Nefertiti's Family

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18 years 5 months ago #17148 by emanuel
Replied by emanuel on topic Reply from Emanuel Sferios
Rd,

I re-read your original post, but I still don't understand what you are mystified about. Maybe you can explain it again. All I see is an R12 and R7 image of the Nefertiti strip with a messed up brightness/contrased. The alignment grid only shows (to me) that they are, indeed, the Nefertiti strip. The fact that our minds can "connect the dots" and create an outline of Nefertiti in the R07 strip is not compelling to me at all, because we know what we are supposed to be looking for. In other words, to me it doesn't confirm that the image is there. And again, we don't need confirmation that the image is there, because we already know it is there from the M03 strip. What we need is more data to assess whether the image (which we know is there) is artificial or not.

Also, it's not surprising that when you try to go from R07 or R12 backwards to M03 by adjusting the brightness/contrast in the other direction, that your end result does not match perfectly what you get when you start with M03 and go forward. This could be easily explained by any number of variables like different sun angles, cloud-cover, slightly differnt camera position, etc.

The only thing that mystifies me is why the Nefertiti strip and the four others closest to it are messed up. That is the question we should try to answer.

So am I not understanding something you said?

Emanuel

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18 years 5 months ago #15223 by rderosa
Replied by rderosa on topic Reply from Richard DeRosa
<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by emanuel</i>
<br />The only thing that mystifies me is why the Nefertiti strip and the four others closest to it are messed up. That is the question we should try to answer.

<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Bingo!!

The thing we are mystefied by is the "WHY?" of it. Why are these images not as good? That's what we want to know. We know they match. That's how we started the discussion, what we don't know is why they are so screwed up. Hopefully Tom will be able to shed some light on this when he comes back. Maybe there's a simple answer, but if you look at the acquistion parameters in the post (compiled by Neil) there's no obvious answer.

That was our whole point, that these other images of the Profile Girl and scene exist, but that they aren't clearly resolved like the other ones.

rd

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18 years 5 months ago #10544 by neilderosa
Replied by neilderosa on topic Reply from Neil DeRosa
The data we posted showed no obvious reason for the darkened images that I could see. Emanuel may be right about the only ones being darkened are around the Profile, but it would help to have a someone else double check that. I saw that problem a lot in the Cydonia region, especially in the context images. But that is anecdotal evidence; you can't call it a "conspiracy" without proof. Maybe Tom can shed some light on this.

Neil

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18 years 5 months ago #15224 by emanuel
Replied by emanuel on topic Reply from Emanuel Sferios
Did everyone notice in the descriptions of all the "R" strips linked above it says either, "Dust-raising event monitoring in Syria/Claritas region," or "Dust devil monitoring in southwest Syria Planum?"

I didn't know that MGS was capable of monitoring dust-devils, which I have always thought are much smaller than the camera's resolution could effective capture. Also, aren't these strips supposed to be "public request" images? If so, why do they say they were instead monitoring "dust-raising events?"

Emanuel

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18 years 5 months ago #10545 by tvanflandern
I'm now back from my travels. As usually happens, there are too many messages to go through them all and comment. Anything not already answered and needing my input should be raised again.

My impression from reading the last few messages is that the budding image processors in this thread don't yet understand how the spacecraft camera works. The MGS camera can see a much wider range of brightnesses than the human eye. Whereas we have to wait for you eyes to adjust to the brightness or darkness, the MGS camera can see both immediately.

With a greater range of brightnesses, greater contrast also becomes possible. So the camera can be set to look at a bright area or a dark area and stretch the contrast just for it, or it can take in the whole scene and provide contrast between the brightest and darkest things in it. There are 256 possible brightnesses. If the camera takes a longer-than-average exposure, lots of medium-to-high brightness objects will all look the same brightness (saturated), whereas more brightness levels will be available to separate dark objects that differ only slightly in brightness. And vice versa.

The first step in examination of any image or image extract is to adjust the brightness and contrast for the whole image into the range that the human eye is most comfortable with. That is necessary to make the image look the way we would see it if we were there. Without that step, the image contains a great deal of information that our eyes cannot see because the brightness or darkness is out of our visual range.

Every strip image had some preset exposure to emphasize bright or dark features or to take in the whole dynamic range without any extra separation at any particular brightness. None of these images are "messed up". There were simply taken with different exposures, allowing greater brightness resolution at some brightness level and less resolution at other brightness levels.

For image comparison purposes, pick a feature that you wish to optimize and adjust all images of it so that they have the same range of brightness for your selected feature. This is an easy process in Photoshop. Also, learn to use manual rather than automatic adjustments for better results. That way, you can make sure that especially bright or dark spots in your image don't keep you from stretching the contrast in a feature of special interest to you. Later on, you can learn how to use a curve for the contrast stretch so you can get just the emphasis you need. -|Tom|-

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18 years 5 months ago #15226 by emanuel
Replied by emanuel on topic Reply from Emanuel Sferios
Thanks Tom. All I have to say then is that it's just a darn shame that there were extra-bright dust storms happening in the same camera sweep as Nefertiti both times the area was photographed, thus eliminating the details inthe area we were all hoping to see.

Emanuel

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