Target accuracy in a full survey

After a target is registered, feedback on the accuracy is displayed at the side of the target in the Registration tab. This feedback takes the form of two traffic light icons. This is a rapid way of interpreting registration accuracy. The coloured icons enable the user to visually skim through the results, focusing quickly on the targets causing concern. These appear as amber or red in the components browser.

The diamond shape refers to the inter distance between the selected target and its neighbors within the scan. These inter distances are compared against the corresponding inter distances in the survey.

The circle shape refers to the distance between the picked target in the scan and the corresponding target position in the survey post registration. Generally, there should be more than 5 target correspondences in every scan to ensure accurate registration.

The traffic lights will be red, amber or green. The thresholds for these colours can be changed in the File > Options > Gateway tab.

Anything between 0 and the amber threshold will be green. Anything between the amber threshold and the red threshold will be amber. Anything above the red threshold will be red.

The recommended values are amber = 0.003m and red = 0.006m. If the threshold is altered during registration, an automatic update of target accuracy is carried out respective to the new settings.

As soon as two targets have been selected within a scan, provided a survey is attached to model, the system shows the accuracy of the target fitting. As this process is ongoing as targets are selected, poorly fitted targets will be highlighted instantly, allowing an immediate refit. This saves a great deal of time later on identifying rouge targets. Numerical error readings are provided in the Attributes window for confirmation.

Improving the accuracy of poorly fitting targets

The example shown below demonstrates poor accuracy on target 091:

Inaccurately fitted targets such as this can be reviewed by right-clicking on the target in the Registration panel and selecting Show Context. This shows the graphical representation of the pick against the 3D point cloud.

Targets can be re-picked by clicking on the center of the target in the target identification window within the BubbleView, entering the target name and selecting OK. This will present a warning as shown below that the target has already been picked. Select Yes to accept or No to cancel.

Targets can also be temporarily disregarded by right-clicking on the target in the Registration tab and selecting Do not use for Registration. Targets that have the Do not use for Registration feature applied are shown with a red strikethrough as shown below on target 130.

The image shown below demonstrates the scan registration after the Do not use for Registration feature has been applied to a target. The registration of the scan is now good. This feature can be removed if necessary by right-clicking again on the target and selecting Use for Registration.

When the registration is complete you can then move on to the next scan. This should be repeated for all scans in the project.

Target sizes can be changed in the File > Options > Gateway tab.

After the Registration is complete, it is good practice to update the scan headers. This stores the position, rotation and targets in the .zfc file itself rather than just the project file. This means that registered scans can be added to another project still in the correct position. This is also useful for service providers delivering to users using AVEVA Point Cloud Manager Modeller or AVEVA Laser Modeller.

Note: The .zfc files generated using AVEVA Point Cloud Manager 4.4.2 or later versions support an extended range and hence cannot be read by earlier versions of Point Cloud Manager and AVEVA Laser Modeller/AVEVA Point Cloud Manager Modeller.

To update the scan headers, right-click the group node and select Scan Headers > Update ZFC Headers.

To update the ZFS scan headers, right-click the group node and select Scan Headers > Update ZFS Headers. This preserves the positions of the aligned scans when used in a different project. You can then use the ZFS scan files to produce different outputs, such as Cloudworx, TruView and so on, without having to re-register the scans in another registration toolset.