Merging Photogrammetry and Laserscan - Beginner

Please feel free to ask other members for help with certain projects
Post Reply
Khajiit
I have made <0 posts
I have made <0 posts
Posts: 2
Joined: Fri Jan 20, 2017 4:56 pm
7
Full Name: Ilyas KARKACHE
Company Details: SATF-CONGO
Company Position Title: Project Manager
Country: Congo

Merging Photogrammetry and Laserscan - Beginner

Post by Khajiit »

Hello,

First of all I'd want to congratulate you all after reading some of the topics of this forum. People in here seem to be really passionate about what they do and truly know what they're talking about!

I myself am convinced about the potential of this new technology and that's why I'm currently working on a project of aerial photogrammetry (from drone). One of my clients to be wants me to make a 3D model from one of his buildings. I know how to do it since I learned to use ERDAS, and I am still not convinced about the use of either PhotoScan or Pix4D...
But that is not my main problem. My client told me he wants me to somehow merge his already acquired laserscan data with the results of my photogrammetry...

Why would it be interesting to do so? And most of all, how do you do that??

It has been a very long time since I last used a Leica Laserscan system or ERDAS, so please don't be too harsh on me :) Just looking for some explanations and tips!

Thank you very much,

Khajiit
User avatar
gilles_3DR
V.I.P Member
V.I.P Member
Posts: 235
Joined: Mon Dec 08, 2014 11:41 am
9
Full Name: Gilles Monnier
Company Details: Hexagon
Company Position Title: 3DR Technical Manager
Country: France
Linkedin Profile: Yes
Has thanked: 2 times
Been thanked: 28 times

Re: Merging Photogrammetry and Laserscan - Beginner

Post by gilles_3DR »

Hi khajiit,

In order to answer your first question: why would it be interesting to do so, I'd say it's because the photogrammetry and the laser scannig will not get the same data. In your case, for a building, you would scan the interior and use uav for the exterior maybe.

As for your second question about the tool to use in order to.merge the data, I'd say it all depends!
The main reason is that there are many different software packages available which all allow you to do different things from scanner and photogrammetry point clouds!
What kind of modeling do you need? External only? Or also the interior? How complex is the building? Simple & modern (mainly planar surfaces) or with a nice but complex facade?

All the best,
User avatar
RobM
I have made 100> posts
I have made 100> posts
Posts: 101
Joined: Mon Aug 22, 2016 9:55 am
7
Full Name: Robin Miller
Company Details: My own boss
Company Position Title: Managing Director
Country: Germany
Linkedin Profile: No
Been thanked: 14 times

Re: Merging Photogrammetry and Laserscan - Beginner

Post by RobM »

Hi Khajiit,

I`ve done this task quiet a few times. There are many ways to merge UAV and Laserscan Pointclouds.
One would be to use the same coordinate system for both, which is pretty easy if you use a total station. But since your customer already has existing pointcloud data from his scanner, I doubt that his files are georeferenced and you can get into the same system that easily.

So heres what I would suggest: Take a look at his pointcloud. If you have distinctive points that can be seen with your UAV mark those and export them (this could be done in Trimble Realworks, Faro Scene or AutoCad to name a few). I personally use Agisoft Photoscan, so I would import those distinctive points via CSV and use them as control points to register your photos before making the dense pointcloud. When exporting the pointcloud make sure you use the coordinate system you configured your GCPs. Merge the pointclouds with RECAP. Since now they should be in the same coordinate system, all you have to do is import your pointcloud files into one recap project.

Hope this helps
Attreyu
I have made 50-60 posts
I have made 50-60 posts
Posts: 59
Joined: Sat Mar 26, 2016 6:26 pm
8
Full Name: Dragos Ioan Coste
Company Details: 3Deva
Company Position Title: Founder
Country: Romania

Re: Merging Photogrammetry and Laserscan - Beginner

Post by Attreyu »

Hello,

I've been asking around the forum for this during the last year, but this is a quite "strange" topic. I'll share my thoughts:

First you need to determine what exactly is that the customer needs, because it can be one of the following:

If they want a colored pointcloud - this is kind of easy. You need to merge the two pointclouds, from the laser scanning and the photogrammetry. In order to do so, you need to register the two and merge them on common GCPs - this means that you'll need to use the drone's GPS and that the photos need to have embedded geo-info.

If they want a mesh which has the detail of the laser scan combined with the texture quality from the photogrammetry - then it gets tricky.

This would mean that you have to find a way to fuse the images and the laser pointcloud.

I know that you can use a RGB pointcloud and convert it to a textured mesh using MeshLab, but the quality of the texture is not very good.

You can also use a classic scanner with a HDR camera and set up a solution which involves mounting the scanner on a vehicle or on a drone - this can be done by integrating the scanner and a GNSS unit in order to referrence the photos and the static scans in real time - but this can't be done at the stage you're now at, since the laser scan has already been collected.

The last option is the ideal one - fusing the photos with the laser scan, and export it as a colored polygonal mesh - the method involves registering the two sets of data and stitching the photos over the laser scanned pointcloud - I know of only one software which pretends to do this - Capturing Reality.

https://www.capturingreality.com/Product

The process goes like this:


youtu.be/M6Uf8kjfbSA

Also:


youtu.be/0LvRiVnzoyI
www.3deva.com - Digitalisation, Pointcloud to Mesh conversions, Virtual Reality
jamesworrell
V.I.P Member
V.I.P Member
Posts: 537
Joined: Mon Jun 16, 2014 1:45 pm
9
Full Name: James Worrell
Company Details: Bennett and Francis
Company Position Title: Director
Country: Australia
Linkedin Profile: Yes
Location: Brisbane, Queensland, Australia
Has thanked: 14 times
Been thanked: 87 times
Contact:

Re: Merging Photogrammetry and Laserscan - Beginner

Post by jamesworrell »

Latest version of Bentley Context Capture is supposed to be able to merge UAV+scan .. uses the accuracy from the scan and textures etc from the drone. Don't know much about it other than that ..
User avatar
LPaulCook
V.I.P Member
V.I.P Member
Posts: 485
Joined: Sat Jul 18, 2015 9:42 pm
8
Full Name: L Paul Cook
Company Details: Land surveyor doing LiDAR
Company Position Title: President
Country: United States
Linkedin Profile: Yes
Location: Santa Barbara CA
Has thanked: 47 times
Been thanked: 44 times
Contact:

Re: Merging Photogrammetry and Laserscan - Beginner

Post by LPaulCook »

It looks like you can do this in Recap.

Has anybody tried that?

Tell us how that worked for you and what the process is like.

Thanks
L. Paul Cook, PLS
www.LPC3D.com
Khajiit
I have made <0 posts
I have made <0 posts
Posts: 2
Joined: Fri Jan 20, 2017 4:56 pm
7
Full Name: Ilyas KARKACHE
Company Details: SATF-CONGO
Company Position Title: Project Manager
Country: Congo

Re: Merging Photogrammetry and Laserscan - Beginner

Post by Khajiit »

Hello ,

Thank you very much for your answers, they are realy helpful and make me go deeper in my thoughts and choices.
gilles_3Dreshaper wrote: What kind of modeling do you need? External only? Or also the interior? How complex is the building? Simple & modern (mainly planar surfaces) or with a nice but complex facade?
I guess it is important to give those details I forgot: I'm working on external modeling, on a very complex building with pipes everywhere, and I'm afraid my drone won't be able to cover up all the areas that's couldn't have been scanned from the inside, but hey, at least that'll be done.
RobM wrote:Hi Khajiit,

I`ve done this task quiet a few times. There are many ways to merge UAV and Laserscan Pointclouds.
One would be to use the same coordinate system for both, which is pretty easy if you use a total station. But since your customer already has existing pointcloud data from his scanner, I doubt that his files are georeferenced and you can get into the same system that easily.
I'm not sure if I will obtain those distinctive points before the work. They may want me to merge the two models afterwards. I doubt that their model is georeferenced too, and I fear that I can't even find more than 2 or 3 tiny dinstinct areas of interest to help merge everything together. How would it be possible to do so in that case?
Attreyu wrote: The last option is the ideal one - fusing the photos with the laser scan, and export it as a colored polygonal mesh - the method involves registering the two sets of data and stitching the photos over the laser scanned pointcloud - I know of only one software which pretends to do this - Capturing Reality.
Your last option is the one which caught my interest the most. But I've been recently told that 3DReshaper would be the best soft to do the job. What do you think about that?
User avatar
gilles_3DR
V.I.P Member
V.I.P Member
Posts: 235
Joined: Mon Dec 08, 2014 11:41 am
9
Full Name: Gilles Monnier
Company Details: Hexagon
Company Position Title: 3DR Technical Manager
Country: France
Linkedin Profile: Yes
Has thanked: 2 times
Been thanked: 28 times

Re: Merging Photogrammetry and Laserscan - Beginner

Post by gilles_3DR »

Khajiit,
I'll let others answer your last question! :D
However, do not hesitate to request our support team a temporary license to test the SW and ask them about what they would suggest to process the data.
tbwester
V.I.P Member
V.I.P Member
Posts: 904
Joined: Fri Apr 20, 2012 1:49 pm
11
Full Name: Thad Wester
Company Details: Clarity Scanning
Company Position Title: President
Country: USA
Linkedin Profile: Yes
Location: SC
Has thanked: 1 time
Been thanked: 2 times

Re: Merging Photogrammetry and Laserscan - Beginner

Post by tbwester »

This is easy to do with already acquired scan data in pix4d. or agisoft.
ravindranarayanan
I have made <0 posts
I have made <0 posts
Posts: 1
Joined: Sun Aug 26, 2018 5:51 pm
5
Full Name: Ravi
Company Details: KG Energy Construction and Technology
Company Position Title: CEO
Country: Scotland

Re: Merging Photogrammetry and Laserscan - Beginner

Post by ravindranarayanan »

HI Khajiit,

How are you? Just wondering have you had a resolution on your question? Im planning to do the similar for one of my project. And tips/helps would be appreciated.

Cheers,
Ravi
Post Reply

Return to “Request Help With Projects”