Using facial symmetry in the illumination cone based 3D face reconstruction

Facial symmetry can be used as the prior knowledge to supplement shape information in face techniques such as shadow compensation or pose correction. In this paper, we demonstrate the application of the facial symmetry assumption in 3D face reconstruction. We horizontally mirror non-frontal illumination face images and align them to the original images using rigid transformation and optical flow based non-rigid registration. We observe that the resultant images can be used as reasonable estimates of the images of the face under new lighting conditions. We used them in the illumination cone based 3D face reconstruction of which the original method requires seven face images under different illuminations as input. We reveal that by utilizing the mirrored face images, the illumination cone based 3D face reconstruction can actually be performed by using no more than three differently illuminated face images. Experimental results on the YaleB database show that the reconstructed 3D face model is highly accurate. Fundamentally, the mirrored face images improve the support of the illumination cone which can be useful to not only 3D face reconstruction but also other subspace based face techniques such as face recognition.