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Tuesday, January 13, 2009

AI and Robots: Highschool Students Register With Their Faces

In a previous post we discussed challenges to facial recognition apps and what people had to do (or choose to do) to get by (or bypass it). Does that mean the technology is not ready for the real world? Today we'll see a case where it is used in real world environment and is actually working quite well.

At the City of Ely Community College in UK, sixth-graders are now check-in and out of school registers using their faces. The facial recognition technology is provided by Aurora and the college is one of the first schools in UK to trail the new technology with its students.

So how does the technology work? The scanning station is equipped with infra-red lights and a regular video camera. Each infra-red sensor actually has two parts: an emitter and a receiver. The emitter shoots out an series of infra-red signals and the receiver detects the infra-red lights deflected back by objects in front of the sensor (a simple example would be the auto-flushing toilets in public restrooms). Then by analyzing the strength and pattern of the received signals, the sensor can sense how far the object is from the sensor. This allows the scanner to create a range (depth) image of the object in front of it. So the resulting image is a 3D surface, unlike a regular 2D image from a camera.

Combining this 3D surface with the 2D image taken from the video camera, features are extracted from the entire data set, then each set of features is tagged with a student ID (we know which face it is because each student has to be scanned at the very beginning so the data can be stored in the database). At the time of the scan, it is a simple machine learning classification problem, and I suspect that they probably just used nearest neighbor to match features with an individual student. You can click the image below to see a video of this from the original news article.

Click image to see video.
So how do people like this high-tech face recognition system? Principal Richard Barker said:
With this new registration technology, we are hoping to free up our teachers' time and allow them to spend it on what they are meant to be doing, which is teaching

As for the students, they love the idea of taking responsibility for their ow n registration and using Mission Impossible-style systems.


So why did this specific application turn out to be a success? That's the question we really should be asking. I think we have to attribute the success to the following factors:
  • This is a combination of 3D depth image with a 2D image, which allows the creation of many features (and some of them got the job done).
  • The college has a relatively small number of six-grader students. Classification becomes easier when you don't have to recognize a face out of millions of faces (like in the airport security check case).
  • The student is also required to enter a pin. This further improves accuracy. I guess the facial recognition technology is really there to prevent students from signing other people in and out.
  • Most importantly, the consequence of errors is very low. What if a face is not recognized correctly? The worst that could happen is a erred record in the registration. It's not like that the student would be marked as a terrorist at an airport, which could have severe consequences.
I certainly hope to see more and more successful facial recognition applications out there people can focus on what they enjoy to do instead of what they have to do.

Picture of the Day:

I think this would make a perfect picture for today.
Here I present: Lanny in 3D