Aligning Sensors to 6 Degrees of Freedom

The tools described in the following sections are only intended to be used with G2 sensors.

The alignment of a system of sensors to 6 degrees of freedom involves the use of one of two Surface measurement tools (Surface Align Wide or Surface Align Ring), which creates a set of transformations and stores them in an XML file. The resulting alignment is more accurate compared to the other methods available on the Alignment panel, and includes compensations for X angle rotations. Note that in order to apply the transformations to scan data, you must use a "stitching" tool that corresponds to the tool used to create the transformations. For more information, see the sections below.

• Surface Align Wide: Use this tool if the sensors are in a wide (that is, side-by-side) layout. Sensors may be slightly angled on the Y axis, that is, in an arc above the target. Sensors must be on the same side as the target: no data is supported on the other side. The tool is designed for up to eight sensors. The tool aligns to a multi-column truncated pyramid plate alignment target to produce the transformations necessary to stitch scans of production targets from individual sensors into a single frame of Surface scan data. In a single-sensor system, you can also use the tool to compensate for X angle rotation. (Note that in a single-sensor system, Y offset is not calculated or used.) For more information, see Wide Layouts (Surface Align Wide Tool). The workflow / data flow is as follows:

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• Surface Align Ring: Use this tool if the sensors in a multi-sensor system are in a ring or partial ring layout. The tool aligns to a double-sided truncated pyramid alignment target to produce the transformations necessary to stitch scans of production targets into a single frame of Mesh scan data. For more information on performing this type of alignment, see Ring Layouts (Surface Align Ring Tool). The workflow / data flow is as follows:

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Both tools produce XML initialization / calibration transformation files, and can optionally load previously saved "Start" initialization / calibration files, which is useful if you need to set the system up again These XML files are found in C:\GoTools\SurfaceAlign\.

Using Uniform Spacing During the Alignment

LMI strongly recommends disabling Uniform Spacing on the Scan page for the alignment procedure, as this will simplify the configuration of the alignment tools. (For more information on configuring uniform spacing, see Scan Modes.) After you have completed the alignment procedure, you can enable Uniform Spacing if your application requires it: the setting does not have to match between the alignment procedure and in jobs you use in production.

If you decide to configure the sensors to use uniform spacing, additional parameters are displayed in the Surface Align Wide and Surface Align Ring tools. Furthermore, for technical reasons, when you use uniform spacing you must set "artificial" offsets between sensors on the Scan page and then copy certain values from there to the tool's parameters. For information on the additional steps required if you enable Uniform Spacing during the alignment, see Wide Layouts (Surface Align Wide Tool) or Ring Layouts (Surface Align Ring Tool), depending on your layout.