Photogrammetry with DJI

bogdanditu · Jun 16, 2014

i see the pc ground station is capable of Photogrammetry.
Has enybody done it? how does it work? i asume it does not work with P2V ans P2V+...i olso asume you need the ground station kit for your phantom...does anybody have this? have you tried it? cand you show me a result?
I am thinking of aerial 3D modeling...and afther printing it on a 3d printer...do you think it's possible? i would like to scan an important building...or a house...something like that...and then print it on 3d. Is this posible with DJI? Will i be able to save the Photogrammetry data in .sli format (i think that is used for 3d printers).
Hope to hear some interesting responses on this topic.

npalen · Jun 16, 2014

viewtopic.php?f=7&t=6255
There might be something here of interest.

chuddly · Jun 16, 2014

I have not done it...but i do have a 3d printer and have messed with scanning a bit. I wont say its impossible...but it would be VERY difficult to get a good scan. Even if you had a better quad than the DJI. The subject and camera have to be VERY VERY stable and at any fixed distance. Now think about how much your quad moves in the air even in gps mode when its fighting to stay in one place. The way i will put it is IF you had a VERY stable quad on a VERY calm day and a VERY iconic building with shapes specific to that building only then you MIGHT be able to get a scan of it that would be usable after some computer doctoring of it. The 3d printer is much further along than the 3d scanner. 3d scanning is good for small fixed things you can control the environment of. live and large things are a major problem. To confirm your question thought....Yes most 3d printers use STL file formats. But most 3d file formats can be converted to others with some specialized tools.

traeger23 · Jun 16, 2014

You might already be aware of it, but Autodesk has a free app for building 3D models off of multiple source photos, called 123D Catch. You can run it online, or use their dedicated PC app (no Mac support as of now). More info is here:

http://www.123dapp.com/catch

They have an iPhone/iPad app as well (although this would be harder to use with a Phantom or other quad), and they all work reasonably well using even pretty uneven source photos. You get a reasonably detailed model that uses your source photos for texture maps, which is then exportable to pretty much whatever other 3D app you're using (exportable formats are .obj, .stl and .3dp).

Again, I've thrown several series of handheld shots at it, and gotten reasonably good results. Plus, it's hard to argue with free.

npalen · Jun 16, 2014

Thanks for link to 123dapp !!! That's exciting stuff !!! I've been looking for a good excuse to buy a 3D printer and this may just be it.

chuddly · Jun 17, 2014

before you fully commit to a 3d printer you should know that they are not a "consumer" level yet. with the Phantom being the most consumer ready quad out there buying a 3d printer would be like buying a quad and having to wind the motors your self. There are more consumer ready ones (makerbot) but the price is also double or triple what other printers are. I just want you to realize what you are stepping into before you jump in and regret it. Its a great hobby but takes ALOT of tinkering to get right. Imagine Phantom tinkering x100 and your close.

npalen · Jun 19, 2014

I've been watching the development of 3D printers for several years now and agree that they are not quite out of the "tinkering stage". The idea of melting weedeater string to make a part just doesn't smack of precision. The latest low end liquid resin/laser printers show some promise but, again, may be a while.

chuddly · Jun 19, 2014

The ABS printers have more accuracy than you would think..but the resin ones are absolutely awesome! If you want to see some REAL precision check out the DLS (direct laser sintering) printers that print in real metal and can do such great work that they do surgical hip joints with no machining required after printing. Those are pricey but man are they neat

MonsieurAnon · Jun 20, 2014

I'm a former professional from the Games and Animation industry and it's my opinion that a part of the problem with 3D scanning at the moment is the end user. People seem to expect to be able to wave around a set of cameras on a stick and have a precise replica of their environment. It may not be there, but it is definitely possible to get good photogrammetry results from small quadrotors.

I've done a number of scans using a Samsung NX-1100 and the Vision camera that have been of a useful commercial value and they have been much cheaper (read faster) to produce than walking around with a crane and a tripod.

The issues that people are having when they tinker is that often they're not used to handling complex 3D meshes. Many tinkerers and printing hobbyists use engineering programs, not art programs and these are not designed to handle these files at all. Ask any number of hobby groups or forums and they'll recommend open source or freeware junk like 123D or Blender.

What you need to be doing is treating it like a part of a pipeline. One job that I worked on, for example, used a high resolution 3D scanner on ~30cm objects. We were getting details so small you couldn't see them with the naked eye and asides from sitting the object on the turn-table it was completely automated.

Further down the pipeline, the 3D artist only needed to do 2 things; produce low poly geometry from the scan and press render ... and they had better normal maps and textures than could be done by hand. We were producing art assets that normally would take ~40 man hours in as little as 8. But the tinkerer thinks that he can do all of the above in a hobbyist program, without consulting a single professional and in less time.

npalen · Jun 20, 2014

I'm excited about this topic as it hits a couple areas of interest. I've volunteered to map our parish church grounds which includes the church that is listed on the National Historic Register as well as several other buildings. The church was built in the very early 1900's using native limestone and incorporates flying buttresses, the first of it's kind West of the Mississippi.
I've been doing the mapping in 2D CAD but would dearly love to apply some photogrammetry to get a 3D rendition of the church and other buildings. Then enter 3D printing where it would be icing on the cake to produce 3D models of the entire complex.
I will try to post a Google Earth shot of the church in a followup post and maybe you guys can give me some opinions on the complexity and feasibility of the project.

DroneRookie · Jun 20, 2014

Give Autodesk Recap a look. It is in its infancy, a little buggy, but I have been able to produce some 3D geometry that I was happy with. Here is a promo video from Autodesk showcasing what someone did with it. I will attest, it's not quite as clean and smooth as the video makes it look but still pretty cool and very promising.

http://youtu.be/5lQVH3hSh0c

And here is one more showing how you church example could integrate with design software (like Revit).
http://youtu.be/9vTG6lLFoKc

MonsieurAnon · Jun 21, 2014

npalen said:
I'm excited about this topic as it hits a couple areas of interest. I've volunteered to map our parish church grounds which includes the church that is listed on the National Historic Register as well as several other buildings. The church was built in the very early 1900's using native limestone and incorporates flying buttresses, the first of it's kind West of the Mississippi.
I've been doing the mapping in 2D CAD but would dearly love to apply some photogrammetry to get a 3D rendition of the church and other buildings. Then enter 3D printing where it would be icing on the cake to produce 3D models of the entire complex.
I will try to post a Google Earth shot of the church in a followup post and maybe you guys can give me some opinions on the complexity and feasibility of the project.

npalen; I'm not sure what you're flying or how competent you are but here is what I would do:

1. Fly a grid with a downward facing camera, slowly and carefully, taking raw stills that overlap by ~80% ... less overlap is possible if your photos are tagged with GPS data. Do this on an overcast, bright day if you want a textured model later on ... as shadows are very difficult to remove after the fact.

2. After you've finished the grid, keep on flying, turning very slowly (so overlap is still ~80%) so that your camera faces forward and sees the sides of any objects that are obscured in the top down shots (walls, fences etc.). Given the church is probably an important highlight do a full 360 of it, facing its walls, taking at least 20 stills.

3. Download the free trial of Agisoft Photoscan on a computer with 16+gb of RAM (ideally 128gb). Process the shots (there are video tutorials).

4. Export the final, textured mesh in a few formats ... since it's a free project, put them online wherever you can.

5. If you don't have a 3D printer, you could get it printed on Shapeways out of a variety of materials, so long as the model has had some treatment.

npalen · Jun 21, 2014

Can someone tell me how to link to a jpg in Photobucket or, better yet, post the picture here?
Thanks

MonsieurAnon · Jun 21, 2014

I use imgur.com for hosting ... and you want to use their large thumbnail, as this forum doesn't resize.

Use the following code:

Code:

[url=the full image url][img]the thumbnail url[/img][/url]

Or for low resolution images:

Code:

[img]the thumbnail url[/img]

For example:

Code:

[url=http://i.imgur.com/ZlS9BJd.jpg][img]http://i.imgur.com/nwAESxw.jpg[/img][/url]

npalen · Jun 21, 2014

http://s976.photobucket.com/user/palenn ... how/CHURCH

Edit: I appreciate your input MonsieurAnon but I was still confused on how to embed an image so used the photobucket link.
I was surprised to see that Google Earth also has a street view 3D of the church. You can see it by zooming in to 800 E. Court St., Beloit KS in Google Earth.

cburnha · Sep 29, 2014

I work for a civil engineering company and we are looking to use the photos taken from a drone to create CAD surfaces. If the photos aren't used directly or provided to the clients would this still qualify as commercial use? Could we get an airworthiness permit an get permission to use a drone in this context?

dlunk · Sep 29, 2014

cburnha said:
I work for a civil engineering company and we are looking to use the photos taken from a drone to create CAD surfaces. If the photos aren't used directly or provided to the clients would this still qualify as commercial use? Could we get an airworthiness permit an get permission to use a drone in this context?

I did some quick research on this subject. I have read some where that you are not allow to use for commercial use, even if no money is directly profited from the use there of. After a while of searching and reading I came up with this:

"Any operation not conducted strictly for hobby or recreation purposes could not be operated under the special rule for model aircraft.
Clearly, commercial operations would not be hobby or recreation flights. Likewise, flights that are in furtherance of a business, or incidental to a person’s business, would not be a hobby or recreation flight."

I found this on page 10 of a document named "Interpretation of the Special Rule for Model Aircraft" found here: https://www.faa.gov/uas/media/model_aircraft_spec_rule.pdf

That pdf was found on the following site: https://www.faa.gov/uas/regulations_policies/

I'm not expert in this subject, so take my post with a grain of salt, but this is what I've come up with so far taken from official FAA text. I suppose with how things are starting to shape up it may be possible to get approval for that kind of work. They have approved use up in the Arctic region (http://www.faa.gov/news/updates/?newsId=73981), and now the film industry.

rgc2005 · Sep 29, 2014

I am highly interested in this subject. There are now a few resellers and a kickstarter at http://www.dronesmadeeasy.com/.
Would this service work?????
Is it worth the price?
Would investing the time and dollars into doing it myself be worth the effort?

MonsieurAnon · Sep 30, 2014

Those guys look to be at about where I am, if not slightly behind when it comes to developing their methods and product, but then again, I have spent about that much of my own money figuring this stuff out.

Are you asking if $4,000 is worth the price for photogrammetry of a property that you need a 3D model of? I could definitely undercut them significantly if you are flying a drone yourself, but you'd have to provide me with photos and there might be a bit of back and forth. Can you link me to an area on Google Maps that you need 3D scanned and explain what the model would be used for?

What resources do you already have? A Phantom 2? A licence for Agisoft Photoscan Pro? A decent, lightweight camera?

If yes to all of the above, then all you need is a process to make the above work for you ... and here's where my second pitch comes in: I sell a universal camera mount on Shapeways that can make a Phantom better suited for Photogrammetry. A few people are already doing this at archaeological sites using my gear.

cburnha · Oct 2, 2014

I've been working on this for a few days now and have talked with several people from the FAA. There is a exemption under section 333 that allows you to fly a UAS commercially. One requirement for the exemption talks about have an airmen certificate. Has anyone had to get one of these for flying their drones as a hobby and how hard is it?