Multi-view facial capture using binary spherical gradient illumination

High resolution facial capture has received significant attention in computer graphics due to its application in the creation of photorealistic digital humans for various applications ranging from film and VFX to games and VR. Here, the state of the art method for high quality acquisition of facial geometry and reflectance employs polarized spherical gradient illumination [Ghosh et al. 2011; Ma et al. 2007]. The technique has had a significant impact in facial capture for film VFX, recently receiving a Technical Achievement award from the Academy of Motion Picture Arts and Sciences [Aca 2019]. However, the method imposes a few constraints due to the employment of polarized illumination, and requires the camera viewpoints to be located close to the equator of the LED sphere for appropriate diffuse-specular separation for multiview capture [Ghosh et al. 2011]. The employment of polarization for reflectance separation also reduces the amount of light available for exposures and requires double the number of photographs (in cross and parallel polarization states), increasing the capture time and the number of photographs required for each face scan.