High resolution...through digital interpolation...

[Guest]

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Mxsmanic wrote:

> Bubbabob writes:
>
>>I suggest that you look into the field of deconvolution algorithms. Images
>>CAN be improved.
>
> No, they cannot.

Yes. They can. Typically on very high quality signal to noise data it is
possible to obtain about a factor of 3x increase in apparent resolution
on the brightest points using one of the regularised deconvolution
methods like Maximum Entropy. The critical requirement is that you must
know or be able to determine the blurring characteristics of the imaging
system exactly in order to use them. It helps if everything is in the
same focal plane - as is the case in astronomy where the techniques were
developed.

The question is posed in the form "what positive sky brightness
distribution when measured by this equipment would give data consistent
with the observations to within the measurement noise". It is routine in
radio astronomy and frequently used in optical when the instrumental
resolution is a limiting factor on the science.

It has been possible since about 1978 and is more or less routine now in
many fields of scientific endeavour. It is even within the capabilities
of most home PCs and packages are available for amateur astronomers...

>>NASA/HST do it every day. Not to mention the NRO and a few
>>other black ops.
>
> No, they don't. It's mathematically impossible, even for the spooks.

No it isn't. Knowing a priori that image brightness is always positive
is a tremendously powerful constraint on deconvolution algorithms.

There will be some artefacts in any deconvolved image but there is also
a better representation of what the target looks like as opposed to the
conventional image as recorded by the sensor. They worry a great deal
about validating these methods and cross checking - one such is:

http://www.stsci.edu/stsci/meetings/irw/proceedings/briggsd.dir/briggsd.html

Google: +deconvolution +superresolution +regularized
will get you more especially in ADS abstracts.

Regards,
Martin Brown

 

[Douglas]

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"Ron Hunter" <rphunter@charter.net> wrote in message
news:x7C4e.1390$iW5.771@fe04.lga...
> Sigh.
> Ok, let's start a firestorm here.
> IF you have taken a picture at, say 4mp, and the picture has a lot of
> sharp lines, some at angles to the horizon, then you CAN get a better
> looking picture if you interpolate to a larger size, but ONLY because the
> interpolation algorithm is able to insert pictures that are the same as
> what would have been captured by a higher resolution sensor. They aren't
> 'real', but they end up in the same place as a real one would be, so the
> difference is rather more theoretical than practical.
>
> That said, the utility of this kind of interpolation is limited, and will
> rarely give you noticeably better results than just processing the picture
> with Photoshop.
>
>
> --
> Ron Hunter rphunter@charter.net

All are you always so far off the mark Ron?
Just how do you think labs like www.fstoponline.com.au actually make 4 foot
wide photographs from 6 Mp files? Maybe they do it with mirrors? No? Then
maybe they do it with such poor quality, the clients of the few hundred
Professional Photographers who use their service are all blind? No... I
don't think that's the answer either. I know... They're Australians. Aussies
don't know soap from clay do they? Geez, you can sell them bloody Aussies
any line, eh? No you can't.

They, like hundreds of other labs around the world use software to
interpolate files as small as 3.5 MP and print them at 20"x30" every day
with such stunning detail as they started out with, not even you could tell
the prints were not just everyday photos from Medium Format film. Such is
the world of digital enlargements as development passes you by.

Don't go there Ron, you have no idea what your are talking about and until
you do, all you will manage is to make yourself look stupid.
http://users.tpg.com.au/hpc/examples2.htm

Douglas

 

[Guest]

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Confused wrote:
> On Wed, 06 Apr 2005 06:58:36 +0200
> In message <33r6511j3p48qth3penttsq5ctslfn9o0h@4ax.com>
> Mxsmanic <mxsmanic@hotmail.com> wrote:
>
>
>>Bubbabob writes:
>>
>>
>>>I suggest that you look into the field of deconvolution algorithms.
>>>Images CAN be improved.
>>
>>No, they cannot.
>>
>>
>>>NASA/HST do it every day. Not to mention the NRO and a few
>>>other black ops.
>>
>>No, they don't. It's mathematically impossible, even for the spooks.
>
>
> Point of order: He said...
>
> Images CAN be improved.
>
> ...which is true.
>
> How much improvement is possible? That is the question.
>
> Jeff
How much improvement depends mainly on the subject matter. If it is
mostly random shapes, such as trees, and grass, not a lot. Regular
shapes with sharp lines and edges, quite a bit.
The closer the interpolated pixels are to the reality of the scene, the
more apparent improvement there will be.


--
Ron Hunter rphunter@charter.net

 

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Douglas wrote:
> "Ron Hunter" <rphunter@charter.net> wrote in message
> news:x7C4e.1390$iW5.771@fe04.lga...
>
>>Sigh.
>>Ok, let's start a firestorm here.
>>IF you have taken a picture at, say 4mp, and the picture has a lot of
>>sharp lines, some at angles to the horizon, then you CAN get a better
>>looking picture if you interpolate to a larger size, but ONLY because the
>>interpolation algorithm is able to insert pictures that are the same as
>>what would have been captured by a higher resolution sensor. They aren't
>>'real', but they end up in the same place as a real one would be, so the
>>difference is rather more theoretical than practical.
>>
>>That said, the utility of this kind of interpolation is limited, and will
>>rarely give you noticeably better results than just processing the picture
>>with Photoshop.
>>
>>
>>--
>>Ron Hunter rphunter@charter.net
>
>
> All are you always so far off the mark Ron?
> Just how do you think labs like www.fstoponline.com.au actually make 4 foot
> wide photographs from 6 Mp files? Maybe they do it with mirrors? No? Then
> maybe they do it with such poor quality, the clients of the few hundred
> Professional Photographers who use their service are all blind? No... I
> don't think that's the answer either. I know... They're Australians. Aussies
> don't know soap from clay do they? Geez, you can sell them bloody Aussies
> any line, eh? No you can't.
>
> They, like hundreds of other labs around the world use software to
> interpolate files as small as 3.5 MP and print them at 20"x30" every day
> with such stunning detail as they started out with, not even you could tell
> the prints were not just everyday photos from Medium Format film. Such is
> the world of digital enlargements as development passes you by.
>
> Don't go there Ron, you have no idea what your are talking about and until
> you do, all you will manage is to make yourself look stupid.
> http://users.tpg.com.au/hpc/examples2.htm
>
> Douglas
>
>
I don't understand what you are arguing about. You said the same thing
I did, then you disagree with me? Maybe it is you who doesn't know what
he is talking about.

So who looks stupid now?


--
Ron Hunter rphunter@charter.net

 

[Guest]

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Ron Hunter wrote:
>
> Douglas wrote:

> > They, like hundreds of other labs around the world use software to
> > print them at 20"x30" every day

> > with such stunning detail as they started out with,

and there is the true answer.

what they started out with,
and nothing more.

to maintain visual sharpness,
the ratio of megapixels must increase proportional to the area,
or you must move back when you look at it.

I have done 90x90 from 5 mp.
looks great, and does what it was intended to do.

<http://www.vircen.com/rpd/index.cgi?mode=image&album=/72dpi&image=Animal%20Connection018.JPG>

but it was printed at 72dpi.


> > Douglas
> >
> >
> I don't understand what you are arguing about. You said the same thing
> I did, then you disagree with me? Maybe it is you who doesn't know what
> he is talking about.
>
> So who looks stupid now?
>
> --
> Ron Hunter rphunter@charter.net

 

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Don Stauffer wrote:
> Ron Hunter wrote:
>
>> Bubbabob wrote:
>>
>>> Mxsmanic <mxsmanic@hotmail.com> wrote:
>>>
>>>
>>>> You can't improve an image through any type of manipulation. You will
>>>> never have better quality than the image had when originally recorded.
>>>> Interpolation is the creation of an optical illusion; it does not
>>>> improve real image quality.
>>>>
>>>
>>>
>>> I suggest that you look into the field of deconvolution algorithms.
>>> Images CAN be improved. NASA/HST do it every day. Not to mention the
>>> NRO and a few other black ops.
>>
>>
>>
>> yes, and if you had their processing power in your camera, you could
>> probably do wonders too. Maybe NEXT year...
>>
>>
> Also, NASA and HST resolution improvement often hinges on having a good
> idea of what an object is, and optimizing algorithms that assume the
> shape of an object.
>
> This allows a powerful sharpening. BUT- one needs to be careful. If you
> use too much gain in these types of processes, even noise begins to look
> like the subject you assumed it was.
>
> An example. Lets say you are trying to improve a picture of a human
> face. You can determine what the spectral content (spatial spectrum,
> not temperal), and optimize algorithms for that spectral content.
> However, if you are not careful, this process can turn almost anything
> into something that looks like a human face.

Like the human brain does? Grin.


--
Ron Hunter rphunter@charter.net

 

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"Eric Gill" <ericvgill@yahoo.com> wrote:
> JPS@no.komm wrote in news:sl3651p1vbv6i6clo8fvumcunbd4s56sus@4ax.com:
>
> > In message <d2uuq1$894$1@news.ucalgary.ca>,
> > Bryan Heit <bjheit@nospamucalgary.ca> wrote:
> >
> >>Interpolation CANNOT improve resolution.
> >
> > Yes, but the Fuji 7000, when it outputs 6MP from its 6MP sensor *is*
> > interpolating, with loss. At 12MP, it is also interpolating, but with
> > *no* loss.
>
> I'm not sure how you would arrive at that conclusion.

The Fuji cameras have sensors that are rotated 45 degrees. What that means
is that they can't be read out at their native resolution without losing
information, and have to be read out at double resolution to retain all the
information captured. The resulting image is a 12MP image that has 6MP of
information.

> It's much bigger brother the S3, for example, produces very good 6mp
> images, but it's 12 mp images aren't on par with those from a true 8MP
> body:
>
> http://www.dpreview.com/reviews/fujifilms3pro/page21.asp

Exactly<g>. Fuji's idea that rotating the sensor increases resolution is, of
course, hogwash.

David J. Littleboy
Tokyo, Japan

 

[steve]

Archived from groups: rec.photo.digital (More info?)

David J. Littleboy wrote:


> The Fuji cameras have sensors that are rotated 45 degrees.

I don't see why this should automatically make a difference in the real world. I can
see that having the pixel array parallel to lines in the subject woud make sense,
such as a subject with lots of lines that are vertical and horizontal. OTOH, a
picture of a pyramid would seem to be perfectly suited to a sensor that is rotated.

I'll venture into areas on which I don't have all the details to touch on the OP's
question and other responses.

Anybody who has looked at a RAW image should be able to see that software
interpolation can vastly improve on the unprocessed image that was actually captured.
It's all (scientific) guesswork, but I think that any reasonable description of the
result will be that it results in "finer detail" in the finished image even if some
characterize it as artificial.

If the algorithm can adjust the existig pixels based on adjacent pixels to create the
processed image, there's no reason that new pixels can't be created with the same
method. The only real debate should be about how many new pixels can be created
before the unrealistic ones outnumber realistic ones enough to degrade the image. If
a sensor captured an image of fine black lines on a white background, where each
line was half the width of the pixel and the lines were perfectly parallel to the
array I expect the result could be that half of the pixels would be black and half
would be white. Or they could all be a uniform gray. To be interpolated (some people
may need to check to see that the definition isn't "guessing", BTW) as a series of
lines the algorithm would presumably have to have a built in bias to "look for" lines
or edges and the pixels certainly couldn't be a uniform gray. How would the resulting
image compare to the image of a field of dots that were all half the size of a pixel
and perfectly centered on each pixel in the array? I realize that's completely
unrealistic in the real world, but I'm guessing the resulting picture would be pretty
unrealistic.

The main point is that *all* processed images coming out of the camera are the result
of interpolation, so it is clearly capable of improvement over the unprocessed values
of individual pixels.

--
Steve

The above can be construed as personal opinion in the absence of a reasonable
belief that it was intended as a statement of fact.

If you want a reply to reach me, remove the SPAMTRAP from the address.

 

[Guest]

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In article <d2ugk2$psk$1@sparta.btinternet.com>,
"Des" <plinioREMOVEdesignori@btopenworld.com> 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?
>
Interpolation can be quite 'clever' or really dumb. It depends on how
much time someone has spent on getting things right. However the fact
remains - an 8mpxl camera will deliver a better image than a 6mpxl
camera interpolated to 12mpxl. But that 12mpxl image can look as good as
the 6mpxl and 12 megapixels will give more leeway when cropping and
correcting perspective if you're trying to print A3. Filters and
interpolation works in a similar way in PSP etc, but I feel the camera
will do it better.

The only way you can see if any advantage exists if a visual comparison
- it's like the Dolby noise reduction for noisy audio cassettes - some
people like it, other don't and if you, personally are satisfied with
the quality, then it IS the better way.

I'm sure the photo hacks working for print media will do 'anything' to
get that shot.

 

[Guest]

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Ron Hunter wrote:
>> An example. Lets say you are trying to improve a picture of a human
>> face. You can determine what the spectral content (spatial spectrum,
>> not temperal), and optimize algorithms for that spectral content.
>> However, if you are not careful, this process can turn almost anything
>> into something that looks like a human face.
>
>
> Like the human brain does? Grin.
>
>
Yep, I didn't want to say it, but since you did, I certainly agree. We
are wired that way- the algorithm is built into the old Mk 1 brain 🙂

 

[Guest]

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Ron Hunter <rphunter@charter.net> writes:

>> The 6 MP Fuji cameras are 6 MP cameras that happen to require the use of
>> a 12 MP output file to convert between diagonal and row/column image
>> form without loss of information.

>Rather like a scanner with 600dpi optical in the scan across the field,
>and 1200dpi in the long side as the stepper motor makes 1/1200" steps?
>Works for me.

Well, vaguely similar. The scanner in 1200 DPI mode is capturing
more *real* information in the vertical direction, although at low
contrast. The Fuji cameras capture no more nor less information than
other 6 MP cameras; they just maximize resolution in a different
direction.

Dave

 

[Des]

Archived from groups: rec.photo.digital (More info?)

"Des" <plinioREMOVEdesignori@btopenworld.com> wrote in message
news:d2ugk2$psk$1@sparta.btinternet.com...
> 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.

Thanks for all the postings on my initial enquiry; reading them has
confirmed me in my intentions to use the camera's normal resolution and do
the improvement later in Corel PhotoPaint.
Of course I can't add information where none has been recorded during the
initial exposure, but here's what I'd do once I had the image.
I'd load the image to Corel, and apply Noise/Remove Moiré, followed by
Remove Noise, then a couple of passes of 80% Adaptive Unsharp.
Then I'd turn my attention to the contrast/colour/brightness and tweak them
to increase the apparent clarity of the image. From there (if I wanted to go
further) I'd seek out features in the image that were capable of being
enhanced/straightened by applying straight-edged (or segments of the
circular shaped) masks, sampling the colours and making the edges crisp and
smooth.

I accept that I'm not `bringing out' extra information from the camera's
image; we've already established that's impossible.
It's possible to add more detail using information from the user's brain,
though, and to produce an image more representative of the subject than was
originally available through the camera alone.

Thank you folks!

Des.

 

[Guest]

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On Wed, 06 Apr 2005 10:09:33 -0500, Ron Hunter <rphunter@charter.net>
wrote:

>Confused wrote:
>
>> How much improvement is possible? That is the question.
>>
>How much improvement depends mainly on the subject matter. If it is
>mostly random shapes, such as trees, and grass, not a lot.

Disagree. These are excellent subjects for fractal representation.

> Regular
>shapes with sharp lines and edges, quite a bit.

The vector approach works well here, yes.

--
Owamanga!
http://www.pbase.com/owamanga

 

[Guest]

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Ron Hunter writes:

> And if you took a picture of something that was all vertical and
> horizontal lines?

I'm not interested in test charts.

> You could then interpolate to just about any level,
> and the picture would be an accurate representation of the original, and
> the same as from a camera with whatever resolution you could find.

Really? Try doing that with a picture of a picket fence.>

> This
> is a rather limited case, of course, but it does illustrate the point.
> IF the subject matter lends itself to interpolation, then much
> improvement, indistinguishable from 'real' can be had.
> So, what does your information theory have to say about that?

That there is no net increase in information.

--
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Owamanga <owamanga(not-this-bit)@hotmail.com> writes:

> This is a very narrow-minded view of the problem.

It's a harsh reality.

> Your motto: "They said it couldn't be done, so I didn't try".

It cannot be done, no matter how much one tries.

> If objects can be correctly identified by software, they can be
> re-rendered at any resolution.

Only if the software contains all the detail concerning the objects. In
other words, only if all the detail is already present (the fact that
the software contains it instead of the captured image doesn't alter the
constraints of information theory).

In practice, no software can do this outside of the most trivial test
cases.

> Image recognition can read the text, identify each
> letter, identify the font used and re-render it at 100 times the
> original, maintaining the angle, color balance and texture from the
> original.

Some fonts are so slightly different that they cannot be identified in
this way.

> Software
> development moves fast, and even though we may not have the magic
> 'enlarge' button in Photoshop yet, it *will* be there one day.

No, it won't.

What we will have is capture at higher resolutions instead.

This reminds me of a claim I heard from someone long ago who said that
the future would be shaped by ever-improving compression algorithms. In
fact, it has been shaped by ever-increasing bandwidth.

--
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On Wed, 06 Apr 2005 17:47:09 +0200, Mxsmanic <mxsmanic@hotmail.com>
wrote:


>> Your motto: "They said it couldn't be done, so I didn't try".
>
>It cannot be done, no matter how much one tries.

I seem to recall this was said about powered flight, too.

--
Bill Funk
Change "g" to "a"

 

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Don Stauffer writes:

> Also, NASA and HST resolution improvement often hinges on having a good
> idea of what an object is, and optimizing algorithms that assume the
> shape of an object.

But that's just another way of saying that they have additional image
data.

--
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On Wed, 06 Apr 2005 17:48:21 +0200, Mxsmanic <mxsmanic@hotmail.com>
wrote:

>Don Stauffer writes:
>
>> Also, NASA and HST resolution improvement often hinges on having a good
>> idea of what an object is, and optimizing algorithms that assume the
>> shape of an object.
>
>But that's just another way of saying that they have additional image
>data.

It's another way of saying NASA have an open minded approach to
problem solving.

--
Owamanga!
http://www.pbase.com/owamanga

 

[Guest]

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Ron Hunter writes:

> I have explained how it IS possible, and how it IS done.

You've overlooked the covert channel, as I've pointed out in a separate
post.

--
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[Guest]

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JPS@no.komm writes:

> Define "it".

Producing an image that contains more detail than was available in the
original capture.

> You're talking about increasing maximum sampling resolution; they're
> talking about restoring contrast lost to MTF and AA filters.

You cannot restore contrast, you can only simulate it.

--
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[Guest]

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Martin Brown writes:

> Yes. They can. Typically on very high quality signal to noise data it is
> possible to obtain about a factor of 3x increase in apparent resolution
> on the brightest points using one of the regularised deconvolution
> methods like Maximum Entropy.

Apparent resolution is not actual detail.

> The critical requirement is that you must
> know or be able to determine the blurring characteristics of the imaging
> system exactly in order to use them.

If you know enough to fully reconstruct missing detail in the image, you
don't need the image in the first place.

> No it isn't. Knowing a priori that image brightness is always positive
> is a tremendously powerful constraint on deconvolution algorithms.

Knowing anything in advance adds image information.

If that advance knowledge doesn't match the reality of the original
scene, though, the results can be hugely misleading.

--
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[Guest]

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JPS@no.komm wrote:
> In message <d2uuq1$894$1@news.ucalgary.ca>,
> Bryan Heit <bjheit@nospamucalgary.ca> wrote:
>
>
>>Interpolation CANNOT improve resolution.
>
>
> Yes, but the Fuji 7000, when it outputs 6MP from its 6MP sensor *is*
> interpolating, with loss. At 12MP, it is also interpolating, but with
> *no* loss.

This seems to be a specific issue with fuji cameras, whom for some
reason rotated their CCD which defies all logic when it comes to
imaging. The large majority of camera will not benefit from
interpolation because they are designed properly, and can read the full
CCD resolution without interpolation. I cannot think of a single reason
why fuji would do this, aside from some sort of rip-off marketing gimic.

I do a lot of imaging for scientific purposes (predominantly
microscopy), and we avoid any image interpolation due to it's tendency
to induce artifacts. I take this knowledge into my photography as I
know that the uninterpolated image I produce will be truer then an
interpolated image. Afterwards I can alter the image as I see fit -
interpolation, cropping, etc, but by not interpolating on the camera you
give yourself the maximal ability to alter your image as what you start
with is the raw, completely unprocessed image. Once interpolated it is
impossible to get back to the raw image.

Keep in mind that the raw image is the maximal amount of detail your
camera can capture - interpolation can produce a larger image with the
appearance of greater resolution, but in reality the image is no more
detailed (and possible less detailed) then the original image.

Bryan

 

[Guest]

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In message <q71851p1ohrtb9ehrq7q0c58go763lldrd@4ax.com>,
Mxsmanic <mxsmanic@hotmail.com> wrote:

>JPS@no.komm writes:

>> You're talking about increasing maximum sampling resolution; they're
>> talking about restoring contrast lost to MTF and AA filters.
>
>You cannot restore contrast, you can only simulate it.

If you know how much the pixel-to-pixel contrast is attenuated, you can
bring it back up again, albeit by increasing the capture artifacts as
well.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

 

[Guest]

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Mxsmanic wrote:

> Martin Brown writes:
>
>>Yes. They can. Typically on very high quality signal to noise data it is
>>possible to obtain about a factor of 3x increase in apparent resolution
>>on the brightest points using one of the regularised deconvolution
>>methods like Maximum Entropy.
>
> Apparent resolution is not actual detail.

Some of it is. You can know the positions and relative positions of
bright point sources much more accurately than to the nearest pixel even
with relatively crude deconvolution methods.

>>The critical requirement is that you must
>>know or be able to determine the blurring characteristics of the imaging
>>system exactly in order to use them.
>
> If you know enough to fully reconstruct missing detail in the image, you
> don't need the image in the first place.

Rubbish. You only need to know the point spread function. And the
positivity constraint - but there are still a lot of all positive images.
>
>>No it isn't. Knowing a priori that image brightness is always positive
>>is a tremendously powerful constraint on deconvolution algorithms.
>
> Knowing anything in advance adds image information.

No it adds additional information beyond the actual raw image. Namely:

The point spread function that the original target image was convolved
with to make the raw data.

And usually that there can be no regions of negative intensity in the
real world.

Taken together these provide the basis for genuine superresolution.
>
> If that advance knowledge doesn't match the reality of the original
> scene, though, the results can be hugely misleading.

The *fundamental* point that you are missing (perhaps by being
deliberately obtuse) is that there are never any negative brightness
regions in the real world. We sense things by light arriving at the
detector. This a priori knowledge provides the basis for most of the
enhanced resolution achieved by modern deconvolution codes and it is
very real from an information theoretic point of view.

Regions of frequency space where no data was measured can be
reconstructed reliably by imposing the positivity constraint. The answer
may not be perfect but it is a heck of a lot better than the raw image.

Regards,
Martin Brown

 

[Confused]

Archived from groups: rec.photo.digital (More info?)

On Wed, 06 Apr 2005 09:47:42 GMT
In message <2fO4e.1779$5F3.1443@news-server.bigpond.net.au>
Posted from BigPond Internet Services
"Douglas" <decipleofeos@hotmail.com> wrote:

> ...
> http://users.tpg.com.au/hpc/examples2.htm

"...harnessing the power of several powerful microprocessors."

Please, edumacate us. What programs and processors?

Jeff