TY - JOUR A1 - Pérez Cagigal, Manuel AU - Valle Herrero, Pedro José AU - Colodro Conde, Carlos AU - Villo Pérez, Isidro AU - Pérez Garrido, Antonio T1 - Covariance of lucky images for increasing objects contrast: diffraction-limited images in ground-based telescopes Y1 - 2016 SN - 0035-8711 UR - http://hdl.handle.net/10317/6699 AB - Images of stars adopt shapes far from the ideal Airy pattern due to atmospheric density fluctuations. Hence, diffraction limited images can only be achieved by telescopes without atmospheric influence, e.g. spatial telescopes, or by using techniques like Adaptive Optics or Lucky Imaging. In this paper, we propose a new computational technique based on the evaluation of the COvariancE of Lucky Images (COELI). This technique allows to discover companions to main stars by taking advantage of the atmospheric fluctuations. We describe the algorithm and we carry out a theoretical analysis of the improvement in contrast. We have used images taken with 2.2 m Calar Alto telescope as a testbed for the technique resulting that, under certain conditions, telescope diffraction limit is clearly reached . KW - Arquitectura y Tecnología de Computadoras KW - Atmospheric effects KW - Techniques: high angular resolution KW - Techniques: image processing KW - 2209.90 Tratamiento Digital. Imágenes LA - eng PB - Blackwell ER -