White House roof edited in USGS photos

Mxsmanic wrote:
Steve Andrew writes:
Hmmmm... interesting. If not optical, then what alternatives are there,
apart from radar?.

Digital image processing.

And how does that get you from 10cm resolution to 0.5cm resolution?

miguel
--
Hit The Road! Photos and tales from around the world: http://travel.u.nu

Mxsmanic wrote:

Steve Andrew writes:

Really ? - I suggest you do your math and play around with the
Rayliegh
criteria. Try calculating the diameter of the lens required to
resolve a
wris****ch for an altitude of around 250-300km. It is generally
accepted by
those who know that current resolution is in the order of 10cm.

No, it is generally _acknowledged_ that the current resolution is in
this range. Actual resolutions tend to be classified.

The belief that government is not subject to the laws of physics is
always hilarious when encountered.

Spy satellites long ago abandoned purely optical imaging.

Super-resolution techniques use "purely optical imaging".

You aren't talkin' out of yer ass now, are ya?

"Dave Head" wrote in message
...
On Wed, 12 May 2004 09:46:52 +0100, "Keith Willshaw"
wrote:

They wouldnt stop a 767 in a terminal dive bit would
add to the destruction and death toll.

Would, if it kills the pilot, or disrupts the electronics or hydraulics,
which
seems likely considering the hail of bullets.

Nope inertia rules. Many of the kamikazes which hit US
warships in WW2 were in exactly that position at impact.

It takes a LOT of energy to deflect 100+ tons of metal
and fuel moving at 500 knots

Keith

Tiny Human Ferret writes:

Of course, since these images are captured over time, it might be
possible to determine the type of a watch, but actually reading the time
won't be possible, since it won't be the same time in any of the
sequence of captures. ;-)

You know what time intervals separate the images; just rotate them to
compensate, and the hands of the watch will be in the same place. With
suitable enhancement you'll be able to read the watch.

Where there's a will, there's a way.

--
Transpose hotmail and mxsmanic in my e-mail address to reach me directly.

Paul Cooper writes:

1) The atmosphere isn't stable enough to allow detailed registration
of the images

Insofar as the atmosphere is predictable and measurable in its
distorting behavior, this is not a problem. Additionally, to the extent
that these distortions are random, they cancel out.

2) Most targets you'd be interested in seeing that much detail of are
moving!

If you know what type of motion they are in, you can compensate for
that, too.

--
Transpose hotmail and mxsmanic in my e-mail address to reach me directly.

writes:

The belief that government is not subject to the laws of physics is
always hilarious when encountered.

Nobody is violating the laws of physics.

Before radio, people were convinced that it was a physical impossibility
to talk on one continent and be heard on another.

Super-resolution techniques use "purely optical imaging".

It depends on what you mean by purely optical. Just a lens and a focal
plane are somewhat passé in certain applications, although they are
still used widely elsewhere.

--
Transpose hotmail and mxsmanic in my e-mail address to reach me directly.

Patrick writes:

Telling the time from space? Just buy a watch!

Some watches receive their time from space now.

--
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Patrick writes:

Didn't you just love that "Enemy of the State" movie?

I've never seen it.

Now why would the cash-strapped DOD spend up to $1B in commercial imagery if
they have all the spy satellites with far greater accuracy?

They don't always need greater accuracy, whereas they need very large
volumes of imagery at lower resolutions. The same reason why someone
might buy a set of road maps instead of paying for more accurate
satellite images.

--
Transpose hotmail and mxsmanic in my e-mail address to reach me directly.

On Wed, 12 May 2004 20:38:44 +0200, Mxsmanic
wrote:

Paul Cooper writes:

1) The atmosphere isn't stable enough to allow detailed registration
of the images

Insofar as the atmosphere is predictable and measurable in its
distorting behavior, this is not a problem. Additionally, to the extent
that these distortions are random, they cancel out.

2) Most targets you'd be interested in seeing that much detail of are
moving!

If you know what type of motion they are in, you can compensate for
that, too.

The atmosphere most certainly is not predictable and stable on the
metre length scales required. It is a turbulent fluid, which varies
across the width of a large telescope, and in seconds. We're not
talking about weather systems, here, we're talking about the minor
turbulence that makes stars twinkle. Astronomical telescopes (with
mirror systems weighing tons) can compensate for it, using techniques
such as artificial stars coupled with serious computing. It wouldn't
be practical in space.

If you know what kind of motion your target is in, you don't need a
spy satellite! It would also require a downlink band-width that would
be completely impractical.

Finally, the best results from super-resolution work give you an
improvement in effective pixel size that is (generously) half the
pixel size of the input. Worth while for scientific motionless
targets, but hardly useful for intelligence.

Paul

On Wed, 12 May 2004 20:41:27 +0200, Mxsmanic
wrote:

writes:

The belief that government is not subject to the laws of physics is
always hilarious when encountered.

Nobody is violating the laws of physics.

Before radio, people were convinced that it was a physical impossibility
to talk on one continent and be heard on another.

Super-resolution techniques use "purely optical imaging".

It depends on what you mean by purely optical. Just a lens and a focal
plane are somewhat passé in certain applications, although they are
still used widely elsewhere.


The laws we're talking about aren't limited to lenses and focal planes
either. Any system that lets electromagnetic waves in is limited by
the Rayleigh criterion.

Paul