Processing of face images and its applications

Human faces convey various information, including that is specific to each individual person and that is part of mutual communication among persons. I nformation exhibited by a "face" is what is called "non-verbal information" and usually verbal media cannot easily describe such information appropria tely. Recently, detailed studies on the processing of face images by a comp uter have been carried out in the engineering field for applications to com munication media and human computer interaction as well as automatic identi fication of human faces. Two main technical topics are the recognition of h uman faces and the synthesis of face images. The objective of the former is to enable a computer to detect and identify users and further to recognize their facial expressions, while that of the latter is to provide a natural and impressive user interface:on a computer in the form of a "face." These studies have also been found to be useful in various non-engineering field s related to a face, such as psychology, anthropology, cosmetology and dent istry. Most of the studies in these different fields have been carried out independently up to now, although all of them deal with a "face." Now in vi rtue of the progress in the above engineering technologies a common study t ools and databases for facial information have become available. On the basis of these backgrounds, this paper surveys recent research trend s in the processing of face images by a computer and its typical applicatio ns. Firstly, the various characteristics of faces are considered. Secondly, recent research activities in the recognition and synthesis efface images are outlined. Thirdly, the applications of digital processing methods of fa cial information are discussed from several standpoints: intelligent image coding, media handling, human computer interaction, caricature, facial impr ession, psychological and medical applications. The common tools and databa ses used in the studies of processing of facial information and some relate d topics are also described.