Refocus an image digitally

Discussion in 'Digital Photography' started by wayne, Jan 9, 2006.

  1. wayne

    wayne Guest

    Hi All,

    Below is the link to my take on the latest research on being able to
    refocus images digitally:
    <http://www.dimagemaker.com/article.php?articleID=400>

    Cheers,

    Wayne

    Wayne J. Cosshall
    Publisher, The Digital ImageMaker, http://www.dimagemaker.com/
    Assistant Director, International Digital Art Award
    Writer and educator in graphic design, photography, digital technology
    Personal art site http://www.artinyourface.com/
     
    wayne, Jan 9, 2006
    #1
    1. Advertising

  2. wayne

    Marvin Guest

    wayne wrote:
    > Hi All,
    >
    > Below is the link to my take on the latest research on being able to
    > refocus images digitally:
    > <http://www.dimagemaker.com/article.php?articleID=400>
    >
    > Cheers,
    >
    > Wayne
    >
    > Wayne J. Cosshall
    > Publisher, The Digital ImageMaker, http://www.dimagemaker.com/
    > Assistant Director, International Digital Art Award
    > Writer and educator in graphic design, photography, digital technology
    > Personal art site http://www.artinyourface.com/
    >
    >

    It isn't a brand new idea, but it may be that the Stanford group has done a better job of
    it. The name for the method is "deconvolution". A Google search for pages with both
    words, deconvolution and photo, gave 82,100 hits.
     
    Marvin, Jan 9, 2006
    #2
    1. Advertising

  3. wayne

    Rich Guest

    On Mon, 09 Jan 2006 12:16:02 -0500, Marvin <>
    wrote:

    >wayne wrote:
    >> Hi All,
    >>
    >> Below is the link to my take on the latest research on being able to
    >> refocus images digitally:
    >> <http://www.dimagemaker.com/article.php?articleID=400>
    >>
    >> Cheers,
    >>
    >> Wayne
    >>
    >> Wayne J. Cosshall
    >> Publisher, The Digital ImageMaker, http://www.dimagemaker.com/
    >> Assistant Director, International Digital Art Award
    >> Writer and educator in graphic design, photography, digital technology
    >> Personal art site http://www.artinyourface.com/
    >>
    >>

    >It isn't a brand new idea, but it may be that the Stanford group has done a better job of
    >it. The name for the method is "deconvolution". A Google search for pages with both
    >words, deconvolution and photo, gave 82,100 hits.


    There are some image processing programs that do this such as Maxim DL
    and they did it when the Hubble telescope first went up because of the
    spherical aberration it suffered from.
    http://www.cyanogen.com/products/maxim_main.htm

    Part of the manual:

    Deconvolution

    Maximum Entropy and Lucy-Richardson Deconvolution are advanced image
    restoration algorithms that can remove the effects of blurring in an
    image. These algorithms, first pioneered for radio astronomy, became
    very important for visible-light astronomers when the problems with
    the Hubble Space Telescope were discovered.

    Outside of astronomical applications, the same image technique can be
    applied to just about any image, from microscope pictures to security
    camera video frames. The only essential requirement is that the image
    be blurry! Note that images taken with very short focal length cameras
    may have limited resolution, yet they may have too few pixels to
    properly sample the blur that is in the image. If the pixels in the
    camera do not resolve the blur, then no image processing algorithm can
    improve the resolution; deconvolution will not improve the image.

    Two things are required for deconvolution to work. The first is a
    model of the blur, known as the Point-Spread Function (PSF). The PSF
    tells the deconvolution algorithm how the image was blurred; it is
    essentially an image of a perfect point source taken with the same
    camera. For astronomical images, it is often easy to determine the
    point-spread functions since every single star image represents the
    PSF. For other types of images, it may be necessary to guess at a
    model; MaxIm DL includes features that help you choose the best model.

    The second piece of information required is some information on the
    noise level and the average background level in the image. MaxIm DL
    has to know how hard to work at deconvolving each pixel; it uses a
    noise model and knowledge of the background level to do this.
     
    Rich, Jan 9, 2006
    #3
  4. wayne

    wayne Guest

    Yup, it is not a new technique. I think the original work was done back
    in the 1930's. The Sanford team's take on adding the filter before the
    CCD is an interesting one.

    Cheers,

    Wayne

    Wayne J. Cosshall
    Publisher, The Digital ImageMaker, http://www.dimagemaker.com/
    Assistant Director, International Digital Art Award
    Writer and educator in graphic design, photography, digital technology
    Personal art site http://www.artinyourface.com/

    Rich wrote:
    > On Mon, 09 Jan 2006 12:16:02 -0500, Marvin <>
    > wrote:
    >
    > >wayne wrote:
    > >> Hi All,
    > >>
    > >> Below is the link to my take on the latest research on being able to
    > >> refocus images digitally:
    > >> <http://www.dimagemaker.com/article.php?articleID=400>
    > >>
    > >> Cheers,
    > >>
    > >> Wayne
    > >>
    > >> Wayne J. Cosshall
    > >> Publisher, The Digital ImageMaker, http://www.dimagemaker.com/
    > >> Assistant Director, International Digital Art Award
    > >> Writer and educator in graphic design, photography, digital technology
    > >> Personal art site http://www.artinyourface.com/
    > >>
    > >>

    > >It isn't a brand new idea, but it may be that the Stanford group has done a better job of
    > >it. The name for the method is "deconvolution". A Google search for pages with both
    > >words, deconvolution and photo, gave 82,100 hits.

    >
    > There are some image processing programs that do this such as Maxim DL
    > and they did it when the Hubble telescope first went up because of the
    > spherical aberration it suffered from.
    > http://www.cyanogen.com/products/maxim_main.htm
    >
    > Part of the manual:
    >
    > Deconvolution
    >
    > Maximum Entropy and Lucy-Richardson Deconvolution are advanced image
    > restoration algorithms that can remove the effects of blurring in an
    > image. These algorithms, first pioneered for radio astronomy, became
    > very important for visible-light astronomers when the problems with
    > the Hubble Space Telescope were discovered.
    >
    > Outside of astronomical applications, the same image technique can be
    > applied to just about any image, from microscope pictures to security
    > camera video frames. The only essential requirement is that the image
    > be blurry! Note that images taken with very short focal length cameras
    > may have limited resolution, yet they may have too few pixels to
    > properly sample the blur that is in the image. If the pixels in the
    > camera do not resolve the blur, then no image processing algorithm can
    > improve the resolution; deconvolution will not improve the image.
    >
    > Two things are required for deconvolution to work. The first is a
    > model of the blur, known as the Point-Spread Function (PSF). The PSF
    > tells the deconvolution algorithm how the image was blurred; it is
    > essentially an image of a perfect point source taken with the same
    > camera. For astronomical images, it is often easy to determine the
    > point-spread functions since every single star image represents the
    > PSF. For other types of images, it may be necessary to guess at a
    > model; MaxIm DL includes features that help you choose the best model.
    >
    > The second piece of information required is some information on the
    > noise level and the average background level in the image. MaxIm DL
    > has to know how hard to work at deconvolving each pixel; it uses a
    > noise model and knowledge of the background level to do this.
     
    wayne, Jan 10, 2006
    #4
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Holmespundit
    Replies:
    0
    Views:
    430
    Holmespundit
    Sep 8, 2004
  2. Harry Liston

    filtering digitally

    Harry Liston, Aug 22, 2003, in forum: Digital Photography
    Replies:
    3
    Views:
    320
    Graham
    Aug 27, 2003
  3. MB

    A Day Out - digitally

    MB, Dec 25, 2003, in forum: Digital Photography
    Replies:
    0
    Views:
    345
  4. Maurice Blanchard

    Late to Digital, Leica Slow to Refocus

    Maurice Blanchard, Sep 23, 2008, in forum: Digital Photography
    Replies:
    3
    Views:
    307
    dj_nme
    Sep 24, 2008
  5. hbird

    Software to refocus pihotos

    hbird, Jun 22, 2011, in forum: Digital Photography
    Replies:
    10
    Views:
    1,020
    John Turco
    Jul 15, 2011
Loading...

Share This Page