British Telecommunications Public Limited Company

British Telecommunications Corporation

Philip J Sheppard

Michael Peter Hollier

Antony William Rix

Philip Gray

Richard Jb Reynolds

Jianxiong Bai

Andrew Nicholas Mortlock

Douglas M Traill

Nicholas James Wallin

Simon Milner

An image representing a three-dimensional object is modelled as a stored set of parameters representing a model of a three-dimensional object and at least two two-dimensional images of the object, each image representing the object from a unique direction of view (x, y, z). The parameters include parameters defining the positions of a plurality of vertex points in a virtual space and parameters defining relationships between vertex points and hence surface elements of the object. For at least a subset of the surface elements a measure relative to each direction of view is determined, each measure being representative of the deviation of the surface of the element from the normal to the direction of view. The direction of view which exhibits the least deviation is then identified and texture applied to the surface element from the two-dimensional image which corresponds to the identified direction of view.

Generating an image of a three-dimensional object

A test stimulus includes two signals R , S. Signal S is transmitted to a customer equipment interface and over a system under test to a complementary remote apparatus. The test apparatus has two inputs processed by a number of functional elements. The first input is the reference signal R . The other input is a corresponding test signal R&prime; generated at remote test apparatus as a test signal R, identical with reference signal R , and transmitted over the system under test via the customer interface. These two versions of the same test signal are compared. Firstly, the signals R , R&prime; are processed by a psycho-acoustic model, the output of which is transmitted to a perceptual layer, and then to a conversion unit which also receives a further input from a non-optimum loudness rating unit. The output from the conversion unit is transmitted to a signal quality determination unit, which also receives an input from the customer equipment interface. The non-optimum loudness rating unit processes inputs from the customer equipment interface and signal generator. During an iterative process, the signal generator receives feedback control from the signal quality determination unit. The remote test apparatus similarly receives a modified version of signal S (viz S&prime;) from the network and compares it with a locally-generated reference version S . In an alternative arrangement the same test apparatus is connected to both test points of the network and processes both signals S and R, either serially or in parallel.

Measurement of signal quality

Echo cancellation using cross-correlation of buffered receive and

Trained artificial neural networks using an imperfect vocal tract model

Analysis of audio quality using speech recognition and synthesis

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Ipswich, United Kingdom

Philip J Sheppard