Error analysis and self-correction of an inductive linear displacement sensorZhao, Jiang-yu; Wang, Yang; Li, Mi; Tang, Qi-fu
doi: 10.1117/12.3032407pmid: N/A
Error analysis on a PCB based inductive linear displacement sensor is introduced in this paper, and a self-correcting method independent of external reference for the sensor is proposed in this paper. This method is mainly aimed at the linear displacement error of short period caused by manufacturing and assembly of sensor prototype. In this paper, only the 1-order, 2-order and 4-order errors common in the measurement process are studied. Therefore, studying from the output signal, the generation mechanism of three kinds of errors has been traced theoretically, and the functional relationship between the output signal and error has been calculated, thus establishing the short-period error function model of the relevant sensor signal. In the experimental verification stage, four comparative tests were carried out, which effectively verified the feasibility of the self-correcting method. The results of prototype experiments show that the measurement accuracy of the sensor prototype has been effectively improved. The 1-order error is reduced by about 64.5%, the 2-order error is reduced by about 3.8%, the 4-order error is reduced by about 83%, and the total error is reduced from 51.6m to 36.2m.
Phase-locked taper array for mid-infrared quantum cascade lasers with Talbot cavitiesZhang, Shiya; Zhu, Lianqing; Li, Mingyu; Wang, Rui; Cui, Jintao
doi: 10.1117/12.3032520pmid: N/A
Power scaling in large-area quantum cascade lasers (QCLs) often leads to a degradation of beam quality and the emission of multi-lobed far-field patterns. In this study, we present a tapered QCL array featuring an integrated Talbot cavity on one side of the array, employing a diffraction coupling scheme. By controlling the Talbot length to one-half the Talbot distance (Zt/2), phase mode operation can be selectively achieved. Optimized in-phase mode operation is attained through careful adjustment of the Talbot cavity length. The far-field radiation pattern for in-phase operation comprises five lobes, with a central maximum lobe exhibiting a half-maximum width of 4.8, accompanied by four side lobes. The separation between adjacent lobes measures approximately 14.3. Ongoing research efforts are crucial to achieving enhanced beam performance and minimizing optical losses associated with integrated Talbot cavities.
Calibration of the rotary scale of the primary standard for position angleZou, Dian; Xiao, Meiliang; Huang, Yao; Fang, Yi; Shi, Yongsheng; Xue, Zi; Gu, Yuling; Yang, Yu; Zhu, Weibin
doi: 10.1117/12.3032714pmid: N/A
A calibration of primary standard rotary scale was carried out based on the establishment of new calibration system. The angle metrological performance including index error, interpolation error, repeatability, and resolution were calibrated separately by comparison with optical polygon and accompanying-calibration angle encoder. The methods of crosscalibration and self-calibration were applied to make the calibration results traceable to circle-closure. The calibration results reveal that the index error is within 0.04", the interpolation error is within 0.076", the repeatability is better than 0.005", and the resolution is better than 0.002", which meet NIM's recent requirement of metrological performance for the reproduction of position angle at primary level.
Study on energy band design of mid-wave infrared high-gain quantum cascade laserHan, YZ; Zhang, Dongliang; Lu, Lidan; Zhu, Lianqing
doi: 10.1117/12.3032441pmid: N/A
Because of its superior performance, infrared lasers are frequently employed in medical detection, infrared imaging, gas detection, and space optical communication. This work proposes a new simple energy band structure for radiation at room temperature, based on energy band simulation. The results showed that the components for Ga0.34In0.66As/Al0.68In0.32As, as potential well/base layer, by optimizing the core area, in this simple cascade cycle structure can achieve high - optical gain. By growing two different strain superlattices, the growth rate and composition of superlattices are calculated, and finally the growth of epilayer without mis-matches is realized. AFM analysis sample has good surface morphology.
Error modeling of the runway-type magnetohydrodynamic linear vibration sensor based on the SSA-BP neural networkXu, Mengjie; Mo, Jiahui; Xia, Chenyan; Yang, Tao
doi: 10.1117/12.3032507pmid: N/A
The magnetohydrodynamic (MHD) linear vibration sensor is a new type of vibration measurement sensor, which has the characteristics of fast response and strong anti-interference. In order to improve the measurement accuracy of the MHD linear vibration sensor, the error of the sensor is studied in this paper. Since the singular spectrum analysis algorithm can eliminate the coupling effect of the data and improve the robustness of the error model, this paper combines the singular spectrum analysis algorithm (SSA) with the BP neural network, and use the SSA-BP neural network to establish the error model of the MHD linear vibration sensor. The experimental results show that the average absolute error of the output signal of the MHD linear vibration sensor compensated by the SSA-BP neural network error model was reduced by 1 time, the signal-to-noise ratio was increased by 7 times, and the correlation coefficient was greater than 0.9.
Experimental measurement method of full tension of silk thread during winding processLi, Kun; Liu, Yi; Song, Han; Wang, Boyi; Huang, Anyi
doi: 10.1117/12.3032683pmid: N/A
The tension of fiber winding is one of the important factors in the performance of fiber. It is particularly necessary to measure the tension during the fiber winding process and to monitor the fiber tension after winding. This article adopts the method of optical fiber winding and uses OFDR (Optical Frequency Domain Reflectometry) demodulation technology to simulate fiber winding, and briefly introduces the principle of OFDR technology. Through experiments, the strain distribution of the full range of the fiber is measured. The measurement results are basically consistent with the calculation results.
Research on the expansion method of metal wear sample library based on improved CycleGAN networkXin, Shi; Gao, Ruipeng
doi: 10.1117/12.3032748pmid: N/A
Metal wear detection is an essential aspect of metal materials research. However, obtaining wear data for certain metals can be challenging, impacting detection accuracy. This paper proposes expanding the metal wear sample library using an improved CycleGAN. This method optimizes the composite model by replacing the L2 paradigm of the cycle loss function with the LPIPS function. This enables the generated images to have the fundamental outlines of metal wear samples and additional detail variability while enhancing the training network's resolution and stability. Experimental results demonstrate that the CycleGAN network with the improved loss function significantly improves the quality of the generated images from the metal wear dataset compared to the primary CycleGAN network. Specifically, the SSIM and PSNR values enhanced by 6.38% and 9.34%, respectively.
Three-dimensional reconstruction system aided by image calibration using color ICP based on graph optimizationXu, Baoxin; Tao, Wei
doi: 10.1117/12.3032448pmid: N/A
The 3D reconstruction with multiple RGBD sensors is favored for its excellent real-time performance and high accuracy, where the performance largely depends on the precision of calibration among RGBD sensors. This paper proposes a graph-optimization-based calibration method for multiple RGBD sensors. Initially, a coarse calibration is assisted by the Zhang's calibration method; based on this, a fine calibration is further conducted through ColorICP to correct the extrinsic parameter estimation between each pair of sensors. Concurrently, this method computes the information matrix of the extrinsic parameter estimation. Utilizing both the extrinsic parameter estimation and the information matrix, a pose graph is constructed for global optimization estimation. The efficacy of this scheme in enhancing the accuracy and robustness of multi-RGBD calibration is demonstrated through applications in a gazebo simulation environment and a physical 3D reconstruction system built with four Intel Realsense L515 cameras, showcasing the potential applications of multi-RGBD sensor 3D reconstruction technology.
A detection method for ship based on the improved YOLOv7-tinyCao, Hong; Wu, Jigang
doi: 10.1117/12.3032490pmid: N/A
Aiming at the problems of poor real-time performance, high leakage rate and false detection rate of existing ship detection methods in complex environment, we propose a ship detection method based on improved YOLOv7-tiny algorithm. The clustering algorithm is used to solve the problem that the preset anchor frame is not applicable to the extreme target size detection of ships; the GSConv lightweight convolution module is introduced to enrich the feature information; and the Efficient multi-scale attention (EMA) mechanism is integrated into the backbone feature extraction network to improve the model's ability to perceive the target with large multi-scale differences in the location information. location information. The recognition accuracy of this paper's model in SeaShips dataset is 97.2%, which is 2.9% higher than that before the improvement, and the model size is reduced by 16.3%. This paper's method carries out comparative validation experiments with Faster R-CNN, YOLOv5, YOLOv7, etc., and this paper's method improves by 7.1%, 3.6%, and 1.0% compared to them, respectively, and the experimental results show that this paper's The experimental results show that the algorithm has the advantages of high accuracy and robustness, which provides a theoretical basis for intelligent and efficient ship detection.
Application of robot 3D laser line scanning measurement path planning method based on suboptimal viewpoint in free-form surface parts measurementChen, Chen; Jia, Huakun; Lin, Bo; Zhang, Jiyan; Wang, Xiangyang; Yu, Liandong
doi: 10.1117/12.3032492pmid: N/A
The scanning measurement path planning of free-form surface parts is an important factor in ensuring the accuracy and efficiency of scanning measurement. This paper proposes a robot scanning measurement path method based on the suboptimal viewpoint method for high-precision and high-efficiency measurement of free-form surface parts. Firstly, scanning points are generated based on the CAD model of free-form surface parts. Then, based on the measurement angle and distance of the 3D laser scanner, the candidate pose of the 3D laser scanner is generated for the sampling points, and the optimal pose of the 3D laser scanner is generated based on the suboptimal viewpoint. Finally, the optimal scanning measurement path for the robot is generated. The computer simulation and experimental results show that this method can effectively improve the measurement efficiency while ensuring the measurement accuracy.