Researchers at Osaka University study the expressiveness of android faces using motion capture cameras and identify ways in which they still lack the complexity of real human reactions, which may help guide future robot design
Credit: Ishihara, Iwanaga, and Asada, Comparison between the Facial Flow Lines of Androids and Humans, Frontiers in Robotics and AI, 2021
Osaka, Japan – Researchers from the Graduate School of Engineering and Symbiotic Intelligent Systems Research Center at Osaka University used motion capture cameras to compare the expressions of android and human faces. They found that the mechanical facial movements of the robots, especially in the upper regions, did not fully reproduce the curved flow lines seen in the faces of actual people. This research may lead to more lifelike and expressive artificial faces.
The field of robotics has advanced a great deal over the past decades. However, while current androids can appear very humanlike at first, their active facial expressions may still be unnatural and slightly unsettling to us. The exact reasons for this effect have been difficult to pinpoint. Now, a research team at Osaka University has used motion capture technology to monitor the facial expressions of five android faces and compared the results with actual human facial expressions. This was accomplished with six infrared cameras that monitored reflection markers at 120 frames per second and allowed the motions to be represented as three-dimensional displacement vectors.
“Advanced artificial systems can be difficult to design because the numerous components have complex interactions with each other. The appearance of an android face can experience surface deformations that are hard to control,” study first author Hisashi Ishihara says. These deformations can be due to interactions between components such as the soft skin sheet and the skull-shaped structure, as well as the mechanical actuators.
The first difference the team found between the androids and adult males was in their flow lines, especially the eye and forehead areas. These lines tended to be almost straight for the androids but were curved for the human adult males. Another major difference was with the skin surface undulation patterns in the upper part of the face.
“Redesigning the face of androids so that the skin flow pattern resembles that of humans may reduce the discomfort induced by the androids and improve their emotional communication performance,” senior author Minoru Asada says. “Future work may help give the android faces the same level of expressiveness as humans have. Each robot may even have its own individual “personality” that will help people feel more comfortable.”
The article, “Comparison between the facial flow lines of androids and humans,” was published in Frontiers in Robotics and AI at DOI: https://doi.org/10.3389/frobt.2021.540193
About Osaka University
Osaka University was founded in 1931 as one of the seven imperial universities of Japan and is now one of Japan’s leading comprehensive universities with a broad disciplinary spectrum. This strength is coupled with a singular drive for innovation that extends throughout the scientific process, from fundamental research to the creation of applied technology with positive economic impacts. Its commitment to innovation has been recognized in Japan and around the world, being named Japan’s most innovative university in 2015 (Reuters 2015 Top 100) and one of the most innovative institutions in the world in 2017 (Innovative Universities and the Nature Index Innovation 2017). Now, Osaka University is leveraging its role as a Designated National University Corporation selected by the Ministry of Education, Culture, Sports, Science and Technology to contribute to innovation for human welfare, sustainable development of society, and social transformation.
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