How to process PIX4Dcatch datasets in PIX4Dmatic

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PIX4Dcatch is a powerful tool for terrestrial data acquisition that combines the following to get the most out of your mobile device:

  • Image acquisition.
  • LiDAR acquisition*.
  • RTK geolocation with viDoc RTK rover.

PIX4Dmatic is well suited to process these datasets and has incorporated many features to combine and take advantage of the unique qualities of these sources.

 
*Note: Currently, LiDAR support is only available from LiDAR-capable iPhones and iPads. For more information: PIX4Dcatch FAQ - What are the recommended devices?

How to import a PIX4Dcatch dataset into PIX4Dmatic

With a completed PIX4Dcatch project on a mobile device, it is ready to be exported and processed using PIX4Dmatic.

  1. From the PIX4Dcatch app, Pix4Dcatch logo open the project to be processed in PIX4Dmatic.
  2. Export the project from the mobile device by tapping Export all data export.jpg and save to a local folder.

    PIX4Dcatch project dialog

    Tap the menu iconmenu iconaccessing the export dialog.

    For more information: Export PIX4Dcatch Data (iOS/Android).

  3. Open PIX4Dmatic PIX4Dmatic logo light.
  4. To create a new project, import the project data. The _inputs folder contains all the captured data and is aptly named projectname_inputs. Different files will be visible in this folder depending on the device used for capture.

    Projects captured with LiDAR capable devices.

    Confidence DepthMap jpg tags

    When importing projects taken with LiDAR capable devices, import all Confidence.tiffs, DepthMap.tiffs, and Image.jpgs. The Confidence.tiff and DepthMap.tiff files represent the LiDAR depth data, while the Image.jpg files represent the image content.

    Projects without LiDAR data

    jpg tag

    When importing projects captured without a LiDAR capable device, the _inputs folder contains the Image.jpgs reflecting the image content.

    PIX4Dmatic drag drop start new project

    New projects can be easily created by dragging and dropping the necessary files or the _inputs folder directly onto the PIX4Dmatic home page. PIX4Dmatic will import all of the required files.

How to process a PIX4Dcatch dataset in PIX4Dmatic

With a new project opened and all the data imported, PIX4Dmatic is ready for processing. In most cases, the default processing options can be used to process PIX4Dcatch projects. There are a few PIX4Dcatch-specific settings to select and are highlighted in each section. 

Calibrate

Calibrate is the first step in processing. A good starting point is to select the PIX4Dcatch template with the Trusted location and orientation pipeline.

PIX4Dcatch processing template calibrate

PIX4Dmatic Calibrate options dialog.

Use depth maps are available and activated by default for projects captured with LiDAR depth data. This can be toggled off if desired. When enabled, the depth maps generated with PIX4Dcatch are used for better calibration.

 
Note: Using PIX4Dcatch data that contains supplemental LiDAR data can help eliminate GNSS and IMU drift. For more information: PIX4Dmatic: combined LiDAR and photogrammetry workflow.

Depth point cloud

PIX4Dmatic Depth point cloud checkbox

PIX4Dmatic Depth point cloud checkbox

The Depth point cloud is generated from LiDAR depth maps. This option is only available for PIX4Dcatch projects captured with a LiDAR-capable device.

 
Tip: The generation of the depth point cloud is typically faster than running the Densify step to generate a dense point cloud. Running the Depth point cloud step can give a quick insight into the quality and completeness of the project. It can also be combined with the dense point cloud to get a more complete fused point cloud. Refer to Depth and dense fusion for more information.

Densify

PIX4Dmatic densify dialog

PIX4Dmatic Densify options dialog

The Densify step generates a dense point cloud from the images. Besides the default settings, there are two optional selections to make that can directly benefit PIX4Dcatch projects. They are the Noise and Sky filters.

  • Noise Filter

  • Sky Filter

Depth & dense fusion

The Depth & dense fusion option combines the point cloud generated from images with the one generated from LiDAR depth maps.

PIX4Dmatic Depth and dense fusion

PIX4Dmatic Depth & dense fusion option dialog

The fused point cloud is often denser and more complete in areas where traditional photogrammetry may struggle to reconstruct complex geometries or homogeneous textures.

Mesh

Select to generate a 3D mesh. The Input and Template fields have PIX4Dcatch-specific selections to make. 

PIX4Dmatic mesh options dialog

PIX4Dmatic Mesh options dialog

  • Input

    When processing PIX4Dcatch data containing LiDAR depth maps, the mesh can be generated with one of the following point clouds:

    • Dense point cloud.
    • Depth point cloud.
    • Depth & dense fusion point cloud.
  • Template

    Select the PIX4Dcatch template as this is optimized for terrestrial projects.

All the Mesh settings are outlined in Processing options - Mesh. Select the options that provide the most accurate reconstruction depending on the subject.

DSM

Select to generate a Digital Surface Model(DSM). The Input field has PIX4Dcatch-specific selections to make.

PIX4Dmatic_DSM_dialog.jpg

PIX4Dmatic DSM options dialog

  • Input

    When processing PIX4Dcatch data containing LiDAR depth maps, the DSM can be generated with one of the following point clouds:

    • Dense point cloud.
    • Depth point cloud.
    • Depth & dense fusion point cloud.

All the DSM settings are outlined in Processing options - DSM. Select the options that provide the most accurate reconstruction depending on the subject.

Orthomosaic

Select to generate an Orthomosaic. The Oblique and Deghosting toggles can provide PIX4Dcatch projects with improved quality.

PIX4Dmatic_orthomosaic_dialog.jpg

PIX4Dmatic Orthomosaic options dialog

All the Orthomosaic settings are outlined in Orthomosaic - PIX4Dmatic. Select the options that provide the most accurate reconstruction depending on the subject.

Exports

Select the desired exports for each processing option plus the Quality report.

PIX4Dmatic_exports_dialog.jpg

PIX4Dmatic Exports options dialog

When processing PIX4Dcatch data containing LiDAR depth maps, each point cloud .las option will be available for export if the processing option is selected. When exporting the DSM and Orthomosaic, there are further options to consider. These export settings are outlined in their respective articles: Processing options - DSM, and Orthomosaic - PIX4Dmatic.

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