Processing of Face Images and Its Applications

摘要

Human faces convey various information, in- cluding that is specific to each individual person and that is part of mutual communication among persons. Information exhibited by a “face.”　is what is called　“non-verbal information” and usually verbal media cannot easily describe such information appropri- ately. Recently, detailed studies on the processing of face images by a computer have been carried out in the engineering field for applications to communication media and human computer in- teraction as well as automatic identification of human faces. Two main technical topics are the recognition of human 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 fields related to a face, such as psy- chology, anthropology, cosmetology and dentistry. Most of the studies in these different fields have been carried out indepen- dently up to now, although all of them deal with a “face.” Now in virtue of the progress in the above engineering technologies a common study tools and databases for facial information have become available. On the basis of these backgrounds, this paper surveys recent research trends in the processing of face images by a computer and its typical applications. Firstly, the various characteristics of faces are considered. Secondly, recent research activities in the recognition and synthesis of face images are outlined. Thirdly, the applications of digital processing methods of facial information are discussed from several standpoints intelligent image coding, media handling, human computer interaction, caricature, facial impression, psychological and medical applications. The common tools and databases used in the studies of processing of facial information and some related topics are also described.