Re: DCT and DWT common spectral features

K. wrote:

for instance, if you were to do IDWT on only
LH3 subband from this example you would get some approximation of the
input image. now the question is, which set of DCT coefficients (taken
from ALL 8x8 blocks - e.g. elements 7,8,9 and 15 from each block or
something like that) would give SIMMILAR results after IDCT. then i
would consider those two sets of coefficients to capture "simmilar"
information about an image.

You can zero all the high frequency components in the DCT domain and still get a decent reconstruction of the image ... in both cases you are approximately low pass filtering the image. Very approximately though, you certainly wont be able to get a 1:1 mapping between these two subsets of coefficients.

PS. try capitalization, and it's similar.
.

Relevant Pages

  • Re: erf in Forth
    ... I reworked the Chebyshev approximation so that the range of erf is ... shortens the coefficients array quite considerably, ... fdup 2x f@ f* ...
    (comp.lang.forth)
  • Re: approximation by series expansion
    ... The taylor expansion usually fails on one end of the intervall and when you ... Chebyshev approximation is realy quite good. ... I have a formula for the coefficients: ...
    (sci.math)
  • A small numerical error of A. Einstein
    ... I seem to have discovered a small numerical error in Einstein's ... and then to approximate the coefficients: ... coefficient, -0.186, representing the slope of a linear approximation. ...
    (sci.physics.research)
  • Re: erf function in C
    ... > probability) as part of their math libraries? ... * guarantee the error is less than one ulp for erf. ... we use rational approximation to approximate ... * Coefficients for approximation to erf in ...
    (comp.lang.c)