From Google Maps to Google Caves
Most of us are probably familiar with that iconic scene in Star Wars where the Rebel Alliance, gathered around a 3D holographic view of the Death Star, plan the destruction of the evil Galactic Empire’s doomsday weapon.
Fortunately for the rebels, Princess Leia stole the plans for the Death Star and embedded them in R2D2. Now, say you weren’t so fortunate. What would you do to get a good working map of the Death Star, or, returning to reality, an office building, if you were pressed for time? Well, you could send a guy in with a cell phone, and he could count his steps and describe it to you. As fun as that sounds, there’s now a better way.
Researchers at MIT have created a portable sensor system that creates a digital map of its surrounding area in real-time. Worn as a frontpack (a word I just coined meaning the reverse of a backpack), the device takes a multitude of measurements as the wearer moves through an environment, and sends the data to a laptop that compiles all the data into a constantly evolving map. It was designed by MIT’s Computer Science and Artificial Intelligence Laboratory to be used by emergency responders at a disaster site, allowing them to explore the site and evaluate its structural integrity prior to sending in a full rescue team.
The device uses a variety of sensors to create this map, including a laser rangefinder, accelerometers, gyroscopes, a camera, and a barometer. The laser rangefinder sweeps a laser beam around and measures the time that it takes the light pulses to return. The gyroscope is used to determine whether or not the rangefinder is tilted (meaning the person is not walking perfectly upright) and corrects the rangefinder data accordingly to get an accurate measurement. The camera takes pictures of the surrounding area every few meters and the processing program combines these photos with the other sensor data to create a more accurate map.
There are still flaws with the device. One flaw is that the generated map can become skewed if the wearer returns to a place previously visited. Since the wearer will never be at the exact same spot at the exact same tilt angle twice, the walls that were previously mapped may suddenly appear several feet further away and skew the map. The purpose of the camera is to provide photos that will allow the computer to correct these types of errors.
Another flaw that had to be overcome early on was the device’s lack of ability to determine what floor the wearer was on. Without this ability, as the wearer went from the 1st to the 2nd floor, all the 1st floor data would be overwritten because it would appear to the computer that different measurements were coming from a location previously mapped. This was solved with the addition of a barometer that can sense slight differences in air pressure as the altitude is changed.
There is a lot of potential for civilian use as well. You could explore and instantly map caverns and caves, posting the map online for others to use. You could map out a whole forest tree by tree, simply by walking through it. Archaeologists could use it to create maps of past civilizations buried under centuries of sediment.
Besides these more noble purposes, imagine the fun that could be had with this device. You could hide the pack under an accomplices clothes and have him walk around, then show a friend your laptop and convince him you found the real Marauder’s Map from Harry Potter. You could slip this sensor pack inside of your friend’s work bag, then call him later that day with a voice changer and reenact that famous scene from the Matrix where Morpheus guides Neo away from the Agents, with yourself seeming omnipotent as you describe every detail of his movement and nearby surroundings (yes that was my third movie reference).
The possibilities are endless…
Chris Rendall has a BS in Engineering from UT Austin, graduated with Honors. He is contributing to a book, Smart Building Systems for Architects, Owners, and Builders.