An analysis of quantisation noise of multiresolution structure of analog-to digital converters (ADC) is performed. It shows how the noise level as well as the resulting noise spectrum is changing with a level of sampled signal. The theoretical formulas are approved by numerical simulation and experimental measurements performed by PC measuring card emulating two channels ADC structure. The resu...

In a digital communication system, the analog signal that the receiver receives with its radio frequency front end is converted into digital format by using the analog-to-digital converter (A/D converter, ADC). Quantisation takes place during the conversion from continuous amplitude signal to discrete amplitude signal, leading inevitably to losses in information which are dependent on the numbe...

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JPEG XR is considered as a lossy sample data compression scheme in the context of iris recognition techniques. It is shown that by optimising the JPEG XR quantisation strategy, JPEG XR default quantisation as well as JPEG2000 based iris recognition can be improved in terms of EER. The optimised JPEG XR quantisation strategy shows good performance across a wide range of iris feature extraction t...

Image compression is concerned with reducing the amount of data needed to represent an image. Efficient image representation is achieved by exploiting the statistical and psychovisual redundancies of an image. This reported focusses on the main principles of information theory, which provides a framework for efficient signal coding from a statistical perspective. Two of the fundamental theories...

This paper discusses the theory of dithered and noise-shaped quantisation, and in particular their application to Nyquist rate digital audio. Dither is shown to be essential if quantisation-related distortion is to be avoided. Careful application of noise-shaping is shown to be of audible beneet by increasing the perceived dynamic range of a signal. Various drawbacks of the technique are discus...