Abstract: An architecture component for use in performing a wavelet transform of a sampled signal, and an architecture including such components are disclosed. The architecture component includes a multiplier, and a multiplexor to multiplex a number n of filter coefficients onto the multiplier. The multiplier processes n consecutive samples with consecutive coefficients, successive multiplier outputs being stored for subsequent processing to generate an output of the filter after every n samples. The wavelet transform may be a discrete wavelet transform or a wavelet packet decomposition. The architecture component may be configured to multiplex two or more coefficients onto a multiplier. Embodiments are disclosed in which the components are derived from a parameterized description in a hardware description language.

Abstract: The invention relates to a method and apparatus for compressing an image data signal. The apparatus includes a compression control module arranged to eliminate frequency components produced from the image data signal which have a magnitude less than a threshold value. The apparatus compares the volume of the compressed image data signal with a target volume and selects to increase or decrease the applied compression level depending on the outcome of the comparison. The compression level is increased by increasing the threshold value and deacreased by decreasing the threshold value. The compression level, or ratio, is thus adaptable in real-time in order to meet a target volume for the compressed image. This is particularly advantageous in applications where, for example, the compressed image signal is to be transmitted over a fixed bandwidth link. The method and apparatus of the invention are particularly suitable for use in the implementation of the JPEG basline image compression standard.