This study introduces a colour‐to‐greyscale conversion method using colour clustering and multidimensional scaling that preserves region integrity, that is, it preserves edge structure without low‐frequency distortion. Edges can be extracted from the resulting greyscale images and the results will be close to those obtainable from the original colour image. We compare with prior‐art colour‐to‐greyscale conversion and a recent colour‐edge extractor and show superior performance in each case.

In order for model-based coding to be used on a head-and-shoulders video sequence, such as would be encountered in a videophone application, it is first necessary to form a model of the head. This model must be correctly conformed to the subject's face as it appears at the beginning of the video sequence transmission, so the subsequent deformations of the model accurately depict changes in the face and head from frame to frame. This paper proposes a method which allows this conformation to be performed entirely automatically. The method presented utilizes flexible template matching and a steepest-gradient search method to determine the optimal conformation of a generic facial model to represent a given single frame of a face. Results illustrating the success of the method are given and the limitations of the algorithm are discussed.

The authors examine the design and performance of LNTP, a connection-orientated transport-level protocol for local area networks (LANs) in the 4.2 BSD Unix operating system. Various measurements are taken, and LNTP's performance is compared to that of TCP/IP (ARPAnet's Transmission Control Protocol), a LHN protocol which is often used in LAN environments. The optimum values of various LNTP parameters are determined, some theoretically and others empirically. The theoretical results are compared to the experimentally observed values. It is concluded that LNTP does indeed outperform TCP/IP. However, due to the overhead of the non-LNTP specific protocol layers, this improvement is not as great as it might be. Nonetheless, LNTP proves itself to be a viable replacement for TCP/IP.>

The need for tools to aid the implementation of user interfaces is highlighted. Techniques for the production of good user interfaces are outlined and facilities to ease implementation of interfaces designed using these techniques are suggested. Emphasis is placed on the need for multi-level adaptable interfaces, and the need for a separate, high-level specification of an interface. A dialogue development system intended for use with interactive systems written in Ada is proposed.

This work describes the Aeronutronic Ford Programmable Array Processor (PAP). The PAP is a high-speed programmable signal processor which has been designed to perform functions such as those required by a narrowband communications terminal. The PAP design employs many of the features of a dedicated pipeline processor while maintaining the flexibility of a programmable signal processing computer.