## Filters

Feature Extraction - Filters

Remove Outliers - This check box when marked excludes outliers from the feature based on the Standard deviation multiple value. This only functions for Auto Surface Point, Auto Plane, Auto Cylinder, Auto Sphere, and Auto Flush & Gap.

- The feature extractor evaluates the feature internally two or more times on the first at

- tempt to get the standard deviation based on all points.

- In successive attempts, it re-evaluates the feature using only points which are in the range of the outlier multiplied by the Σ. The sigma is the range, in the Gaussian distribution of the deviations, where the 68.2% of the best points used for fitting the feature lay.

So, in the first evaluation the standard deviation is evaluated on all points. In a normal distribution this could be represented as follows:

This means that the best points are in the interval from 0 to 1Σ. For example, if you wanted to get only points in that range, you would need to specify an outlier value from 0 to 1. Worse solutions would be obtained if you used higher outlier values.