1. Available Photogrammetry Engines

Aether integrates two industry-leading photogrammetry processing engines:

• Pix4Dengine
• PIX4Dengine v2 (only available on designated domains for further information please contact your sales representative)​
• Agisoft Metashape

These engines are built into the processing workflow and leverage the cloud-computing capacity offered by Aether to produce results quickly.

2. Can I process photogrammetry out of Aether and load it?

Yes. If you already own processed data you can load it, e.g. Orthomaps, DSM, Point Cloud. So that you can run Aether advanced analytics without having to redo a photogrammetry process.

You can also upload data such as single pictures, and skip the photogrammetry step if:

• either not required: for instance Automatic Defect Detection and Analysis‍, an analytic running from single images only
• or if you want to process photogrammetry later, use Aether first as safe data storage.

3. What kind of dataset can I process with each of the built-in engines?

We recommend selecting:

• Pix4D for RGB, multispectral, and thermal datasets*
• PIX4Dengine v2 for RGB
• Agisoft Metashape for RGB datasets only, for 3D reconstruction

4. What happens if I upload a dataset that is not compatible?

You may need to use other categories of datasets than your usual one. The category of data is detected during the upload process. In case you upload a data set that is not compatible with the default photogrammetry engine, the user interface will offer you to override the default setting for an appropriate alternative.

5. How to create photogrammetry presets?

According to your business, you may require only one engine on a daily basis. It is possible to define the preferred Photogrammetry Engine as a preset for the Company‍ (with all its projects) or within a certain Project‍.

5.1. For an existing Project

Step 1 - Open a Project and select Show project info from the top bar drop-down menu, which results in opening the project information panel on the left side:

Step 2 - Go to the "PHOTOGRAMMETRY PRESETS" section:

Step 3 - Click on "CREATE".

Step 4 - A pop-up will open with the photogrammetry settings. Adjust the settings (description given in section 6 below) and then click SAVE.

• A message is displayed on the information panel and chosen options are listed

• This preset could be updated anytime later.

5.2. For an entire Company

Company Managers‍ have administration rights allowing them to define the settings that will apply across all managed Projects, per Company.

Step 1 - At the bottom of the left panel, press Administration icon.

Step 2 - Click on "Companies" (1) and select the company on the list (2), for which you want to adjust the photogrammetry default settings.

Step 3 - Click on "CUSTOMIZE PRESET" in the Photogrammetry settings section.

Step 4 - A pop-up will open with the photogrammetry settings. Adjust the settings (description given in section 6 below) and then click SAVE.

6. What are the different photogrammetry services and options?

6.1 Pix4D Options

6.1.1 Execution mode: Self-service or Advanced

• The self-service option shall be used to get automated results from the engine without the assistance of an Alteia production member.
• Advanced option will notify the Alteia production staff and photogrammetry will be handled and then delivered to Aether with their assistance and quality control.

6.1.2 Custom Settings

Selecting both Pix4Dengine and Custom allows you to set below parameters:

• Generate Light Reflectance Map: for Agriculture & Forestry projects.
• Keypoints image scale: this changes the scale of the image used to find matching features. Lower (1/2, 1/4) scales will allow projects to map faster, but with lower accuracy.
• Calibration method: this allows the user to declare the usage of a highly accurate geolocation and orientation system (E.g. flying with RTK). Do not select this if you are unsure, as the resultant models are likely to fail.
• Point cloud image scale: This defines the scale of the images at which additional 3D points are computed. Lower (1/8, 1/4) scales produce faster, less dense clouds.
• Point cloud density: This parameter defines the density of the point cloud vs. the pixel density of the original images. The low settings produce faster, less dense clouds.
• Point cloud minimum matches: The minimum number of matches per 3D point represents the minimum number of valid re-projections of this 3D point to the images.
• DSM method: This defines the method that is used for the Raster DSM generation. The method will affect the processing time and the quality of the results.
• Orthomosaic resolution: This allows for the selection of a custom resolution in terms of GSD.
• Mesh resolution: This allows for the selection of a mesh resolution.
• Rematch: Allows to add more matches after the first part of the initial processing, which usually improves the quality of the reconstruction.
• Internal Param Optimization: Defines which internal camera parameters of the camera model are optimized.
• Radiometric Correction: Allows to calibrate and correct the image reflectance, taking the illumination and sensor influence into consideration.
  • Auto: the best radiometric correction is selected according to the different types of corrections available. For example, if a reflectance target and sun irradiance data are available, they will be taken into account.
  • No correction: no radiometric corrections
  • Camera only: the camera properties and settings (+ reflectance target if any) are taken into account. This is the default parameter when recommended settings are selected for multispectral sensors.
  • Camera and Sun Irradiance: same as above, including the sun irradiance sensor information
  • Camera, Sun Irradiance and Sun angle: same as above, including sun angle
  • Camera, Sun Irradiance, Sun angle using DLS IMU: same as above, but sun angle based on DLS IMU.
• Noise filtering: selection of noise filtering
• Surface Smoothing: Selection of surface smoothing
• Orthomosaic resolution: This allows for the selection of a custom resolution in terms of GSD

6.2 PIX4D engine v2 Options

6.2.1 Execution mode: Self-service or Advanced

• The self-service option shall be used to get automated results from the engine without the assistance of an Alteia production member.
• Advanced option will notify the Alteia production staff and photogrammetry will be handled and then delivered to Aether with their assistance and quality control.

6.2.2 Recommended Settings

The recommended settings are 3D-oriented and save execution time using fast orthomosaic. So use the Custom settings if you want to have a high-quality orthomosaic.

Recommended settings:

• Calibration template: LARGE
• Point cloud densification template: NADIR
• Mesh templates: LARGE
• Mesh textures templates: DEGHOST
• Orthomosaic pipeline: FAST

6.2.3 Custom Settings

Selecting both Pix4Dengine v2 and Custom allows you to set below parameters:

• Calibration templates

      LARGE: Optimized for use with aerial non-multispectral image captures of large scenes.  
      FLAT: Optimized for aerial nadir data sets of flat, possibly low-texture, scenes. Well suited for multispectral cameras (rigs).  
      MAPS_3D: Optimized for small (less than 500 images) aerial nadir or oblique data sets with high image overlap acquired in a grid flight plan.  
      MODELS_3D: Optimized for aerial oblique or terrestrial data sets with high image overlap.  
      CATCH: Specifically designed for data sets captured by PIX4Dcatch. 

• Point cloud densification templates

      NADIR: Optimized for aerial nadir image capture.
      OBLIQUE: Optimized for aerial oblique or terrestrial image capture

• Mesh templates

      LARGE: Optimized for large scenes and aerial nadir image capture.  
      SMALL: Optimized for small scenes and aerial oblique or terrestrial image capture.  
      TOWER: Optimized for tower-like structures.  

• Mesh textures templates

      STANDARD: Optimized for well-reconstructed geometries and image captures with no or few occluding or moving features.  
      DEGHOST: Optimized for imperfect geometries and image captures with many occluding or moving features. 

• Orthomosaic pipeline

      FAST : Speed-oriented algorithmic pipeline.  
      FULL : Quality-oriented algorithmic pipeline.  
      DEGHOST : Algorithmic pipeline targeted at removal of moving objects. 

• DSM settings

      URBAN: Optimized DSM for urban areas, construction sites and buildings.
      RURAL: Optimized DSM for rural areas, agriculture or low texture captures.

6.2.4. Settings advice by use case

According to your use cases, you may use the settings as recommended below. 

• RGB Nadir for orthomosaic
  • Calibration template: LARGE
  • Point cloud densification template: NADIR
  • Mesh templates: SMALL
  • Mesh textures templates: STANDARD or DEGHOST
  • Orthomosaic pipeline: FULL or DEGHOST
• RGB Nadir for 3D Modeling
  • Calibration template: LARGE
  • Point cloud densification template: NADIR
  • Mesh templates: LARGE
  • Mesh textures templates: STANDARD or DEGHOST
  • Orthomosaic pipeline: FAST
• RGB Oblique for 3D Modeling
  • Calibration template: LARGE
  • Point cloud densification template: OBLIQUE
  • Mesh templates: LARGE
  • Mesh textures templates: STANDARD
  • Orthomosaic pipeline: FAST

6.3 Agisoft Metashape Options

Self-Service and Advanced photogrammetry options are both available as with Pix4D

• Custom Settings: 5 profiles can be selected: 

• Recommended - By default: By default settings – mainly adapted to photogrammetry processing in Mines and Quarries context.
• Recommended - Quality Medium: Same settings as “By default”, but the Dense Point Cloud is set to Medium. Mainly adapted to voluminous data sets for Mines and Quarries, Agriculture and Forestry context.
• Medium with 10cm/pixel for output rasters: Same settings as “Quality Medium”, but the output rasters (ortophoto and DSM) will be set at 10cm per pixel. To be used if the CRS is in meter. Mainly adapted to voluminous data sets. 
• Medium with 3ft/pixel for output rasters: Same settings as “Quality Medium”, but the output rasters (ortophoto and DSM) will be set at 0.3ft per pixel. To be used if the CRS is in feet. Mainly adapted to voluminous data sets. Note: There is currently a display error: the setting is 0.3ft and not 3ft.
• Vegetation Encroachment: Profil to select when the photogrammetry outputs are used for the Vegetation Encroachment analytic (for Power Lines). Output rasters will be set at 25cm/pixel.