Special issue on vision for human-computer interaction

We are at the beginning of an unprecedented growth period for computer vision. Although image processing and machine vision have long had established roles in manufacturing and industrial automation, only now are we witnessing an increase in the number of applications relying on image understanding. Computer vision technologies have become more prevalent in the past decade in both the commercial and the consumer markets. Technologyfriendly areas have experienced the most noticeable influx of computer vision techniques to provide more and better services, particularly in the gaming and automotive industries, but also in medicine, security and space exploration. This special issue of Computer Vision and Image Understanding highlights one particularly promising yet challenging task for computer vision: the facilitation of human– computer interaction (HCI). Vision is an appealing input ‘‘device’’ owing to its non-invasiveness, its small form factor while potentially observing a large space, its ubiquity and its software-based configurability. Vision-based interfaces (VBI) offer more natural ways to interact, akin to human–human interaction, and the flexibility to provide disabled computer users with highly specialized means of interaction. The trend is clear, as Professor Matthew Turk, a leading HCI researcher, summarizes: ‘‘There has been growing interest in turning the camera around and using computer vision to look at people, that is, to detect and recognize human faces, track heads, faces, hands, and bodies, analyze facial expression and body movement, and recognize gestures’’ (Communications of the ACM, January 2004/Vol. 47, No. 1). Although vision-based HCI as a research area emerged almost two decades ago, it has now reached a level of maturity that makes it a serious contender for building interaction devices and for implementing interaction means. A much larger and vastly improved array of methods, faster and cheaper computers, better imaging chips and optics, coupled with a more detailed understanding of the human visual system have brought forth such VBIs as the EyeToy, driver drowsiness monitoring, vehicle occupant detection for safe airbag deployment, and surgery guidance.