Processing options

Orthomosaic - PIX4Dmatic

 

Orthomosaic

Create an orthomosaic based on the digital surface model (DSM) and the images.

Access:
  • Click Process processing options and enable the Orthomosaic option.
  • On the Menu bar, click Process > Orthomosaic...

It allows users to change the following processing options:

Important: The orthomosaic receives as input the DSM and the positions of the images. If the DSM is noisy or the reconstruction is not optimal, the orthomosaic will be distorted. Make sure that the results of the Calibrate, Densify, and the DSM are optimal before generating the Orthomosaic.
Tip: If holes are present in the generated orthomosaic, enable the Interpolation parameter in the DSM processing options before generating the orthomosaic:

Pix4Dmatic orthomosaic interpolation_on

Pix4Dmatic orthomosaic interpolation off

Resolution

  • Resolution: Defines the spatial resolution used to generate the orthomosaic.
      • The orthomosaic resolution is the same as the resolution of the DSM. For example, if the DSM resolution is set to 5 cm then the orthomosaic resolution is also 5 cm.

    Orthomosaic

Algorithm

  • Algorithm: Allows switching between the orthomosaic creation algorithms.
    • HW accelerated (Default): The generation of the orthomosaic will be computed using a GPU-capable algorithm. This option can contribute to reduced processing time.
    • Standard: The generation of the orthomosaic will be computed using the standard algorithm.

Deghosting

  • Deghosting (default - disabled): Removes objects that move during the flight when generating the orthomosaic. For example, a moving car on images will not appear on the generated orthomosaic, when the Deghosting option is enabled.
Note: This function increases the processing time and memory consumption. It may also discard fine details, depending on calibration and DSM accuracy.
Example: Generated orthomosaic with Deghosting option enabled (left) and disabled (right).

PIX4Dmatic Deghosting enabled

PIX4Dmatic Deghosting disabled

Oblique

Oblique (default - disabled): Enabling this option improves the orthomosaic for oblique projects.

Note: This function increases the processing time and memory consumption.
Example: The orthomosaic generated with oblique images is likely to contain holes. In those cases, enabling the Oblique processing option generates a more complete orthomosaic.

PIX4Dmatic orthomosaic oblique

PIX4Dmatic_orthomosaic oblique disabled

PIX4Dmatic orthomosaic oblique enabled

Exports

The following formats are available when exporting the orthomosaic:

Export JPG format settings

For the JPG format the following export settings are available:

  • Quality (90% - default): Defines the compression of the exported file and the JPG quality setting.
    • 90%: The default quality value is set to 90% as it is almost indistinguishable from the quality of 100% but the image file created is twice as small.
    • 100%: A quality of 100% results in the best quality but the largest file size this means that it has low compression.
    • 0%: A quality of 0% results in a small file size but very low quality but it has the highest compression.
  • Image size (L- default): Defines the size of the exported file.
    • L: Highest possible resolution that can be achieved using the JPEG format. May require more time and memory to open in some third-party software. The exported image will keep the original size unless it exceeds the maximum JPG size which is 65535 × 65535 px (~17 GB uncompressed).
    • M: High-resolution image, a good compromise for many applications that do not require the maximum number of details. The exported image will have a maximum size of 16000 × 16000 px. If the image exceeds this size, the result is to limit the maximum dimension of the image to fit the 16.000 × 16.000 px.
    • S: Standard image resolution, good for opening quickly in third-party viewers, sharing by email or on the web. The exported image will have a maximum size of 4000 × 4000 px. If the image exceeds this size, the result is to limit the maximum dimension of the image to fit the 4.000 × 4.000 px.
      Example: For a file with the original size of 7172 × 6117 pixels, the exported file with Image size:
      • L: 7172 × 6117 pixels (Image scale 100%).
      • M: 7172 × 6117 pixels(Image scale 100%).
      • S: 3586 × 3058 pixels (Image scale 50%).

        PIX4Dmatic_L_image_size.png

        PIX4Dmatic_M_image_size.png

        PIX4Dmatic_S_image_size.png

Export GeoTIFF format settings

For the GeoTIFF (.tiff) format the following export settings are available:

  • Compression (LZW compression, Enabled - default): Defines the compression of the exported file. 
    • LZW compression - Enabled: No data is lost during the compression of the file and the .tiff is not degraded. This results in a smaller file size of the exported file. 
    • LZW compression - Disabled: No compression is used during the export. This results in a larger file size of the exported file.
  • File Type (Single - default)
    • Single: The image will be exported in a single file. 
    • Tiles (2048 px - default): The image will be exported in tiles with a predefined size of 1024 px, 2048 px, or 4096 px. The origin of the tiles is the top left corner of the project boundary. 
  • Image Scale (100%- default): Defines the scale of the exported file.
    • 100%: The exported image will keep the original size.
    • 50%: The exported image will be scaled to 50% of the original size.
    • 25%: The exported image will be scaled to 25% of the original size. 
      Example: For a file with the original size of 10000 x 10000 pixels, the exported file with Image scale:
      • 100%: 10000 x 10000 pixels.
      • 50%: 5000 x 5000 pixels.
      • 25%: 2500 x 2500 pixels.
  • Save as...:
    • Single: Specifies the path and the file name of the exported file.
    • Tiles: Specifies the destination folder.
Tip: Images exported as a single .tiff file include overviews (pyramid of resolution) so that they can be opened instantly and efficiently in other compatible third-party software (e.g. QGIS).
Note: The Exports - Orthomosaic GeoTIFF option is disabled by default. To export the orthomosaic:
  • On the Menu tab, click File > Export orthomosaic...
  • In the Export orthomosaic dialog, select the export settings.
  • Click Export.