Deconvolution software, any practical value?

Discussion in 'Digital Photography' started by Rich, Mar 6, 2006.

  1. Rich

    Rich Guest

    Would this kind of thing have any practical applications with
    everyday digital images? They seem to use it in more than a few
    scientific applications. Some of these packages cost $10,000 or more
    so I'm wondering what it can do beyond what current
    consumer/photographer image enhancement technologies (i.e, functions
    built into Photoshop, etc) we use?
    Here's one of the companies that offer it:

    http://www.vaytek.com/MicroTomeWin.html
    Rich, Mar 6, 2006
    #1
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  2. Rich

    tlianza Guest

    Hi to all,

    Deconvolution software is a numerical operation which applys a filter
    designed to remove the effect of a convolution. When we photograph an
    image, the scene is convolved with the point spread function of the lens in
    the camera, and the sensor. This convolution basically blurs the image a
    bit. If we had a perfect measure of those two functions, they can be
    removed , by deconvolution, and the image would appear to be sharper. This
    operation is limited by noise, and , if the sensor is solid state, sampling
    of the image by the sensor.

    The sharpening algorithms used in photoshop (with the exception of unsharp
    masking) are a form of deconvolution, but with an arbitrary estimate of the
    blurring function. Unsharp masking is an image dependant operation, while
    the deconvolution operations are independent of image data.

    Deconvolution routinely occurs in high end point and shoot cameras as well
    as in some D-SLRs. The manufacturer has knowledge of the lens and detector
    MTF response and they can perform an appropriate inverse filter. When
    properly done, in-camera sharpening can be quite effective in removing the
    effects of lens and sensor blurring. Unfortunately, as I mentioned before,
    this operation is often limited by sensor noise. For this reason, it
    sometimes better to do no correction until the final "size" of the image has
    been arrived at by all the editing functions. I generally shoot with a
    small amount of in camera sharpening turned on when I am at low ISO ratings.
    At low light levels, I turn this off and do sharpening operations after the
    image has been sized for output.

    We also use deconvolution algorithms in our spectral measurement devices
    like the i1Pro spectro photometer.

    The deconvolution algorithm is almost identical to what you would do for an
    image.

    It's actually quite routine in all of our digital photo work.

    Take care,
    Tom L.
    --
    Tom Lianza
    Director of Display and Capture Technologies
    GretagMacbeth LLC
    3 Industrial Drive
    Unit 7&8
    Windham, NH 03087
    603.681.0315 x232 Tel
    603.681.0316 Fax


    "Rich" <> wrote in message
    news:...
    > Would this kind of thing have any practical applications with
    > everyday digital images? They seem to use it in more than a few
    > scientific applications. Some of these packages cost $10,000 or more
    > so I'm wondering what it can do beyond what current
    > consumer/photographer image enhancement technologies (i.e, functions
    > built into Photoshop, etc) we use?
    > Here's one of the companies that offer it:
    >
    > http://www.vaytek.com/MicroTomeWin.html
    tlianza, Mar 6, 2006
    #2
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  3. Rich

    Jac Guest

    tlianza <> wrote:
    : Hi to all,
    :
    : Deconvolution software is a numerical operation which applys a
    : filter designed to remove the effect of a convolution. When we
    <snip rest of post>

    That was just an excellent, excellent post! Thank you **very** much, Tom.
    :)

    j.
    Jac, Mar 6, 2006
    #3
  4. Keep in mind that there is deconvolution, where you have measured your
    blur function, and blind deconvolution, where you haven't or couldn't.
    Applying a pseudo-inverse filter (an approximation of the Wiener
    filter) is fast and effective for deconvolution. The expensive
    packages, however, use the Richardson-Lucy method, but I believe this
    is too time-consuming for most people. As far as I can see, we are the
    only ones offering an easy pseudo-inverse.
    Now I think you are talking about blind deconvolution. Most popular is
    MatLab with the image processing toolkit. Matlab is very powerful if
    you are willing to learn it. We tried to gear our software towards
    those who do not want to make a big commitment. And I may be biased,
    but I believe our blind deconvolution method works better than theirs.
    The program is 'free-to-try' and has several walk-through demos.

    Best Regards,
    Jim C
    JimAtQuarktet, Mar 6, 2006
    #4
  5. Rich

    Annika1980 Guest

    >Deconvolution software is a numerical operation which applys a filter
    >designed to remove the effect of a convolution.


    How does this differ from the DxO software?
    Annika1980, Mar 6, 2006
    #5
  6. Rich

    Tom2000 Guest

    On Mon, 6 Mar 2006 07:32:59 -0500, "tlianza" <>
    wrote:

    >Hi to all,
    >
    >Deconvolution software is a numerical operation which applys a filter
    >designed to remove the effect of a convolution. When we photograph an
    >image, the scene is convolved with the point spread function of the lens in
    >the camera, and the sensor. This convolution basically blurs the image a
    >bit. If we had a perfect measure of those two functions, they can be
    >removed , by deconvolution, and the image would appear to be sharper. This
    >operation is limited by noise, and , if the sensor is solid state, sampling
    >of the image by the sensor.
    >


    Tom, you just confirmed something I've suspected for a long time.

    I was listening to a space mission on NASA TV a few years ago. The
    controller asked the astronaut for the serial number of the lens they
    used for a particular series of photos. Right then, I figured that
    NASA had characterized all the lenses used on that particular mission,
    and were able to correct, in post processing, for a particular lens's
    aberrations.

    Imaging Resource's PMA video interview with DXO further confirmed my
    suspicions. In fact, it sounds like DXO has taken this principal to
    extremes.

    Thanks!

    (another) Tom
    Tom2000, Mar 6, 2006
    #6
  7. > We tried to gear our software towards
    > those who do not want to make a big commitment. And I may be biased,
    > but I believe our blind deconvolution method works better than theirs.
    > The program is 'free-to-try' and has several walk-through demos.
    >
    > Best Regards,
    > Jim C


    I am assuming that you are referring to "Tria." If so, I'd like to report
    that I can't get it to do anything useful ... the program seems very buggy
    and turns my computer into a snail. If you were referring to another
    program, please correct me. Thanks.
    Charles Schuler, Mar 7, 2006
    #7
  8. Annika1980 wrote:
    >>> Deconvolution software is a numerical operation which applys a
    >>> filter designed to remove the effect of a convolution.

    >>
    >> How does this differ from the DxO software?


    DxO have projections for specific lens designs. The software under
    discussion takes the process a little further into the unknown by working
    without lens specific data. One of the reasons DxO works is that Canon and
    Nikon keep pumping out lenses which create faulty images.

    The part which facinates me is if the faults of Canon "L" series lenses or
    Nikon lenses are so predictable, how come the makers haven't fixed them and
    introduced a new model designation costing twice as much? Interesting thing
    too is that the only Leica lens DxO cater to is plastic element "vario" on
    Panasonic cameras. No Ziess modules either.
    Tropical Treat, Mar 7, 2006
    #8
  9. Rich

    HvdV Guest

    Rich wrote:
    > Would this kind of thing have any practical applications with
    > everyday digital images? They seem to use it in more than a few
    > scientific applications. Some of these packages cost $10,000 or more
    > so I'm wondering what it can do beyond what current
    > consumer/photographer image enhancement technologies (i.e, functions
    > built into Photoshop, etc) we use?

    There is one vast difference between deconvolution sw for photographic
    pictures and the $10,000 scientific package for microscopy you mention: that
    and other scientific packages are intended to recover as reliable as possible
    3D objects from image data, which is something different than 'beautifying' a
    2D image. For example, all blur has to be removed from the image so that
    after processing each image plane only contains the objects which are in it.
    In other cases objects have to be recovered from noisy 10 photon/pixel data
    sets, or images are so large (> 10Gpix) that the software needs to be capable
    of running efficiently on large computers. To develop all that including the
    necessary support level makes for expensive software.

    -- Hans
    HvdV, Mar 7, 2006
    #9
  10. Rich

    Guest

    Speaking of examples, there is an interesting page here:

    http://www.bialith.com/Research/BARclockblur.htm

    Check out what he allegedly got from the blurred clock image....
    Interestingly, he states:

    "images shown here are half actual size and jpeg compressed (as such
    they cannot be downloaded for attempted repeat of these results)"

    Hmmmmm. And there are no other examples. Puzzling. (I can't help
    wondering what an averaged version of all those attempts would look
    like, but I can't be bothered..) In some ways, these images
    demonstrate my point - s/he gets some fascinating, almost unbelievable
    results, but look at all the artefacts..
    , Mar 7, 2006
    #10
  11. Rich

    bugbear Guest

    Tom2000 wrote:
    >
    > Tom, you just confirmed something I've suspected for a long time.
    >
    > I was listening to a space mission on NASA TV a few years ago. The
    > controller asked the astronaut for the serial number of the lens they
    > used for a particular series of photos. Right then, I figured that
    > NASA had characterized all the lenses used on that particular mission,
    > and were able to correct, in post processing, for a particular lens's
    > aberrations.


    One would want well characterized lenses anyway, for other purposes,
    esp photgrammetry.

    Knowledge of the lens means you know more about, and can make
    better use of, the data captured by that lens.

    BugBear
    bugbear, Mar 7, 2006
    #11
  12. Rich

    Martin Brown Guest

    wrote:

    > Speaking of examples, there is an interesting page here:
    >
    > http://www.bialith.com/Research/BARclockblur.htm
    >
    > Check out what he allegedly got from the blurred clock image....
    > Interestingly, he states:
    >
    > "images shown here are half actual size and jpeg compressed (as such
    > they cannot be downloaded for attempted repeat of these results)"


    In fairness to that web page the examples look roughly in line with what
    should be possible for a well characterised point spread function.

    Seems odd that they don't make the original image and psf available. It
    would not be difficult to confirm the Memsys results or the
    Lucy-Richardson (and they look about right). Weiner is seldom offered
    these days because of its tendency to ring excessively on sharp edges.

    The Gull&Daniel paper in Nature (1978) uses a much older algorithm but
    still shows the power of the method in action for scientific imaging.

    >
    > Hmmmmm. And there are no other examples. Puzzling. (I can't help
    > wondering what an averaged version of all those attempts would look
    > like, but I can't be bothered..) In some ways, these images
    > demonstrate my point - s/he gets some fascinating, almost unbelievable
    > results, but look at all the artefacts..


    The price you pay for the extra resolution are some new artefacts that
    were not in the conventional image. There is no free lunch.

    However, sometimes it is more important to detect and locate fine detail
    precisely than to have a cosmetically pleasing image.

    Regards,
    Martin Brown
    Martin Brown, Mar 7, 2006
    #12
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