Hi, I'm Rami Tamimi. Behind me here is a surveying total station. And this is an iPhone 12 Pro. This
is the iPhone 12 Pro's Lidar Sensor. And the surveying community has been obsessed over
this sensor, as they wonder if its accuracy is even measurable. Lots of people are saying
that this sensor can only be used for AR video games and modeling work and that using it for
measurements is very dangerous. And to an extent, that's true. This is a one thousand dollar phone,
so the sensor on here cannot compare to a sensor that's on a 50,000 dollar LiDAR system, let alone
a system that's 200,000 dollars. The question still remains is how accurate is the LiDAR sensor
on the iPhone 12 Pro? Now this is a total station, and as surveyors we trust its accuracy. Out of all
the equipment that we use this is definitely one of the more accurate and precise tools because
it takes relative measurements in comparison to absolute measurements, like GPS units. The
measurements that we take from the total station will be our baseline measurements, and the
scan data that we get from the LiDAR sensor will then be compared to the data we get from the total
station. Any differences we see between the two data sets will indicate that the LiDAR sensor
might be less accurate by a certain degree. If you enjoy this type of content and you want to learn
more about Surveying and LiDAR systems, be sure to like this video. Also subscribe to the YouTube
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the community and share your surveying experience with Surveyors around the world. All right so
this is the strip of curb that we're going to be studying. We're going to start by taking a
back a curb shot over here. Then, we're going to take a gutter shot right in front of it. Next,
where the concrete breaks I want to take another shot right here. And then, a shot in the back
to see this distance. Also, we're going to take another shot down here for the gutter. Next we'll
take another back of curb shot right before the elevation changes. And then, we'll take another
back of curve shot at the bottom here as well as a gutter shot and that'll be all the points that we
collect with the total station. These are typical measurements that we would take, back a curb,
gutter, whenever we're doing a topographic survey. So the best way to test this sensor is
on data collection that we would actually do in the industry. All right, so I've gone ahead and
set up this total station. Now if you don't know how to do that, I did make a video a while back.
Go ahead and watch that real quick and then come back to this video so that you can figure out the
procedure, but make sure you understand how this total station is set up. Once I've set the total
station up I am going to need to take the height of this instrument because we are going to be
taking vertical elevations so it's important to know how high up our total station is.
All right, and it looks like we are at 5.24; looks like 5.24. All right, cool. All right,
now I've set a backsight all the way on the other side of the street and this is going
to just set up my control network. It's a very simple control network I've got the
height of the rod and I'm going to now take a direct measurement using the total station.
Measure. Okay cool, we've got a measurement to the backside. Now, I'm going to go over
the setup parameters for our total station. All right, so I'm at the setup menu here
we are occupying point number one, our instrument height is 5.24 feet we're sighting point number
two that's where the back side is, and the backside height is 5.22 feet. I'm gonna go
and hit backsight. Okay and I'm gonna check the distance in comparison to what we have on record.
Boom. Our delta is zero in the horizontal, and zero in the vertical. So we are
right on with our coordinates. I'll hit the set angle button which will set our angle to zero, and
I'll hit check and there we go our instrument is here siting the backsight. And if we look at the
total station we can see that the horizontal angle is at zero degrees so we should be good to go. Now
what I'm going to do is take measurements along this little strip of curve and we're going to be
measuring with the total station and then later on scanning it with our iPhone's LiDAR sensor.
All right, let's get started. All right. I'm going to start by sighting the first point. Okay, good.
Good.
Three more shots. All right, good.
All right, one more. All right, looking good. Okay, great, we're done collecting data. Now
the only thing i want to do is just rotate the total station and check zero to make sure that
nothing happened no misalignments or any orientation issues happened.
All right, and let's take a look and our horizontal angle is at one second so we are
all good. All right now I've got the iPhone 12 Pro Max and right here is the LiDAR sensor. Now
we're going to be testing this LiDAR sensor's accuracy in comparison to the total station
measurements that we just took. The goal here is to use the results of the LiDAR sensor and
compare them to the baseline measurements of the total station. All right, so I've got the
LiDAR sensor on and we're going to go ahead and scan this little bit of curb. And start
recording data. There we go. Go nice and slow here, okay. I'm going to come over on this side
and continue to scan. And I think that should be good. It's going to go ahead and generate our TIN.
Get in here, and look at that, very nice. Come over on this side, you can look at the vertices
here, and yeah you can see it's a pretty tight TIN. Look over here, yeah. I'm going to go ahead
and share this. What kind of export do I want here? We'll select point cloud. We're going to
select LAS, okay I've set myself the LiDAR. And there you go, now we've got the scan and
we're gonna head back into the office and compare this data to what we got with the total station.
Hello, and welcome to the office. All right, so I've gone ahead and loaded up AutoCAD Civil 3D
and imported the LAS file into Recap, which is Autodesk's version of point cloud processing. And
then, I brought in the point cloud from recap and this is the final result. As you can see,
we have the curb, not too bad actually, it looks pretty good. So it's gonna be a little tricky to
maneuver through this but we're gonna do our best to pick out all the points that we need for this
project. So as I zoom into this point cloud I'm actually gonna increase the size of the
points briefly here. So where you see the color change here between the asphalt and the curb
is not necessarily where the elevation changes. So how do we find the exact change of the elevation?
Well, when we click on the point cloud we come up here where it says scan colors,
I'm going to drop down this menu and go down to elevation and you can see now the point cloud has
changed and now I'm going to decrease the size of the points. So it's a little easier to see
the features. Okay, so you can see now majority of this point cloud is turned green and that's
because it's taking all the values of the point cloud. We're really only concerned with the curve
and so what I'm going to do is come over to the color mapping. Okay, and what we're going to do
now is we're going to deselect the "apply to extents of point cloud" option. This is now
utilizing every point on the point cloud and again we only need the points that are around the curve,
so we're going to deselect it. And now it's going to ask us a few questions. It's going to ask us
what we want our minimum elevation to be. During the first control point I assumed an elevation
of 100. So I'm just gonna say the minimum elevation is 100 and a maximum elevation: now
these curbs, they're usually within half a foot to a foot in height. So I'm going to just say the
maximum should be 101 feet and then the interval height it's giving me a default of one-tenth
but I want to be a little more precise than that. I would like five hundredths of a foot. So, I'm just
going to type in 0.05 okay. All right cool, now it's saying we're going to have 20 different colors
around our spectrum. Okay, all this looks good to me so I'm going to go ahead and hit ok. And as you
can see, the points that are north of an elevation of 101 remain at their RGB values, and elevations
of points that are below 100 also retain their RGB color values. But everything in the middle
between 100 and 101 we now have a color for it. Okay so what I'm going to start by doing now is
just increasing the size of these points so that it's easier to see it's really hard to do this
kind of work when the points are so tiny. So we've increased the size of the points. Okay. All right,
I'm gonna go ahead and start with the curb. All right, this looks like a decent angle looks like
going up. This is roughly the point so I'm going to use the "3DPOLY" command which is going to create a
3D polyline. And I have the "3DOSNAP" command on which is that little blue circle with an x on it.
It's kind of hard to see I'm trying to bring it here to the white points yeah you see it there.
So I'm going to use that to help me select my point and I think I'm going to pick this point
right here. Okay, we're going to come over to this side of the curb and as you remember the curb
breaks so when you want to select the point where it breaks. And I can see the break is right here
so I want to select right where the color changes right there, perfect. Then we're going to come down
before the color changes again to the light blue so right there, perfect. Then we can see here's the
curb before it depreciates down. Okay, right there and now I want to come down to where the wall is,
I want to get that back corner I think it's going to be the lowest point which is like this yellow
right here and select it and end the line, great! And if I go ahead and just freeze the point cloud
you can see I've now traced the curb of the point cloud and now let's go ahead and do the gutter.
So I'm going to thaw out the point cloud again and we're going to select points. All right, I'm going
to go ahead and change my layer to LiDAR Gutter and I'm going to orient myself here. This
might be a good spot right here. Again you can see when the elevation decides to start going up, it's
like right at the start of the orange so that'll be when I start to click. So, 3DPOLY, selecting
right here and I'm going to come over to rotate a little bit so we can see where that break is it's
happening right here so I want to try to get a shot of the gutter in this location right here.
Okay and I want to select it right here and one more point. Okay, cool. Now we've got both the curb
and the gutter in, I am going to just go ahead and freeze our point cloud. If we take a look here
you can see the profile now that, that looks like a curb and gutter. Look at that! All right so what
I'm going to do now is I'm going to open up the point creation toolbar and I'm going to
create some points along these polylines. Just go to point creation tool, miscellaneous manual,
we'll come here we'll select this one. Okay now, I'm going to change this layer to LiDAR gutter.
Okay, point creation. We're going to come back over here and we're going to select these points. Here
and right here. If I come into points, I select edit points, now I've got a group of points here
with Northings, Eastings and Elevations. Now I'm just going to right click, select export,
it's going to ask me where I want to export these points to and I've selected the destination
of where I want to export. And I'm just going to call this LiDAR points and I want to save it as a
CSV and okay. And there we go now we've saved the points. Let's go ahead and open up that CSV and
then open up our points from our total station and begin comparing the coordinates. Here, we have
the coordinates of the total station and here we have the coordinates of the iPhone's LiDAR system.
Now, I know a lot of people are thinking. Rami, how in the world did you get this point cloud to be
on the same local system as your total station. And to that, I have to come clean and tell you
the exact procedure that I used when I imported the point cloud. I referenced two points from the
total station these two points allowed me to align my point cloud to the local system that we have.
It was the only way I was able to tie these two data sets together. So that means, two of
these points are going to have zero difference points 102 and 107 are going to be exactly the
same okay I just want everyone to be very clear about that. The differences from those two points
have nothing to do with the accuracy because I did an alignment. What we are going to look at
are all the other points because this will show the relative distance between the points whether
or not the LiDAR sensor on the iPhone 12 Pro can genuinely measure differences in distance and in
elevation. So what we're going to do is create a simple equation of "=" and I'm going to select
the northing of point 101 and subtract it from the northing of 101 on the LiDAR data set. Okay. I'm
going to click on this and copy the formula all the way down and copy it over and I'm going to
highlight these cells and block them because just like I explained these points were used
for alignment. If you have more questions please leave me a comment I will do my best to answer
what I did in my procedure. Okay, now let's look at some of these differences I'm literally blown
away. Point number 101 has literally a difference in Northing about 0.04', 0.08'
in the Easting, and 0.05' in elevation. That's crazy, that is really, really close. Point
number 103 has a difference of about 0.30' in the Northing, 0.09' in
the Easting and man the elevation is right on 0.03' again so close, I did not expect that.
Point number 104, Northing 0.25', Easting looks about 0.10' difference
again elevation 0.01' that... I'm more blown away about the elevation differences because it
almost seems like elevation is so hard to achieve, but here we are coming in at about a hundredth of
a foot. 105 we've got 0.15' again that's following the trend here. The easting is about
0.05' and elevation this time is about 0.14'. Still super tight super good I
really like that. Point number 106, we've got about 0.20' in the northing 0.60' in the easting,
now this is the biggest difference that we have. Again, elevation 0.02. And the last point, we've got
a difference in northing 0.07' easting 0.06' and elevation is 0.09'
so again I'm really blown away by how within a tenth I would say comfortably a tenth,
definitely some spots like right here where it was you know 0.20', 0.60', but elevation
wise we were good and this could really be just me picking the wrong spot, you know. You saw
how difficult it was, it wasn't the easiest task in the world. There's better software out there
unfortunately the iPhone's LiDAR doesn't give you an intensity output as well which would be amazing
to have so all I had to rely on was the elevation changes. Nonetheless for the amount of work that I
did I was able to extract some relatively accurate data and I think now as us surveyors continue
to discuss the accuracy of this LiDAR sensor, I've done an actual test and I have to say
it was beyond my expectations. I did not see this coming. I was really expecting half a foot to a
foot of difference but for it to be about you know one-tenth in difference you know I would
say that's pretty astonishing and very impressive. I hope you guys like my video today, if you've got
questions or suggestions, I highly encourage you to leave a comment down below I would love
to interact with you I want to see what you guys think you know was this scientific enough, should
we do more testing, tell me what your thoughts are what should we do to further this. If you like
this kind of content and you want to see more be sure to like this video. Also subscribe to my
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