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Line-structured light 3D measurement is often used for 3D contour reconstruction of objects in complex industrial environments, where light plane calibration is a key step. In this paper, we propose a calibration method for a line-structured optical system based on a hinge-connected double-checkerboards stereo target. First, the target is moved randomly in multiple positions at any angle within the camera measurement space. Then, by acquiring any one image of the target with line-structured light, the 3D coordinates of the light stripes feature points are solved with the help of the external parameter matrix of the target plane and the camera coordinate system. Finally, the coordinate point cloud is denoised and used to quadratically fit the light plane. Compared with the traditional line-structured measurement system, the proposed method can acquire two calibration images at once; thus, only one image of line-structured light is needed to complete the light plane calibration. There is no strict requirement for the target pinch angle and placement, which improve system calibration speed with high accuracy. The experimental results show that the maximum RMS error of this method is 0.075 mm, and the operation is simpler and more effective to meet the technical requirements of industrial 3D measurement.

The microlens array has been widely applied in LED lighting source due to its special optical properties, but most of the research lacks the analysis and optimization of the complete mathematical models. Hence, the new design method of a free-form surface microlens array optical system is proposed in this paper. Based on the characteristics of TIR and the law of refraction, a complete mathematical model of the free-form microlens is established. By numerically solving a set of differential equations, the profile of the free-form surface microlens is obtained. Then we rotate the profile to get the free-form surface microlens. Finally, the proposed microlens array is simulated and analyzed in near-field and far-field situations, respectively. We also discuss the influence of microlens array characteristics on illumination performance. The result shows the uniformity and efficiency have been improved, both of which can reach more than 90%.

Polarized structured light is a novel method to measure shiny surface. However, the SNR of the captured image was affected by the additional polarizing filter. And the blurred influence of camera defocus was also strengthened. The accuracy of fringe edges detection was reduced. In this paper, a polarized-state-based structured light coding strategy and a phase image estimation method are proposed to improve the measurement robustness. To preserve the coding message in the complex environment, a special polarized-state-based coding strategy is adopted. To reduce the error which induced by additional polarizing filter and extracting the information from the saturated areas as much as possible, a phase image estimation method based on Stokes parameter is proposed. Compared with the traditional polarization-based structured light system, the experimental setup of proposed method is configured without any additional hardware. The experiment shows that the interference of camera defocus is remarkably reduced and the robustness of fringe edges detection is improved.

Objectives: To evaluate the relationship between alpha epithelial sodium channel (alpha-ENaC) T663A polymorphism and the risk of essential hypertension. Methods: This meta-analysis was conducted between November 2014 and February 2015 in Shanghai Medical Instrumentation College, Shanghai, China. We collected all published available case-control data (N=12) identified through PubMed, Web of Science, Scopus, and Chinese National Knowledge Infrastructure (CNKI) up to December 2014. The pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using the fixed- or random-effect model. Results: Although subgroup analysis showed that alpha-ENaC T663A polymorphism was associated with essential hypertension in North American individuals (OR=1.55, 95% CI=1.22-1.98, p =0.0003), our meta-analysis results did not confirm such association overall (OR=1.03, 95% CI=0.92-1.15, p =0.62). The lack of association was further confirmed by the non-superiority test ( p less than 0.0001). Conclusion: Alpha-ENaC T663A polymorphism might not be a risk factor for essential hypertension. Saudi Med J 2015; Vol. 36 (9): 1039-1045 doi: 10.15537/smj.2015.9.11822

Emerging evidence shows that interleukin (IL)-10 gene polymorphisms can regulate its expression level and thus influence person's susceptibility to preeclampsia. However, various published results were inconsistent. To explore the association between maternal IL-10 gene polymorphisms and preeclampsia, we performed a meta-analysis based upon 11 individual studies here. Our meta-analysis results indicated that IL-10 -819 C/T (C versus T, OR = 1.28, 95% CI = 1.08-1.50, P = 0.003) and -592 C/A (C versus A, OR = 1.28, 95% CI = 1.03-1.59, P = 0.03) polymorphisms were associated with preeclampsia. Although there was no overall association between -1082 A/G polymorphism and preeclampsia (G versus A, OR = 0.93, 95% CI = 0.77-1.13, P = 0.49), such association existed among Asian (G versus A, OR = 1.29, 95% CI = 1.04-1.60, P = 0.02) and South American (G versus A, OR = 0.72, 95% CI = 0.54-0.94, P = 0.02) populations in the subgroup analysis stratified by continents.

Present raw geo-tagged photo routes cannot provide information as enough as complete GPS trajectories due to the defects hidden in them. This paper mainly aims at analyzing the large amounts of geo-tagged photos and proposing a novel travel route restoring method. In our approach we apply the Hidden SemiMarkov model and Mean Value method to demonstrate migration discipline in the hot spots and restore the significant region sequence into complete GPS trajectory. At the end of the paper, a novel experiment method is designed to demonstrate that the approach is feasible in restoring route, and there is a good performance. Index Terms Geo-tagged Photo, Hot spot, Travel route, Route restoring, Trajectory mining

The damage mechanism of a cracked material due to laser beam thermal shock is an important problem when the interactions of high power laser beam with materials are studied. The transient thermal stress intensity factors (TSIFs) for a center crack in an infinite plate subjected to laser beam thermal shock are investigated. When the crack is in the heat affected zone, the compressive thermal stress causes the crack surface to come into contact with each other over a certain contact length, but the high tensile stresses around the crack tip tend to open the crack. In this case, the problem may be treated as a pair of embedded cracks problem with a smooth closure condition of the center crack. The TSIFs and the crack contact lengths are calculated with different laser beam spatial shapes. The TSIFs induced by thermal shock are in marked different from those induced by general mechanical loading.