No abstract

A forest made of an infinite biperiodic array of trees over a lossy ground, is illuminated by a linearly polarized electromagnetic plane wave in the range of 20 to 90 MHz. Due to the ratio of the wavelength to the array period, only the specular mode is propagative. Therefore, a reflection coefficient is computed and not a backscattering coefficient. It is obtained by means of a full wave approach, based on an integral representation of the electric field. This approach takes into account all possible interactions between each component of the medium as well as ground penetration and provides full information on the phase of the scattered field. Two models of the forest are developed, the two layers one where trees are separated and the four layers one whee the canopy is replaced by an equivalent homogeneous medium. The low frequency (VHF) used here make this homogenization possible and allows one to consider trees with simple shape, the wave being unable to sense details of a tree. 4 Numerical Results 4.1 Validity of the Born Approximation 4.2 Influence of the Age of the Trees 4.3 Influence of the Representation of the Trees 5 Conclusion Appendix A. The Dyadic Green's Function for the 2LM and the 4LM A.1 The Dyadic Green's Function for the 2LM A.2 The Dyadic Green's Function for the 4LM Appendix B. Elements of the Matrix [I kj ] References

This paper develops a digital decoding design for the imaging system with phase coded lens. The phase coded lens is employed to extend the depth of filed (DoF), and the proposed design is used to restore the special-purpose blur caused by the lens. Since in practice the imaging system inevitably contains manufacturing inaccuracy, it is often difficult to obtain precise point spread function (PSF) for image restoration. To deal with this problem, we develop a flow for designing filters without PSF information. The imaging system first takes a shot of a well-designed test chart to have a blur image of the chart. This blur image is then corrected by using the perspective transformation. We use both of the image of the test chart and the corrected blur image to calculate a minimum mean square error (MMSE) filter, so that the blur image processed by the filter can be very alike to the test chart image. The filter is applied to other images captured by the imaging system in order to verify its effectiveness in reducing the blur and for showing the capability of extending the DoF of the integrated system.Keywords: phase coding, extended depth of field, computational imaging, digital decoding, image restoration, minimum mean square error filter

In view of the start up of the 14 TeV pp Large Hadron Collider the quark anti−quark reactions leading to the final states W + W − , W ± Z 0 and Z 0 Z 0 are studied, in the frame work of the Standard Model (SM ), using helicity amplitudes. The differential and total cross sections are first evaluated in the parton anti-parton center of mass system. Subsequently they are transformed to their expected structure in pp collisions through the parton anti-parton Energy Density Functions which are here derived from the known Parton Density Functions of the proton. In particular the single and joint longitudinal polarizations of the di-boson final states are calculated. The effect on these reactions from the presence of s-channel heavy vector bosons, like the W ′ and Z ′ , are evaluated to explore the possibility to utilize the gauge boson pair production as a probe for these 'Beyond the SM ' phenomena.

No abstract