k-distribution-based approaches are promising models for radiation calculations in strongly nongray participating media. Advanced k-distribution methods were found to achieve close-to benchmark line-by-line (LBL) accuracy for strongly inhomogeneous multi-phase media accompanied by several orders of magnitude smaller computational cost. In this paper, a k-distributionbased portable spectral modu...

We derive the power spectrum P(k) of the density perturbations produced during inflation up to second-order corrections in the standard slow-roll approximation for an inflaton with more than one degree of freedom. We also present the spectral index n up to first-order corrections including previously missing terms, and the running dn/d ln k to leading order.

Frequency domain properties of an image are used for precise detection of edge orientation in color and multi-spectral imagery. The orientation estimation is established as a minimization problem, formulated as a tensor method, and simplified by solving its dual in terms of spatial partial derivatives of the image. First, spectral density distribution around each pixel is obtained. The edge ori...

This paper presents a new voice activity detection (VAD) method using the Gaussian distribution and a uniformly most powerful (UMP) test. The UMP test is employed to derive the new decision rule based on likelihood ratio test (LRT). This method requires the Rayleigh distribution for the magnitude of the noisy spectral component and the adaptive threshold estimated from the noise statistics. Exp...

LED luminaires with controllable luminous flux are increasingly used, mainly due to the need reduce electricity consumption, which is equivalent of improving energy efficiency a lighting installation. Changing dimming level changes spectral power distribution luminaire or light source. Knowledge characteristics including relationships provides opportunity optimize control algorithms and predict...

an ideal fusion method preserves the spectral information in fused image without spatial distortion. the pca is believed to be a well-known pan-sharpening approach and being widely used for its efficiency and high spatial resolution. however, it can distort the spectral characteristics of multispectral images. the current paper tries to present a new fusion method based on the same concept. in ...

This work presents a fusion of Log Gabor Wavelet (LGW) and Maximum a Posteriori (MAP) estimator as a speech enhancement tool for acoustical background noise reduction. The probability density function (pdf) of the speech spectral amplitude is approximated by a Generalized Laplacian Distribution (GLD). Compared to earlier estimators the proposed method estimates the underlying statistical model ...

The current paper proposes an improved reproduction algorithm that can produce a realistic image of a real scene based on the spectral distribution of light and objects, as perceived by human eyes. First, a backward ray tracing method is used where the spectral distribution of objects and illuminants is used to represent the physical characteristics in the real world. Next, an improved shading ...