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
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out. The link is in the description. Be a part of 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 YouTube channel and turn on the bell notifications
so you don't miss out on any of my latest content. Also if you'd like to take this conversation over
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and be a part of our community and interact with surveyors all around the world. Thanks guys
for watching, and I'll see you guys next time.
TL;DR: He was able to retrieve some "relatively accurate" measurements and it was "beyond his expectations".
Edit: Reddit platinum? Wow thanks!
UK surveyor here. Use total stations and laser scanners (point clouds like he picks the iPhone points of).
Actually very impressed at the accuracy. Never seen the iPhone LiDAR in use but very quick and great it has photogrammetry seemingly baked in, even if no intensity is fantastic. Using a very expensive Leica P40 it takes so long for photos we typically don't bother and just use intensity/elevation combined with mobile pictures for reference.
Wouldn't trust it for anything high accuracy based on those results but for soft detail it looks like a fantastic quick alternative.
Could easily envision using this in a complex area alongside a "proper" scanner with a couple targets to minimise occlusion. Again, where accuracy is not strict.
Hey look, that's me. Glad to see I'm Reddit famous now! But I hope everyone enjoyed the video and learned a thing or two!
more to the point
Watching this man surveying in feet hurt my brain.
The limiting factor is the effective range of Apples LiDAR -less than 4 metres.
He should have made this video 52 weeks ago.
He should do a review of the iPhone 13 Pro to see if it's more accurate than "relatively".
We use Matterport cameras for work (fire investigation) and I did some tests to see if we could use the iPad/iPhone lidar to get a similar result for smaller jobs. In a well-lit room in my house - so not even a dark fire loss site - I found the measurements to be off by 20% on average. Certainly not something we would be able to present to a client.
Not to mention the quality of lidar scanning apps, or even the Matterport app, were both subpar. It’s an interesting technological addition to the phone, but the it’s not really at the point of use for business purposes where accuracy is paramount.