[{"data":1,"prerenderedAt":386},["ShallowReactive",2],{"project-20813557":3},{"id":4,"name":5,"line":6,"line_source":7,"title":8,"url":9,"domain":10,"maker":11,"posted_at":12,"year":13,"points":14,"comments":15,"rank_in_year":16,"shown_in_year":17,"top":18,"tier":19,"category":20,"subcategory":21,"format":22,"keywords":23,"reception":28,"sentiment":29,"stance_mix":30,"scored_comments":34,"aspects":35,"strip":42,"post_text":45,"what":46,"said":60,"maker_in_thread":157,"shape":162,"grid":167,"attempts":349,"same_week":350,"maker_shows":43,"maker_hidden":378,"reader_version":379,"card":380},"20813557","fkMigration.jl","Wave-based non-line-of-sight computational imaging in Julia","title","Show HN: Wave-based non-line-of-sight computational imaging in Julia","https:\u002F\u002Fwww.analytech-solutions.com\u002Fanalytech-solutions\u002Fblog\u002Fnlos.html","analytech-solutions.com","krrutkow",1566934207,2019,375,71,66,2195,4,"legend","languages","computational imaging library","library",[24,25,26,27],"non-line-of-sight imaging","f-k migration","julia","computational imaging","curious",0.057,{"positive":18,"neutral":31,"mixed":32,"critical":33},36,0,3,43,{"performance":36,"idea":37,"execution":39,"docs":40,"design":41},{"positive":32,"critical":32},{"positive":38,"critical":33},2,{"positive":38,"critical":32},{"positive":32,"critical":32},{"positive":32,"critical":32},[33,33,33,33,33,43,44,44,32,33,33,33,32,32,32,32,43,32,32,44,43,33,32,33,33,33,33,33,33,33,33,32,32,44,33,33,33,33,33,33],1,5,null,{"problem":45,"audience":45,"pricing":45,"motivation":45,"time_to_build":45,"stack":47,"openness":58,"stage":59,"team_size":59},[48],{"value":49,"source":50,"evidence":51},"Julia","maker",[52,55],{"id":53,"by":11,"text":54},"20813641","Direct link to the Julia project repository: https:\u002F\u002Fgithub.com\u002Fanalytech-solutions\u002FfkMigration.jl",{"id":56,"by":11,"text":57},"20813884","From my experience it is one of the most productive programming languages to develop in, and the code can be iterated on to reach performance that is as good as C or Fortran code.","open_source","unknown",{"praise":61,"objections":82,"requests":104,"questions":116,"alternatives":139},[62,74],{"value":63,"source":64,"evidence":65},"Interesting, analogous to seismic imaging and synthetic aperture radar work","commenter",[66,70],{"id":67,"by":68,"text":69},"20815982","MrSpiffy","This is quite analogous to exploration seismic imaging, including the Stolt migration. Thank you for sharing this.",{"id":71,"by":72,"text":73},"20817203","lokimedes","Fascinating. I have been using the same approach to generate synthetic aperture radar images, but having a non-radar platform to test the processing algorithms with is quite…",{"value":75,"source":50,"evidence":76},"Julia is productive and fast for numerical code",[77,78],{"id":56,"by":11,"text":57},{"id":79,"by":80,"text":81},"20813782","phonebucket","I cannot answer for the author, but for projects which build a lot of expensive numerical routines from scratch, Julia is a good fit: The JIT overhead is a small price compared…",[83,93],{"value":84,"source":64,"evidence":85},"Resolution is limited by photon counts and surface properties",[86,90],{"id":87,"by":88,"text":89},"20816120","mohn","The quantization of light is going to be a serious limit. The detector elements of a camera could be made pretty sensitive, but they can't detect fewer than one photon. In NLOS…",{"id":91,"by":11,"text":92},"20814006","At least surfaces that are anisotropic scattering, highly absorbing surfaces, and temporal resolution of the laser and shutter will all affect the image's spatial resolution.",{"value":94,"source":64,"evidence":95},"Reconstructions are blurry and only reflectivity, not color",[96,100],{"id":97,"by":98,"text":99},"20813752","billconan","wait, why can it see color? if this algorithm is based on the speed of light traveling (similar to ultrasonic), I would think it won't show color? the resulting image shows the…",{"id":101,"by":102,"text":103},"20814704","3JPLW","Not color, but reflectivity.",[105],{"value":106,"source":64,"evidence":107},"Use multiple wavelengths or phase information for better results",[108,112],{"id":109,"by":110,"text":111},"20817312","uasm","> \"In NLOS (and traditional photography) the scene to be imaged is illuminated with N photons but the detector only receives M photons worth of signal back, where M\u003C\u003CN.\" How…",{"id":113,"by":114,"text":115},"20830834","GistNoesis","Yes. The best views will be from projections whose camera position is at a point scanned by the laser. With the f-k migration algorithm, the output is in fact the aligned sum of…",[117,128],{"value":118,"source":64,"evidence":119},"What hardware is needed to capture the data?",[120,124],{"id":121,"by":122,"text":123},"20814726","amingilani","Wait, what is the hardware required for capturing this kind of data? Can I do this with a point-and-shoot camera?",{"id":125,"by":126,"text":127},"20814785","snazz","The picosecond shutter time scale part and high speed control of a powerful laser would make that awfully difficult.",{"value":129,"source":64,"evidence":130},"Could WiFi or radio be used instead of light?",[131,135],{"id":132,"by":133,"text":134},"20813952","samstave","Can you apply these theories to using a wifi AP to read the 3d layout of the room\u002Fspace based on RSSI and its various interferences? Could you make a 3D scanner app in…",{"id":136,"by":137,"text":138},"20814116","mbarronj","Not only wave length, but also beam width. The laser is spatially very compact. Radio waves need larger antenna apertures to be that focused. It's hard to get tight spatial…",[140,150],{"value":141,"source":64,"evidence":142},"Femto-photography (MIT) and passive NLOS imaging",[143,146],{"id":144,"by":122,"text":145},"20814790","There was a similar technique discussed in a Ted Talk using femto-photography, which had an animation showing how it was done for an ELI5[0]. The talk contains references future…",{"id":147,"by":148,"text":149},"20815010","lopmotr","There are passive NLOS imaging technologies based on shadows: https:\u002F\u002Farxiv.org\u002Fpdf\u002F1807.02444.pdf…",{"value":151,"source":64,"evidence":152},"WiFi-based through-wall imaging (MIT Wi-Vi)",[153],{"id":154,"by":155,"text":156},"20818187","pjc50","I think it was actually 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