Three-dimensional measurement with fringe projection sensor has been commonly researched. However, the measurement accuracy and efficiency of most fringe projection sensors are still seriously affected by image saturation and the non-linear effects of the projector. In order to solve the challenge, in conjunction with the advantages of stereo vision technology and fringe projection technology, an adaptive binocular fringe dynamic projection method is proposed. The proposed method can avoid image saturation by adaptively adjusting the projection intensity. Firstly, the flowchart of the proposed method is explained. Then, an adaptive optimal projection intensity method based on multi-threshold segmentation is introduced to adjust the projection illumination. Finally, the mapping relationship of binocular saturation point and projection point is established by binocular transformation and left camera–projector mapping. Experiments demonstrate that the proposed method can achieve higher accuracy for high dynamic range measurement.

In this study, a group of 313 workers occupationally exposed to vinyl chloride monomer (VCM) and 141 normal unexposed referents were examined for chromosomal damage using the cytokinesis-blocked micronucleus (CBMN) assay in peripheral lymphocytes. We explored the relationship between genetic polymorphisms of XRCC1 ( Arg194Trp , Arg280His and Arg399Gln ), MGMT ( Leu84Phe ) and hOGG1 ( Ser326Cys ) and susceptibility of chromosomal damage induced by VCM. Polymerase chain reaction–restriction fragment length polymorphism techniques were used to detect polymorphisms in XRCC1 , hOGG1 and MGMT. It was found that the micronuclei (MN) frequency of exposed workers (4.86 ± 2.80)‰ was higher than that of the control group (1.22 ± 1.24)‰ ( P < 0.01). Increased susceptibility to chromosomal damage as evidenced by higher MN frequency was found in workers with hOGG1 326 Ser/Cys genotype [frequency ratio (FR) = 1.21, 95% confidence interval (CI): 1.02–1.46; P < 0.05], XRCC1 194 Arg/Trp (FR = 1.12, 95% CI: 1.00–1.25; P < 0.05) and XRCC1 280 Arg/His and His/His genotypes (FR = 1.12, 95% CI 1.00–1.26, P < 0.05). Moreover, among susceptibility diplotypes, CGA/CAG carriers had more risk of MN frequency compared with individuals with wild-type CGG/CGG (FR = 1.67, 95% CI: 1.19–2.23; P < 0.05). MN frequency also increased significantly with age in the exposed group (FR = 1.13, 95% CI: 1.00–1.28; P < 0.05). Thus, CB-MN was a sensitive index of early damage among VCM-exposed workers. Genotype XRCC1 Arg194Trp , Arg280His , hOGG1 Ser326Cys , diplotype CGA/CAG and higher age may have an impact on the chromosome damage induced by VCM

Benefiting from the characteristics of full field scanning, high resolution and high precision, digital fringe projection measurement technology has been widely used in three-dimensional measurement. For the cylinder pose detection, due to the influence of occlusion and noise, the obtained three-dimensional point cloud information is usually incomplete, resulting in the unreliable object parameters after point cloud fitting. In view of the above problems, a cylinder fitting method with incomplete point cloud data based on the cutting plane is proposed. Firstly, the point cloud is processed by bilateral filtering method to reduce the influence of outliers and noise points. Then, according to the principle of forming ellipse on cylinder cutting plane, some equidistant cutting planes are selected. At the same time, in order to reduce the influence of outliers on fitting, the random sampling consistency algorithm is used for ellipse fitting with the points on each cutting plane, that is, the ellipse parameters corresponding to each cutting plane can be obtained. Finally, random sampling consistency algorithm is applied for cylinder axis fitting with the ellipse centers of all the cutting planes, calculating the axis vector of the cylinder. Thus, the parameters of the cylinder detected are obtained. The experimental results of stepped cylinder with diffuse reflection and metal cylinder show the effectiveness and high precision of the proposed method.

Traditional KDP polishing methods, such as magnetorheological finishing (MRF), ion-beam figuring (IBF), and chemical mechanical polishing (CMP), are limited by either hard-to-remove residual particles, unavoidable heating effect, or applicability that is restricted to large-sized KDP. The abrasive-free jet polishing (AFJP) is regarded as a promising polishing method that can circumvent the above issues. KDP AFJP makes use of a thermodynamically and kinetically stable ionic liquid (IL) microemulsion that contains nanometer range water droplets evenly dispersed in the non-aqueous carrier liquid. The sprayed out nanoscale water droplets can remove material through dissolution. In this paper, the normal impinging of a nanoscale water droplet on the KDP surface is investigated. And then a materials removal model is proposed for water droplets. This model considers two major modes, namely deformation of a water droplet in compressing and deformation restoring of a water droplet in slipping process. Finally, KDP AFJP spot experiments were then conducted to validate the model veracity. The proposed model fits well with the simulation and experimental results which further suggest KDP AFJP’s feasibility. This proposed model provides a good explanation for KDP AFJP’s removal mechanism.

The dwell time algorithm is one of the key technologies that determines the accuracy of a workpiece in the field of ultra-precision computer-controlled optical surfacing. Existing algorithms mainly consider meticulous mathematics theory and high convergence rates, making the computation process more uneven, and the flatness cannot be further improved. In this paper, a reasonable elementary approximation algorithm of dwell time is proposed on the basis of the theoretical requirement of a removal function in the subaperture polishing and single-peak rotational symmetry character of its practical distribution. Then, the algorithm is well discussed with theoretical analysis and numerical simulation in cases of one-dimension and two-dimensions. In contrast to conventional dwell time algorithms, this proposed algorithm transforms superposition and coupling features of the deconvolution problem into an elementary approximation issue of function value. Compared with the conventional methods, it has obvious advantages for improving calculation efficiency and flatness, and is of great significance for the efficient computation of large-aperture optical polishing. The flatness of φ150 mm and φ100 mm workpieces have achieved PVr₁₅₀ = 0.028 λ and PVcr₁₀₀ = 0.014 λ respectively.