DEMO_IMAGECOMPRESSION Image compression using N-term approximation
This demo shows how to perform a simple imagecompression using either
a Wilson basis or a Wavelet. The compression step is done by
retaining only 5% of the coefficients.
Figure 1: Wilson and WMDCT basis
This right figure shows the image compressed using a DWILT basis with
8 channels. This corresponds quite closely to JPEG compression,
except that the borders between neigbouring blocs are smoother,
since the DWILT uses a windowing function.
The left figure shows the same, now
using a MDCT basis. The MDCT produces more visible artifacts, as the
slowest changing frequency in each block has a half-wave
modulation. This is visible on otherwise smooth backgrounds.
Figure 2: Wavelet
The Wavelet used is the DB6 with J=5 levels. On the right figure
the standard layout has been used, on the left the tensor layout
was used.
Url: http://ltfat.github.io/doc/demos/demo_imagecompression.html
Package: ltfat