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Earth Input Devices The Military Technology

A Portable Laser Backpack For 3D Mapping 66

wooferhound writes "A portable laser backpack for 3D mapping has been developed at the University of California, Berkeley, where it is being hailed as a breakthrough technology capable of producing fast, automatic and realistic 3D mapping of difficult interior environments. ... The backpack is the first of a series of similar systems to work without being strapped to a robot or attached to a cart. At the same time, its data acquisition speed is very fast, as it collects the data while the human operator is walking; this is in contrast with existing systems in which the data is painstakingly collected in a stop-and-go fashion, resulting in days and weeks of data acquisition time. It utilizes novel sensor fusion algorithms that use cameras, lasers range finders and inertial measurement units to generate a textured, photo-realistic, 3D model that can operate without GPS input and that is a big challenge."
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A Portable Laser Backpack For 3D Mapping

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  • Re:Cavers (Score:3, Interesting)

    by Ostracus ( 1354233 ) on Saturday September 18, 2010 @02:38AM (#33618074) Journal

    I can imagine this being quite useful for cavers (also known as spelunkers) by allowing them to model large caverns quickly to look for exits.

    Or, alternately, if it works in the dark because it's lasers, you could use it as an alternative to night vision.

    Actually what came to mind was the mapping of building interiors for the purpose of historic preservation...or games. :)

  • by Scorpinox ( 479613 ) on Saturday September 18, 2010 @03:57AM (#33618282)

    This thing is very very cool. Though we do have faster ways already than "painstakingly collecting in a stop and go fashion". I've worked with lasers attached to low-flying aircraft and also attached to a truck that can drive about 40 miles an hour. Two passes with the truck is just as good as this backpacks data. We primarily mount tracks on the truck and drive it on railroad tracks to collect data for upcoming rail projects. You can check out the technology at

  • Re:Big Challenge (Score:3, Interesting)

    by Yetihehe ( 971185 ) on Saturday September 18, 2010 @04:23AM (#33618340)
    If your job can be replaced with a computer program, you should not be doing it, or you will be known as The Indexer [].
  • by Scorpinox ( 479613 ) on Saturday September 18, 2010 @06:26AM (#33618716)

    Hence why I said that this is very cool :) I can think of more than a few instances where this backpack would come in handy. Unfortunately, noone is really dumping a lot of money into mapping caves, since there isn't anyone about to start constructing inside them. Right now the majority of the laser scan work I've done is for buildings where the original schematics are lost, or painfully out of date. I did once scan a rockslide so that someone could analyze what went wrong after the fact, but even that was over a large highway.

  • Re:Big Challenge (Score:2, Interesting)

    by Scorpinox ( 479613 ) on Saturday September 18, 2010 @06:28AM (#33618730)

    Yes, I'm painfully aware of this. Lucky for me, there is still a lot of QA/QC work to be done to make sure that the program worked correctly and the model isn't screwed up.

  • by occamsarmyknife ( 673159 ) on Saturday September 18, 2010 @02:18PM (#33621282)

    Actually, the issues of indoor 3D mapping are significantly more challenging than doing so from a plane or ground vehicle outdoors.

    Advances in MEMS sensors for acceleration and position make knowing the position of the lidar base much easier and more accurate.

    Inertial sensors arn't a panacea, especially the MEMs-based ones. MEMs-based inertial sensors are MUCH less accurate than the systems used in survey equipment. Even the best high-end MEMs inertial systems are quite noisy, and while top-of-the-line optical (not MEMs) gyros can be extremely accurate and give you orientation with very low drift over time, the basic premise of an accelerometer makes knowing position impossible over any length of time. Remember - you have to integrate the signal TWICE to get position, that adds up to a lot of noise. Also, I'm pretty sure from looking at their backpack that they arn't using a MEMs based IMU.

    and it is nothing new. it's been flown in planes (by the USGS to map the coastline of the US), attached to vehicles of all kinds.

    When you are outdoors you have access to GPS, and that makes all the difference. It gives you the corrections needed to maintain an accurate knowledge of position over long distances and after sharp or erratic maneuvers. Additionally, when your sensors are mounted to a plane or vehicle the scan to scan motion is roughly linear, i.e. planes don't jump up and down and side to side a lot. People walking bounce all over the place, and that makes your position estimates from accelerometers alone next to useless for more than a few steps.

    This "advance" is really nothing that anyone knowlegable in the art couldn't predict or produce.

    There's a reason why there are lots of companies that provide high-accuracy outdoor mapping, both ground and air-based, and none that provide high-accuracy indoor mapping without requiring fixed, surveyed markers and slow, step-by-step scanning from rigidly mounted scanners. Nobody knowledgable in the art, as you say, can do it yet.

    To do indoor mapping successfully you have to align each data scan with other data scans - the most common way to do this to use a SLAM (simultaneous localization and mapping) algorithm. While this has been well explored using planar lidar data from a rolling base in 2D, and reasonable well implemented on a rolling platform in 3D (often assuming level floors, etc...) putting it on a human means you have to solve the problem fully in 3D with noisy data and very poor odometry over long distances. This has been demonstrated (somewhat poorly) in the past on a single-floor basis, but aligning data from multiple floors or wings connected by a single long corridor is not at all a solved problem. The end result of most of these indoor approaches is a map that is topologically correct, but spatially very flawed. Without a global reference to correct your position, a long, straight, hallway may curve a little bit, a turn that should be 45 degrees might end up as 40 degrees, and those errors very quickly add up to a spatially incorrect map.

"If the code and the comments disagree, then both are probably wrong." -- Norm Schryer