A Fast Iterative Blind Image Restoration Algorithm Successful blind image deconvolution algorithms require the exact estimation of the Point Spread Function size, PSF. In the absence of any priori information about the imagery system and the true image, this estimation is normally done by trial and error experimentation, until an acceptable restored image quality is obtained. This paper, presents an exact estimation of the PSF size that yields the optimum restored image quality. The paper also describes a least squares PSF estimation, instead of the slow iterative update, that is commonly used in Iterative Blind Deconvolution software, IBD. Moreover, a technique is also proposed to improve the sharpness of the deconvolved images, by constrained maximization of the detail wavelet-coefficient entropies. Several simulations are given to verify these results.

This paper presents a new method for solving post-nonlinear blind source separation (PNLBSS). It proposes a modified Gaussianization technique for recovering PNLBSS systems. The proposed technique overcomes the failure of classical Gaussianization schemes to work properly in some PNL mixture with severe nonlinearity characteristics. It is found that the failure is due to the multi-modality of the probability distributions (pdf), of the received nonlinear mixture. In order to estimate the eceived pdf, the paper proposes an accurate nonparametric evaluation of the pdf signal and its entropy functions . The pdf estimation is based on using Bspline wavelet transform as the smoothing filter for the data histogram distribution. The paper also proposes a pre-mapping scheme that transforms multi-modal pdf to a uni-modal one, and thereby makes them Gaussianable. Several illustrative examples are given, to verify the ability of the proposed technique to estimate pdf signal, recover PNLBSS mixture with severe nonlinearity characteristics.

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Secondary flows are noxious to axial compressor performance. To overcome and control those secondary flows, vortex generators are used as a passive control device. Controlling secondary flows will lead to a further improvements in the compressor performance. A new design of vortex generator is considered in this investigation in order to control secondary flows in axial compressor cascade at design and off-design conditions. Numerical simulations of a three-dimensional compressible turbulent flow have been performed to explore the effect of the vortex generators on the reduction of secondary flows. Six different incidence angles are used for the off-design operation investigations. Based on the simulation results, the pressure, velocity, and streamline are used to follow up the development of the secondary flows. Thence, total pressure loss coefficient, static pressure rise coefficient, difference in flow deflection angle, and diffusion factor are estimated. Results indicate that vortex generators have a significant effect on the development of secondary flows at off design operation as they cause a reduction in total pressure loss, they also affect the loading behavior of the cascade as they cause a slight change in the cascade deflection, and a slight decrease in the diffusion factor which causes unloading of the blade. Static pressure rise is significantly reduced at negative incidence angles while a slight reduction occurs at positive incidence angles. In a word, the new design of the vortex generator enhances the cascade aerodynamic performance and enlarges the operating range of the cascade towards the positive incidence region.