Evaluation and visualization of facial massage effects by using ultraviolet stereo-image correlation

Background/purpose This study proposes a technique for visualizing the effect of facial massage using stereo-image correlation with melanin pigment. Method In this method, the melanin pigment of a subject's face is made visible by using an ultraviolet light and utilized as a random pattern for stereo-image correlation. Stereo-pair images of the face with the melanin pigment before and after facial massage are recorded using a desk-sized measurement equipment. Then, the deformation of the face by the massage can be obtained based on the principle of stereovision. The effectiveness of the proposed method is demonstrated by applying it to the massage effect evaluation of eight subjects (females in their 40s). Results The results show that the massage effect can be visualized from the displacement and strain distributions across the face obtained by the proposed method. In addition, it is observed that the face is displaced significantly by the massage and individual differences between the subjects can be captured. Conclusion The proposed method is effective for evaluating the effect of a facial massage when the painted pattern disappears due to the applied cream during the massage.