I know, it sounds like something out of a Sci-Fi movie where people are arrested for crimes before they commit them. Oh wait, that movie was already made.
Engineers here are developing a computerized surveillance system that, when completed, will attempt to recognize whether a person on the street is acting suspiciously or appears to be lost. In the recent Proceedings of the 2008 IEEE Conference on Advanced Video and Signal Based Surveillance, James W. Davis and doctoral student Karthik Sankaranarayanan report that they’ve completed the first three phases of the project: they have one software algorithm that creates a wide-angle video panorama of a street scene, another that maps the panorama onto a high-resolution aerial image of the scene, and a method for actively tracking a selected target.
So does this mean that the machines will have to know who you are?
According to the creators, no. “In our research, we care what you do, not who you are. We aim to analyze and model the behavior patterns of people and vehicles moving through the scene, rather than attempting to determine the identity of people. We are trying to automatically learn what typical activity patterns exist in the monitored area, and then have the system look for atypical patterns that may signal a person of interest — perhaps someone engaging in nefarious behavior or a person in need of help.”
This system is more accurate than the traditional camera methods for several reasons. When surveillance operators look through a traditional camera they get only a tiny image — what some refer to as a “soda straw” view of the world. As they move the camera around, they can easily lose a sense of where they are looking within a larger context. The Ohio State software takes a series of snapshots from every direction within a camera’s field of view, and combines them into a seamless panorama.
How does the camera create an accurate panorama? Well, the software maps locations within the fish-eye view onto an aerial map of the scene, such as a detailed Google map. A computer can use this information to calculate where the viewspaces of all the security cameras in an area overlap. Then it can determine the geo-referenced coordinates — latitude and longitude — of each ground pixel in the panorama image.
If this all seems a little bit ‘Big Brother’ to you just wait. The computer is going to try and judge your intentions.
To first determine what constitutes normal behavior, they plan to follow the paths of many people who walk through a particular scene over a long period of time. A line tracing each person’s trajectory will be saved to a database. “You can imagine that over a few months, you’re going to start to pick up where people tend to go at certain times of day — trends,” one of the researchers said. People who stop in an unusual spot or leave behind an object like a package or book bag might be considered suspicious by law enforcement.
Mimes watch out. You may be pegged as a terrorist by the computer when you do your sneaking immitation or your wind walk. While this system has potential it lacks the one thing that humans have, context.