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De-convoluted Image Of Tempel 1
ugordan
post Dec 2 2005, 08:32 AM
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QUOTE (Airbag @ Dec 2 2005, 04:02 AM)
Note that deconvolution only really works if you know the specifics of the original convolution process, e.g. the spherical abberation of the HST's main mirror. If you just apply some random deconvolution until you start seeing things, you probably just are.
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That was precisely what I was trying to get at. To prove to Harry once and for all that the details he brings out of the images are processing artifacts, nothing else.

JRehling, you're absolutely right, your approach would be much simpler to do than what I proposed. So simple in fact that it makes me wonder why I haven't thought of it before smile.gif


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Toma B
post Dec 2 2005, 09:26 AM
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QUOTE (Airbag @ Dec 2 2005, 06:02 AM)
Note that deconvolution only really works if you know the specifics of the original convolution process, e.g. the spherical abberation of the HST's main mirror. If you just apply some random deconvolution until you start seeing things, you probably just are.
*


In other words there is NO DECONVOLUTION...It's just what's in Adobe Photoshop called Brightness/Contarast/Sharpen etc...
Sorry Harry that's just not it...
Nice little pictures thou... smile.gif


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Harry
post Dec 2 2005, 10:29 AM
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QUOTE (Airbag @ Dec 2 2005, 03:02 AM)
No, that is not the same at all - you can't create information when it is not there to begin with.

Deconvolution works when trying to correct an image that has undergone convolution, e.g. because of the effects of diffraction limited optics. Deconvolution will then attempt the reverse mathematical process to "undo" the original convolution. Of course, in all image processing operations, some information is lost - it is just a matter of what kind of information you want to optimise at the expense of others.

Note that deconvolution only really works if you know the specifics of the original convolution process, e.g. the spherical abberation of the HST's main mirror. If you just apply some random deconvolution until you start seeing things, you probably just are.

Airbag
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Honestly saying, I'm not sure whether the blurry appeared on the image was owing to the reprocessing or the optical system on HST.

As the reference, I attached again the previous images (their colors have been changed) and the image of Io taken by Galileo probe.
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ugordan
post Dec 2 2005, 10:37 AM
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QUOTE (Harry @ Dec 2 2005, 11:29 AM)
Honestly saying, I'm not sure whether the blurry appeared on the image was owing to the reprocessing or the optical system on HST.
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Those images of the four Galilean satellites were taken some time before Galileo arrival, IIRC, and *after* the optics on the HST have been fixed. It's simply because the resolution of the satellites isn't all that great and the images were *magnified*, hence the blurry look. No optics issues.


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tedstryk
post Dec 2 2005, 02:16 PM
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QUOTE (Airbag @ Dec 2 2005, 03:02 AM)
No, that is not the same at all - you can't create information when it is not there to begin with.

Deconvolution works when trying to correct an image that has undergone convolution, e.g. because of the effects of diffraction limited optics. Deconvolution will then attempt the reverse mathematical process to "undo" the original convolution. Of course, in all image processing operations, some information is lost - it is just a matter of what kind of information you want to optimise at the expense of others.

Note that deconvolution only really works if you know the specifics of the original convolution process, e.g. the spherical abberation of the HST's main mirror. If you just apply some random deconvolution until you start seeing things, you probably just are.

Airbag
*

Well, in the case of HRI on Deep Impact, where it is a matter of simply being out of focus (as opposed to spherical aberation on HST, where some light is brought to a focus, while other light is out of focus to varying degrees). Is that if you have some point source images, you can figure out the point spread, which will allow you to proceed. But as for pulling sub pixel information out of single images, it simply can't be done - you can't create information that is not in the image.

Super-resolution is somewhat effective because it utilizes multiple images, taking advantage of the fact that their pixels don't overlap exactly (if they do, it doesn't work).


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tedstryk
post Dec 2 2005, 02:18 PM
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Harry, Ugordan is right. That image of Io is not blurry. It is just greatly enlarged.


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Harry
post Dec 3 2005, 10:53 AM
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As you all imagine, it's indeed hard task to find any blurred images which are not reprocessed among published astronomical photos, for any blurred images are reprocessed, or simply are not published.

The following images are for Vesta taken by HST and its de-convoluted image processed by Focus Corrector (focus depth:=4, iterations:=9).
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deglr6328
post Dec 3 2005, 07:01 PM
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But that Vesta image IS processed. If it werent it would look like this or simillar.
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tedstryk
post Dec 3 2005, 07:50 PM
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QUOTE (Harry @ Dec 3 2005, 10:53 AM)
As you all imagine, it's indeed hard task to find any blurred images which are not reprocessed among published astronomical photos, for any blurred images are reprocessed, or simply are not published.

The following images are for Vesta taken by HST and its de-convoluted image processed by Focus Corrector (focus depth:=4, iterations:=9).
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In the case of most missions, they are imaging targets that are at an infinity focus, and their focus doesn't change. Real blurring is from vibrations and motion smear. And that Vesta image is enlarged.


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Harry
post Dec 4 2005, 01:12 PM
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QUOTE (deglr6328 @ Dec 3 2005, 07:01 PM)
But that Vesta image IS processed. If it werent it would look like this or simillar.
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Oh, is it a moon or asteroid? I tried to de-convolute that image with Focus Corrector. In the following figures the left side is the picture you've posted (with downscaling to 1/2) and the right side is its de-convoluted image.
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Harry
post Dec 4 2005, 01:44 PM
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And I applied median filter to the image you've posted. The following pictures are the image after applying median filter (left) and its de-convoluted image processed by Focus Corrector (right).
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Harry
post Dec 5 2005, 10:04 AM
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The image of Vesta taken by HST (left) and its de-convoluted image (right) processed by Focus Corrector (focus depth:=4, iterations:=9)
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Harry
post Dec 6 2005, 01:30 PM
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The image of Vesta taken by HST (left) and its de-convoluted image (right) processed by Focus Corrector (focus depth:=4, iterations:=9)
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Rob Pinnegar
post Dec 6 2005, 01:38 PM
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Those are some nice pictures, Harry. Deconvolution is a bit of a tricky process --we also use it in geophysics, so I know a bit about it -- but if done right it can produce good results.

By the way, although the process is called "deconvolution", when it has been applied to an image we say that the image has been "deconvolved" rather than "de-convoluted". That's just a bit of jargon. It does sometimes confuse people.
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Harry
post Dec 7 2005, 01:57 PM
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QUOTE (Rob Pinnegar @ Dec 6 2005, 01:38 PM)
Those are some nice pictures, Harry. Deconvolution is a bit of a tricky process  --we also use it in geophysics, so I know a bit about it -- but if done right it can produce good results.

By the way, although the process is called "deconvolution", when it has been applied to an image we say that the image has been "deconvolved" rather than "de-convoluted". That's just a bit of jargon. It does sometimes confuse people.
*

Thank you. In a discussion I heard some person used "deconvolve" but other person used "deconvolute". In the field of geophysics, the verb "deconvolve" is commonly used?

The following images are for Vesta taken by HST (left) and its "deconvolved" image (right) processed by Focus Corrector (focus depth:=4, iterations:=9)
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