Messages

1

General / Re: 3cm absolute accuracy without any ground control points using Agisoft

« on: September 24, 2016, 02:55:20 AM »

Yes it is compatible with ebee, Sirius, Falcon and any other airframe, according to http://www.riseabove.com.au/ppk-gnss-system-for-multirotor-and-fixed-wing-uav

2

General / Re: How is the EXIF data from Drone/UAV/UAS obtained by the on-board GPS

« on: September 22, 2016, 12:24:00 AM »

There is a solution to geotag photos with 3cm accuracy for almost any drone with no ground control, see this post: http://www.agisoft.com/forum/index.php?topic=5884.0

3

General / Re: 3cm absolute accuracy without any ground control points using Agisoft

« on: September 19, 2016, 02:20:45 AM »

That's correct. PPK system requires a base station for post processing. Similar to RTK (real time Kinematic) but doesn't need to receive the base station correction via radio link while flying. See some more detailed information in the product page here: http://geomatics.com.au/

4

General / Re: 3cm absolute accuracy without any ground control points using Agisoft

« on: September 17, 2016, 11:40:07 PM »

All valid and good points. Some more technical details which would clarify the achievable accuracy:

• Quality and sensitivity of the GNSS receiver used in building a PPK system plays the most important role in getting a robust and clean solution for all camera stations. The one that I was referring has been built based on latest generation of triple frequency Novatel GNSS receivers with highest performance in airborne application.(Export restricted though).
  
  Second important point is precise time synchronisation between camera exposure at the very middle of the exposure time and the GPS time. There are lots of factors and internal electronic delays involved in this, mentioned PPK system is well engineered to take care of all of these factors in a smart way.  There is a one time calibration procedure, which effectively models all of these factors. For the calibration flight a good network of GCPs is required, this procedure is same procedure as calibrating a million dollar metric aerial camera and its direct geo-referencing system.
  
  Once the PPK system calibrated, correction parameters are applied autonomously to any other flights which then provides very reliable accuracy without using any GCPs.
  
  Regarding check points requirement, I'd say check points are just for cross checking and proving the claimed accuracy. They are not used in photogrammetry at all for improving the results, just used for monitoring the errors and totally optional.
  
  From my 20 years of photogrammetry experience with drones and manned aircraft, a good surveyor must always cross check the results irrespective of what technology is used. I always use one or two GCPs to to make sure that camera focal length variation, for example due to temperature variation, and operator errors are taken care in photogrammetry and always get better than 3cm absolute accuracy. 
  

A good thing is all of these issues are well considered in the mentioned PPK system and in its post processing software , so just by following the provided calibration procedure, users don't need to worry about all of these complexities. (same as if you don't calibrate your autopilot you wouldn't be able to get desirable flight pattern).

 



 

5

General / 3cm absolute accuracy without any ground control points using Agisoft

« on: September 17, 2016, 07:09:22 AM »

Just wanted to share an exciting technology that enables any drone to produce 3cm absolute mapping accuracy without GCPs. This video shows check points residuals' using Agisoft Photoscan Professional:
 https://www.youtube.com/watch?v=nT4LRm4FAxE

A white paper available in here: https://www.gim-international.com/content/news/precise-uav-camera-positioning-for-3d-mapping

6

General / Re: Some general questions about Photoscan

« on: May 03, 2016, 01:39:14 PM »

Hi Sascha,

Regarding your first question for visualizing 3D pdf and memory issue, instead of 3D pdf, you can use 3D data streaming functionality by uploading DEM, orthomosaic and pointclouds directly from Agisoft ( File->Upload DEM, Orthomosaic, pointcloud) to 4DMapper, then you can visualize, digitize, measure and share in full 3D with almost no high end computer or memory requirement. It streams the full resolution data to any browser which supports WebGL(most of the recent browsers support WebGL).

Btw, you can create a free account here to upload directly form photoscan: https://app.4dmapper.com/

John

7

General / Re: Draw 3D Polylines

« on: April 30, 2016, 11:38:08 PM »

Hi Karol,

Exporting digitized 3D features to dxf from pointclouds will be possible in next version of 4DMapper. Currently you can only export digitized points, polylines and polygons from orthomosaic or DEM to 3D dxf (you can directly upload orthomosaic or DEM from photoscan to your account).

John

8

General / Re: Draw 3D Polylines

« on: April 30, 2016, 07:03:46 AM »

New version of Agisoft, supports uploading DEM to 4DMapper, (File->Uplaod DEM) then you can digitize 3D polylines, polygons and save them as 3D dxf in your computer. You can create a free 4dmapper account at https://app.4dmapper.com/