Hi Guys,
We purchased a drone last week to make pointclouds from the photos.

We seem to have terrible results when we process the photos in Autodesk Recap.

The first problem seems to be that when we look at the properties in the JPEG, there is long and lat information, but the altitude says 0!!! i guess this makes it extremely difficult for the software to stitch together the photos. PLease help?

Also, the pointcloud and mesh are upside down, and completely the wrong orientation.

Also not sure what coordinates system to use, we are in the UK so should we just leave it on the one that is automatically selected.

any help would be greatly appreciated.

thanks in advance.

Steve

but the altitude says 0!!!

Do you know which altitude Autodesk is reading? There are 3 altitude references in a DJI EXIF image.
(Currently there is a bug in the EXIF data where DJI falsely reports 1.2m in the absolute altitude field)

Also not sure what coordinates system to use

If unsure, start with WGS84.

thank you for the response. attached is a screen shot of the EXIF data from one of my images. When i try to import the photos into Recap photo the corrdinates system it seems to suggest is UTM84-30N.

Is WGS84 more suitable?

So this altitude problem is on a setting i can sort out at the moment?

many thanks

Steve Holly Posted at 2018-10-23 08:59
[view_image]

thank you for the response. attached is a screen shot of the EXIF data from one of my images. When i try to import the photos into Recap photo the corrdinates system it seems to suggest is UTM84-30N.

The proposed projection UTM84-30N is OK as long as your mapping area is between long 6°W and 0°.

Look at your images with exiftool.exe (Windows). Find the altitude which look bogous to you.

Absolute Altitude               : +1.20 (????)
Relative Altitude               : +50.00
GPS Altitude                    : 600 m Above Sea Level

Put the GPS altitude into the Absolute Altitude field. On how to to this, check this EXIFTOOL Help link

Appreciating your help.

your right when we extract the information the absolute altitude is 1.20m

the relative altitude is -133.97

and the GPS altitude is 0!!!! so even if I could use the EXIFtool properly, I would not be able to enter the correct GPS altitude into the absolute altitude field.

I have no idea what to do about this, and have emailed DJI directly, with no luck.

this must be part of the reason my 3d models are so bad. Any further ideas on this ?

Steve Holly Posted at 2018-10-23 10:34
Appreciating your help.

your right when we extract the information the absolute altitude is 1.20m

If you know your altitude where the images are taken, enter that value into all your images.

For a single image the syntax would be:
exiftool -"AbsoluteAltitude"=610 test.jpg (setting that field to 610m)
and
exiftool -"GPSAltitude"=610 test.jpg (setting GPS altitude to 610m)

Do the changes on all of your images (make a backup first) and try Autocad again.

WingSpeed Posted at 2018-10-23 10:41
Hi, Sorry for the late response. I have clarified your concern with our higher team and I would recommend
keeping an eye on the DJI website for any further updates. Please kindly try IMU calibration. Thank you for understanding and patience.

thank you for your reply. Does this look unusual to you? we are new to this so just want to check this doesnt look normal. many thanks