Atanas P. Gotchev

Towards compound stereo-video quality metric: a specific encoder-based framework

We suggest a compound full-reference stereo-video quality metric composed of two components: a monoscopic quality component and stereoscopic quality component. While the former assesses the trivial monoscopic perceived distortions caused by blur, noise, contrast change etc., the latter assesses the perceived degradation of binocular depth cues only. We use the structural similarity index as a measure for perceptual similarity and design a multiscale algorithm for obtaining a perceptual disparity map and a stereo-similarity map to be used in the suggested metric. We verify the performance of the metric with subjective tests on distorted stereo images and coded stereo-video sequences with a final aim to build a perceptually-aware feedback for a H.264 based stereo-video encoder

A Survey of Signal Processing Problems and Tools in Holographic Three-Dimensional Television

Diffraction and holography are fertile areas for application of signal theory and processing. Recent work on 3DTV displays has posed particularly challenging signal processing problems. Various procedures to compute Rayleigh-Sommerfeld, Fresnel and Fraunhofer diffraction exist in the literature. Diffraction between parallel planes and tilted planes can be efficiently computed. Discretization and quantization of diffraction fields yield interesting theoretical and practical results, and allow efficient schemes compared to commonly used Nyquist sampling. The literature on computer-generated holography provides a good resource for holographic 3DTV related issues. Fast algorithms to compute Fourier, Walsh-Hadamard, fractional Fourier, linear canonical, Fresnel, and wavelet transforms, as well as optimization-based techniques such as best orthogonal basis, matching pursuit, basis pursuit etc., are especially relevant signal processing techniques for wave propagation, diffraction, holography, and related problems. Atomic decompositions, multiresolution techniques, Gabor functions, and Wigner distributions are among the signal processing techniques which have or may be applied to problems in optics. Research aimed at solving such problems at the intersection of wave optics and signal processing promises not only to facilitate the development of 3DTV systems, but also to contribute to fundamental advances in optics and signal processing theory.

3DTV Broadcasting and Distribution Systems

In this paper, the authors present three-dimensional television (3DTV) broadcasting and distribution systems that are employed to deliver a pair of stereoscopic images to mobile users, as well as users at home. First, mobile 3DTV systems and services based on DMB and DVB-H are respectively introduced. Second, fixed and high-definition 3DTV systems and services based on terrestrial digital broadcasting are described along with an introduction of experimental 3DTV services in Korea. To be specific, the authors summarize 3DTV systems from the viewpoints of target services, system and user requirements, system configurations, broadcasting trials, related standards, and technical challenges.

Wavelet domain Wiener filtering for ECG denoising using improved signal estimate

A new two-stage algorithm for electrocardiographic (EGG) signal denoising has been proposed. It combines wavelet shrinkage with Wiener filtering in the translation-invariant wavelet domain. A time-frequency dependent thresholding has been proposed and grounded for obtaining a more adequate signal estimate in the first stage of the algorithm. It is related to ECG signal morphology and hence outperforms other thresholding approaches in this area. The experiments carried out on pathological and normal ECGs have shown better algorithm capabilities in comparison with other thresholding algorithms while suppressing parasite electromyographic (EMG) signals (the noise) and preserving diagnostically important ECG signal features.

Computer technologies for 3D video delivery for home entertainment

The paper overviews the state-of-the-art in the area of 3D video content creation, coding, transmission, and display. Computer technologies for 3D video capture, format conversion and compression, as well as network technologies for 3D video delivery are briefly described. Standardization activities in the area are reviewed as well. As of 3D displays, special attention is driven to the most mature technology in that field --- the so-called auto-stereoscopic displays delivering 3D visual sensations to single or multiple users without any special glasses. Conclusions about the open questions before the 3D technology reaches the users homes are drawn.

Crosstalk Measurement Methodology for Auto-Stereoscopic Screens

Autostereoscopic displays utilizing slanted lenticular sheets produce specific artifacts. These artifacts affect the perception of a 3D scene, and are caused by a process which can be modeled as inter-channel crosstalk. We propose methodology for measuring such a crosstalk for arbitrary multiview 3D display. The measured data might be used for optimizing multiview image sets for a given display.

Suppression of electromyogram interference on the electrocardiogram by transform domain denoising

A method for suppression of electromyogram (EMG) interference in electrocardiogram (ECG) recordings is presented. By assuming that the EMG is long-term non-stationary Gaussian noise, two successive decompositions were proposed, and the data transformed for Wiener filtering. Successive ECG cycles were rearranged and aligned by the R-wave, forming a matrix containing separated heart cycles in its rows. A short-window discrete cosine transform (DCT) was applied to the columns of the matrix for inter-cycle de-correlation. Next, Weiner filtering in a translation-invariant wavelet domain was performed on the DCT-transformed matrix rows for de-correlation of the data into each ECG cycle. The method resulted in an improvement in the signal-to-noise ratio of more than 10 db, a threefold reduction in mean relative amplitude errors and reduced ripple artifacts around the signal transients, thus preserving the waveform in diagnostically important signal segments.

Schemes for multiple description coding of stereoscopic video

This paper presents and compares two multiple description schemes for coding of stereoscopic video, which are based on H.264. The SS-MDC scheme exploits spatial scaling of one view. In case of one channel failure, SS-MDC can reconstruct the stereoscopic video with one view low-pass filtered. SS-MDC can achieve low redundancy (less than 10%) for video sequences with lower inter-view correlation. MS-MDC method is based on multi-state coding and is beneficial for video sequences with higher inter-view correlation. The encoder can switch between these two methods depending on the characteristics of video.

Powerline interference suppression in high-resolution ECG

The efficacy of four powerline interference suppression methods was tested for application in high-resolution electrocardiogram (ECG). The goal was minimal distortion of the original signal micro-potential waveform, combined with maximum noise reduction. Simulated low amplitude His-bundle potentials were used for the evaluation. Several objective parameters were measured, such as mean square error and mean absolute error. The methods were applied for His-bundle potentials recovery from real surface ECG signals. Synchronous intracardiac signals with well expressed His potential were recorded and used for reference. Modified time-domain subtraction and regression subtraction methods were found superior to notch filters and spectral interpolation.

Diffraction field computation from arbitrarily distributed data points in space

Computation of the diffraction field from a given set of arbitrarily distributed data points in space is an important signal processing problem arising in digital holographic 3D displays. The field arising from such distributed data points has to be solved simultaneously by considering all mutual couplings to get correct results. In our approach, the discrete form of the plane wave decomposition is used to calculate the diffraction field. Two approaches, based on matrix inversion and on projections on to convex sets (POCS), are studied. Both approaches are able to obtain the desired field when the number of given data points is larger than the number of data points on a transverse cross-section of the space. The POCS-based algorithm outperforms the matrix-inversion-based algorithm when the number of known data points is large.