Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.

Pattern Recognition and Machine Learning

The paper discusses the theory behind the dual-tree transform, shows how complex wavelets with good properties can be designed, and illustrates a range of applications in signal and image processing The authors use the complex number symbol C in CWT to avoid confusion with the often-used acronym CWT for the (different) continuous wavelet transform The four fundamentals, intertwined shortcomings of wavelet transform and some solutions are also discussed Several methods for filter design are described for dual-tree CWT that demonstrates with relatively short filters, an effective invertible approximately analytic wavelet transform can indeed be implemented using the dual-tree approach

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The dual-tree complex wavelet transform

Digital processing of speech signals

A fractional delay filter is a device for bandlimited interpolation between samples. It finds applications in numerous fields of signal processing, including communications, array processing, speech processing, and music technology. We present a comprehensive review of FIR and allpass filter design techniques for bandlimited approximation of a fractional digital delay. Emphasis is on simple and efficient methods that are well suited for fast coefficient update or continuous control of the delay value. Various new approaches are proposed and several examples are provided to illustrate the performance of the methods. We also discuss the implementation complexity of the algorithms. We focus on four applications where fractional delay filters are needed: synchronization of digital modems, incommensurate sampling rate conversion, high-resolution pitch prediction, and sound synthesis of musical instruments.

Splitting the unit delay [FIR/all pass filters design]

Digital Coding of Waveforms

A new method to realize arbitrary time-frequency plane tilings together with critical sampling in block-recursive filterbanks is presented. The method leads to pole-zero approximation of the target channel transfer functions. Perfect reconstruction within the limits of the approximation error can be achieved.

Block-recursive, multirate filterbanks with arbitrary time-frequency plane tiling

A codec for wideband 12kHz speech and audio in a video conferencing application is proposed in this paper. The codec is based on warped linear predictive coding algorithm which utilizes the auditory Bark frequency resolution. The structure of the codec is described and the main issues on the real-time implementation are discussed. The codec is integrated to a video conferencing product which is a video codec PC-board. The algorithm is implemented in a Texas TMSC31 digital signal processor.

Warped linear predictive audio coding in video conferencing application

Audio Coding with Auditory Time-Frequency Noise Shaping and Irrelevancy Reducing Vector Quantization

This paper introduces a computational model that automati­ cally segments acoustic speech data and builds internal repre­ sentations of keyword classes from cross-modal (acoustic and pseudo-visual) input. Acoustic segmentation is achieved using a novel dynamic time warping technique and the focus of this paper is on recent investigations conducted to enhance the iden­ tification of repeating portions of speech. This ongoing research is inspired by current cognitive views of early language acqui­ sition and therefore strives for ecological plausibility in an at­ tempt to build more robust speech recognition systems. Results show that an ad-hoc computationally engineered solution can aid the discovery of repeating acoustic patterns. However, we show that this improvement can be simulated in a more ecolog­ ically valid way.

Unto K. Laine

Papers

Block-recursive, multirate filterbanks with arbitrary time-frequency plane tiling

Warped linear predictive audio coding in video conferencing application

Audio Coding with Auditory Time-Frequency Noise Shaping and Irrelevancy Reducing Vector Quantization

Discovering Keywords from Cross-Modal Input: Ecological vs.Engineering Methods for Enhancing Acoustic Repetitions

Higher pole correction in vocal tract models and terminal analogs