Shinkichi Namura

A three-dimensional measuring system for the human face using three-directional photography

This study was intended to develop a three-dimensional measuring system of the human face for clinical use, to ensure a high precision and a simple input operation by means of a personal computer and to measure the degree of its accuracy. With this system, it is possible to measure automatically two-dimensional coordinates of hundreds of grid points on photographs of the human face with an image scanner as a reading device and to calculate their three-dimensional coordinates with a computer. An orthognathic surgical case illustrates this technique in which the patients face is displayed before and after the surgery on a cathode-ray tube (CRT), with the three-dimensional coordinates obtained with this system. A cubic plaster cast with a certain degree of irregularity has been constructed to measure the precision of this system. Comparison was then made between the three-dimensional coordinates obtained with this system and the coordinates obtained with the contact three-dimensional measuring system. The mean of errors and the standard deviation were 0.04 +/- 0.24 mm for the X coordinate, 0.03 +/- 0.16 mm for the Y coordinate, and 0.08 +/- 0.23 mm for the Z coordinate. Thus the accuracy of this system is high enough for the measurement of the human face.