ModifyCompensatorClean Displacement Field

The Clean Displacement Field command enables you to remove couples of points (or move some of them) considered as not consistent, that could have been detected through the Show Displacement Field command, so as to avoid the presence of inconsistencies while creating the desired deformation through the Identify Displacement Field command.

The command compares the displacement vector of the field, with the average displacement vector of all the couples of points in the neighborhood. The displacement vector is the one between the couple formed by the initial and by the target points selected for Browse for Initial Points and Browse for Target Points, respectively.

Under the Neighborhood node, you can find options enabling you to define the neighborhood both in terms of shape (in the Zone drop-down list you can choose Box, Sphere or Ellipsoid) and of distances once the shape has been chosen. For example, if you choose a Box, you will have to supply the Box size on X, Box size on Y and Box size on Z values.

The consistency criteria can be either the Distance between the two vectors, or their Angle, as you can choose in the Consistency Deviation Criterion drop-down list under the Show inconsistencies node. The specified Threshold value will be used to assess the consistency.

Feedbacks about target points, displacement values (minimum, maximum and mean), and inconsistent points can be displayed in the selection list under the corresponding nodes (on selecting its check boxes). Graphs can also be obtained using the Graph node available under Show displacement field. See "Displaying graphs in Compensator" for details on how to obtain graphs in Compensator.

The cleaning method for detected inconsistencies can be selected in the Clean Inconsistencies drop-down list:

• Delete initial & target points
  to remove both the initial and the target point which are generating the inconsistency.
• Keep target points
  to preserve the target point at its location and to move the initial one to a more consistent location.
• Keep initial points
  to preserve the initial point at its location and to move the target one to a more consistent location.

The No. loops option enables you to run the filtration process a specified number of times, to remove points progressively. You need to enter the number of times the process will be looped in the corresponding text box. When the No. loops = 1, the command is run only one time to remove some points according to the chosen criteria. However, due to the removed points, the neighborhood and average computations changes. Hence, by running the filtration loop again, the program could find some more points to remove.

Every time the Apply () button is selected, new point files are generated. If file.pt was the original file name, you will have:

• file_clean#.pt
• file_bad#.pt

where "clean" files contain the cleaned set of points, "bad" files contain the removed points and # is a progressive number automatically incremented at each click on () in the same session.