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A Mobile Robot For Modeling The World In 3D
Roland Piquepaille writes "A German team from Fraunhofer AIS has coupled a fast autonomous robot with a 3D laser scanner to digitize the environment. The team reports about their work in this article, one of fifteen on the subject of machine perception published by ERCIM News. "Kurt3D is an autonomous mobile robot equipped with a reliable and precise 3D laser scanner that digitalizes environments. High quality geometric 3D maps with semantic information are automatically generated after the exploration by the robot." This overview tells you more about the four-step method used to generate 3D models with this robot and contains several pictures of Kurt3D and its 3D laser."
Modeling the tops of things is probably going to be a disadvantage for this one, but typically shape and height are enough for most scenarios, what the top looks like is not usually as much of an issue (though we can likely determine if the top is round/triangular/flat if we can get far enough away).
The advantage of this over an animator's definition is accuracy. If you want an exact 3d model of a building for, say architectual purposes, you want to know exactly where that sphere is in the room, not some abstract rendition by an artist (not to mention that my office has no spheres in it, but much more complex objects instead.
You can find "laser" rangefinders in magazines such as US Cavalry. Typically these actually use an infrared beam rather than a true laser. And yes, it works by determing the time it takes for the reflection to be returned.
The advantages of having a robot do this type of work rather than a typical 3D animator are several. First, they can work anytime, at odd hours. Second, robots don't ask for a raise. Third, they don't take shortcuts unless they're programmed to. Can't say the same for any 3d modellers.
It seems like writing "there's a sphere of radius 3 centered here" would take less time than waiting for the robot to scan it.
It probably would. But is that sphere really radius 3? What if it was radius 2.65? How long would it take for the modeller to drive to the site, measure the sphere, remeasure to make sure it really _is_ a sphere and not an ellipsoid, then drive back and input the data?
---- El diablo esta en mis pantalones! Mire, mire!
It looks barely mobile. The greatest problem is that it is wheeled, which instantly reduces its versatility. Even worse, the wheels are very small and the undercarriage nearly scrapes the ground. If the goal is-- as the headline claims-- to model the world, you'd think they would want a land-based platform capable of either navigating extreme terrain, or an aerial platform that could ignore navigational problems posed by arduous terrain (e.g., a sattelite, airplane, or dirigible).
As is, it is limited to extremely controlled 3D environments. Perfect for mapping a room, but not much more. However, it occurs to me that this technology may be the atavistic precursor to 3D video cameras.
The Franhofer Institute has been doing some nice work with MEMS mirrors, and I was expecting something new from them.
There's a very nice true 3D solid state rangefinder out of Switzerland, but it's a continuous beam device and thus very limited in range. Works fine indoors, though.
Imaging laser rangefinder technology is lousy, because product volume is so low. Five companies have exited the field in the last decade. There are several mechanical scanners available, all using scanning technologies abandoned by television in the 1940s. All-electronic solutions have been developed as prototypes, but they're not shipping yet.
Once this problem is cracked, mobile robotics is going to get much better.
I had a similar idea a while back of using 2 cameras aligned side by side. each with a servo motor to give it 20 degrees of freedom either way. By taking a snapshot of both images, you could use motion detection routines (i.e same ones used to encode mpeg)to see how far the images differ from each other and move the camera's angles until the 2 images virtually parallel each other. Then, taking the angles of the cameras, a simple triangulation calculation would tell approximately how far an object is to the camera. A passive range finder if you will. The advantages of using 2 pictures is that you would do a lot of easy image processing routines to figure out the walls and ceilings without having to work with just a cloud of points. I called my invention.. "2 cameras on a stick". Alas I didn't have the funding to pursue the idea further.