Messages

91

General / Re: Export DTM(Digital Terrain Model) as orthophoto binary mask.

« on: July 18, 2016, 04:18:14 PM »

As one solution that I can imagine I can generate DSM and then generate DTM and then just subtract DTM from DSM DIFF= DSM-DTM to obtain only "objects map" and then binarize DIFF image using some threshold.

But for some reason photoscan generates DSM and DTM slightly different especially on borders of valid area, also slightly different size.
How to fix this problems?
Also my question is how to gerate orthomap exatly the same size?

My test data from here
https://github.com/OpenDroneMap/odm_data_bellus/tree/4ea68df4c03a495fa3476dc157de5f90afe9d72d
Here is results. Tiff files are float32 so you need special viewer for them, also images are downsampled by x2 factor.

DSM
https://habrastorage.org/files/c06/34c/d6e/c0634cd6ec4f45fab161f5ab4bfd009a.tif

DTM
https://habrastorage.org/files/561/37b/635/56137b63568043a6ab39214eda6be5ed.tif

Orthomap
https://habrastorage.org/files/bc2/742/394/bc27423946494ef1af163ca5b468cb3e.png

DIFF= DSM-DTM
https://habrastorage.org/files/65b/9ab/99c/65b9ab99c4e04ab59b9ed5b35716f82e.tif

After clean up DIFF by using threshold
https://habrastorage.org/files/9be/bde/8b6/9bebde8b66a04afabf101b34c25503b5.tif

After making diff binary
https://habrastorage.org/files/128/c29/d0c/128c29d0c29a4e5d9049ee6318220d48.png

92

General / Re: Export DTM(Digital Terrain Model) as orthophoto binary mask.

« on: July 18, 2016, 02:27:54 PM »

Yes, but I need binary mask of ground and binary mask of objects like houses, vegetation etc.

93

General / Re: Moving object removal

« on: July 18, 2016, 02:19:54 PM »

Do you mean image masking ?
Using masks (page 53) http://www.agisoft.com/pdf/photoscan-pro_1_2_en.pdf

94

General / Export DTM(Digital Terrain Model) as orthophoto binary mask.

« on: July 18, 2016, 12:18:06 PM »

Here is a tutorial to create DTM(Digital Terrain Model)
http://www.agisoft.com/index.php?id=35

But I want to know, is there any way to export  DTM as orthophoto binary mask, i.e. I want to overlay this mask with orthophoto to make sure point cloud classification done correctly and buildings are detected.

95

General / Moving object removal

« on: July 18, 2016, 12:07:26 PM »

I have some data from UAV, but I have problems with moving objects (for example cars).

Is there any way to automatically detect and remove such object from orthophotoplan?

96

General / Vertical and horizontal accuracy of point cloud?

« on: February 19, 2016, 07:42:55 PM »

What is theoretical vertical and horizontal accuracy of point cloud without using GCP points (just using GPS positions of images from UAV)?

How it depend on camera model, flight height, image overlap, UAV GPS accuracy?

97

General / Re: Vertical error in DSM to Ground Control

« on: February 19, 2016, 04:59:59 PM »

What is general procedure to compute errors of DSM regarding to geoid?

98

General / Draw gravity vector

« on: February 18, 2016, 01:22:24 PM »

How to draw gravity vector in GUI?

Gravity vector defined as normal to elipsoid or normal to geoid.