Quality assessment by region in spot images fused by means dual-tree complex wavelet transform

This work is motivated in providing and evaluating a fusion algorithm of remotely sensed images, i.e. the fusion of a high spatial resolution panchromatic image with a multi-spectral image (also known as pansharpening) using the dual-tree complex wavelet transform (DT-CWT), an effective approach for conducting an analytic and oversampled wavelet transform to reduce aliasing, and in turn reduce shift dependence of the wavelet transform. The proposed scheme includes the definition of a model to establish how information will be extracted from the PAN band and how that information will be injected into the MS bands with low spatial resolution. The approach was applied to Spot 5 images where there are bands falling outside PAN’s spectrum. We propose an optional step in the quality evaluation protocol, which is to study the quality of the merger by regions, where each region represents a specific feature of the image. The results show that DT-CWT based approach offers good spatial quality while retaining the spectral information of original images, case SPOT 5. The additional step facilitates the identification of the most affected regions by the fusion process.

Análisis técnico-económico de acceso al mercado alemán EPEX SPOT

Acciona Energía dispone en Alemania de 150 MW de potencia instalada. Todos ellos de energía eólica, en un total de doce parques eólicos situados en la sur del país. El proyecto tiene por objeto comparar las distintas modalidades de venta de energía procedente de fuentes renovables que ofrece el estado alemán para la cartera de activos de Acciona Energía, llegando a una conclusión final de cuál de ellas es la más aconsejable. Para ello se ha realizado un estudio del funcionamiento y normas del mercado Epex Spot de la electricidad y de la legislación alemana correspondiente a la materia, así como un seguimiento exhaustivo de producción y otras variables de los parques eólicos para su análisis. Los cálculos y las estimaciones realizados llevaron a la conclusión, que la mejor opción era la venta directa en el mercado Epex Spot, para lo que primero habría que darse de alta como agente en dicho mercado. Aunque esta opción asuma mayores riesgos también ofrecería un aumento considerable de ingresos. ABSTRACT Acciona Energía has 150 MW of power capacity in Germany, all of them wind energy in a total of twelve installations, located in the south of the country. The main goal of the project is to compare the different ways to sell the energy which became from renewable source that German state offers for Acciona’s asset portfolio, finding the most advisable conclusion. To do so a study of standards and rules of Epex Spot electricity market and German law related to this topic has been made. In addition of an exhaustive monitoring of energy production and others wind farms variables has been analyzed. The reckoning and estimations saw the conclusion that the best option was the direct sell in Epex Spot market, in order to do that the first of all is to register as market agent. Despite this options assume bigger risks, it provide a substantial increase in income

Merit function for the evaluation of color uniformity in the far field of LED spot lights

The scope of the present paper is the derivation of a merit function which predicts the visual perception of LED spot lights. The color uniformity level Usl is described by a linear regression function of the spatial color distribution in the far field. Hereby, the function is derived from four basic functions. They describe the color uniformity of spot lights through different features. The result is a reliable prediction for the perceived color uniformity in spot lights. A human factor experiment was performed to evaluate the visual preferences for colors and patterns. A perceived rank order was derived from the subjects’ answers and compared with the four basic functions. The correlation between the perceived rank order and the basic functions was calculated resulting in the definition of the merit function Usl. The application of this function is shown by a comparison of visual evaluations and measurements of LED retrofit spot lamps. The results enable a prediction of color uniformity levels of simulations and measurements concerning the visual perception. The function provides a possibility to evaluate the far field of spot lights without individual subjective judgment. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Optimization of optical systems for LED spot lights concerning the color uniformity

Spotlighting is one illumination field where the application of light emitting diodes (LED) creates many advantages. Commonly, the system for spot lights consists of a LED light engine and collimating secondary optics. Through angular or spatial separated emitted light from the source and imaging optical elements, a non uniform far field appears with colored rings, dots or patterns. Many feasible combinations result in very different spatial color distributions. Several combinations of three multi-chip light sources and secondary optical elements like reflectors and TIR lenses with additional facets or scattering elements were analyzed mainly regarding the color uniformity. They are assessed by the merit function Usl which was derived from human factor experiments and describes the color uniformity based on the visual perception of humans. Furthermore, the optical systems are compared concerning efficiency, peak candela and aspect ratio. Both types of optics differ in the relation between the color uniformity level and other properties. A plain reflector with a slightly color mixing light source performs adequate. The results for the TIR lenses indicate that they need additional elements for good color mixing or blended light source. The most convenient system depends on the requirements of the application.