Error: Point Cloud rotated / inverted / upside down in the rayCloud

Error

The point cloud appears upside down / rotated in the rayCloud and at the Pix4D Desktop outputs (orthomosaic, kml file, DSM).
 

Description

The area of the project appears significantly rotated or turned at the results. On the Quality Report on Computed Image Positions section, there might be a big rotation of the input camera position and the optimized one.


Cause
 

An inverted or rotated model can stem from difference sources such as:

  1. project is not georeferenced (no image geolocation, no GCPs). When processing images with no image geolocation, if no GCPs are used the final result have no scale, orientation and absolute position information.
  2. one flight line. Projects of a single flight line even if they have image geolocation, might face ambiguities in the orientation. 
  3. big difference between the initial and computed camera parameters. There is also big difference between the initial focal length and the optimized one as it is calculated by the calibration process.

 

Solution

If processing images with no geolocation or a dataset consisting of one flight line, and GCP coordinate information available:

  • Use GCPs to georeference the model: 202558699.

If processing images with no geolocation, and GCP coordinate information is not available:

To reduce the difference between initial and optimized camera internal parameters: 202560899.

 

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