Wavelets, Curvelets and Multiresolution Analysis Techniques in Fast Z Pinch Research

摘要

Z pinches produce an X ray rich plasma environment where backlighting imagingof imploding targets can be quite challenging to analyze. What is required is adetailed understanding of the implosion dynamics by studying snapshot images ofits in flight deformations away from a spherical shell. We have used wavelets,curvelets and multiresolution analysis techniques to address some of thesedifficulties and to establish the Shell Thickness Averaged Radius (STAR) ofmaximum density, r*(N, {\theta}), where N is the percentage of the shellthickness over which we average. The non-uniformities of r*(N, {\theta}) arequantified by a Legendre polynomial decomposition in angle, {\theta}, and theidentification of its largest coefficients. Undecimated wavelet decompositionsoutperform decimated ones in denoising and both are surpassed by the curvelettransform. In each case, hard thresholding based on noise modeling is used.