9.2.1
Create or Load a Scene
You might begin by creating a scene as described in section 3.4 – by loading an entire directory
of files from a scan session. You might already have created a scene (perhaps while scanning)
and now just need to open it. If you would like to use our sample data, we suggest not loading
the scene but rather creating a new scene with just the files needed for this exercise. In this way,
the files are not already aligned. To create a new scene with the sample data:
Open File – with v1_color.rtpi found in the v1 directory.
Insert file – with the other two range data files found in the v2 and v3 directories
(one at a time)
Note: Though we will be working with color range data, range alignment works
with range data without color as well. In general, we recommend doing range
alignment before doing color alignment.
9.2.2
Select the Range Align Tab
Picking the
Range
Align
tab displays a new toolbar of functions specific to this operation.
Initially, the
1:New
button will be enabled, as it is the first of 4 required steps for aligning range.
1:New Group
Select the
1:New Group
button. You’ll be asked to specify the file to base your alignment on (a
file that is already aligned). Often a scene will have a large scan, perhaps 360
°
, that covers most
of a room – a ‘reference’ scan. It is advantageous to choose a large scan like this as it will tend
to provide overlapping regions with other scans.
Next you’ll be asked to select an unaligned file to align. It doesn’t matter which you pick – but
there must be some significant overlap between scans in order to align them. If these two files
are not already open in windows, SceneVision will open them.
Note: If you open the two range files before selecting the New Group button,
they will be at the top of the lists from which you choose files. This is helpful
when working with a large number of files.
Note: You will use two windows for this process – one for each range data file.
There are two convenient functions in the Window menu to help with this. Tile
Horizontally and Tile Vertically will fill the entire SceneVision window with
your open windows – with no overlap. If you have just the two windows open
they’ll be put into a good position for doing color alignment.
In addition, a Correspondence Group will be created in the Correspondence Groups folder of the
scene tree.
Select Correspondence Points
After you’ve specified your files, the
Create Correspondence Point
button (
) is automatically
selected. You will now select corresponding points in each window to begin the alignment.
Selecting points is similar to creating landmark points – except that you must select them in
pairs.
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