I would like to hear from the photogrammetrists out there.  Does the inspire camera work for creating digital mosaics and DSMs with software like photoscan.  
If anyone can take a grid of overlapping photos for me, then I can test it out and post the results back here.

My Inspire isn't getting here for another week or so.

Thanks

We've found to do true accurate photogrammetry you need an automated flight plan and precise placement of the images for overlap.  I think the images will do fine for sub 10CM accuracy but gotta get waypoints and automated shutter down first.   I will be happy to go do a grid manually for you if you give me the dimensions you prefer.  Would you need GCPs or no?  email me at travis@flyboync.com and we can try and work it out.

TravisSRT Posted at 2015-2-4 09:50
We've found to do true accurate photogrammetry you need an automated flight plan and precise placeme ...

I did a test of imagery from the inspire 1.  I flew some simple loops around the Local harbormaster building and captured 90 Images.  I found that Pix4d was able to read the exif with geotag tags and generate a good densified point cloud.  It would be better with either IOC or "ground station" functionality but can als be due manually for small project ares.

Matt,  
Interesting question.  

I would appreciate if you could post your findings.  I was thinking of using the Agisoft software in the future so any info on this subject will be grately appreciated.

pinpointmapping Posted at 2015-2-4 16:06
I did a test of imagery from the inspire 1.  I flew some simple loops around the Local harbormaste ...

Hi - would you mind sharing your workflow. I tried a couple of flights with 90 images - but pix4d showed only around 10 differend gps locations and was not willing to compute them. pix4d is working on a flight-plan app for the inspire though.

Hello everyone, I am new to this forum and the DJI family of products. I am very interested to have found this thread. I am in the process of looking at and learning Pix4d (Discovery) and have purchased an inspire to photogrametry. My DJI in in them mail as I type this. I am wondering what is the pixel size of the still pictures the camera takes.

Also, I too hope that there is some sort of flight plan at some point.
Have you guys tried to take Nadir photos or are you doing projections ?

There really isn't much to the "work flow".  I have been using a Sensefly eBee Fixed wing UAV for the past 18 months and the software it comes with is called "Postflight Terra3D eBee" and is "Powered by Pix4D".  This  experience has allowed me better understand the criteria for images to be calibrated by the software.  The biggest point is image OVERLAP.  A specific spot on the ground really needs to be visible in multiple photos, minimum 3, but 5+ seems better.... When I used the Pix4D Discovery App, the initial geotag location for the images from my Inspire 1 where not very good.  It associated each of the 90 images to only 6 different Geotag locations, however the image EXIF data was sufficient for the software to run processing and generate a very nice 3d Point Cloud.  I will be doing further tests in the coming weeks.  It is my understanding that Pix4D does intend to include support for the Inspire 1 within their new Pix4D Capture App (currently only supports Phantom Vision+ models), but for now you can Manually capture images that will work.  
For my initial test data I flew a simple grid pattern over the facility taking images every few "meters" from a NADIR perspective (Camera pointed straight down), then I flew 2 additional loops around the facility at different heights (about 30 & 60ft altitude) and captured multiple images from an Oblique perspective (roughly same distance from structure & Camera at ~45 degree angle).  I then copied the images from the SD card onto a 1TB SSD drive and started a new project with Pix4D Discovery and selected the "alternate" processing option for NADIR & Oblique Imagery.  It took about an hour on an iMac 2.9GHz Quad-core with 32GB Ram to run the processing and produce a nice 3D point cloud.

pinpointmapping Posted at 2015-2-5 02:03
There really isn't much to the "work flow".  I have been using a Sensefly eBee Fixed wing UAV for th ...

Very cool. The sensefly stuff is pretty interesting. I own a Parrot Bebeop and have been using that to learn the workflow and software as well as to fly. I have had some pretty decent  results. I would love to talk to you offline to exchange some thoughts. Do you think that is possible?

FoxSTI Posted at 2015-2-5 02:12
Very cool. The sensefly stuff is pretty interesting. I own a Parrot Bebeop and have been using tha ...

Happy to provide more detailed info offline,
Contact me at pinpointmapping@gmail.com

pinpointmapping Posted at 2015-2-5 02:03
There really isn't much to the "work flow".  I have been using a Sensefly eBee Fixed wing UAV for th ...

Thanks pinpointmapping, I also run the Sensefly Ebees, they rock.

I wonder why the geotags are clumping up like you say...

Is there any chance I could grab the images you captured and test them on my system?

Matt

^ What is the price of one of those if you don't mind me asking?

I have been experimenting with the Pix4d Discovery App and the Inspire a bit.  I previously used a Phantom 2 with GoPro 3+, which didnt have any GPS data so using the inspire was already a step up.  I flew around a construction site to see how well it picks up stockpiles and got a really nice densified point cloud.  I also heard that the ios app is working on inspire support.  

Taking the photos manually and getting enough overlap wasnt the easiest thing to do on the inspire so using the app will definitely give a more evenly spaced grid of photos with adequate overlap.  Cant wait for them to update the app and try it out!

Next step is to make some GCP's and see how it turns out.

FoxSTI Posted at 2015-2-5 03:43
^ What is the price of one of those if you don't mind me asking?

An standard Ebee is about 30k, with RTK onboard it is 60k.

Matt.hooker.qui Posted at 2015-2-5 05:48
An standard Ebee is about 30k, with RTK onboard it is 60k.

30 to 60K?  Yikes. It better be super accurate...
Is photogrametry that precise, to where equipment pricing is starting to match the pricing of terrestrial lasers?

I think those are Canadian prices, I got my eBee for 25k USD.  A big hunk of that is the image processing and flight planning software.  The recent offerings by 3Drobotics is more affordable, coming in ~10k.    Prices will continue to drop,   UAVs are the future of spatial data collection.  Right now you can get an inspire 1 (with batteries and iPads) for around 4k, add in 8700 for pix4d, and you have a good start on generating high accuracy and resolution GIS data.

I've just spent the afternoon taking pictures at the local castle and then importing them into Pix4d. It's my first time using this software so I've not worked out how to or if I can export images. The attached is a screen shot so the resolution is not great but it gives an idea of the file. The reconstruction was based on 17 images taken of this façade.

Here is the sample that Pinpointmapping provided me, but ran through Photoscan

Tower Survey

Matt.hooker.qui Posted at 2015-2-5 03:21
Thanks pinpointmapping, I also run the Sensefly Ebees, they rock.

I wonder why the geotags are cl ...

If GPS data like that on phantom V2+ Then DJI is only recording data to the second making it less than great for true photogrametrey I have asked the question a number of times as to accuracy of Inspire GPS data but not gotten a response from DJI .. Would suggest they improve the accuracy being recorded if they don't want their units to simply be seen as 'toys'... I use Agisoft and have created some pretty decent 3d landscapes ... Found that strapping on a Garmin Forerunner and postprocessing the pics with GPS PHOTOLINK has created a better product than using the data attached to v2+ photos by the DJI Camera. . Had hoped better from DJI with Inspire...that said the S900 does not do that great a job with the IOSD and WKM...not easy to match event to GPS loci as time is not recorded on event (shutter trigger on F1) again raised issues with DJI ...no response...update...Had a chance to get Inspire out and get some photos...would appear in file details that decimal seconds of long lat are now being recorded ...Great to see need snow to melt to collect real data and model.

ajgraham.waitro Posted at 2015-2-9 02:37
I've just spent the afternoon taking pictures at the local castle and then importing them into Pix4d ...

HI ajgraham,

Nice!

Did you use Inspire 1 to have the pictures or different drone? Arre the GPS data captured from the images EXIF?

Thanks!

pinpointmapping Posted at 2015-2-5 02:03
There really isn't much to the "work flow".  I have been using a Sensefly eBee Fixed wing UAV for th ...

Hi pintpontmapping,

Thanks for the info, it is very usefull!

I am an agruciltural engineer, (also IT) and I gonna use my inspire and pix4d for agriculture!
So, if you dont mind I may contact you directly.

csabal Posted at 2015-2-22 18:10
Hi pintpontmapping,

Thanks for the info, it is very usefull!

Last week, I took my Sensfly eBee & DJI inspire to a farmer on Maui to map out some shade trees in anticipation of them planting Cacao (chocolate) soon.  I encountered some issues with my Ebee, so resorted to the inspire.  The end result was ~800 images  over the ~40acre area with a final pixel resolution of only .61 inches.  Pix4d took about 18 hours to process everything and the final output was/is sharp and the detail in the resulting .LAS far exceeded what I anticipated.  I'm looking forward to them automating the flight/image capture portion, and believe the DJI Inspire 1 will be a solid photogrammetry platform.  I also had a chance to fly the inspire up along the famous "Haiku stairs" also known as "stairway to heaven" here on Oahu to document a recent landslide that took out a section of the trail/stairs.  It really impressed the "land managers" as they were able to stay at the trailhead as the drone flew up about 200 meters along the knife edge ridge and while broadcasting back a 720p video feed of the damage.
Feel free to contact me via pinpointmapping@gmail.com if you have questions.
Aaron

csabal Posted at 2015-2-22 18:03
HI ajgraham,

Nice!

Hi, Yes I used my Inspire. I have been building a better model of the same castle using a combination of the Inspire, camera on my Xperia Z1 and GoPro Hero 2 attached to the bike. The castle is surrounded by trees which makes access with the Inspire difficult but it is a much better camera than the other 2.

I used Pix4d to reconstruct the model based on the GPS data from the Inspire to provide a set of reference points. It works very well and Pix4d has good documentation but I can't export anything because of the demo licence. The images are just screen captures. I've also been experimenting with using the gopro on the bike to map trails but without any GPS tags the alignment of the trail drifts.

There are some very interesting points being made in here.

Does anyone know of any software that can create the 3D model of a building or landscape which can then be exported to CAD?

For Exporting to CAD I would recommend Global Mapper for both raster and vector data

Brilliant Thanks

All images taken by inspire.

I have done a few projects now with the inspire and have just now found that it is recording the elevation as meters above takeoff rather than meters above sea level.  Does anyone know how to change this?  It would be very helpful for creating more proper DEMs without true ground control.

Thanks

Hooks Posted at 2015-3-6 07:04
I have done a few projects now with the inspire and have just now found that it is recording the ele ...

Are you sure about this? If that is the case then I would report this as a bug.
Georeferencing photographs should always be done based on GPS readings and not including any offset to another origin (Home Point).
Can you please submit the data to DJI and keep us informed with findings?
Thanks,
Bogdan

I just sent an email of to DJI LA,  maybe they can shed some light on this.  I really hope this is not something intentional or even worse, some kind of hardware limitation(I doubt this is the case though).  

The Z measurement is normally more "suspect" than X or Y for GPS and unfortunately "Sea Level" really isn't Level at all.  There is an entire science devoted to it the shape of the world (Geodesy).  I believe GPS Altitude or Z measurements typically are based on Spheriod models and the separation between the Datum and Spheroid varies all around the world.  You can read more on this via ArcGIS help info http://webhelp.esri.com/arcgisde ... ow_they_are_related
I believe they are using the onboard Barometer to provide a more situationally accurate Z measurement (based on Take off location).  If you want super accurate XYZ data, you need to use Survey quality GPS equipment that allows for Differential correction against known points.  Put down a couple Ground control Points/Aerial targets within your project area, record those via high accuracy GPS and then use that data to calibrate the entire project.  I've done projects with full size planes equipped with LIDAR sensors, and that data needs groundcontrol too.

pinpointmapping Posted at 2015-3-7 04:39
The Z measurement is normally more "suspect" than X or Y for GPS and unfortunately "Sea Level" reall ...

Thanks for the response.  That is the workflow I currently go through for my industrial projects.  However many of my clients do not need the exact accuracy you describe but they do like to have the elevation within reason to reality.  In such cases they opt out of having me go out with the Leica unit and just go off of the onboard GPS readings for accuracy.  

Some clients use Geoverse to display these data sets. Within the viewer it allows the user to view the coordinates and elevation of any spot the mouse hovers over.  When x and y are relatively accurate but z is reading 14m rather than the expected 750m or thereabouts, it does not help the viewer to achieve proper spatial awareness.

I would rather get the z measurement from the GPS rather than the barometer as it would be more in keeping with what other UAVs do.  (really only speaking about the Ebee by Sensefly as those are the only other UAVs I currently use).

I am having some issues with curvature of my point cloud.  Does anyone know how to fix this other than using GCP's?  I have some very rough gcp's without a target that I'm trying to use to flatten the model out but it doesnt seem to be working.  I'm using Pix4d.

I had to remove all geolocation data from the photos because the elevation of the photo gps data is in elevation above takeoff, which obviously doesnt match up with the rough GCP data.

jsclark89@gmail Posted at 2015-4-11 01:14
I am having some issues with curvature of my point cloud.  Does anyone know how to fix this other th ...

I'd try leaving the geoTags intact in the images, then process in Pix4d or photoscan and manually offset the resulting DSM to accurately reflect the surface elevation.  You can use something like Global Mapper for that.

My workstation is free for the next couple of days and I don't mind processing on my end with photoscan to test your imagery if you want.

hey guys, what type of GPS are you guys using for GCPs?
I just got a quote for one of them at 34K... Doesn't make sense unless I asked for the wrong thing.

Thanks Hooks, that is very generous.  I managed to fix the really bad curvature by messing with my gcp's (I will definitely make legit targets and have a high accuracy survey of next time) but it flattened it out enough to get a decent contour map that was enough for us to use.

FoxSTI - I got a quote for a trimble geo7x handheld gps with cm accuracy for around 20k... 34k sounds a little high.  We're just renting these days but it works great.  Just need to improve my GCP targets and I think I should be able to have a very high accuracy model.

Hooks Posted at 2015-4-12 08:17
I'd try leaving the geoTags intact in the images, then process in Pix4d or photoscan and manually  ...

Hey if you wanted my photos let me know how I should get them to you.  If you already have some data to play with don't worry about it too much, accuracy of this model wasnt completely essential but it was interesting to see the curvature in the resulting model.

jsclark89@gmail Posted at 2015-4-14 05:22
Hey if you wanted my photos let me know how I should get them to you.  If you already have some da ...

Sorry for the late reply, I have been pretty busy lately.

You can put an image set in Dropbox and send me the link if you still want me to try it out.

Hooks Posted at 2015-5-5 11:31
Sorry for the late reply, I have been pretty busy lately.

You can put an image set in Dropbox and ...

Hey Hooks! Its okay, I got the information that I needed from it and will get some better GCP's next time I do it for a project.  Its pretty easy to do and hopefully pix4d will be able to get the app compatible with the inspire soon!