Topics

1

Python and Java API / Extracting time consumed for metashape running.

« on: October 16, 2019, 10:16:16 AM »

Hello

I am running metashape-pro with python scripting.

After aligning cameras I save the project.

This is the part of the code.
###################################
for frame in chunk.frames:
    # you can specify the degree of accuracy
    frame.matchPhotos(accuracy=Metashape.MediumAccuracy)
chunk.alignCameras()
doc.save(dir_to_be_saved+"/project.psz", chunks = [doc.chunk])
##################################

Is there any way to check the time consumed for aligning cameras?

Thank you in advance!

2

Python and Java API / python scripting code for camera path estimation.

« on: September 24, 2019, 09:08:23 AM »

Hello.

I have to extract camera path for a given sequence of photos.

I have 2 questions.

1) Does accuracy setting affect the accuracy of camera path? If so, which setting do you recommend (It would be best to set it to HighestAccuracy but it will take too much time)

2) Could you write very simple (it is okay if it is not fully functional) python script for computing path and saving it.

Thank you !

3

General / Specifying distance between two points.

« on: May 14, 2019, 06:12:59 AM »

Hello

I am constructing 3D model of broken pottery pieces.
My goal is to put the broken pieces together to recover its original shape.
In order to do so, I need to make sure that all the 3D models have same scale as each other.
I guess photoscan ( I am using professional) has a function of specifying distance between two points in the photo
so the program can use it as a ground truth dimension.
Could you let me know I can I set ground truth distance between two points in cameras?

4

General / Setting the orientation (rotating) the exported 3D point cloud

« on: February 13, 2019, 11:05:58 AM »

Hi,

##Context##
I used PhotoScan for 3D reconstruction from a sequence of spherical images. I exported the reconstructed 3D model as a 3D point cloud (.ply file) and the estimated camera poses (.xml file). I open the 3D point cloud in MeshLab and it is not straight. Part of the reasons is that the 360-degree spherical camera that we used was hand-held (so not straight). In our case, we know the vertical direction of the first image (by manual interaction with an external software), and we can compute a rotation that can map this vertical direction to the up-direction [0,0,1]. (we know the vertical direction *only* of the first image). This vertical direction is a 3D vector u=(ux,uy,uz) in the camera coordinate system (z pointing up).

##Goal##
We would like to apply this rotation (or 3D transformation) to the exported 3D point cloud using Matlab so that the 3D point cloud becomes correctly oriented (should be straight/vertical). We tried several things (we are familiar with 3D points manipulation and 3D transformations) but none of them worked. The problem seems to be in the coordinate systems of the 3D point cloud and/or the spherical cameras. Any tips?


##What we tried##
Let R and T be the rotation and translation of the first image (from the estimated camera poses in the xml file). Let Rup our rotation matrix to straight up the direction.
We tried:
- directly applying Rup (and also its inverse) to the 3D point cloud
- We applied -T (to move the 3D point cloud to the origin) and applied our Rup (and its inverse)
- we also applied R^{-1} then Rup
- we also applied -T, then R^{-1} (so that the first image has its "default" orientation" and at the origin) and then Rup (and also its inverse)
- among other things
However the resulting 3D point cloud is not straight.

Side note: we checked this rotation and it is correct: by applying this rotation to the spherical image, we can obtain a new spherical image (and its equirectangular image) which is straight.

5

General / Inquiry about coordinate system and spherical image.

« on: February 13, 2019, 09:38:48 AM »

In  photoscan, where is the z vector of a spherical camera?
Does it point upwards, or downwards or "towards the scene?

Also  we have a gyroscope attached to our spherical camera. we know the gravity direction (in the camera coordinate system, z pointing downwards) of the first image from the gyroscope, i.e. v=(vx,vy,vz). How to make the 3D point cloud aligned with the gravity direction?

6

General / Spherical image and real world coordinate

« on: February 10, 2019, 05:49:03 PM »

Hello!

I would like to know relation between spherical image and real world coordinate.

I guessed that ground is parallel to xy plane but in reality it wasn't.

Since I have no background knowledge about 3D reconstruction, could you please give me some information

about coordinate system defined in photoscan?