Current Issue : April - June Volume : 2015 Issue Number : 2 Articles : 4 Articles
The automatic radioscopic inspection of industrial parts usually uses reference based methods. These methods select, as benchmark\nfor comparison, image data from good parts to detect the anomalies of parts under inspection. However, parts can vary within the\nspecification during the production process, which makes comparison of older reference image sets with current images of parts\ndifficult and increases the probability of false rejections. To counter this variability, the reference image sets have to be updated. This\npaper proposes an adaptive reference image set selection procedure to be used in the assisted defect recognition (ADR) system in\nturbine blade inspection. The procedure first selects an initial reference image set using an approach called ADR Model Optimizer\nand then uses positive rate in a sliding-time window to determine the need to update the reference image set.Whenever there is a\nneed, the ADR Model Optimizer is retrained with new data consisting of the old reference image sets augmented with false rejected\nimages to generate a new reference image set. The experimental result demonstrates that the proposed procedure can adaptively\nselect a reference image set, leading to an inspection process with a high true positive rate and a low false positive rate....
To apply the fundamental parameters method at the con focal setup the knowledge of the sensitivity of the spectrometer is required\nwhich depends on the characteristics of two X-ray lenses: one in the excitation channel and another in the detection channel.\nFor the particular case of poly chromatic excitation, the theory shows that the focalization properties of the excitation lens for all\nincident energies affect the X-ray fluorescence intensity. Therefore the traditional calibration method based on the measurement\nof standard samples becomes unstable since the number of required fitting parameters is too high. To reduce these parameters a\nprevious characterization of the excitation lens by a simulation program was employed giving rise to a simplified con focal setup\ncalibration.The developed calibration method was applied for a con focal spectrometer implemented in the Brazilian Synchrotron\nRadiation Source (LNLS) with white be am.The experimental parameters of the sensitivity were obtained from depth profile analysis\nof several pure thin films. The calibrated con focal setup was used to quantify reference standards in order to validate the calibration\nprocedure. Our results for elemental concentrations show relative errors less than 15% for the quantitative analysis of a light matrix\nreference standard....
The variation of concrete pores under the action of freeze-thaw cycles was investigated experimentally by using the X-ray CT.\nFirstly, the statistical characteristics of pores of concrete specimens were obtained by using the X-ray image analysis. Secondly, the\nvariation of porosity and pore volume of concrete pores were analyzed and discussed by comparing with above characteristics.\nThirdly, the failure process of the concrete specimens acted by the freeze-thaw cycles was investigated by scanning the interior\nof concrete specimens. The results showed that the pore volumes of concrete pores whose volumes were located at the interval\n[0.5mm3, 20mm3] have no big variation in both the amounts and volume of concrete pores, while others were found to have huge\nchange during the process of experiment. The extent of damage acted by the repeated freezing and thawing gradually ranged from\nsurface to complete disintegration of the interior of concrete specimens after 30 cycles of freeze-thaw acting....
A high precision slit in ultra-high vacuum is designed to develop a good performance soft X-ray interference lithography (XIL)\nbeam line at Shanghai Synchrotron Radiation Facility (SSRF). In order to define the secondary source and enhance the performance\nof the beam line,many technical difficulties need resolving to design the precision slit.Therefore, to obtain reasonable design scheme,\nit is necessary to analyze the structural characteristics, the movement situation, the force state, the thermal load state, and the\ncooling state of the precision slit deeply by numerical simulation. The simulation results and the testing results demonstrate that\nthe mechanical precision of the slit is at a high level and satisfies the requirements of the beam line....
Loading....