Human vision can be characterized as a variable resolution system-the region around the fovea (point of attention) is observed with great detail, whereas the periphery is viewed in lesser detail. In this work, we show that spatially varying sensing (resembling the human eye) can indeed be useful in videoconferencing. A system that can incorporate multiple and moving foveae is described. There are various possible ways of implementing multiple foveae and combining information from them. Some of these alternative strategies are discussed and results are compared. We also show the advantage of using spatially varying sensing as a preprocessor to JPEG. The methods described here can be useful in designing teleconferencing systems and image databases.

A fundamental drawback to increasingly popular ATM-based switching is the possibility of information loss with congestion. We demonstrate that with intelligent, fovea driven priority assignment of image data, we can reduce the negative impact of information loss over ATM networks. ATM standards allow a single bit to indicate high or low packet priority. To reduce the effect of this restriction we introduce the concept of priority dithering. Network multimedia multicast scenarios over heterogeneous link capacities where foveal prioritization would be of benefit are described. Network simulation results of this method are included which demonstrate the advantages of priority dithered foveal prioritization over traditional methods.

In this paper, we study the properties of all major counter-based compaction schemes when the circuit under test is affected by delay or stuck-open faults. We present an error model that accurately describes the behavior of such circuits. The error model inherits from the asymmetric error model. Using this model, we compute exact aliasing probability for any test session length; we also determine the asymptotic aliasing probability. Examples that compare aliasing in counter-based compaction with aliasing in LFSRs indicate that the latter is more "predictable".>

A new method for videoconferencing using the concept of spatially varying sensing is introduced. Various techniques are discussed for combining information obtained from multiple points-of-interest (foveae) in an image. A fovea can be used to follow a moving object of interest as well. A fast videoconferencing prototype for desktop computers is also described.