iPhone 13 Pro LiDAR vs. Survey Total Station Accuracy

hi i'm rami tamimi behind me here is a surveying 
total station and this is the iphone 13 pro   today we're going to be analyzing the iphone 13 
pro's lidar sensor and we will be comparing the   data from this lidar sensor to a high accuracy 
surveying total station now what we have here is   apple's new iphone 13 pro they've included their 
second generation lidar sensor next to their three   camera sensors that they've all upgraded so 
the question is how accurate is this lidar   sensor in comparison to a total station a 
robotic total station is one of the most   accurate pieces of equipment used in the surveying 
industry the relative accuracy that we can achieve   with a surveying total station is usually between 
100th and 200th of a foot so it's safe to assume   that this piece of equipment is a great benchmark 
to use for testing relative accuracy a total   station like this can cost anywhere between 20 
to 60 000 us dollars and a professional-grade   lidar sensor can easily run you up to 180 000 by 
taking several measurements of features using a   total station and then extracting those locations 
from the data set we get from the lidar sensor   we can calculate the relative accuracy of 
the iphone 13 pros lidar sensor now if you   enjoy this type of content and you want to learn 
more about surveying and lidar sensors be sure   to subscribe to the youtube channel and turn 
on the bell notifications so you're notified   anytime we release new videos now for today's 
video we're going to be measuring 15 different   points and i've marked all these points using a 
piece of chalk and i'm going to go over exactly   why we're analyzing these points and what we hope 
to achieve by measuring these specific locations   points number 101 and 102 will be used 
to analyze how the iphone's lidar sensor   can handle the elevation change between a 
curb and a gutter points 103 104 106 107   109 110 and 111 will be used to compare a feature 
extraction of the sidewalk we want to see how well   the iphone's lidar can position the sidewalk in 
comparison to the total station point number 105   is a pk nail a pk nail is generally used in the 
surveying industry to set control points so i'm   curious to see if the lidar sensor is going to 
be able to pick up this feature and whether or   not the accuracy of this point using the lidar 
sensor is going to be relatively the same as the   total station point number 108 is the center of 
the storm sewer manhole manholes are really common   utility structures that we see in the construction 
industry so by scanning it with the lidar sensor   i want to see how accurately we can get to the 
center of this manhole as well as identifying   the rim elevation points number 112 113 114 and 
115 will be used to map out the curb and gutter   as well as analyze the change in elevation just 
like we did with points 101 and 102.

And that's   it that is what we're going to be surveying today 
this is a very realistic example of what we would   do in the industry so by comparing the total 
station and the lidar sensor on a site like   this we should be getting a real world example 
of what to expect in terms of relative accuracy   all right let's start by setting up the survey 
total station if you're unsure on how to set   up a surveying total station check out this video 
that i made a while back it kind of goes over the   fundamentals of setting up the tripod placing 
your total station over a point and leveling   it as precise as possible so watch that if you 
don't know how to set up a total station and   then come back to this video all right and i am 
measuring an instrument height of 5.04 5.04 feet okay and i'm going to set my back sight right here 
make sure the bubble is in the center and point it   in the direction of the total station now i'm 
going to take a distance using the total station   to the backsight and using this distance i'm 
going to then create my local coordinate system   okay and we're pointing the total station to the 
backsight i'm going to go ahead and take a reading   okay and after taking that reading we can see that 
the distance between both the total station and   the backsight is 24.009 feet and the elevation of 
the backsight is 100.289 feet so using these two   distances we can now assign coordinates for our 
backsight and set up our control network and now   we're at the setup menu we are occupying point 
number one which is where the total station is   instrument height which is the total station's 
height which we measured at 5.04 feet backsight   point which is point number two and the height 
of the backsight is 5.29 feet i'll hit backside   and check as you can see we have zero error 
which means that our control network is set   up i'll hit set angle and now we're ready 
to go now i'm going to be using this little   1.4 foot rod this little rod will help 
us stay as close as we can to the ground   and minimize any kind of errors usually a six 
foot rod is fine it really won't create that   much error but for the purpose of this experiment 
i want to try to do this as clean as possible   so that is why we're going to use this 1.45 
foot rod for all of our foresights i'm also   going to attach this receiver sensor on top of 
the prism so that we can utilize the robotic   functionalities in this total station and it'll 
find the position of this rod without me having   to point at it this does not impact the height 
of the rod as this is going on top of the prism   all right looking good i'm going to start by 
setting the rod here on point number 101 okay   and the bubble is leveled all right now i'm gonna 
have the total station search and find the prism all right perfect we're locked on okay now 
that we're locked in on the prism i'm gonna   go ahead and assign this as point number one 
zero one this is a gutter so i will call it   gutter and the prism height is 1.45 feet 
and now we can take this observation all right now i've set this up on the 
curb so i could just change this to   curve and we'll take the next shot and 
that's pretty much the procedure i'm going   to go ahead and do this for the rest of the 
15 points okay point number 103 0.104 0.105 0.106 107 108 109 110 111 112 113 114 and finally 115   and there we go 15 points and as you can see 
all of our points are here all of them are also   labeled appropriately based on the feature that we 
measured i'm just gonna go ahead and finalize this   by checking into our backside and making sure 
that our horizontal angle is still set to zero   okay and measure and we can take a look here and 
see that our horizontal angle is zero degrees so   we're all set with the total station measurements 
now that we're done taking measurements with the   total station it's time to test the iphone 13 pros 
lidar sensor before we get started i just want to   let you guys know that i started surveyshirts.com 
here you'll find a large range of surveying   apparel the shirts come in different sizes and 
colors so please check out surveyshirts.com let's   get more survey shirts out there for all of our 
fellow surveyors to wear now i'm going to be using   the 3d scanner app this app is available for free 
on the app store so i'm going to go ahead and open   up the app and as you can see here we are in the 
low res mode i'm going to switch over to high res   and with the high res on i have some options that 
i can go through first i can select the confidence   level that i want my scan to have the higher the 
confidence the more accurate the position of the   point is in relation to other points this also 
means that there was a strong return on the point   so by setting this confidence level to high you're 
going to have a lower number of points because the   threshold for high accuracy points is a lot higher 
so i'm going to set this to high actually because   i want to have the most accurate points uh when 
doing the scan next we have the range the range   will tell us how far out you want the scan to go 
if i have a short range it's only going to capture   points that are a lot closer to me the more i 
increase the range the further points are then   collected of course anything after 5 meters will 
not be collected i am going to set the range to 5   meters because i want to collect as many points 
in our field of view next we have masking which   if we're doing modeling work i'll definitely want 
to mask the object that i am scanning i don't want   the background to show up if i'm doing uh modeling 
work but because we're doing mapping work where   we're measuring the terrain i want to make sure we 
capture everything so i'm going to leave masking   off and finally we have resolution the resolution 
indicates how much detail we want in our scan   if we increase over to 20 millimeters this will 
reduce the resolution because now we're scanning   at a much higher scale which is why you see the 
house there but if i lower the resolution i can   set it to five millimeters which would 
scan something as detailed as an apple   now that i have all my settings in place 
i can go ahead and start scanning our site okay okay looking good all right and as you can see we have our scan 
right here looks to be pretty good i'm gonna   go ahead and process the colorized scan now 
all right and there we go the colorized scan   is done you can go ahead and turn on 
the tin look at that look how incredible   that is i love looking at this interface and being 
able to see all the connection points for all the   points that were scanned using the lidar sensor 
now let's take the data from the total station   as well as the scan that we got from the iphone 
13 pros lidar sensor and analyze it in the office   why hello there welcome to my office which is 
actually in my house all right let's import all   the data into autocad civil 3d we'll start with 
the total station points i'm going to go over to   insert points from file and i'm going to add 
points and i'm going to select my iphone 13 file   and there we go the point format is point number 
northing easting elevation and description so all   of my points are here we'll go ahead and just 
click ok and there we go we have all of our   points here's point number one where the total 
station was point number two where the backsight   was and then everything curb gutter curb gutter 
curb gutter the sidewalks pk nail and the manhole   okay now let's go ahead and import our point cloud 
that came from our iphone 13.

I'll come up to the   insert tab under point cloud i'll select 
attach this is my point cloud file so i'm   going to open it now it's going to ask me where i 
want to place this point cloud it doesn't really   matter where i place it because i'm going to 
end up aligning it to the points that i shot   with the total station relative path is fine 
select insertion point i'm gonna just do 49.50   because 5000 5000 is where the site is located so 
i'm going to move it 50 feet off of that site 4950   elevation i'll just set this to 100 because that 
was the elevation of our assumed coordinate system   the scale will keep it set to one because we don't 
want to rescale the point cloud and the rotation   will keep it at zero and we'll hit okay and there 
we go point cloud is here if i select it you can   see the insertion point 4950 4950 elevation 100 
zero rotation and scale of one so now when you   look at this point cloud you can see we have the 
rgb values of all the points the points are kind   of small so i'm going to select this and increase 
the size to i don't know seven that way when i   zoom in i can really see the points so i can see 
it right there now it's not the best practice to   use the rgb values because there could be a 
shift between the lidar points and the camera   that was used to take the colored picture because 
the lidar points are then assigned colors based on   those pictures so if there's any kind of drift 
between the two sensors then the colored points   are going to be drifted the best way to visualize 
this is going to be by setting this over to normal   and you can actually see where there are changes 
in elevations so what i'm going to do because   it's really difficult to pick the points in this 
visualization setting i'm going to pick the points   with the rgb values but then i'm going to check 
the normal visualization to make sure that it's   actually where it needs to be so we'll switch 
back to scan color and now we're going to align   the point cloud to the total station points 
it'll ask me to select an object i'm going to   select my point cloud and that's going to ask for 
the first point so the first point is going to be   right here and i see some red so i think that's 
where the point is and now i'm going to select   104 now it's going to ask for a second source 
point so the second point we said let's do this   bottom point here and point number 112 is over 
here now it's going to ask me if i want to scale   my point cloud and i'm going to say no because i 
don't want to change the locations of these points   so the relative distances between all these points 
will stay the same it's just now they're being   aligned to the total station points so that we 
can have everything on the same coordinate system   so i'm going to say no and that's it the point 
cloud is now on the same coordinate system as   the total station points all right now we're 
going to start the feature extraction from the   point cloud that we got out of the iphone 13 pro 
to begin i'm going to freeze the total station   points so that we're not confused by them when 
we go to select the points on the point cloud i   created a layer called lidar points so i'm going 
to select that and set it as my current layer   alright so we're going to go to points point 
creation tools and if i bring this over here   i can take a look at some of these settings the 
biggest one is the default layer we're going to   use the current layer and when i come down to 
point identification we're going to start with   point number 201 all points that are 100 are going 
to be points that came out of the total station   all points that are 200 will be points that we 
extracted from the point cloud that came out of   the iphone 13 pro so all this looks good to me i 
can close out of that and start creating points so   we'll come down here this is our first point and 
i can see where there's the red marking so i will   select here it'll ask me for a description this 
is a gutter and now it's assigned an elevation   this is the elevation that it's taking from the 
point cloud so we're always going to accept this   elevation because that's our measured elevation 
from the data set that we have all right if we   look over here point number 201 is created right 
and i've tilted the point cloud a little bit here   so i can at least see the edge of the curve and 
select the right point so this right here curb and   give it the elevation and this is the procedure 
of feature extraction so i'm going to quickly go   through the rest of the 15 points and extract all 
of them okay point number 103 concrete point 104   concrete point 105 the pk nail point number 106 
concrete okay point number 107 concrete point 108   manhole storm sewer point number 109 concrete 
point number 110 concrete point 111 concrete point   112 is a curb 113 gutter point number 114 curb 
and finally point number 115 gutter all right if   we take a look here all the points are in there 
i'm going to go ahead and freeze our point cloud   these are all the points that we just extracted 
from the point cloud i'm going to bring back the   point cloud and i want to change the visualization 
of the points to normal so that we can take a   look and see and make sure everything that we 
selected is exactly where it needs to be so now   we can highlight the curb gutter much more defined 
and it's not relying on the rgb values okay this   all looks to be in the correct place yep this 
curve and gutter looks good what's really going   to show is where there's like intersection 
of features like right here where there's a   driveway and a curve so this point looks to be 
in the correct spot this looks to be the center   of the manhole this right here along the sidewalk 
and driveway looks good so yeah all the points are   matching up to the point cloud like it should 
so that means the camera sensor and the lidar   sensor calibrated correctly and all the rgb values 
are accurately placed so now let's go ahead and   export all the points so that we can bring it into 
excel and compare all the numbers all right point   number 101 which was the first gutter shot that we 
took we have a difference in northing of 0.04 ft   difference in easting of 0.1 feet and the distance 
in elevation 0.22 feet i've also included the   millimeter conversions so if you're outside of 
the us and you want the metric differences there   you go this honestly isn't too bad i feel like 
the elevation is a little more than i thought it   would be i thought it would be a little less than 
that overall positioning wise we're only off by a   tenth that's pretty good when we look at the curve 
we have slightly more error 0.08 0.14 0.19 in the   elevation so yeah again i'm seeing a little more 
error than i would have liked point number 103 we   are right on in the northing pretty much right on 
in the easting and only a tenth off in elevation   and i like that that's pretty good that tells me 
that um within that distance between 0.104 and 103   there wasn't too much of a difference in there 
104 we really can't use to test the accuracy   because we used it to do the alignment you might 
be wondering why this isn't 100 zero and that's   because i didn't pick the exact same location when 
i did the alignment versus when i did the feature   extraction so forgive me but um i was off by about 
a hundredth of a foot nonetheless let's move on   to the next point that pk nail was off about 
one tenth in the northing and easting and only   300th in the elevation so that's pretty good i'm 
pretty satisfied with that one 0.106 which was   along the concrete we were off eight hundredths 
in the northing right on in the easting and pretty   much right on with the elevation so that's pretty 
good 107 which is a point on the concrete across   from the manhole we have about two tenths in the 
northing one tenth in the easting and one tenth in   the elevation that's actually pretty good i know 
the northing's a little high but um the elevation   came out really good on that one so i'm pretty 
satisfied the manhole that we shot 108 0.17 0.13   and then about two tenths in the elevation not too 
bad actually i think that's pretty good definitely   not something i would trust for any kind of design 
work because that room elevation really needs to   be much more accurate but for what we did it 
wasn't too horrible looks like points number   209 210 and 211 share about two to three tenths 
difference in the northing 10 to 15 hundredths   in the easting and about two to three tenths in 
elevation and that's because we're moving about 30   feet away from the start of our scan so i think 
that 30 foot move uh did cause a little bit of   drift error so i i can see why that would be point 
number 112 northing and easting two tenths and one   tenth again that's probably from the drift from 
how far out we went i'm not going to compare the   elevation because we use that point for alignment 
points 113 114 and 115 which were the curbs and   gutters uh they seem to all share very similar 
results two tenths in the northing about one tenth   in the easting five hundredths for 115 so that's 
pretty good and elevation one to two tenths and   so overall my thoughts you know if you're looking 
for one to two tenths of accuracy you probably end   up finding it there's still drift error that 
is occurring with the iphone's lidar sensor   so this isn't perfect for mapping however if you 
supplement it with some additional control points   recognize the margin of error and what your 
realistic expectations should be the lidar   sensor is relatively accurate it does a pretty 
good job of maintaining its positional accuracy   and the rgb values are lining up pretty good 
with the lidar points so you shouldn't have   any issues using the rgb point cloud to do feature 
extractions i definitely want to do more testing   with this iphone and start incorporating more 
control so that we can increase the accuracy as   much as possible i hope you guys enjoyed today's 
video if you did please like the video i put a lot   of effort into this and i really appreciate 
you guys watching this all the way through   if you enjoy surveying lidar iphones all this 
great technology be sure to subscribe to the   youtube channel and turn on the bell notification 
so you don't miss out on any future uploads check   out our private facebook group the link is in the 
description we have surveyors from all over the   world talking about the exciting projects that 
they're working on so definitely be a part of   our community and share with us all your surveying 
experience be sure to check out surveyshirts.com   if you want to buy surveying apparel and 
with that i will see you guys next time

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