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Reprocessing Historical Images - II, Restoring images from antiquated and/or poor quality sources
tedstryk
post Aug 29 2008, 03:34 PM
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I figure that it is time for another thread like this. I still find it astonishing to see the versions of a lot of images that are reproduced over and over again. For example, this is the last mosaic of Triton taken before the close encounter began. The version on the Planetary Photojournal is on the left, my version on the right. Clearly, this image was produced as part of the "instant science" campaign. They did a superb job getting images to the public in a speedy manner, but they are extremely rough, since the team was busy running the spacecraft. However, it is this version that keeps being recycled. Worse, the version on the photojournal is clearly scanned from a printed copy, causing further degradation.

Attached Image


Here is a similar comparison, this time using Proteus (still 1989N-1 on the Planetary Photojournal!).

Attached Image


This discussion started in the thread about Viking crescents but was getting off topic, so I thought I would start a new thread here.


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Stefan
post Aug 30 2008, 02:34 PM
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QUOTE (tedstryk @ Aug 29 2008, 05:34 PM) *
Here is a similar comparison, this time using Proteus (still 1989N-1 on the Planetary Photojournal!).


Ted, let me first say that I greatly enjoy and admire your work. But I wonder why sometimes it has a bit of a "painted" look (it's almost as if I see "brush strokes"). You can see it clearly in your Borrelly image (saw that one on Emily's blog), and also here on Proteus. Here I actually prefer the original Proteus image on the left, which I think is closer to what I would see with my own eyes. How do you achieve this effect, and are you convinced that all the detail on the right is "real"?

Love your Triton image!

Stefan.
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tedstryk
post Aug 31 2008, 10:56 PM
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QUOTE (Stefan @ Aug 30 2008, 02:34 PM) *
Ted, let me first say that I greatly enjoy and admire your work. But I wonder why sometimes it has a bit of a "painted" look (it's almost as if I see "brush strokes"). You can see it clearly in your Borrelly image (saw that one on Emily's blog), and also here on Proteus. Here I actually prefer the original Proteus image on the left, which I think is closer to what I would see with my own eyes. How do you achieve this effect, and are you convinced that all the detail on the right is "real"?

Love your Triton image!

Stefan.

The painted look is from severely underexposed raw data. As a result, high contrast detail is sharp, low contrast detail is not, and is sometimes lost entirely. I am on vacation, but I have a sequence of Proteus that I will post when I get home that shows the Protean features rotating, confirming that they are real. The version on the left hides the problem by blurring the image, but the high contrast fine detail is wiped out in the process.

In the case of Borrelly images (and also in the case of out of focus images), a similar problem is created by desmearing.

ElkGroveDan, I make these from the raw frames on the PDS. The "official" versions came from the Planetary Photojournal.


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chiron
post Sep 1 2008, 05:39 PM
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Hi Ted

I have to agree what Stefan says. I think the normal Images does not contain so much detail. Its easy to say it for Proteus, since there is only one image where this moon is bigger on an image than about 100-150 pixels. Its the frame number C1138920.

A simply Conversion of the PDS Data to the png format without any change is here:
http://www.bernd-leitenberger.de/download/C1138920.png

Proteous is very dark, nearly at the same level as the background, therefore you have much noise on the picture. The planetary photojourna made out of this noise structures and your pictures made much more details out of it - but i think they are not in the original image.

I think you should test your method and validate the results. You can do this by example, if you use the same method with an old viking or mariner 9 image and compare it with an image with better resolution by mex or you work on voyager iamge of the moons of saturn and compare with an cassini image. Without validation, that you really show hidden details and not create only new details from noise, the images are nice to watch but scientific worthless.
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Stefan
post Sep 1 2008, 08:38 PM
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QUOTE (chiron @ Sep 1 2008, 07:39 PM) *
Its the frame number C1138920.

Now, I have not worked with Voyager images, and unfortunately lack the time to dive into that. So I simply took that raw GIF image and carefully stretched it:

Attached Image


I also inspected the intensity profile across the moon and noticed that any "detail" on the left side of Proteus is of the same order as the noise in the adjacent dark space. Now I'm sure that careful dark current subtraction and flat fielding will extract more detail from this image, and I would be eager to see the intermediate results.

QUOTE (tedstryk @ Sep 1 2008, 08:57 PM) *
The detail is very consistent. I wasn't confident of it until I saw the features in the second closest set, which is a multi-frame sequence that I could stack to reduce noise.

The middle, stacked image looks perfectly natural, and I trust all detail to be real. The image on the right, however... from what I see in the raw image I suspect that most of the fine details on the left side of the moon are artifacts. Did you apply some sort of sharpening algorithm or (I hesitate to use the word) deconvolution?

Stefan.
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tedstryk
post Sep 1 2008, 09:28 PM
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If you notice, there aren't interpretable features on the left side except at the very top. There are tantalizing hints, but much less can be seen.

Tasp, it is pretty straightforward. When you process an underexposed image, when you deconvolve an out of focus image, or when you desmear an image, high contrast details are recovered but low contrast ones that are simply not in the data are lost. Hence, high contrast detail is sharp, and low contrast detail is lost. Add to that the fact that in some cases, particularly when you are dealing with an underexposed image, some lower contrast detail can be recovered by binning it 2x2 or even 4x4. However, binning costs spacial resolution. Hence, lower contrast details that are recovered appear amorphous when compared to the high contrast details. That is why the limb looks sharp, as does the area where the illumination angle makes for nice shadows. However, the features look amorphous on the left side because there are no high-contrast features (in other words, no shadows). That is what creates that brush-stroke like effect.


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tedstryk
post Sep 1 2008, 09:40 PM
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Here is an example of a mosaic that combines a lot of things. The lower part of the mosaic uses nice, sharp frames. The portions toward the terminator are from two smeared frames. The one on the left-hand side is severely smeared. The brush-strokey texture begins to emerge. The night side regions, being severely underexposed, are affected even more. This mosaic, especially the nightside coverage, was very well received at this year's LPSC.

Attached Image


This set, in some places a stack of four images although not all images cover the whole limb or to the top, 4x4 binning was required to bring out the unlit areas which, just like in the above case, were blended back into the image but look much blurrier (in this case, even the limb wasn't detectable without binning. Hence, it isn't sharp either.

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Here is a more distant view showing more territory.

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tedstryk
post Sep 1 2008, 10:14 PM
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More related to my original post, here is the Triton approach sequence I put together. The upper quarter or so of the last image is reprojected from earlier frames as it was clipped. Some of the sets are underexposed, which leads to some of the effects discussed earlier.

Attached Image


I am presently working on the receding views.

Here are some of them in progress.

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Also, here is an extract with an apparent crater in three of the images (lower arrow in the first image, only arrow in the other images). There is also a strange, spiral feature marked with the upper arrow in the first image.

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Also, here are some Saturnian shots.

Enceladus (best OGV shot)

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Highest resolution mosaic

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Dione - second highest resolution view (Voyager 1)

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Highest resolution mosaic.

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Voyager 2


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Tethys Voyager 1

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Voyager 2

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Posts in this topic
- tedstryk   Reprocessing Historical Images - II   Aug 29 2008, 03:34 PM
- - Decepticon   WOW! Love it. More!   Aug 30 2008, 01:17 AM
- - Juramike   Got any tips or tutorials with before and after pi...   Aug 30 2008, 02:21 AM
- - ElkGroveDan   I can't get enough of this kind of thing. Tha...   Aug 30 2008, 02:23 AM
- - CAP-Team   Wow that Proteus result is stunning! So much s...   Aug 30 2008, 07:16 AM
- - Stefan   QUOTE (tedstryk @ Aug 29 2008, 05:34 PM) ...   Aug 30 2008, 02:34 PM
|- - tedstryk   QUOTE (Stefan @ Aug 30 2008, 02:34 PM) Te...   Aug 31 2008, 10:56 PM
|- - chiron   Hi Ted I have to agree what Stefan says. I think ...   Sep 1 2008, 05:39 PM
|- - tedstryk   Here is an example of the sequence.. Chirin, th...   Sep 1 2008, 06:57 PM
|- - Stefan   QUOTE (chiron @ Sep 1 2008, 07:39 PM) Its...   Sep 1 2008, 08:38 PM
|- - tedstryk   If you notice, there aren't interpretable feat...   Sep 1 2008, 09:28 PM
|- - tedstryk   Here is an example of a mosaic that combines a lot...   Sep 1 2008, 09:40 PM
||- - tedstryk   More related to my original post, here is the Trit...   Sep 1 2008, 10:14 PM
||- - ugordan   Great work, Ted! I especially like the Triton ...   Sep 2 2008, 08:07 AM
||- - tedstryk   Thanks. I eventually hope to do more of the image...   Sep 2 2008, 09:51 AM
|- - Stefan   QUOTE (tedstryk @ Sep 1 2008, 11:28 PM) I...   Sep 2 2008, 09:53 AM
|- - tedstryk   It is there, and I have brightened it in this vers...   Sep 2 2008, 11:11 AM
- - tasp   Would another means of validating the image be to ...   Sep 1 2008, 07:37 PM
- - djellison   I would agree - Stefan, you're not reading wha...   Sep 2 2008, 11:27 AM
|- - tedstryk   This is another image that I find interesting. I ...   Sep 2 2008, 12:02 PM
|- - Stefan   This discussion is obviously going in the wrong di...   Sep 2 2008, 02:28 PM
|- - tedstryk   Stefan, I discussed this earlier in the thread, bu...   Sep 2 2008, 05:11 PM
- - Tayfun Öner   I must agree with Stefan's skepticism. Ted...   Sep 2 2008, 02:48 PM
- - Tayfun Öner   Ted, let's take your Proteus image as an examp...   Sep 2 2008, 06:10 PM
|- - tedstryk   Are you referring to the smallscale 'features...   Sep 2 2008, 06:21 PM
- - Tayfun Öner   Yes I am, I have no problem with the features that...   Sep 2 2008, 06:47 PM
|- - tedstryk   This is an alternate take in which I tried to wipe...   Sep 2 2008, 07:58 PM
|- - tedstryk   Here is my Borrelly image at its original size. T...   Sep 2 2008, 09:53 PM
- - 4th rock from the sun   Hi, Just my small contribution to this topic. Her...   Sep 2 2008, 10:08 PM
|- - tedstryk   QUOTE (4th rock from the sun @ Sep 2 2008, 10...   Sep 3 2008, 12:04 AM
|- - tedstryk   Here is my calibrated base. Keep in mind that in ...   Sep 3 2008, 01:05 AM
|- - tedstryk   Here is another image that is shown in a very odd ...   Sep 6 2008, 09:53 PM
- - elakdawalla   I think it's fascinating to see a comparison o...   Sep 2 2008, 10:29 PM
- - PDP8E   Emily, I'll give it a shot !! (and t...   Sep 2 2008, 10:46 PM
|- - tedstryk   QUOTE (PDP8E @ Sep 2 2008, 10:46 PM) Emil...   Sep 3 2008, 12:01 AM
- - elakdawalla   In the spirit of teaching a man to fish... Voyage...   Sep 2 2008, 11:18 PM
- - tasp   If this suggestion involves much work, my apologie...   Sep 7 2008, 01:15 AM
|- - tedstryk   The data issues with those are totally different. ...   Sep 7 2008, 02:34 AM
- - tasp   I have no way of knowing how much effort is involv...   Sep 7 2008, 03:37 PM
- - PDP8E   Well....it has been about 2 weeks...two weddings, ...   Sep 18 2008, 01:53 AM
|- - tedstryk   One thing that I wanted to emphasize. The thing th...   Sep 18 2008, 03:13 AM
- - jekbradbury   I decided to take a look at the Proteus image as w...   Sep 19 2008, 12:39 AM
- - 4th rock from the sun   Hi all, I wrote a small program in Actionscript 3...   Feb 3 2009, 06:13 PM
|- - tedstryk   That looks like a good result, but could you expla...   Feb 4 2009, 02:46 AM
|- - 4th rock from the sun   "I am assuming this is used to reduce the ...   Feb 4 2009, 11:13 AM
|- - ugordan   QUOTE (4th rock from the sun @ Feb 4 2009, 12...   Feb 4 2009, 11:48 AM
|- - tedstryk   I have completed the Mariner-7 Meridiani mosaic. ...   Feb 17 2009, 09:53 PM
- - dvandorn   Ted -- is it true that Endeavour Crater is resolve...   Feb 18 2009, 01:37 AM
|- - mhoward   I can see a slight darkening where Endeavour is, I...   Feb 18 2009, 01:51 AM
|- - tedstryk   Yes, it is a barely detectable smudge. However, w...   Feb 18 2009, 02:36 AM
- - Phil Stooke   Yes, the trio of craters, with Endeavour at the no...   Feb 18 2009, 07:58 PM
|- - tedstryk   Yes, it does, especially in color. The image on t...   Feb 18 2009, 09:29 PM
- - vk3ukf   Hi, thanks for these pics, love them. I had to ha...   May 23 2009, 11:16 PM
|- - tedstryk   What did you use as your data source?   May 24 2009, 02:45 AM
- - vk3ukf   The sources were all from the net from various pla...   May 24 2009, 09:35 AM
|- - tedstryk   I think they come from http://nssdc.gsfc.nasa.gov/...   May 24 2009, 12:17 PM
- - vk3ukf   Yes, that's the d version alright, the h versi...   May 24 2009, 12:36 PM
- - peter59   Picture #1 Image source: NSSDC - 35 mm microfilm...   May 24 2009, 03:56 PM
- - vk3ukf   Hi Peter59, nice images. A 35mm film archive. Ca...   May 27 2009, 06:42 PM
- - jasedm   Not strictly reprocessing, more updating... I rece...   Jun 30 2009, 08:12 PM
- - Stu   QUOTE (jasedm @ Jun 30 2009, 09:12 PM) .....   Jun 30 2009, 10:03 PM
- - lyford   Very cool!   Jul 1 2009, 12:58 AM
|- - tedstryk   I've been fooling around with some really conv...   Aug 13 2009, 05:22 PM
|- - Stu   QUOTE (tedstryk @ Aug 13 2009, 06:22 PM) ...   Aug 13 2009, 05:41 PM
- - Phil Stooke   Fantastic, as usual, Ted. The Tempel 1 departure ...   Aug 13 2009, 06:59 PM
|- - tedstryk   I would have to look more carefully...I am tempted...   Aug 13 2009, 10:07 PM
- - Stu   He'll be far too modest to plug it himself, so...   Sep 10 2009, 09:17 PM
|- - tedstryk   I have added some updated versions of Galileo...   Sep 12 2009, 03:34 AM
- - machi   Hello I send some mosaics from Mariner 9. And so i...   Nov 8 2009, 08:04 PM
|- - 4th rock from the sun   Nice Mariner 9 images, really smooth. Good work.   Nov 9 2009, 10:34 AM
|- - tedstryk   Nice work!   Nov 9 2009, 05:02 PM
- - machi   Thanks! Now for something completely differen...   Nov 10 2009, 08:30 PM
|- - ugordan   QUOTE (machi @ Nov 10 2009, 09:30 PM) Now...   Nov 11 2009, 11:54 AM
- - cbcnasa   Machi very excellent work   Nov 11 2009, 12:32 AM
- - machi   Global mosaic from Mariner 9. Recent work.   Nov 11 2009, 11:14 AM
- - machi   I send one original image from Mariner 9 (mosaic i...   Nov 11 2009, 01:02 PM
- - ElkGroveDan   What is your source for the raw data? The one abo...   Nov 11 2009, 02:09 PM
- - machi   My personal archive is converted from http://pds-i...   Nov 11 2009, 02:21 PM
- - ElkGroveDan   I didn't realize that the data that old was av...   Nov 11 2009, 02:49 PM
- - machi   I think that these images are oldest electronicall...   Nov 11 2009, 03:04 PM
|- - john_s   I remember that mosaic well! I think it was ...   Nov 11 2009, 09:10 PM
- - Phil Stooke   "I think that these images are oldest electro...   Nov 12 2009, 02:47 PM
- - machi   Fantastic! Thank you very much. I didn't k...   Nov 12 2009, 03:46 PM
|- - tedstryk   The Mariner 6-7 images on that site have a few iss...   Nov 13 2009, 03:26 AM
|- - peter59   QUOTE (tedstryk @ Nov 13 2009, 04:26 AM) ...   Dec 25 2009, 02:00 PM
- - machi   Another variant of Miranda mosaic.   Nov 13 2009, 04:09 PM
|- - tedstryk   Excellent work!   Nov 14 2009, 04:02 AM
- - machi   Thanks! Especially in this case, I have strong...   Nov 14 2009, 08:32 PM
- - peter59   6N03 .. and bonus IMAGE 6N3 CAMERA A GRN2 FI...   Dec 25 2009, 02:03 PM
|- - tedstryk   Peter, I strongly agree.   Dec 25 2009, 04:07 PM
- - machi   "New" images from Mariner 9.   Jan 7 2010, 07:40 AM
- - Bjorn Jonsson   That first image is great - one of the best images...   Jan 12 2010, 12:39 AM


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