Standard zerotrees are adapted
to directionlets. The children at finer scales are grouped in
anisotropic and oriented clusters.
Numeric compression results obtained using the standard wavelet
transform and directionlets and shown for two images: Lena
The results are shown for very low bit-rates (< 0.2bpp). The gain is
significant (> 1dB).
The image Lena
at the bit-rate 0.0395bpp using the two methods. The reconstructions
have PSNR = 23.51dB and 26.07dB, respectively. The artifacts in the
reconstruction obtained by directionlets are aligned with local
dominant orientations in the image and are less visually perceptible.