M3dregInquire

Inquires the number of registration elements in the 3D registration context, or the number of registration result elements in the 3D registration result buffer. SET

Inquires the technique for performing the pairwise comparison during each iteration of the registration operation, and establishes how to compute the RMS error.

The best technique for a given registration depends on how many large and flat surfaces the object represented by the point cloud has. Using the correct setting can help avoid registration sliding (when multiple different registration are possible because of large planar surfaces) or diverging (when the registration operation results in the point clouds moving apart). SET

Inquires a stop condition for the iterative registration operation. If the maximum number of iterations is reached, the registration operation stops.

To inquire whether this stop condition was met, call M3dregGetResult() with M_STATUS.

Note that preregistration constitutes the first iteration. SET

Inquires how to perform the preregistration step. SET

Inquires the stop condition for the registration operation that tests the percentage change of the root-mean-square (RMS) error of successive iterations. The RMS error is calculated from the distance between all paired points. You can control how the distance is calculated using M_ERROR_MINIMIZATION_METRIC.

If this stop condition is met, the registration is typically considered correct.

Note that the specified value represents a percentage, so the default value of 0.1 represents 0.1%, not 10%. SET

Inquires the stop condition for the registration operation that tests the root-mean-square (RMS) error of successive iterations. The RMS error is calculated from the distance between all paired points. You can control how the distance is calculated using M_ERROR_MINIMIZATION_METRIC.

If this stop condition is met, the registration is typically considered correct. SET

Inquires whether to enable subsampling before applying the registration.

Settings for subsampling techniques are defined in a subsampling context. Every registration context contains a subsampling context.

To change the settings of the subsampling context, call M3dregInquire() with M_SUBSAMPLE_CONTEXT_ID to first get the MIL identifier of the subsampling context. The subsampling context can then be controlled using M3dimControl() (see the settings available for Subsample context ID). SET

Inquires the ID of the subsampling context within the specified registration context.

Sets the percentage of all possible point pairings to use in a single iteration of the registration operation.

For example, if you specify 80%, then during each iteration, the top 80% of point pairings are used to generate an RMS error and are used to calculate a transformation. This excludes the 20% worst point pairings, which often contains outliers in the reference point cloud. These outliers are typically caused by image noise, occlusion, or object deformity.

Typically, if there are fewer points in the reference point cloud than in the point cloud that will be registered to it, the overlap should roughly equal the ratio of the points in the reference point cloud to the points in the other point cloud.

If the density of points is the same in both point clouds, this ratio could be set to the exact ratio between the two. For example, if there are 100 points in the reference point cloud, 200 points in the point cloud that will be registered to it, and they have a similar density, then the overlap can be set to 50%.

If there are more points in the reference point cloud, this value should be set to a little under 100%. In this case, you should use as many of the points in the reference point cloud as possible while still accounting for outliers. SET

Inquires the index of the iteration from which to copy the transformation matrix or get results. SET