In this work we extend the test utterance adaptation technique used in vocal tract length normalization to a larger number of speaker characteristic features. We perform partially joint estimation of four features: the VTLN warping factor, the corner position of the piece-wise linear warping function, spectral tilt in voiced segments, and model variance scaling. In experiments on the Swedish PF...

In depth from defocus (DFD), when images are captured with different camera parameters, a relative magnification is induced between them. Image warping is a simpler solution to account for magnification than seemingly more accurate optical approaches. This work is an investigation into the effects of magnification on the accuracy of DFD. We comment on issues regarding scaling effect on relative...

Frequency warping is a modifier that acts on sound signals by remapping the frequency axis. Thus, the spectral content of the original sound is displaced to other frequencies. At the same time, the phase relationship among the signal components is altered, nonlinearly with respect to frequency. While this effect is interesting and has several applications, including in the synthesis by physical...

NMR imaging allows to obtain 3D-images by non-invasive treatment of biological structures. In this study intensity-based warping is evaluated by comparing it to landmark-based warping for a four-dimensional analysis of morphological changes in seed development of barley. The datasets of barley grains are obtained at certain development stages by NMR. Warping algorithms reconstruct intermediate ...

This paper describes a software tool developed in the Java language to facilitate time and frequency warping of audio spectra. The application utilises the Java Advanced Image Processing (AIP) API which contains classes for image manipulation and, in particular, for non-linear warping using polynomial transformations. Warping of spectral representations is fundamental to sound processing techni...

Speaker verification systems, in general, require 20 to 30 features as input for satisfactory verification. We show that this feature set can be optimised by appropriately choosing proper feature subset from the input feature set. This paper proposes a technique for optimisation of the feature sets, in an Dynamic Time Warping (DTW) based text-dependent speaker verification system, to improve fa...

We introduce a new image geometric transformation, named tearable image warping, for content-aware image retargeting and recomposition. In tearable image warping, an object is allowed to partially detached from the background during warping, which allows the background to warp more freely without distorting the object. The part of the object that is still attached to the background ensures that...

There are two common methodologies to verify signatures: the functional approach and the parametric approach. In this paper, we propose a new warping technique for the functional approach in signature verification. The commonly used warping technique is dynamic time warping (DTW). It was originally used in speech recognition and has been applied in the field of signature verification with some ...

Comparison of brain imaging data requires the exact matching of data sets from different individuals. Warping methods, used to optimize matching of data sets, can exploit either local gray value distribution or identifiable reference points within the images to be compared. Gray value-based warping, which is more comfortable, cannot be used if gray values include functional information that sho...

Update rules for learning in dynamic time warping spaces are based on optimal warping paths between parameter and input time series. In general, optimal warping paths are not unique resulting in adverse effects in theory and practice. Under the assumption of squared error local costs, we show that no two warping paths have identical costs almost everywhere in a measure-theoretic sense. Two dire...