Is iPhone 12 Pro LiDAR accurate over 200 foot scan?

hi i'm rami tamimi and this is the iphone 12 pro in the last video we were analyzing the iphone 12 pro's lidar sensor and testing its relative accuracy in comparison to a surveying total station by popular demand everyone is asking me what the range is on the iphone's lidar system and does the accuracy decrease the farther along we go in today's video we're going to scan 200 feet with the iphone's lidar sensor and we're going to measure every 10 feet along this 200 foot stretch and compare the measurements to a surveying total station if you enjoy surveying and lidar videos be sure to like this video also be sure to subscribe and turn on the bell notification so you don't miss out on any of the latest content join our facebook surveying group uh the link is in the description we've got surveyors from all around the world sharing what they're doing and what they're up to so check it out and be a part of the community now what we're going to start by doing is establishing a 200 foot line that we can place all of our stakes at using this tape i'm going to drive the end of it here on this side of the property and then i'm going to pull this tape all the way down to the other end of the property and that should give us 200 feet to work with so i'm gonna start here and place the chaining pin so that should give it a pretty good hold and now we're going to pull 200 feet [Music] all right and right there we are at 200 feet all right and now we need to pull tight on this tape so that we have a straight line all right nice and straight and i'm going to now gently lay this tape down and this will now serve as our guideline for where we need to set the stakes all right now i've got 21 stakes here and i'm going to be placing one approximately every 10 feet now this isn't going to be exactly 10 feet which is why we're going to use the survey total station to get the exact location of every stake but for now approximately every 10 feet we will have one stake [Applause] [Applause] you [Applause] so now as you can see we've set one point every 10 feet for the length of our 200 foot line from now on we're going to be referring to that first point as station zero plus zero zero then every ten feet it'll become zero plus ten zero plus twenty zero plus thirty once we get all the way down to the 100 foot stake that'll be station one plus zero zero and then that last station down there the one at the 200 foot mark that's going to be station two plus zero zero we're going to be setting up the total station on station two plus zero zero and then the back sight will be set all the way down on station zero plus zero zero so here at station zero plus zero zero i'm going to set up the backsight i can't see the bubble that's a problem [Applause] how am i gonna see this bubble hold on okay uh here we go now i can see this bubble that looks good i'm gonna point the prism all the way down to the end all right good something tells me i'm gonna need this thing again and now here at station 2.00 i'm going to set up my total station if you don't know how to set up a total station go ahead and check out a video that i made a while back it goes through the details of how to set one up and then after you figure out how to set up a total station come back to this video and continue on all right i'm going to measure the instrument height from the top of the stake because i want the elevation to be at the top of the stake very important okay i come up here i'm getting about four point zero five four foot point zero five now i'm going to go ahead and take a measurement to our backsight and good okay as you can see here the distance between the total station and the backsight is 200.05 wow i was only off by 500 so that's pretty astonishing i did not expect to be that close but okay cool we're going to just zero out our horizontal angle all right now i'm going to go ahead and set up the job on my data collector all right so i'm going to move over to survey store points okay we are occupying point number one back siding two i put in my instrument height and the rod height of the backsight we'll go and hit backsight and we're going to go ahead and check all right and the errors are very minimal within the thousandths this is okay i'm willing to accept these conditions i'm gonna hit set angle and check now we have the total station down here at station two plus zero zero backsight up at station zero plus zero zero all right now we're gonna start measuring all these points using this rod and this bucket let's go all right so i'm going to set this rod right in the middle of the stake [Music] press these legs down get up on the bucket because i'm short now this is bubbled and our rod is at six feet above the top of the stake this is station zero plus one zero okay we're gonna go ahead and take a measurement all right next point station zero plus two zero all right middle of the stake station zero plus three zero all right zero plus four zero station zero plus five zero [Applause] six zero [Applause] seven zero eight zero [Music] nine zero [Applause] station one plus zero zero all right we're halfway done one plus ten one plus two zero this is station one plus three zero station one plus four zero one plus five zero one plus six zero station one plus seven zero station one plus eight zero [Applause] [Music] station one plus nine zero and there we go 21 points recorded um we don't have to measure the last one because we're occupying the last one but what we are going to do now is take a shot on station zero plus zero zero where the backside is and make sure that our horizontal angle is still zero okay and now i'm going to sight the backsight and uh here's what we've got if we look we have a horizontal angle of one second and our slope distance is a hundredth more not a big deal so we check out pretty good all right now that we've finished serving with the total station we're gonna go ahead and pull out the iphone 12 pro and we're going to use the lidar sensor to measure the stakes all right so the lidar scanner is on and we're starting at station zero plus zero zero and i'm gonna go ahead and hit start i'm going to come along here and start scanning and it should grab all of the stakes keep going okay looks good okay nearing the end here i'm gonna stop whoo that is our that's it right there taking a look here i can zoom in man that is our surface you can turn on the tin here you can see just how detailed this tin is i'm gonna go ahead and process out the colorized mesh right now okay and it looks like yep there it is that is the project that looks pretty sweet all right that's it we've measured everything with the iphone's lidar sensor now let's go back to the office and compare the point glad that we get from the lidar sensor to the shots that we took with the total station hello and welcome to the office all right so i've imported both the total station data as well as the lidar point cloud and as you can see here both are in autocad civil 3d now a few people were talking about why i'm not looking at the absolute accuracy of the lidar sensor why is it that i'm aligning the points to the total station points in order to have good absolute accuracy you need to have a good gnss receiver the one that you see on a cell phone isn't that great you're gonna be within several feet the ones that we see in surveying equipment however those gnss receivers are rtk enabled and can get very accurate measurements i promise i'll be going over gnss receivers in a future video but for now i want you to understand that the relative accuracy is the only thing we can look at because absolute accuracy that technology just isn't there for cell phones yet now again in the last video i talked about aligning the point cloud to the points um but i never showed myself doing it so i want to be more transparent with you and actually do it for you on camera so i'm going to type in the align command and then i'm going to select my object so i've selected the point cloud and now i'm going to select the first point i'm going to tilt this there we go and the first point is the stake and i'm going to select this top point here okay and i'm going to rotate back and that top point is this point right here so we're going to align to this point then i'm going to come to the other side rotate back down so we can see that last stake here's the tape at the ground that's funny that i picked it up and selecting the top point of the stake at station plus zero zero and i'm going to rotate this back down and select this node i'll hit enter it's gonna ask me if i want to scale my object to the alignment and i'm going to say no the reason we're going to say no is we don't want to rescale the point cloud if we're doing a transformation and we're you know adjusting our point cloud to some control points then i would say yes totally do it but for the purposes of analysis i want to try to keep this point cloud as raw as possible so i will not be scaling it to the um points that we shot with the total station so i'm going to select no and there we go now the point cloud is right with the points that we shot with the total station so now i'm going to rotate this again so that we can see the tops of the point cloud now this is station zero plus zero zero this is the fence so now what i'm going to do is i'm going to do again a 3d poly line and i'm going to just go ahead and select the top point here right there it's going to come down here there's the next stake select come up here and select and plus nine zero last one and two plus zero zero okay we now have our line i'm gonna just freeze this and you look from top down here here's all the total station points in red x's and then the magenta line is the features that we extracted from the point cloud i'm going to just freeze these total station points and then i'm going to just get the point creation toolbar opened i want to just create points here along this 3d polyline so this is zero plus zero zero and now with all the points created i'm going to open up my tool space i'm gonna right click on points export and i'm just gonna call this the point cloud points [Music] hit open and okay all right now let's go ahead and open up the points that we extracted from the point cloud and compare them to the points that we had on the total station so i've got here the coordinates of the total station on the left coordinates of the iphone lidar system on the right and over here in the far right i'm going to put the differences so i will create a simple equation of equals the northing of the total station minus the northing of the lidar sensor and i will move this across and bring it down just like i said in the last video we don't want to be looking at the points that we did the alignment with the only thing i'm going to look at is the northing of the last point so what i'll do is i'll highlight everything except this one cell and i will come back to this number at the end but i want us to start by looking at the first station off of the back site which is station 0 plus 10. so we have an error in the northing of 13 hundredths and then 1 10 and then elevation 5 hundredths wow that's actually not too bad now this is ten feet off of where we started recording data so um to be off i would say about a tenth in the horizontal and about five hundredths in the vertical not too bad of a start so let's see here on the next one we have an error of 0.163 in the northing 0.134 in the easting and then we're at 900 in the elevation so a little bit more error it seems as we've moved forward station zero plus three zero fourteen hundredth in the northing and then twenty three hundredths in the easting and then we've got sixteen hundredths in the elevation so again we continue to increase in error um as we've moved along this gets a little interesting the northing of station zero plus four zero uh is actually only five hundredths in the northing about three tenths in the e sting and then 14 1500 in the elevation so it's about off just as much as the station before it five plus zero zero again six hundredths and then three and a half tenths in the easting nine hundredths in the elevation a little bit better not too bad station zero plus six zero nineteen hundredths three tenths and two tenths station zero plus seven zero we have eighteen hundredths three and a half tenths in the easting and three tenths in the elevation again now we're starting to get over that a quarter of a foot mark zero plus eight zero we have three tenths in the northing about half a foot in the e sting and two and a half tenths in elevation okay yeah that's starting to get a little bit bigger in error but think about it we are 80 feet off of the backsight so this is 80 feet worth of measuring i mean it's quite a bit of distance at 90 feet we are at about four tenths in the northing half a foot in the easting two tenths in the elevation at 100 feet we've got four tenths in the northing half a foot in the easting and two tenths in elevation so at about 100 feet you're gonna be looking at about half a foot of error and i could keep going through all these but it's not necessary what i do want to look at is station two plus zero zero where it is actually uh almost negative one foot off um and so here's my conclusion after doing all this work for every 100 feet of distance you're looking at about a half a foot of air and this seems to be pretty consistent because after we've gone 200 feet we had about one foot of error so for every 100 feet you're gonna look at about half a foot of air and for every 200 feet you're gonna look at one foot of air okay and so what does that mean it means that the iphone's lidar system shouldn't really be used for uh long corridor mapping you know this is used for small little areas like that curb that i did and i'm looking at this data set and i could easily geo-reference those uh total station points and have a pretty accurate point cloud and that's just a general rule um you know you never want to just rely on the data acquisition you definitely want to tie in your data to some independent control so now we've answered the question the iphone's lidar system for every 100 feet has half a foot of air i hope you guys enjoyed today's video if you did be sure to like the video i put a lot of time and effort into making this content and i want to make sure that i'm delivering high quality and accurate information to you if you enjoy that please subscribe to the youtube channel it means a lot and turn on the bell notifications so that you don't miss out on any future uploads join us on facebook and share with us your experience with surveyors around the world thanks guys for watching and i'll see you all next time

Channel: Rami Tamimi

Views: 45,573

Rating: 4.9299231 out of 5

Keywords: Surveying, Land Surveying, Civil, Civil Engineering, Engineering, Total Station, GPS, GNSS, Boundary, Topographic, Boundary Survey, Boundary Surveying, Topographic Survey, Topographic Surveying, Stake out, Staking, Construction, Construction Layout, Layout, Surveying Engineering, Survey Leveling, Leveling, EDM, Transit

Id: UYZgCWhN5C8

Length: 18min 33sec (1113 seconds)

Published: Thu Aug 12 2021