Re: Convolution-based image interpolation

Michel Rouzic wrote:
Ron N. wrote:
Michel Rouzic wrote:
Ron N. wrote:
Michel Rouzic wrote:
chris_bore@xxxxxxxxxxx wrote:
Michel Rouzic wrote:
who would want to interpolate images by FIRs anyways?

It is quite common to interpolate images by FIRs. This is especially so
in digital video where natural images are concerned, as it may give the
most pleasing visual effect. It can also be very suitable where
interpolation by non-simple integer ratios is needed, as polyphase FIR
filters can be used and are often available as hardware blocks.

oh, I didn't know. my main problem with FIRs in what I want to do is
that it introduces ripples where I don't want any...

Why don't you want ripples? How do you know they don't belong
in the image?

by the way, I'm like a hungry shark only asking to be thrown pieces of
meat at, and all you people is doing is discussing why I would want
that. That's cool, but if you could also throw some names of suitable
bell-shaped functions for image interpolation, I'd appreciate that.

I'm sure that in the end I'll have explained you all why some method
won't work and why I want what i claim to want, but I'm not sure to
even be told the name of a single bell-shaped self-overlapping function
as it's really all I'm asking for.

Inverted Cosine. One cycle.

oh, wow, ok, sounds good. i'll give it a try, thanks alot.

Don't thank me. It won't do what you want. Try it on a ramp signal
( 0, 1, 2, 3, 4, 5, 6, 7 ) . Using a small bell-shaped kernel will
scallop your interpolation. A windowed-Sinc FIR will give you a
much smoother interpolation.


IMHO. YMMV.
--
rhn A.T nicholson d.0.t C-o-M

.

Relevant Pages

  • Re: Convolution-based image interpolation
    ... It is quite common to interpolate images by FIRs. ... interpolation by non-simple integer ratios is needed, ... even be told the name of a single bell-shaped self-overlapping function ...
    (comp.dsp)
  • Re: Convolution-based image interpolation
    ... It is quite common to interpolate images by FIRs. ... interpolation by non-simple integer ratios is needed, ... even be told the name of a single bell-shaped self-overlapping function ...
    (comp.dsp)
  • Re: Convolution-based image interpolation
    ... It is quite common to interpolate images by FIRs. ... interpolation by non-simple integer ratios is needed, ... even be told the name of a single bell-shaped self-overlapping function ...
    (comp.dsp)
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