Here we deal with an image of a poster in memory of the
Spanish Second Republic shown in the first
picture of Fig. 2
. This image is an
pixels that we have processed row by row.
Each row is a vector
The image is affected by structured noise produced when random noise
passes through a channel characterized by a given matrix
The model for each row
of the noisy image is
is a random vector in
The image plus noise is represented
in the middle graph of Fig. 2
In order to denoised the image we consider that every
is well represented in a subspace
spanned by discrete cosines.
More precisely, we consider
The space of the noise is
spanned by the
corresponding to the columns
of the given matrix
The image, after being filtered row by row by the
oblique projector onto
and along the space of the noise,
is depicted in the last graph of
Image of a poster in memory of
the Spanish Second Republic (first picture).
Image plus structured noise (middle picture).
The image obtained from the middle picture by
an oblique projection (last picture).