A single-shot method to reduce the speckle noise in the numerical reconstructions of electronically recorded holograms is presented. A recorded hologram with the dimensions $N\times M$ is split into $S=T\times T$ sub-holograms. The uncorrelated superposition of the individually reconstructed sub-holograms leads to an image with the speckle noise reduced proportionally to the $1/\sqrt{S}$ law. The experimental results are presented to support the proposed methodology.

Quantitative phase measurements obtained with digital holographic microscopes are strongly dependent on the optical arrangement of the imaging system. The nontelecentric operation provides phase measurements affected by a parabolic phase factor and requires numerical postprocessing, which does not always remove all the perturbation. Accurate phase measurements are achieved by using the imaging system in telecentric mode. Unfortunately, this condition is not accomplished when a commercial microscope is used as the imaging system. In this paper, we present an approach for obtaining accurate phase measurements in nontelecentric imaging systems without the need for numerical postprocessing. The method uses an electrically tunable liquid lens to illuminate the sample so that the perturbing parabolic wavefront is cancelled out. Experimental holograms of a Fresnel lens and a section of the thorax of a Drosophila melanogaster fly are captured to verify the proposed method.

This work shows the realization of speckle reduction in the numerical reconstruction of digitally recorded holograms by the superposition of multiple slightly rotated digital holographic images of the object. The superposition of $T$ uncorrelated holographic images reduces the contrast of the speckle noise of the image following the expected $1/T$ law. The effect of the method on the borders of the resulting image is evaluated by quantifying the utilization of the dynamic range or the contrast between the white and black areas of a regular die. Experimental results validate the feasibility of the proposed method.

El presente artículo presenta la revisión del estado del arte de la gerencia del mantenimiento, identificando problemas enfrentados por los investigadores del tema, las metodologías aplicadas y los resultados alcanzados; se hizo una contextualización de la problemática que se está abordando dentro del campo investigativo y se conocieron las tendencias de la investigación en la gerencia del mantenimiento. Con la búsqueda realizada se logró identificar, como principal tema de interés, el diseño, implementación y uso del Sistemas Computarizados de Gestión del Mantenimiento (Computarized Maintenance Management Systems - CMMS) como herramienta para la optimización de la gerencia de activos físicos, con lo cual se deja abierta la necesidad de investigar en este tema, buscando aplicaciones que den solución a los requerimientos del sector productivo para contribuir con su competitividad.