Registration is the re-orientation of two or more objects (point or polygon) that comprise a single object, so that identical regions of different objects are made to overlap and a more complete composite object can be constructed (by means of Points > Merge or Polygons > Merge).
Tools > Registration > Manual Registration allows the user to identify pairs of corresponding points in overlapping regions, and adjusts to the spacial position of the objects such that identified points share the same position in space. Use Manual Registration to achieve a rough alignment before using Tools > Global Registration.
The controls are:
Mode section - specifies the number of points that will be matched on the component objects.
1-point Registration radio button - aligns objects on the basis of a single point (assuming the composite object has a point that is shared by both).
n-point Registration radio button - aligns objects on the basis of three to nine points on each object. You can continue to click pairs of points even after registration has taken place based on the first three pairs. Use Ctrl-Z and Ctrl-Y to undo and redo point selections.
Delete Cells radio button (appears when the objects are ordered point objects) - deletes selected cells in order to simplify manual registration.
Delete Points radio button (appears when the objects are unordered point objects) - deletes selected points in order to simplify manual registration.
Delete Triangles radio button (appears when the objects are polygon objects) - deletes selected polygons in order to simplify manual registration.
Define Sets section -
Fixed radio button and list of sets - click this button, then highlight the name(s) of the component objects whose position(s) must remain fixed during the registration process.
Floating radio button and list of sets - click this button, then highlight the name(s) of the component objects whose position(s) will be adjusted during the registration process.
Show RGB Color checkbox - specifies whether to display the object in color (if color information exists in the object).
Sampling dropdown menu (1 to 100%; for ordered point objects only) - specifies the percentage of points on which to base the calculation.
Register button - moves the Floating object(s) toward the Fixed object(s).
Unregister button - undoes the most recently completed registration.
Clear button - removes the selected reference points from the Fixed and Floating objects.
Modify button - allows tweaking of the Floating object(s) after a registration is complete. This activates the Modify Alignment dialog:
• Modify Alignment dialog -
Select Axis/Direction group - specifies a method of modifying the alignment of the Floating object.
View Plane radio button - modifies the alignment of the Floating object on a plane that is parallel to the user’s screen. To move the Floating object, Left-Click and drag it.
Screen Point radio button - modifies the alignment of the Floating object with respect to a single point.
User-Defined Line radio button - modifies the alignment of the Floating object with respect to a line (defined by two points).
First Point radio button - the next point that you click in the Viewing Area is the first point that defines a line.
Second Point radio button - the next point that you click in the Viewing Area is the other point that defines a line.
Flip Normals button -
Rotate (deg) input field - rotates the object about the defined line or point.
Translate input field - moves the object a specified distance in the direction of the defined line.
Done button - saves the results of this Modify Alignment dialog and returns to the main Manual Registration dialog.
Cancel button - closes the Modify Alignment dialog without saving changes, and returns to the main Manual Registration dialog.
Add to group -
Add to group checkbox - specifies whether to add the Floating object to a named Group in the Model Manager.
Groupname dropdown - specifies the name of a Group to which to add the Floating object. You can override the system-generated name.
Statistics section - presents statistics about the most recent registration process.
Average Distance - indicates the average distance between Fixed and Floating objects.
Standard Deviation - indicates the standard deviation of points in overlapping regions of the two objects.
OK button - saves the new position of the Float object(s) to the Model Manager and terminates the dialog.
Cancel button - closes the dialog without saving new positions to the Model Manager.
Next button - accepts the most recent registration process and allows selection of new Fixed and Floating object(s).
To manually register two or more scans:
In the Model Manager, activate two or more point or polygon objects. One or both can be a group of objects constructed by Tools > Registration > Identify Groups.
Click Tools > Registration > Manual Registration. Note that the Viewing Area breaks into three panels: “fixed”, “floating”, and a view of both the fixed and the float that is named for the view angle such as “top”, “left”, or “front”.
Optionally, delete extraneous points (or polygons) from the fixed, the float, or both. To do so, press the Delete Cells (or Delete Triangles) radio button, selecting cells (or polygons) in the Viewing Area, and press Delete.
Chose a mode:
If your model has a unique location that was captured on all scans, choose 1-Point Registration to align the scans on the basis of this location only.
Choose n-Point Registration to align the scans on the basis of multiple locations. The additional locations increase the probability of accuracy.
Press the Fixed radio button.
In the list below Fixed, click the name of one object to designate it as the scan that will remain fixed while the other objects are adjusted in reference to it. The chosen scan appears in the Fixed panel of the Viewing Area.
Press the Floating radio button.
In the list below Floating, click the name of one object to designate it for repositioning. The chosen scan appears in the Floating pane of the Viewing Area.
Find a pair of corresponding points on the “fixed” and “floating” objects.
Click on a point on the fixed object that is at a location you can easily find on the floating object. For best results, click point(s) of high curvature. Rotate the model if necessary.
Click on the corresponding point in the floating object. The pair of points is given a yellow numbered label.
If you chose n-Point Registration in step 4, repeat step 9 until you see the scans align in the composite pane. If the alignment is faulty, click Clear and return to step 9.
Click Register. The floating scan moves to its new position.
Registration might improve if you click Register again.
If the alignment is faulty, click Unregister and return to step 5. To exert advanced control on the alignment, see Modifying Registration Options.
To add the models to a pre-existing group, check the Add to group box after making sure the intended group is given in the drop-down menu. To use groups to your advantage, see Creating Groups for Simplified Processing.
If you have more than two scans to register (i.e., more than two scans were active in the Model Manager when you began the operation), click Next and repeat steps 4-12 for any additional objects.
Click OK to save the objects in their new positions, or click Cancel to terminate the dialog without saving.