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Porównanie wielomianu i funkcji Fouriera opisujących roczny przebieg temperatury i wilgotności powietrza w Ursynowie SGGW

100%

Rozbicki T. , Rozbicka K.

tom Vol. 13, No. 2

85--93

The aim of the paper is to compare two methods of estimation main meteorological elements annual course - polynomial function and Fourier function. Long-term mean monthly data of Ursynów Warsaw Agricultural University meteorological station was used in the analysis: air temperature, maximum and minimum air temperature, amplitude of the temperature, vapor pressure, saturation deficit and relative humidity. Very high values of squared correlation coefficients calculated for two compared methods indicate that both polynomial form of equation and Fouier function may estimate annual course of air temperature and humidity very good. It is noticed that the coefficients for polynomial equations are slightly better than for Fourier functions, particularly for humidity elements.

A new approach for reduction of the noise from microscopy images using Fourier decomposition

80%

Rasal T. , Veerakumar T. , Subudhi B. N. , Esakkirajan S.

tom Vol. 42, no. 2

615--629

In this paper, an efficient method based on the Fourier decomposition method (FDM) is presented for noise removal of medical microscopic images. We propose an adaptive thresholding technique based FDM for denoising of heavily degraded images. An accurate image deconvolution is done with variance stabilization transformation and multi-scale Wiener filtering as a pre-processing step. The different series of frequency intrinsic band functions (FIBF’s) obtained with FDM which are further separated into noise and signal-significant FIBF’s based on cosine similarity index. The FDM adaptive thresholding technique is used to filter-out the unwanted frequency coefficients related to mixed Poisson-Gaussian noise (MPG). The thresholded FIBF’s and signal significant FIBF’s are combined to obtained reconstructed output. Finally, the optimization is done using mixed noise unbiased risk estimate (MNURE). To evaluate the effectiveness of proposed scheme, we have compared the results of the proposed scheme with six different state-of-the-art techniques. The simulation results verify, the effectiveness of proposed method. The proposed algorithm achieves better performance in terms of four quantitative evaluation measures by reducing the effect of noise.