Method and apparatus for excessive materials removal from intraoral scans

A method comprising:

• receiving a plurality of intraoral scans of a dental site;
• making a plurality of comparisons for a first intraoral scan of the plurality of intraoral scans, wherein each comparison is with an additional intraoral scan of the plurality of intraoral scans, wherein each comparison of the first intraoral scan to an additional intraoral scan comprises:
• making, for each point in the first intraoral scan, a first determination as to whether a surface normal at the point is co-directional with a viewing direction associated with the additional intraoral scan;
• making, for each point in the first intraoral scan, a second determination as to whether the point is behind a corresponding point in the additional intraoral scan;
• and
• labeling each point based on at least one of the first determination or the second determination;
• aggregating labels from the plurality of comparisons;
• determining, based on the labels aggregated from the plurality of comparisons, a plurality of points that satisfy one or more first criteria;
• determining a region comprising the plurality of points that satisfy the one or more criteria;
• determining whether the region satisfies one or more removal criteria;
• and
• removing the region from the first intraoral scan responsive to determining that the region satisfies the one or more removal criteria.

A non-transitory computer readable medium comprising instructions that, when executed by a processor, cause the processor to perform operations comprising:

• receiving a plurality of intraoral scans of a dental site, the plurality of intraoral scans comprising at least a first intraoral scan and a second intraoral scan;
• determining the following for each point in the second intraoral scan based on a first comparison of the first intraoral scan to the second intraoral scan:
• whether a surface normal at the point is co-directional with a first viewing direction associated with the first intraoral scan, wherein points in the second intraoral scan that have a surface normal that is co-directional with the first viewing direction are back-face points;
• and
• whether the point is behind a corresponding point in the first intraoral scan when viewed from the first viewing direction, wherein points in the second intraoral scan that are not behind corresponding points in the first intraoral scan are uncovered points;
• determining a region comprising a plurality of points in the second intraoral scan that are both back-face points and uncovered points;
• determining whether the region satisfies one or more removal criteria;
• and
• removing the region from the second intraoral scan responsive to determining that the region satisfies the one or more removal criteria.