Virtual tape measure for 3D measurements in micro-surgery

A unique measuring tool for use with a surgical operating microscope was developed in prototype form. Stereo-video images of the surgical field obtained through the operating microscope were combined with stereo-computer graphics to create a virtual tape measure. This augmented reality display allows accurate absolute distance measurements to be made between any two points of interest in the 3D surgical space. The overall performance of the system has a 95% confidence interval for the absolute measurement error of 0.2 to 0.7 mm. This paper describes the motivation for the development of the system, the configuration of the hardware and software components, and details of accuracy testing.