A report in the New York Times says the agency has been pulling images from the intercepted communications of foreigners to create a facial recognition database. According to the documents, out of the millions of images the NSA pulls each day, 55,000 are "facial recognition quality" which they feel may have "tremendous untapped potential."
One of the documents from 2010 said the agency is not just after the traditional communications. "It's taking a full-arsenal approach that digitally exploits the clues a target leaves behind in their regular activities on the net to compile biographic and biometric information that can help implement precision targeting," the document stated.
The agency also said that the collection of this photographic data is considered as important as emails, fingerprints, biometrics, and other forms of identification in the effort to monitor and capture terrorists.
There is no number available to show how many Americans have been involved in this type of surveillance. Since the images are considered content of communications and not "metadata," the agency must get approval from the FISA court before capturing them. However, if an American sends an image in a message to person targeted by the NSA overseas, then the protection would not apply.
"Facial recognition can be very invasive," said Alessandro Acquisti, a researcher on facial recognition technology at Carnegie Mellon University. "There are still technical limitations on it, but the computational power keeps growing, and the databases keep growing, and the algorithms keep improving."
Many agencies have databases with facial images of both Americans and foreign nationals but the NSA is the only agency that can match match images collected from private communications.
"We would not be doing our job if we didn't seek ways to continuously improve the precision of signals intelligence activities -- aiming to counteract the efforts of valid foreign intelligence targets to disguise themselves or conceal plans to harm the United States and its allies," said NSA spokeswoman Vanee M. Vines.
Vines also said that the NSA does not have access to the databases containing drivers license and passport photos of Americans but declined to say whether they had access to the database containing the facial images of foreign visa applicants. She also refused to say whether the NSA pulled images of Americans from Facebook and other social media.
The largest program to collect this data is called Wellspring, which strips images from text communications such as email and text messages and can be used to pinpoint locations. One photograph they collected shows several men standing near a dock in 2011. Using the surrounding imagery, they were able to use satellite images to find what the documents call a militant training base near the same dock in Pakistan.