Friday, April 19, 2013

Putting the mosaic together in Boston

The post's title refers to the mosaic of information that can be arranged into a picture of the events leading up to the savage acts. The other mosaic, the way things were for so many unique individuals, can never be put back together.

How This Photo of the Boston Marathon Gives the FBI a Bounty of Data (Wired)
The photo — click to enlarge — shows a lot of people, what they’re wearing and where they’re positioned within the crush of Marathon fans. It’s important to law enforcement, as it “can be of use in putting the mosaic together,” says Robert McFadden, a former Navy terrorism investigator. Crabbe’s wide-angle panoramic photo “could be one of the many critical pieces of the map of the investigation.”

The panorama photo was one of seven shots Crabbe snapped with her phone during a leisurely stroll and later handed over to investigators.
The Wired article starts with a single data point (data set, really), a photo, and follows it part-way through the process the FBI has used during its investigation of the recent bombings in Boston.

...putting the mosaic together. It's a good metaphor for how the people charged with figuring out what happened and who did it go about their work. Read the whole thing.



Also see:
What's Going on Behind the Scenes of Bombing Investigation? Forensic Scientist, Former DHS Official Shed Light on Tech and Tactics (The Blaze)
“Facial recognition technology will play a very small part,” Schiro told TheBlaze in a phone interview.

“A lot depends on the quality of the images you have to work with,” Schiro continued noting that lighting, angle and other factors could really limit the use of facial recognition in the case. Not only that but there would need to be some sort of match for it to recognize.



UPDATE:
Here's another good article about facial recognition and crime solving. I selected the two paragraphs below because they highlight both the organizational issue of interoperability and the technology issues around matching. There are other interesting insights in the rest of the piece.

Facial Recognition Tech: New Key to Crime Solving (The Fiscal Times)
However, it's likely the FBI was unsuccessful in identifying the suspects using FR because either they didn't have a quality image of the wanted persons, or the suspects were not in any of the databases the FBI has access too, Albers said.
...
While facial recognition technology has high-accuracy when used to match a clear image of a person with another passport-style photo, it is not as effective when used with low-quality images like the ones the FBI released on Thursday. The standard for facial recognition to be accurate requires 90 pixels of resolution between the two eyes of the pictured person. The pictures the FBI released of the suspects were about 12 pixels between the two eyes, said Jim Wayman, the director of the National Biometric Center.


and..
Facial-recognition technology to help track down criminals – Humans are still better at it (Kuwait Times)

Search for Boston bombers likely relied on eyes, not software (Reuters)

These last two reminded me of the (Facial Recognition vs Human) & (Facial Recognition + Human) post from November 2011.

In the Boston case, it looks like there were two barriers to effective use of facial recognition technology in identifying the suspects. On the "evidence" (probe) side, the image quality was poor. On the enrollment (database) side the only "correct" match was likely to be in a very large database such as the Massachusetts DMV database.

If only one of these conditions were true — for example a bad probe against a small database, or good probe against a large database — facial recognition technology might have been of more help.

Crowd-sourcing the ID challenge to a large number of human beings that operate with a lot more intelligence and information than facial recognition algorithms is another option. It's been used with photographs since at least 1865 and without photographs since at least 1696.

One crowd-sourcing fact that law enforcement officials must consider, however, is that the suspect is almost certainly in the sourced crowd. If the suspect already knows he's a suspect, that's not a problem. If he doesn't already know he's suspected, that information is the price of getting the public's help which means facial recognition technology will retain its place in the criminal ID toolkit.


UPDATE:
Boston police chief: facial recognition tech didn’t help find bombing suspects (Ars Technica)
“The technology came up empty even though both Tsarnaevs’ images exist in official databases: Dzhokhar had a Massachusetts driver’s license; the brothers had legally immigrated; and Tamerlan had been the subject of some FBI investigation,” the Post reported on Saturday.

Facial recognition systems can have limited utility when a grainy, low-resolution image captured at a distance from a cellphone camera or surveillance video is compared with a known, high-quality image. Meanwhile, the FBI is expected to release a large-scale facial recognition apparatus “next year for members of the Western Identification Network, a consortium of police agencies in California and eight other Western states,” according to the San Jose Mercury News.