmetry, it is expected to obtain better coding performance than biorthogonal wavelets in image coding. This paper proposes an effective implementation of the orthonormal symmetric wavelets composed of a complex allpass filter for image coding. Firstly, an implementation of irreversible real-to-real wavelets for lossy coding is presented by realizing the complex allpass filter. Then, the reversible integer-to-integer wavelets is realized by utilizing the invertible implementation of complex allpass filter. Finally, the coding performance of the orthonormal symmetric wavelets is evaluated and compared with the D-9/7 and D-5/3 wavelets. It is shown from the experimental results that the allpass-based orthonormal symmetric wavelets can achieve better coding performance than the D-9/7 and D-5/3 wavelets