On 05/19/2014 12:55 PM, Liam O'Connor wrote:
I'm a layman, so, keeping it at lay-talk, fundamentally,
how does Google Images recognize two images as having the
same provenance?

And, is it similar to how software find tanks and missiles
in a spy satellite photo?

What I have been told is that they both do an FFT on the
pixel information, and, from that detailed frequency data,
they look for characteristic "signature patterns".

But, I know no more than that (and even that may be wrong).

Can you shed light (in layman's terms) on this process?


Lots of DSP, trial and error involved in calibration and proofing.
Mostly automated, ground penetrating radar, bizarre optical wavelengths,
magnetometers, etc. all integrated in proprietary computer systems.
Between the oil companies and the spooks, remote sensing is very mature
and still very secret. FFT analysis can make anything more visible, to a
point.