when discussing large volumes of remote imagery, and various members
of the amateur team voiced concern
about personal privacy during the process. Although popular media-sharing
Web sites provide widespread access to crowdsourced and aggregated
imagery, they have largely confined
themselves to benign settings (such
as tourism and ornithology), whereas
maritime SAR applications (such as
monitoring marinas and shipping
lanes) seem closer to pure surveillance. The potential for infringing on
privacy raises understandable concern, and the policy issues are not simple. Perhaps our main observation on
this front was the need for a contextual
treatment of policy, balancing general-case social concerns against specific
circumstances for using the data, in
our case, trying to rescue a friend. On
the other hand, while the search for
Tenacious and its lone sailor was uniquely urgent for us, similar life-and-death
scenarios occur on a national scale
with some frequency. So, we would
encourage research into technical solutions that can aggressively harvest
and process imagery while provably
respecting policies that limit image release based on context.
From Imagery to Coordinates
Here, we discuss the processing
pipeline(s) and coordination mechanisms used to reduce the raw image
data to qualified search coordinates—
the locations to which planes were dispatched for a closer look. This aspect
of the search was largely data-driven,
involving significant technical expertise and much more structured and
tool-intensive processes than those
described earlier. On the other hand,
since time was short and the relevant
expertise so specialized, it also led to
simple interfaces between teams and
their software. The resulting amalgam
of software was not the result of a specific architecture, in the usual sense
of the word (archi- “chief” + techton
“builder”). A more apt term for the
software and workflow described here
might be a polytechture, the kind of
system that emerges from the design
efforts of many independent actors.
Overview. The figure here outlines
the ultimate critical-path data and
control flow that emerged, depict-
ing the ad hoc pipeline developed for
Digital Globe’s satellite imagery. In
the paragraphs that follow, we also
discuss the Mechanical Turk pipeline
developed early on and used to process
NASA ER- 2 overflight imagery but that
was replaced by the ad hoc pipeline.