We present a novel paradigm for human to human asymmetric collaboration. There is a need for people at geographically separate locations to seamlessly collaborate in real time as if they are physically co-located. In our system one user (novice) works in the real world and the other user (expert) works in a parallel virtual world. They are assisted in this task by an Intelligent Agent (IA) with considerable knowledge about the environment. Current tele-collaboration systems deal primarily with collaboration purely in the real or virtual worlds. The use of a combination of virtual and real worlds allows us to leverage the advantages from both the worlds.

We propose a perceptually based system for pattern retrieval and matching. The central idea is that similarity judgment has to be modeled along perceptual dimensions. Hence, we detect basic visual categories that people use in their judgment of similarity, and design a computational model that accepts patterns as input and, depending on the query, produces a set of choices that follow human behavior in pattern matching. There are two major research aspects to our work. The first one addresses the issue of how humans perceive and measure similarity within the domain of color patterns. To understand and describe this mechanism, we performed a subjective experiment which yielded five perceptual criteria used in comparison between color patterns (vocabulary), as well as a set of rules governing the use of these criteria in similarity judgment (grammar). The second research aspect is the implementation of the perceptual criteria and rules in an image retrieval system. Following the processing typical for human vision, we design a system to: (1) extract perceptual features from the vocabulary and (2) perform the comparison between the patterns according to the grammar rules. The modeling of human perception of color patterns is new--starting with a new color codebook design, compact color representation, and texture description through multi-scale edge distribution along different directions. Moreover, we propose new color and texture distance functions that correlate with human performance. The performance of the system is illustrated with numerous examples from image databases from different application domains.

We determine the basic categories and the hierarchy of rules used by humans in judging similarity and matching of color patterns. The categories are: (1) overall color; (2) directionality and orientation; (3) regularity and placement; (4) color purity; (5) complexity and heaviness. These categories form the pattern vocabulary which is governed by the grammar rules. Both the vocabulary and the grammar were obtained as a result of a subjective experiment. Experimental data were interpreted using multidimensional scaling techniques yielding the vocabulary and the hierarchical clustering analysis, yielding the grammar rules. Finally, we give a short overview of the existing techniques that can be used to extract and measure the elements of the vocabulary.

We present a novel application for Content Based Retrieval Techniques in Electronic Commerce using Interactive Multimedia, in which visual queries play a central role. We address some of the technical issues in representing and analysing image primitive features that are the building blocks of the MIRACLE system. These can be generalized into a much broader range of applications as well. We believe that Electronic Commerce is a very promising area with much potential for growth and that it covers a spectrum of rich research topics.

This paper describes a practical synthetic visual environment for use in CAD and teleoperation. Instead of using expensive head mounted display systems, we use a standard display and compute smooth shaded images using an AT&T Pixel Machine. The interface uses a VPL DataGlove [9] to track the hand, bringing the synthetic world into the same space as the hand. Hand gesturing is used to implement a virtual control panel, and some 3D modeling tasks. When simple speech recognition was added it markedly improved the interface. We also outline what extensions might be needed for using this kind of interface for teleoperation.

The authors consider an object is undergoing rotational motions, with orientation known at given times, and wish to interpolate the orientation between those times. If the orientations are represented as unit quaternions, this is equivalent to interpolating among a sequence of points on the three-sphere in four-space. They present an algorithm for doing this smoothly. If the object possesses rotational symmetry, then its orientation is given by its axis, and can be represented as a point on the unit sphere in three-space. The problem of interpolating on the sphere is of interest in its own right, and has other applications. The authors have implemented an algorithm for this, and present graphical results.>