De-convoluted Image Of Tempel 1 Options

[Harry]

The following images are for Tempel 1 originally taken by NASA's probe (left) and its de-convoluted image (right). For details of the technique used for that de-convolution, please visit;

http://139.134.5.123/tiddler2/c22508/focus.htm

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[tfisher]

For details of the technique used for that de-convolution, please visit;

http://139.134.5.123/tiddler2/c22508/focus.htm

I took a look at the site you link to; is that program yours? I hope some critique won't come across as offensive. It looks like its claims are rather exaggerated. It just convolves the image with a sharpening kernel, with some parameters on that kernel. The main claim to fame of the parameters it provides seems to be iteration of a small sharpening kernel (where by small, I mean a pixel is affected by pixels from within a small radius). Iterating a small kernel gives some larger kernel; unfortunately this larger kernel will not be the best kernel of that size for most sharpening uses. For instance, you might hope your large sharpening kernel would be pretty much radially symmetric. Iterating a small kernel gives a bad approximation of this.

The Tempel 1 image you post does show some details better than the original (good!) but also has some classical signs of oversharpening like JPEG artifacts being exaggerated and some horizontal lines appearing near the top and bottom edges.

[ElkGroveDan]

The following images are for Tempel 1 originally taken by NASA's probe (left) and its de-convoluted image (right). For details of the technique used for that de-convolution, please visit;

http://139.134.5.123/tiddler2/c22508/focus.htm

OK that is cool Harry. I can use a quickie utility like that. Is it your program?

As with all such tools I prefer to use the revised product as part of a multi-layer image with various transparency levels. Using different algorithims in different layers has proven successful for me. One more tool in the bag of tricks is always appreciated.

[Harry]

To: tfisher

Yes, it's very important to determine the extent of kernel properly. But it must follow heuristic manner. For, if we were to know it previously, we would have corrected the focus before taking the photo!

>Iterating a small kernel gives a bad approximation of this.

That's true. Practically when choosing small kernel on my software (i.e. "Focus Depth" ~ 1), the effect of de-convolution is almost same as that obtained from usual sharpening process.

As you've indicated, some artifacts may appear after applying the software. Those seem to happen less frequently when the quality of original picture is better. If the picture is already processed (s.t. enlargement, filtration, etc.), the artifacts on the picture after applying my software will appear much more frequently.


To: ElkGroveDan

>Is it your program?

Yes, it is. I've developed this software for just correcting the focus on the image, not comparing the result with other software. Namely I haven't compared the sharpened image obtained from my software with that of other sharpening software by myself! If you get better outcome using some other software, could you let me know?

[deglr6328]

Nice work. It really brings out considerable detail in the original. But can it actually be called a deconvolution without direct knowledge of the point spread function of the telescope on DI...? Or am I missing something?

[Harry]

As you've known, the form of point spread function depends on the optical system on which the photo is taken. Since I've developed this software for multi-purpose (i.e. not only for blurred planetary images but also for blurred microscopic images, etc.), the point spread function applied in the software has the simplest form, that is, the point of light is supposed to spread uniformly on the disc. (Do you think it's too simple?)

The following images are for Jupiter's satellite Thebe originally taken by Galileo probe (left) and its de-convoluted image (right). In this time the area of disc mentioned above is set four times greater than that of Tempel 1, since the original image of Thebe seems more blurred than that of Tempel 1.

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[tfisher]

The origin of the blur in the Thebe image you posted is not in the telescope system, but rather in the imaging team's reprocessing of a tiny image. Here is the original image (at full resolution and with a 5x pixel zoom so you can see it), as available here.



As you can see, there isn't that much information available in the picture to begin with -- somewhere around 100 non-black pixels. Sure, maybe you can improve on the original reprocessing somewhat to make a more visually pleasing enlargement, but trying to pull more information out than was in the original data is folly.

[Harry]

Oh, I didn't know the image of Thebe which I've processed was not raw image! By the way, if available, could you upload the raw image of Thebe? For I could not access the link you've shown in the last post. (Or is the attached image in your last post a genuine raw image? I'm afraid of that image is too small to process with my software...)

[tedstryk]

Oh, I didn't know the image of Thebe which I've processed was not raw image!  By the way, if available, could you upload the raw image of Thebe? For I could not access the link you've shown in the last post. (Or is the attached image in your last post a genuine raw image? I'm afraid of that image is too small to process with my software...)

Yes, the image he processed is original. From the result, it seems that the software is just sharping the image, not doing true deconvolution. It is sort of like when I produce what I call "faux-super resolution images." It improves the visibility of already visible features, but, unlike true super-resolution imagery, doesn't yield true new detail.

[Decepticon]

Could this work with the recent HST images of Ceres?

[tfisher]

I could not access the link you've shown in the last post. (Or is the attached image in your last post a genuine raw image?

Sorry, I didn't notice the link I posted was to a cgi results page. Go to this page and click submit.

The image I posted is a direct crop from the raw image. So yes, it is really that small to begin with!

The good news is, if you browse through that data set there are more views of Thebe (and the other moons, etc) that haven't had any public exposure, as they only make press images of the best shots. (Yes, this image was one of the top three best shots ever taken of Thebe!) So you can find images to play with that pretty much only the original mission scientists ever looked at.

[Harry]

Thank you for letting know me the site. It's a very interesting site. I de-convoluted some of those pictures in that site. In those pictures the left side is for original images and the right side is for the images after de-convolution. As you'll see, the de-convolution software is not effective when the original picture is composed of small number of pixels.

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[Harry]

Yes, the image he processed is original.  From the result, it seems that the software is just sharping the image, not doing true deconvolution.  It is sort of like when I produce what I call "faux-super resolution images."  It improves the visibility of already visible features, but, unlike true super-resolution imagery, doesn't yield true new detail.

Probably... but I'm not sure.

[Harry]

Could this work with the recent HST images of Ceres?

OK. If I found a good (and blurred) image of Ceres, I'll try to de-convolute it.

[tedstryk]

Here are all the resolved views of Thebe (shown at original size) we have....very slim pickings.