Reconstruction of neutron penumbral images by a constrained genetic algorithm

Abstract

Penumbral imaging is a technique for imaging of neutrons or other penetrating radiations. The technique uses the facts that spatial information can be recovered from the shadow or penumbra that an unknown source casts through a simple large circular aperture. The limitation is that the straightforward image reconstruction will introduce some significant distortion for a large field of view because of nonisoplanaticity of the aperture point spread function. A genetic algorithm (GA) is proposed for reconstruction of penumbral images, and the technique allows distortion-free reconstruction over a large field of view. Furthermore, because in GA the complicated a priori constraints can be easily incorporated by the appropriate modification of the cost function, the algorithm is also tolerant of the noise.