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I don't have much direct experience with lidar, but with my background in in situ sensing I could probably land a job working with/on it. If I may be so bold as to presume that I just barely qualify as an "expert" here: The lidar in your vacuum (presumably a neato-XV series; if so, you have fine taste sir/madam) is no more than a spinning laser range finder. These work by offsetting a laser from a linear image sensor (imagine a camera with a crazy wide aspect ratio, maybe 256x6 resolution) and calculating distance by simple trigonometry or a pre-calibrated look-up table. These are called spinning parallax lidar. Their output is two dimensional in polar coordinates (angle, distance). More expensive lidar systems use carrier wave phase measurements (modulate the laser to a known signal, look for its reflection and calculate phase difference), direct time of flight measurements (like narrow beam sonic range finding, but with light, requires very expensive timing circuitry), doppler shift, and/or various structured light transformation/interference effects. Some units only use one of these techniques, some use a combination of these techniques. Most of these units operate using a number of lasers simultaneously to spit out 3 dimensional data, either as planar depth maps, or as 3D polar coordinates (angle-x, angle-y, radius). Either way, all of these are expensive because they require very fast and very precise complex analog circuitry, tight controls on noise sources (RF interference, temperature dependence, very good power isolation), tight controls on spurious emissions (GHz oscillators), careful calibration, and most importantly, very complicated software. To me, time of flight is the most interesting, but the least practical/likely to be made inexpensive. For a DIY example of the kind of timing circuitry involved, check out [1]. That said, there's room to make it cheaper. One such way may be to use a structured light transformation technique similar to Kinect, but speed up the camera a bit and modulate the output to a known signal (gives better interference rejection). 1: http://piotr.nikiel.info/?page_id=95 |