Registration

The LineUp® toolbox includes a comprehensive suite of tools for coarse and fine registration of any amount of scans (and not only). The registration process is composed by several steps, depending on adopted survey techniques.

The general flow, here illustrated

starts from a preregistration step that allows you to compute a rough alignment between the imported models. The alignment can be later refined using ICP registration and Bundle Adjustment to choose and refine the good ICPs and discard the wrong ones, in order to reduce the global registration error.

Start

LEVEL

You can simply use the Scan Processing Wizard (also simultaneously with the import phase) and check all the steps, using default parameters.

Advanced

LEVEL

You can manage the registration parameters for your purpose in the LineUp Setting Dialog or you can separately carry out the processes (with Register commands in the LineUp® main window).

In the following paragraph several customized workflows are illustrated. The user can choose the way, depending both on survey techniques adopted and on desired output accuracy. Then the main processes (algorithms) are briefly illustrated.

WF1	After importation of a pre-registered project If you pre-registered your scans with a third part software (as the owner laser scan) you can import the just aligned scans and simply make a fine registration, in order to further reduce the registration error.

WF2	Automatic registration without targets If you made a survey not using targets or markers, with a good overlapping (the minimum overlap of two scans is 20-30% of their surface), the automatic preregistration algorithm permits you to register all the point clouds you want. Then you can decide if you want only to make a cloud to cloud registration or also a bundle adjustment

WF3	Automatic registration using targets If you made a survey using Gexcel’s targets, a special function automatically register a set of scans by detecting and matching targets. Then you can decide if you want only to make a cloud to cloud registration or also a bundle adjustment

WF4	Automatic preregistration failed? Make a manual preregistration If you don’t achieve a good error of alignment using automatic techniques, the manual registration helps you to align two scans (or two generic models) by finding 3 couples of corresponding points among the models. Then you can decide if you want only to make a cloud to cloud registration or also a bundle adjustment You can also choose to follow an alignment per groups procedure.

See in the following links how to implement:

See Georeference step to know how georeference the registered models.