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AF 447 Search to resume (part2)

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AF 447 Search to resume (part2)

Old 28th Apr 2011, 12:46
  #261 (permalink)  
 
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If I see it correctly the DFDR is mounted vertically.
The recorder in the photograph is mounted horizontally. I can't imagine any being mounted vertically.
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Old 28th Apr 2011, 13:49
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Altered image? no..

Centrosphere,

"If you amplify that region with Paint, youīll see that the texture of the pixels.."

It appears to me to be a smudge on the optical window covering the camera. A small camera with a wide-field lens at f/8 or more will show smudges on the front optics as hazy areas in the image. Perhaps it got smudged nosing about in the dirt.
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Old 28th Apr 2011, 14:07
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deSitter,

Nice take. I wonder if an expensive piece of equipment like a ROV, that can take three hours only to arrive at itīs job place, donīt have some gadget to clean the lens in cases like that...............
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Old 28th Apr 2011, 14:08
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The picture of the chassis is a photograph of a computer monitor showing the image from the ROV. So the lens of the camera taking the photograph could have a smudge, the monitor itself could have a smudge,.... and so on and so forth.
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Old 28th Apr 2011, 14:11
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Saturn V,

I think that BEA and the expedition crew wouldnīt be so careless to the point of offering to the world the picture of a dirty monitor...
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Old 28th Apr 2011, 15:47
  #266 (permalink)  
 
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FDR

No way can the FDR have separated on impact with the seabed, I do not believe even a heavy aircraft would sink so fast.. Therefore it is reasonable that it came off upon impact with the surface of the sea and because of the small debris field, it would seem that the plane had a very slow forward speed.. and the tail and/or rudder did not break off in the air.
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Old 28th Apr 2011, 15:57
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Of course the FDR could survive a fall in the sea - the terminal speed would be less than in air, much less, and certainly the FDR is designed to fall out of the sky.
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Old 28th Apr 2011, 16:19
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I believe the "different texture" to be an artifact of the jpg compression. In areas with fewer details (caused by the vanishing of the shadows) the block sizes on which the jpg compression operates become larger. The different texture is a natural consequence of the varying information content with any lossy compression algorithm.
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Old 28th Apr 2011, 16:45
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It could also be the result of fine seabed material beeing expulsed by the impact of the box and subsequently falling in the nearabouts, moved slightly by a water current (therefore in only one direction). The litle dark spots looks like "worm" activity, so it would take a time to appear on the new sediment (biological activity should be very slow there).
My 2 cents.
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Old 28th Apr 2011, 16:45
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I believe the "different texture" to be an artifact of the jpg compression. In areas with fewer details (caused by the vanishing of the shadows) the block sizes on which the jpg compression operates become larger. The different texture is a natural consequence of the varying information content with any lossy compression algorithm.
That is the most likely explanation. Compression is quite high on these web images. Also IF there was a loss of detail in one area because of a small lens contamination the compression will amplify the effect which saves bytes.
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Old 28th Apr 2011, 17:04
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If the area in the center of the image were modified it would show up as a noisier area compared to the surrounding.

My guess is that we're seeing a fogging up on the lense(s).






Forensic Error Level Analysis Results for http://www.bea.aero/...
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Old 28th Apr 2011, 17:29
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alph2Z

I think this was the cleverer approach so far. I wasnīt aware of this kind of thing available on the net, thanks.

But, have a look on what the site claims:

"If parts of the image are from different source files, they may have been saved a number of different times, and thus they will stand out as a different colour in the ELA test."

I donīt think the image was manipulated in this way (say, the juxtaposition of different images). I think that itīs possible that the original image was only "hazed" at the center. I am not sure about the interpretation of the test, but I think that itīs not very suitable to detect this kind of manipulation.
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Old 28th Apr 2011, 17:36
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Limited, jcviggen,

Iīm a little bit skeptical about this explanation.

First: the imageīs geometry donīt seems to be in agreement with your thesis of "vanishing of shadows". I think that it would occur if the source of the light were close to the lens (POV). But when you look to the shadows, you see that some objects display two shadows, inclined with respect one another, what probably means that there are two light sources in some distance of each side of the lens. I think this geometry isnīt very probable to cause any "vanishing of shadows" at the designated place of the image...
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Old 28th Apr 2011, 17:50
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Centrosphere,

my argument is independent of the presence of a "vanishing shadows" effect. The part in the center has fewer features, hence the jpg compression will operate on different scales than in other parts of the images, leading to the impression of a "different texture".

I'm not making any claims as to the origin of this smoother part.
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Old 28th Apr 2011, 17:53
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It looks like a crater made by a heavy object which got buried into the silt.
Could the memory module be there ?
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Old 28th Apr 2011, 17:56
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alph2z
If the area in the center of the image were modified it would show up as a noisier area compared to the surrounding.
Having tweaked it a bit with image processing software, I second the opinion about this picture probably not having been altered. Actually, the first time I looked at it, my impression was that the different aspect of the center area resulted from the sand/mud having been flushed by the blast of the ROV's propeller(s) or turbine(s).

auv-ee will possibly have some interesting comments, especially regarding the altitude at which the ROV operates above the seafloor, and the suspected "washing effect" of the propellers ?
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Old 28th Apr 2011, 18:19
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Limited,

Maybe, but I think youīre taking for granted exactly what the hypothesis of image alteration wants you to belief.

The "fact" that you have less features at the image center, if you think about that, is a parti pris suggested to you by what youīre seeing...
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Old 28th Apr 2011, 19:07
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Has anything been retrieved yet?
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Old 28th Apr 2011, 19:08
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Centrosphere

Iīm a little bit skeptical about this explanation.

First: the imageīs geometry donīt seems to be in agreement with your thesis of "vanishing of shadows". I think that it would occur if the source of the light were close to the lens (POV). But when you look to the shadows, you see that some objects display two shadows, inclined with respect one another, what probably means that there are two light sources in some distance of each side of the lens. I think this geometry isnīt very probable to cause any "vanishing of shadows" at the designated place of the image...
The "Vanishing of shadows" happens differently depending on the number of light sources. If you have only one light source on the optical axis of the lens, you effectively see no shadows at all in the picture. Photographers sometimes use ring flashes surrounding the lens to achieve this. If the sun is the light source, you will see shadows away from the centre of the picture due to the increasing "parallax" angle.

But in this picture there are at least two light sources, one on each side of the lens. On the left side of the picture you see the shadow cast by the left lamp, and on the right side the shadow cast by the right-side lamp. In the middle of the picture both lamps have equal brightness and so each lamp cancels out the shadow cast by the second lamp (unless the feature is big enough so that the lamps create two overlapping shadows). The result is a low contrast area.
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Old 28th Apr 2011, 19:26
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.jpg algorithm

Quote: "I believe the "different texture" to be an artifact of the jpg compression"

Kudos in remembering this possibility!
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