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Difference between "Reoptimize" and "Rematch and Optimize" - PIX4Dmapper

This article explains in detail the difference between Reoptimize and Rematch and Optimize in PIX4Dmapper.


This feature reoptimizes the camera positions and the internal camera parameters. It does not compute more matches between the images, therefore, it is a fast step that improves the accuracy of the project.

It should be used when changes have been applied to the project after step 1. Initial Processing has been completed. Such changes can be:

  • Adding Ground control points.
  • Adding Manual Tie points.
  • Adding Checkpoints.
  • Changing coordinate systems.
  • Disabling images.

For step-by-step instructions about how to Reoptimize a project: Menu Process > Reoptimize.

Rematch and Optimize

This feature computes more matches between the images (and therefore more Automatic Tie Points) and reoptimizes the internal and external camera parameters. Therefore, it takes more time than the Reoptimize feature.

It is recommended to use it:

  • After manually calibrating cameras that were not initially calibrated.
  • For complicated projects where few matches were originally found.
  • To merge individual projects that do not share common images.
  • To optimize step 1. Initial Processing by re-matching images. For projects with more than 500 images, this option is unselected and disabled in the processing options.

For step-by-step instructions about how to Rematch and Optimize a project: Menu Process > Rematch and Optimize.