Archived from groups: rec.photo.digital (
More info?)
Des wrote:
> My camera takes photos in normal resolution but claims to be able to take
> finer photos at a higher pixel-rate through "digital interpolation".
> Surely that's just stretching the image and not worth doing?
> Can't I improve the image to the same degree later using filters in Corel
> Photopaint?
>
> Is there any real advantage in terms of image quality between an image
> that's been digitally interpolated to a higher resolution?
> It's no substitute for a higher resolution CCD in the camera is it?
>
> D.
You have asked what you might call a loaded question, if you haven't
noticed that already. From a technical point of view resolution is the
smallest object that your camera can detect. This is determined by the
number of pixels in the CCD of your camera (and the camera's optics).
Interpolation CANNOT improve resolution. The only way to improve
resolution is to have a CCD with more pixels. Some people will refer to
resolution in respects to how good a picture looks. Although this isn't
the technical definition of resolution it does get at the desired output
of high resolution (i.e. nicer pictures). This may or maynot be
improved with interpolation, but this kind of "pseudo-resolution" is in
the eyes of the beholder.
What interpolation does is increase the size of the image beyond what
the CCD generates. The process which is used basically stretches out
the image and makes educated guesses as to the color of the new pixels
it creates. Although this creates a larger image, there is no more
detail in the larger image then in the original image. In some cases
interpolation may even decrease the overall results of the image due to
the "guesses" it makes when it expands the image. Not only that, but
interpolated images are larger, so you'll be able to take fewer pictures
if you interpolate.
As for what you should do in terms of taking pictures, my advice would
be to take the pictures at your cameras maximum resolution without
interpolation. This will let you get 100% of your camera's resolution,
without wasting any space on your card. If you want to interpolate or
otherwise alter your images afterwards you can do so with a graphics
program such as Paint Shop Pro or Photoshop. These graphics programs
have multiple other filters you can use, aside form interpolation, so
you'll be able to adjust your images to a greater extent on-computer
then you can on the camera.
Bryan