Heuristic reconstruction of three-dimensional laser-imploded targets from x-ray pinhole images

Abstract

Implosion symmetry has long been an important issue in inertial confinement fusion (ICF) research. In order to evaluate the implosion symmetry of ICF, a computer tomography (CT) technique developed for medical diagnostics is traditionally employed. This attempt was made to reconstruct the three-dimensional (3D) compressed core from several x-ray pinhole images. Unfortunately the reconstructed result is often constrained by the number of available pinhole images and is affected by the noise in them. In this article, we propose a heuristic method for 3D image reconstruction from a limited number of pinhole images and in the presence of noise. We represent the 3D compressed core as a summation of 3D Gaussian functions. The 3D image can be reconstructed by estimating the width and height of each Gaussian function. One heuristic method, simulated annealing, is used. The technique has been successfully applied to real laser–plasma experiments for the reconstruction of 3D compressed core utilizing only three x-ray pinhole images.

Three-dimensional reconstruction of integrated implosion targets from simulated small-angle pinhole images

“…200 iterations were performed for each calculation. To quantitatively assess the quality of recovery, a normalized mean square error (NMSE) [21] was defined. The NMSE between the source X and the restored Y was defined as:…”

“…Meanwhile, some methods have been developed and utilized to deal with the 3D reconstruction of a laser implosion target based on pinhole images. A heuristic method using three pinhole images taken from three viewing directions [21] and an integral method using six pinhole images located on three coordinate axes [22] gave good results. Nevertheless, there was an issue with the wide angles of the pinhole images.…”

Processing of spectrally resolved x-ray images of inertial confinement fusion implosion cores recorded with multimonochromatic x-ray imagers

“…The LM method is a singleobjective algorithm, thus all the objectives defined in the PGA have to be redefined into one objective as defined in Ref. 26. The new objective to be minimized is…”

“…26 To this end, the broadband emissivity distribution is written as a linear combination of Gaussian distribution functions as follows:…”

Determination of optimal number of projections and parametric sensitivity analysis of operators for parallel‐ray transmission tomography using hybrid continuous genetic algorithm

“…Recently, Chen et al and Ali et al introduced CT-based techniques using evolutionary approaches for image reconstruction (Ali et al, 2000;Chen et al, 2003). Qureshi et al introduced hybrid continuous genetic algorithm (HCGA) technique for the estimation of d-IRT.…”