Reconstruction of Cranial Surfaces from 3D Point Data
Knowledge of the shape of the human head is paramount to the design and production of protective headwear and head-mounted equipment. Unfortunately, current practices rely on simple size measurements due to the inherent difficulty in analyzing the shape of smooth surfaces, such as the cranial region of the head. This is the second of two collaborative projects between the US Military and the FSU Geometric Morphometric Lab targeting this problem. In the first, we developed new geometric morphometric techniques to analyze male head shape in the US Military using 3D laser scans of bald male personnel. Here, we extend these methods to female head shape. However, many women are unwilling to shave their heads to obtain high quality laser scans so a new method of data collection and processing was developed. A hardware landmarking tool called a FARO arm is used to obtain facial landmarks, a line of points marking the hairline, and a set of points on the cranial region taken by parting the subject’s hair. This data is combined with a full 3D laser head scan (with hair) that has corresponding facial landmarks collected via a software landmarking tool. Using a combination of the ICP algorithm and thin plate splines, we automatically remove the cranial region of the subject scan and replace it with a bald prototype cranial region that has been reshaped to exactly fit the subject’s FARO data. The result is a complete head scan comprised of the subject’s original facial region and an approximated cranial region.