From: spike66 (spike66@attbi.com)
Date: Sat Feb 22 2003 - 14:02:17 MST
Anders Sandberg wrote:
>
> Hmm, do you mean how much people arrive and depart? One might make an
> estimate by looking at two subsequent photos and matching people (using
> a color similarity + distance metric, and a fast bipartite graph optimum
> matching). That would produce an estimated movement field...
> It is somewhat related to the algorithms used in ant tracking I sent a
> few weeks back to Spike, although this does apparently scale better.
Yes and that was way cool. I am still thinking about
ant metrics, but this crowd density thing might
be even more interesting. Looks to me like we could
estimate the density of a crowd based on the way it
reflects radar. We know that radar can be cast over
wide areas. I propose a test where we get about a
thousand volunteers, have them stand on an area the
size of a football field, take a radar image, then
get them to stand between the 20s, take another image,
bring them inside the 40s, at which time it would be
about as densely packed as any crowd ever gets, take
an image.
Then from that, we could compare radar images of a
rally, create a crowd density contour map with
iso-humes, or lines connecting regions of constant
human density and from that estimate how many humans
are present. One such radar image per minute and
one could estimate the number of human-hours. Way
cool Anders! spike
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