Topics

1

Python and Java API / CRS coordinates to Region coordinates

« on: March 29, 2021, 01:23:50 PM »

Hello everyone,

I have a bunding box of which the following quantities are known: center coordinates (northing and easting), width, height and rotation angle, as shown below:



The problem is that all the quantities (center, size) are expressed in the chunk's geographic coordinate system (in this case EPSG:7416).

I would like to set the reconstruction region (chunk.region) using this rectangle, but the units need to be converted to the local reference system first. Furthermore, the rotation angle needs to be converted into a rotation matrix, by assuming that the rotation around the other axes is zero (there is rotation only on the xy plane).

Does anyone have any idea of how to perform (using Python) this conversion, so that I can set:

• chunk.region.center
• chunk.region.size
• chunk.region.rot

starting from a rectangle expressed in the geographic CRS?

The region center.z value, and the size.z value should remain unchanged, only the xy values must be changed according to the rectangle.

I would like to thank anyone in advance,

Andrea

2

Python and Java API / buildTiledModel() optimal parameters

« on: March 24, 2021, 01:39:29 PM »

Hello everyone,

when we build a Tiled Model from the GUI, the "Pixel Size" parameter is calculated automatically, and the "Face Count" parameter can be one of [High,Medium or Low].
I was wondering what are the equivalent parameters that we should pass to the  buildTiledModel() Python function? How can we calculate the pixel_size number automatically, as it is in the GUI, and set the face_count number so that it is equivalent to "High" in the GUI?

Thank you very much in advance,

Andrea

3

General / Info about new "Merge tiled model" option in version 1.7.2

« on: March 22, 2021, 04:43:34 PM »

Hello everyone,

I was wondering what is the purpose, and how to use, the new "Merge tiled model" option in the "Build Tiled Model" dialog window. I tried searching for it in the manual, but it hasn't been updated yet.
Thank you in advance,

Andrea

4

Python and Java API / Render image from camera reference location

« on: March 18, 2021, 05:52:54 PM »

Hi everyone,

I am trying to render an image of a tiled model, using the tiled_model.renderImage method. I would like to render from the camera reference positions (not the estimated ones), of which I know the easting, northing, altitude and yaw, pitch, roll angles. The camera reference values and the tiled model are expressed in the same geographic CRS.

The question is: how can I construct the transformation matrix to use in the tiled_model.renderImage() function, using the reference X,Y,Z and Y,P,R values of the cameras?

I tried constructing a 4x4 transformation matrix by computing a rotation matrix from the euler angles, and concatenating it with the [X.Y.Z] column and adding a [0,0,0,1] row, but I am getting an all-black render...

Thank you in advance,

Andrea

5

General / Capture distance vs reference Altitude

« on: February 17, 2021, 07:34:16 PM »

I am in the process of building a 3D model of a city, using a set o aerial images. The images are acquired by an airplane, using a camera rig with 5 cameras: one looking down (nadir) and four looking obliquely (N,S,W and E) with a tilting angle of -45 degrees.
By reading the documentation, I found that in order to improve the speed of the camera alignment process, it is helpful to use the "Reference Preselection" setting, so that the algorithm knows which cameras are more likely to have matching points. Furthermore, it is recommended, in case of oblique images, to set the average altitude of the cameras in the "Capture distance" option of the reference settings.

My question is: is it necessary to set this "capture distance" option, in the case when the images altitude is already present in the reference panel? Is the images altitude already taken into account during the alignment process, or do I have to set the average altitude anyway? My fear is that the image-wise altitude is more precise than an average, so by overriding it with an average one I'm afraid to lose some accuracy.

Thank you

Andrea