Messages

1

Python and Java API / Re: From world coordinates to pixel coordinates

« on: October 17, 2014, 04:14:06 PM »

Thank you Alexey, it works.

2

Python and Java API / From world coordinates to pixel coordinates

« on: October 17, 2014, 03:42:06 PM »

Hello,

I have tried to use a couple of (adjusted) scripts that were available at the forum, but I didn't work for me... So I hope that someone can give me a hint or script that can help me out.

I would like to transform georeferenced coordinates(x,y,z) in my model to pixel coordinates(somewhere between 0-width,0-height) on a certain photo. I use coordinatesystem EPSG::28992.

I have tried the scripts below, but they didn't give the right pixel coordinates.

Code: [Select]

import PhotoScan as ps

crs = PhotoScan.CoordinateSystem()
crs.init("EPSG::28992")

#test1
photo_0 = ps.app.document.activeChunk.photos[0]

currentChunk  = PhotoScan.app.document.activeChunk
point_geocentric = currentChunk.projection.unproject(PhotoScan.Vector((74183.609,453380.738,3.388)))

(imgx, imgy) = photo_0.project(point_geocentric)
print (imgx, imgy)

#test2
a_camera = photo_0;
transform_matrix = currentChunk.transform * a_camera.transform
point_geocentric.size = 4
point_geocentric[3] = 1
point_local = transform_matrix.inv() * point_geocentric
point_local.size = 3
(image_x, image_y) = a_camera.project(point_local)

print (image_x,image_y)
print("Done")


Thank you in advance.

3

General / Number of GCPs

« on: October 10, 2014, 11:48:37 AM »

Hi all,

I would like to create a very accurate DEM from aerial photos. I have a question regarding the number of ground control points. I would say more GCPs would lead to a more accurate DEM. Am I right?

From the Agisoft Photoscan manual:

In case of aerial photography and demand to fulfil georeferencing task, even spread of ground control
points (GCPs) (at least 10 across the area to be reconstructed) is required to achieve results of highest
quality, both in terms of the geometrical precision and georeferencing accuracy. Yet, Agisoft PhotoScan
is able to complete the reconstruction and georeferencing tasks without GCPs, too.

I am curious about the number of GCPs people use and how large the reconstructed area is? I would like to get a number of GCPs needed per squared (kilo)metre for example.

4

General / Re: Export Points > Meshlab > Import mesh

« on: September 11, 2014, 04:34:23 PM »

Thank you, Alexey.

But this gives me the following problem:

When I use "Export points", I get more points than when I use "Export model".
I would like to edit and filter my points in other software, so I would like to have a lot of points in my point cloud model. After the editing I import the mesh and continue with texture/DEM in Agisoft PS.

Is it correct that I have to use the "Export model" and not "Export points" to continue in PS after some editing/filtering in for example Meshlab?

Or is there a way to export the points/mesh, then edit the points and then import this back into PS?

Thank you in advance.

5

General / Filtering water, vegetation etc.

« on: September 11, 2014, 04:01:18 PM »

Hello,

I am dealing with a 3D model of a beach. I would like to filter everything except the sand before making a DEM. I want to remove water, vegetation, sailboats, beach clubs etc.

Does anyone have a recommendation for good filter software?
Anyone experience with CANUPO plugin from CloudCompare? [ Link: http://www.geosciences.univ-rennes1.fr/spip.php?article1284&lang=fr ]

Any suggestions are very welcome.

6

General / Export Points > Meshlab > Import mesh

« on: September 10, 2014, 03:38:35 PM »

Hi all,

I have some problems with exporting my points, editing them in Meshlab/CloudCompare and then importing them back into Agisoft PS. I have been looking on the forum and internet but did not found the answer to my problem.

After I aligned my photos and build a dense cloud, I exported points as a .PLY file.
I open the data with Meshlab, make a mesh and save it as a .PLY file.
In PS I can open this file.

But now here is my problem:
When I want to continue the proces, the 'Build texture' goes wrong.

Can somebody please tell me what I am doing wrong.

7

General / Approach 3D model beach

« on: September 09, 2014, 03:50:37 PM »

Hello,

I am working on a project of a 3D reconstruction of a beach. I have only been working for a few days now with Agisoft so any help is welcome.

I am trying to create a DEM of my project site after deleting background noise like vegetation in the dunes, sailboats and beach clubs. I included a picture to show the environment.

I would like to know if my approach is correct: I aligned my photos, added ground control points and optimized them by the known coordinates. I export the matching points to another program, filter the vegetation, sailboats and beach clubs, create a mesh in that program and import the mesh in agisoft, than building the texture in Agisoft and create DEM/orthophoto.

The questions I have got:

1) Is my approach correct?

2) Does anyone have a recommendation for software to use for the filter steps? Meshlab?
I also found something very interesting at http://nicolas.brodu.net/en/recherche/canupo/, but I don't know if this can do the trick for me.

3) Is this the way to classify/delete points from the point cloud model? I know the classification is also possible in Agisoft PS, but this seems to be not sophisticated enough for the filtering I mentioned / or it is just me not finding the right parameters

Any help or suggestion is very welcome.