Sánchez Brea, Luis MiguelTorcal Milla, Francisco JoséBernabeu Martínez, Eusebio2023-06-202023-06-202007-08-011559-128X10.1364/AO.46.005027https://hdl.handle.net/20.500.14352/51179© 2007 Optical Society of America. The authors thank Tomás Morlanes for his valuable ideas. This work has been supported by the “Codificación óptica de la posición a escala nanométrica: Nuevas tecnologías y dispositivos ópticos” project (DPI2005-02860) of the Ministerio de Educación y Ciencia of Spain and the “Tecnologías en ecología, alta precisión y productividad, multifuncionalidad, y tecnologías de la información y comunicaciones en Máquina Herramienta” CENIT project of the Ministerio de Industria, turismo y comercio. Sanchez-Brea is currently contracted by the Universidad Complutense de Madrid under the “Ramón y Cajal” research program of the Ministerio de Educación y Ciencia of Spain.We present a technique for determining the contrast of an intensity distribution in the presence of additive noise and other effects, such as undesired local amplitude or offset variations. The method is based on the variogram function. It just requires the measurement of the variogram at only four points and, as a consequence, it is very fast. The proposed technique is compared with other standard techniques, showing a reduction in the error of the contrast measurement.engjournal articlehttp://dx.doi.org/10.1364/AO.46.005027http://www.opticsinfobase.orgopen access535Standard-DeviationÓptica (Física)2209.19 Óptica Física