There's probably pretty good reason this specific bit went open source. The vision tracking community usually tends to make leaps and bounds on open source projects. People will easily be downloading openCV and modifying it in different ways for their home projects. These modifications will then be usefull to darpa.
Considering that the vision tracking isn't a core function of one of their devices they probably aren't as interested in hoarding it. Why not let some other people do the work?
Replay available now: A handful of emerging network technologies are competing to be the preferred wide-area connection for the Internet of Things. All claim lower costs and power use than cellular but none have wide deployment yet. Listen in as proponents of leading contenders make their case to be the metro or national IoT network of the future. Rick Merritt, EE Times Silicon Valley Bureau Chief, moderators this discussion. Join in and ask his guests questions.