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AS17-150-23101 - Lunar Horizon Cropping & Masking

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AS17-150-23101 - Lunar Horizon Cropping & Masking

Post  Admin on Sun May 22, 2011 4:52 pm

LunaCognita wrote:Here is another example of NASA getting caught cropping and masking frames in their Apollo image archives. This is Apollo 17 Hasselblad frame #23101, showing an oblique view of the lunar surface near the crater "Dreyer". All the images I show below are built from the raw high-resolution LPI archive version of Apollo frame AS17-150-23101, but have been resized so that the full frame could be shown here in the thread.

Raw HR link to frame# AS17-50-23101 from LPI

This high resolution version of this frame from the NASA/LPI archive shown above has clearly been manipulated. While the masking of the sky region in this frame is not really detectable in the raw version of this frame, what serves as a dead giveaway that this particular image has been sanitized even prior to any enhancement regime being applied is the fact that the right side horizon line has been very poorly masked here. Just to highlight this a bit better, I cropped the right side horizon area from the raw HR version of this frame so you could see the blatant perfectly straight masking line in full size (below).

Now, in the case of this version of frame 23101 from Apollo 17, a quick look with the "eye dropper" tool reveals that the vast majority of the sky region is solid black, with zero color or luminance data at all being present in much of the blackness of space. However, if we spike the dark sky region to detect and highlight any very subtle image data buried in the darkness, we immediately see that the crop line I highlighted above does not cease at the point where the lunar horizon curves downwards and away, but rather the cropping actually carries on all the way across the image in a perfectly straight line through the apparent solid blackness of space. Here below is a simple "color replacement" spike to highlight the residual evidence that remains to prove the sky region of this frame was sanitized.

When it comes to examining the Apollo archive imagery for evidence of this sort of sanitizing, one thing that this particular Apollo 17 frame allows us to exploit is the fact that this is a color image, and that means it can be broken apart into three distinct layers or channels - one for hue, one for saturation, and one for lightness values. When we take the LPI archive version of frame 23101 and split it apart into these HSL layers, we see that the raw lightness layer (as expected) does not allow for detection of the obfuscative masking across the frame prior to enhancement. When it comes to the hue and saturation layers however, this is one of those cases where, prior to any enhancement at all, the obfuscation shows itself in a very obvious way and is blatantly easy to detect. Here are the three layers for frame 23101 below (with no enhancement applied) so you can see what I mean.




I wanted to highlight this HSL issue here because as you can see above, anytime you are going to go to the trouble of looking closely at any color frames of film from any of the Apollo archives, it is always worthwhile spending the few seconds of time it takes to do a channel-split so you can examine the HSL layers separately. Depending on how the obfuscative regime was applied by the NASA image processing team, sometimes you won't have to look very hard or do any enhancements at all and still get a nice reveal.


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Re: AS17-150-23101 - Lunar Horizon Cropping & Masking

Post  Admin on Sun May 22, 2011 4:53 pm

LunaCognita wrote:Since I was showing the obfuscation of frame AS17-150-23101 above, it is probably worth noting that the previous frame shot just prior - frame# 23100 - which is also an oblique image of the lunar surface, also shows the identical type of horizon masking.

Raw HR link to frame# AS17-50-23100 from LPI

Just to show confirmation of the obfuscative residue, here below is the Saturation Channel when it is split from the raw HR frame. No other "enhancement" required.


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