Aligning Sensors

Alignment is the process Gocator uses to automatically calculate transformations (rotations and transformations / offsets) that are applied to a sensor's scan data while it is scanning targets. If you do not correct for these rotations, scan data may be too distorted for your application, and your measurements may therefore be inaccurate. Alignment is often required for various reasons:

To compensate for sensor mounting inaccuracies relative to the intended scanning surface, and to other sensors in dual- or multi-sensor systems.
To set a Z (height) reference plane, using a flat surface or an alignment target.
To accommodate intentional rotation of sensors, or intentional offsets of sensors in multi-sensor systems.
To merge profiles in dual- and multi-sensor systems so that the combined profiles can be measured (setting a common coordinate system).
Optionally, to determine the encoder resolution (if present) and the speed of the transport system. (In many systems, the reference surface is a conveyor belt.) This is only possible using the first of the two methods described below.

As of Gocator firmware version 6.1, two methods of aligning sensors are available:

A lower-accuracy method that provides up to 5 degrees of freedom (X angle rotations are not compensated for). You perform this type of alignment using the Alignment panel on the Scan page. Although resulting scans are of a lower accuracy compared to the higher accuracy described below, it is often sufficient in applications and is more commonly used. This is the only method available in firmware version 6.0 and earlier. (This method lets you optionally determine encoder resolution or transport speed.)
For G2 sensors only, a high-accuracy method that provides 6 degrees of freedom. Typically used for ring layouts and wide (side-by-side) layouts where high accuracy is required, you perform this type of alignment using specialized tools on the Measure page and special alignment targets. After alignment, scans from individual sensors are transformed and stitched together using measurement tools corresponding to the type of layout (ring vs. wide). The resulting scan data can be measured using built-in or custom GDK tools. An advantage to this method is that due to differences in the algorithm used to combine scans from multiple sensors, performance is improved compared to the other method. Note that although these tools appear on G3 sensors, G3 sensors do not support them.

In some situations, however, the inaccuracies introduced in scan data by not aligning may be acceptable to your application. For more information, see Planning Alignment.

Sensors are pre-calibrated and ready to deliver data in engineering units (mm) out of the box. Alignment procedures do not affect sensor calibration.