Current Issue : July - September Volume : 2013 Issue Number : 3 Articles : 5 Articles
The theoretical description of a simplified end-to-end software tool for simulation of data produced by optical instruments, starting from either synthetic or airborne hyperspectral data, is described and some simulation examples of hyperspectral and panchromatic images for existing and future design instruments are also reported. High spatial/spectral resolution images with low intrinsic noise and the sensor/mission specifications are used as inputs for the simulations. The examples reported in this paper show the capabilities of the tool for simulating target detection scenarios, data quality assessment with respect to classification performance and class discrimination, impact of optical design on image quality, and 3D modelling of optical performances. The simulator is conceived as a tool (during phase 0/A) for the specification and early development of new Earth observation optical instruments, whose compliance to user�s requirements is achieved through a process of cost/performance trade-off. The Selex Galileo simulator, as compared with other existing image simulators for phase C/D projects of space-borne instruments, implements all modules necessary for a complete panchromatic and hyper spectral image simulation, and it allows excellent flexibility and expandability for new integrated functions because of the adopted IDL-ENVI software environment....
An experimental investigation of multiphase flow involving a liquid (water) and a gas (air) is performed. The results for three\r\ndifferent scenarios are presented: fixed bubble, ascending bubble, and dispersed-bubble turbulent pipe flow. This study involves a\r\ncomparison of statistical data collected using two sensing systems, a wavefront sensor and a high-speed video camera. A signal\r\nanalysis technique based on signal attenuation is developed for data collected using the wavefront sensor. The three experiments\r\nperformed provide experimental evidence that the Shack-Hartmann wavefront sensor, operating on signal attenuation, is a viable\r\nmethod for the study of multiphase bubble flows....
The researchers focus on the IRT procedure of heat diffusion in ceramic finishing materials of contemporary architecture. The\r\naim of the research is the development of a method for the thermal characterization of clinkers, a very common ceramic finishing\r\nmaterial of buildings. The first experimental phase was performed in laboratory on clinkers of different shapes, thickness, colors,\r\nand glazing surface. The researchers determined two characteristic parameters related to thickness and thermal conductivity, by\r\nthe interpolation of the heating curve in function of time with an analytical curve (resulted from a particular solution of Fourier�s\r\nequation). This curve allows to obtain a parameter characteristic of the material of the specimens under investigation. At present\r\ntime, the researchers have been studying the correlation between this parameter and the damage level in the specimens; they will\r\nbe testing the model on real-scale study cases in the second experimental phase....
Active thermography gives the possibility to characterize thermophysical properties and defects in complex structures presenting heterogeneities. The produced thermal fields can be rapidly 3D. On the other hand, due to the size of modern thermographic images, pixel-wise data processing based on 1D models is the only reasonable approach for a rapid image processing. The only way to conciliate these two constraints when dealing with time-resolved experiments lies in the earlier possible detection/characterization. This approach is illustrated by several different applications and compared to more classical methods, demonstrating that simplicity of models and calculations is compatible with efficient and accurate identifications....
We present a novel nonlocal mean (NLM) algorithm using an anisotropic structure tensor to achieve higher accuracy of imaging\r\ndenoising and better preservation of fine image details. Instead of using the intensity to identify the pixel, the proposed algorithm\r\nuses the structure tensor to characterize the boundary information around the pixel more comprehensively.Meanwhile, similarity\r\nof the structure tensor is computed in a Riemannian space for more rigorous comparison, and the similarity weight of the pixel (or\r\npatch) is determined by the intensity and structure tensor simultaneously. The proposed algorithm is compared with the original\r\nNLM algorithm and a modified NLM algorithm that is based on the principle component analysis. Quantitative and qualitative\r\ncomparisons of the three NLM algorithms are presented as well....
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