Most connectionist research has focused on learning mappings from one space to another (eg. classification and regression). This paper introduces the more general task of learning constraint surfaces. It describes a simple but powerful architecture for learning and manipulating nonlinear surfaces from data. We demonstrate the technique on low dimensional synthetic surfaces and compare it to nearest neighbor approaches. We then show its utility in learning the space of lip images in a system for improving speech recognition by lip reading. This learned surface is used to improve the visual tracking performance during recognition. ii To appear in Cowan. J.D., Tesauro, G., and Alspector, J. (eds.), Advances in Neural Information Processing Systems 6. San Francisco, CA: Morgan Kaufmann Publishers, 1994. Surface Learning with Applications to Lipreading Christoph Bregler ?;?? ? Computer Science Division University of California Berkeley, CA 94720i bregler@cs.berkeley.edu Stephen M. Om...

Visual speech information from the speaker’s mouth region has been successfully shown to improve noise robustness of automatic speech recognizers, thus promising to extend their usability in the human computer interface. In this paper, we review the main components of audio-visual automatic speech recognition and present novel contributions in two main areas: First, the visual front end design, based on a cascade of linear image transforms of an appropriate video region-of-interest, and subsequently, audio-visual speech integration. On the latter topic, we discuss new work on feature and decision fusion combination, the modeling of audio-visual speech asynchrony, and incorporating modality reliability estimates to the bimodal recognition process. We also briefly touch upon the issue of audio-visual adaptation. We apply our algorithms to three multi-subject bimodal databases, ranging from small- to large-vocabulary recognition tasks, recorded in both visually controlled and challenging environments. Our experiments demonstrate that the visual modality improves automatic speech recognition over all conditions and data considered, though less so for visually challenging environments and large vocabulary tasks.

: In this paper, we review recent research that examines audio-visual integration in multimodal communication. The topics include bimodality in human speech, human and automated lip-reading, facial animation, lip synchronization, joint audio-video coding, and bimodal speaker verification. We also study the enabling technologies for these research topics, including automatic facial feature tracking and audio-to-visual mapping. Recent progress in audio-visual research shows that joint processing of audio and video provides advantages that are not available when the audio and video are processed independently. Keywords: Multimedia communication, Speech processing, Speech communication, Video signal processing, Image analysis 1. Introduction Multimedia is more than simply the combination of various forms of data: text, speech, audio, music, images, graphics, and video. When we discuss multimedia signal processing, it is the integration and interaction among these different media types t...

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. In Proc. European Conf. Computer Vision, pp. 376--387, 1996, Cambridge, UK Developments in dynamic contour tracking permit sparse representation of the outlines of moving contours. Given the increasing computing power of general-purpose workstations it is now possible to track human faces and parts of faces in real-time without special hardware. This paper describes a real-time lip tracker that uses a Kalman filter based dynamic contour to track the outline of the lips. Two alternative lip trackers, one that tracks lips from a profile view and the other from a frontal view, were developed to extract visual speech recognition features from the lip contour. In both cases, visual features have been incorporated into an acoustic automatic speech recogniser. Tests on small isolated-word vocabularies using a dynamic time warping based audio-visual recogniser demonstrate that real-time, contour-based lip tracking can be used to supplement acoustic-only speech recognisers enabling robust re...

We have made significant progress in automatic speech recognition (ASR) for well-defined applications like dictation and medium vocabulary transaction processing tasks in relatively controlled environments. However, ASR performance has yet to reach the level required for speech to become a truly pervasive user interface. Indeed, even in “clean ” acoustic environments, and for a variety of tasks, state of the art ASR system

The visual motion of the mouth and the corresponding audio data generated when a person speaks are highly correlated. This fact has been exploited for lip/speechreading and for improving speech recognition. We describe a method of automatically detecting a talking person (both spatially and temporally) using video and audio data from a single microphone. The audio-visual correlation is learned using a time delayed neural network, which is then used to perform a spatio-temporal search for a speaking person. Applications include video conferencing, video indexing, and improving human computer interaction (HCI). An example HCI application is provided. 1. INTRODUCTION The visual motion of a speaker's mouth is highly correlated with the audio data generated from the voicebox and mouth [5]. This fact has been exploited for lip/speechreading (e.g, [14] [10]) and for combined audio-visual speech recognition (e.g., [3]). We utilize this correlation to detect speakers using video and audio inp...

In this paper we review the major approaches to Multimodal Human Computer Interaction, giving an overview of the field from a computer vision perspective. In particular, we focus on body, gesture, gaze, and affective interaction (facial expression recognition and emotion in audio). We discuss user and task modeling, and multimodal fusion, highlighting challenges, open issues, and emerging applications for Multimodal Human Computer Interaction (MMHCI) research.

The multi-modal nature of speech is often ignored in human-computer interaction but lip deformation, and other body such as head and arm motion all convey additional infor-mation. We integrate speech cues from many sources and this improves intelligibility, es-pecially when the acoustic signal is degraded. This paper shows how this additional, often complementary, visual speech information can be used for speech recognition. Three meth-ods for parameterising lip image sequences for recognition using hidden Markov models are compared. Two of these are top-down approaches that fit a model of the inner and outer lip contours and derive lipreading features from a principal component analysis of shape, or shape and appearance respectively. The third, bottom-up, method uses a non-linear scale-space analysis to form features directly from the pixel intensity. All methods are compared on a multi-talker visual speech recognition task of isolated letters.

We present a new approach to modeling and processing multimedia data. This approach is based on graphical models that combine audio and video variables. We demonstrate it by developing a new algorithm for tracking a moving object in a cluttered, noisy scene using two microphones and a camera. Our model uses unobserved variables to describe the data in terms of the process that generates them. It is therefore able to capture and exploit the statistical structure of the audio and video data separately, as well as their mutual dependencies. Model parameters are learned from data via an EM algorithm, and automatic calibration is performed as part of this procedure. Tracking is done by Bayesian inference of the object location from data. We demonstrate successful performance on multimedia clips captured in real world scenarios using off-the-shelf equipment.