2.5D Tool for custom workflows

Rough surfaces near water bodies or areas with low image texture can sometimes cause artifacts or gaps in the input DSM, which is the geometric basis of the true orthophoto calculation. To achieve true orthophotos of excellent quality, these imperfections need to be removed.

SURE gives you the opportunity to revise and edit the DSM prior to processing further products such as True Ortho, 2.5D Mesh, or 3D Mesh. If corrections are made, the 2.5D Tool feeds the edited DSM back into the pipeline in order to achieve improved final results.

Ultimately, the 2.5D Tool enables you to refine your final products at an intermediate step, sparing you processing time and resources.


Step 1: SURE Data preparation

Process the dense matching clouds and the DSM with SURE, but leave out the True Ortho and DSM Mesh stages.

Step 2: QA

Perform the QA process, for example with the SURE Image viewer or in any GIS software.

Step 3: Editing 

There are several ways in correcting the DSM_Raw clouds:

  • either by editing the input DSM Clouds,
  • or just by interpolating the height from the digitized 3D shapefiles over the area containing the artefacts.

Editing DSM_Raw clouds:

  • Load and edit the affected DSM Cloud tiles, with your preferred point cloud editor, e.g. CloudCompare. Modify the clouds as needed and even complement the clouds using data from other sources.
  • Save the edited clouds in a separate folder to avoid overwriting of original data.
  • We recommend working on the DSM_Raw Clouds, since at this stage DSM rasterization has already been carried out and the amount of points is reduced significantly compared to the Dense Matching Clouds.

Digitizing 3D polygons for DSM/TrueOrhto improvements:

  • During QA the user can digitize polygons over the problematic areas in any GIS/stereo viewer application having as an overlay the DSM/TrueOrtho 
  • the problematic areas can be also automatically identified with the help of the metainformation layers SURE generates.
  • Export these polygons as 3D Shapefiles where each vertex of the shapefile has the correct heigh.  

  

Overview (left DSM without corrections, right DSM overlayed with correcting polygons)


Step 4: Feeding the modified data back into the SURE pipeline

In case that the DSM_Raw clouds were edited:

  • Open the 2.5D Tool. You can find it among the "Tools" section in the GUI's file menu in the processed project.
  • When loading the project's settings, the raw dense clouds are set as "Input Cloud". Instead, you should specify the folder with the edited DSM_Raw clouds plus the neighbouring DSM_Raw cloud tiles. The neighbouring DSM_Raw clouds are needed in order to generate consistent results. 
  • In this case, you have to slightly adjust the parametrization from the Advanced Configuration Toolbox accordingly (see screenshots to the right):
    • among the 2.5D workflow parameters, set the "Required points per cell' value to 1".
  • Adjust parameters as required. For example, you can also alter the GSD and/or tile size or the Area of interest fitting exactly with the tiling scheme boundary.
  • Select the desired processing outputs (True Ortho, DSM Mesh, DSM Mesh Texturing) and start the process by pressing the small play button in the lower right corner.


In case that the digitized 3D Shapefiles are prefered:

  • Open the 2.5D Tool
  • In the "Input Cloud" field, specify the already rasterized DSM clouds (folder \Internal\DSM_Raw\DSM_raw\las). Adjust the parametrization accordingly (see screenshots to the right):
    • among the 2.5D workflow parameters, set the "Required points per cell' value to 1".
  • Adjust parameters as required. For example, you can also alter the GSD and/or tile size.
  • Import the digitized 3D Shapefiles as a waterbody shapefile.
  • Select the desired processing outputs (True Ortho, DSM Mesh, DSM Mesh Texturing) and start the process.


DSM stage reprocessing

Please note that also the DSM stage will be processed again on the basis of the modified point clouds. However, since the rasterization of the dense clouds has already been carried out during the original run of the DSM module, the DSM stage will be finished in a fraction of the time needed for the original DSM generation.