The tibial shaft fracture model was customized by reverse engineering and 3D printing technology, and the biomechanics of the Orthofix Unilateral External Fixator for tibial shaft fracture was studied. Through the design of an orthogonal experiment scheme, the distribution of the Schanz’s nails on the clamp, the distance from the lateral the Schanz’s nails to the fracture end, and the distance from the tibia to the external fixture were measured by the XTDIC-CONST 3D Full-Field Strain Measurement and Analysis System. The experimental results show that when the number of the Schanz’s nails decreased, the bending deformation of the Schanz’s nails will increase from pressure load, which increases the possibility of plastic deformation and fatigue fracture of the external fixator. According to the mechanical analysis results of the nine schemes, the distance from the external fixture to the tibia has the most significant effect on the deformation of the Schanz nail. When installing six Schanz pins in the clip, the distance from the lateral Schanz’s nail to the fracture end is 120 mm, and the distance from the external fixture to the tibia is 30 mm. The comprehensive performance of the scheme is the best.

A light field camera can simultaneously sample a scene from multiple viewpoints with a single exposure, which has unique advantages in portability and depth accuracy over other depth sensors. Noise is a challenging issue for light field depth estimation. Most of the traditional depth estimation methods for noisy scenes are only suitable for non-occluded scenes, and cannot handle the noisy scenes with occluded regions. To solve this problem, we present a light field depth estimation method based on inline occlusion handling. The proposed method integrates the occlusion handling into the anti-noise cost volume, which can improve the anti-occlusion capability while maintaining the anti-noise performance. After the cost volume is constructed, we propose a multi-template filtering algorithm to smooth the data cost while preserving the edge structure. Experimental results show that the proposed method has better performance over other state-of-the-art depth estimation methods in high noise scenes, and can better handle the occlusion problem of depth estimation in noisy scenes.

We describe a modified six-step method to simultaneously measure the inhomogeneity of sample plate and the planarity of the four surfaces in an absolute manner, along with a high-efficiency iterative algorithm for data reduction. Combined with the iterative algorithm, the errors of inhomogeneity and flatness can be estimated with pixel-level spatial resolution in a fast and effective manner. The simulation and experiments prove the validity of the method and the measurement capability of reaching sub-nanometer accuracy. The method presented in this paper is cross-compared with traditional absolute testing method and the method of inhomogeneity. The difference between absolute plane measurements is less than 1.7 nm RMS, and the difference of inhomogeneity measurement accuracy is less than 2.3 nm RMS. The experimental results show that these two methods are highly consistent and have good repeatability, which verifies the accuracy of the methods proposed in this paper. Uncertainty analysis indicates that the proposed method improves the measurement uncertainty, compared with the classical transmission method.

Artificial knee joint plays an important role in improving the joint condition of patients. The surface deviation of artificial knee joint will directly affect the treatment effect of patients. Therefore, it is necessary to evaluate the surface of artificial knee joint with high precision before it is put into use. The slope of the artificial knee joint is complex and varies greatly, and there are great differences in the knee joint surface among different patients. The complexity and unknowability of artificial knee joint make it difficult to measure its surface with high precision. In this paper, a normal vector tracking measurement method based on contact inductance linear displacement sensor (LVDT) is proposed, and a rotary scanning measurement system is built. This method performs curve fitting on the measured points, predicts the changing trend of the measured surface, and adaptively adjusts the sampling position and posture of the LVDT to make it measure approximately along the normal direction of the sampling point, so as to realize the adaptive rotation measurement of the complex and unknown surface with large slope. Through the measurement experiment of the standard ball, the measurement error of the calibration system is about 48.21 μm. In addition, the measurement experiment of the artificial knee joint model is carried out to verify the feasibility of the method.

To prevent people from using the processed turquoise and counterfeit turquoise in medicine, this paper focuses on identifying the raw materials of medicinal turquoise. A turquoise identification system was developed using hyper-spectral imaging technology. The sample standard spectral line was obtained while the applicability was analyzed by the present sample, based on the high-resolution spectral data of ore samples from 6 representative producing areas of natural turquoise in China. A new method was summarized by the differences in correlation coefficients in the range of 400 nm?1000 nm and 400 nm?600 nm of the fake turquoise on the market and an experimental prototype system to identify the true or false of turquoise was developed. Further research will provide technical support to select raw materials in mineral medicine, which will greatly promote the modernization of Tibetan medicine.

Aiming at the problems of low signal-to-background ratio and low wavefront detection accuracy of the adaptive optical system Hartmann sensor under strong background conditions during the day, based on the difference in polarization characteristics between man-made targets and strong backgrounds, a polarized Hartmann wavefront detection technology is proposed. The traditional Hartmann wavefront detection is converted from the intensity dimension to the polarization dimension, thereby effectively improving the signal-to-background ratio and wavefront detection accuracy. The basic methods and principles of polarized Hartmann wavefront detection are described, and the correctness and accuracy of the method are verified through numerical simulations and experiments. Theoretical and numerical simulation results show that the polarized Hartmann wavefront detection technology can effectively improve the signal-to-background ratio and wavefront detection accuracy under strong background conditions, and significantly enhance the ability of the adaptive optical system to work under strong background conditions.

Defocus dithering technology effectively avoids the non-linear effects introduced by commercial projectors and can achieve high-speed dynamic measurement. However, the binary dithering stripes after defocusing and the standard sinusoidal stripes are not completely close, and there will be a certain deviation in the measurement process. Aiming at the measurement error, this paper proposes an optimization method based on an improved binary ant colony algorithm, which optimizes and improves the binary defocus dithering technology from the phase domain to better improve the measurement accuracy. Through the optimization of small-size binary blocks, the entire optimization process is replaced, and the optimization efficiency is improved. Simulation and experimental results prove that this method can achieve effective three-dimensional measurement under different defocus conditions.