The U.S. Navy is deploying robot helicopters that can spot pirate boats -- even when they're in a crowded sea lane.

Unlike their movie versions, real pirates don't identify themselves by flying a jolly roger. Navy ships try to identify the thieves by deploying both drones with cameras and human pilots, but in coastal areas with a lots of boats, it isn't easy to spot the one that's hostile. A sailor might have to watch hours of video to find the right one.

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The Navy turned to a combination of different sensing technologies to address this. Called the Multi-Mode Sensor Seeker, or MMSS, an unmanned helicopter uses high-definition cameras, mid-wave infrared sensors and laser-radar (LADAR) to find the boat.

Meanwhile, sophisticated software allows the helicopter to identify the target independently of the operator. The software on board compares a 3-D image to templates and schematics in its memory.

It's an advance over traditional targeting –- in that case, even with an infrared image, soldiers need to check against a group of known silhouettes. Those are a lot less exact, since a boat could be at an angle, making it harder to identify.

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The software has been successfully tested in shore-based systems against vessels at sea. The next step is testing it in a piloted helicopter, against groups of about seven small boats in a military sea range off the California coast this summer.