最新刊期
卷 32 ， 期 20 ， 2024
- “在计算机视觉领域，研究人员提出了一种新的偏振表面法线估计方法，通过引入新的偏振信息表示和稀疏自注意力机制，显著提高了估计精度和适用性。”摘要：Accurate estimation of surface normal plays a vital role in various computer vision tasks. Physically-based shape from polarization methods have limitations restricting their applications. Conversely， learning-based shape from polarization methods outperform physical methods in both accuracy and applicability. To further improve the accuracy of shape from polarization and make it applicable to a broader range of practical tasks， we proposed a novel method. First， we introduced a new polarization information representation combining Stokes vectors， enhancing the model's ability to extract polarization physical prior information. Then， we integrated a bi-level routing sparse self-attention mechanism to improve the model's perception of global contextual information， enabling better disambiguation of local polarization information. Testing on the DeepSfP dataset and out test data， experimental results demonstrate our proposed method achieves an average angular error of 13.37° on the DeepSfP dataset， outperforming existing methods in all tested metrics including accuracy and angular error. This indicates a significant improvement in normal estimation effectiveness with our proposed method. By introducing a novel polarization information representation and sparse self-attention mechanism， our approach enhances the accuracy and applicability of polar surface normal estimation， providing stronger support for practical task applications.关键词：polarization information representation;sparse self-attention mechanism;shape from polarization
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发布时间：2024-12-18 - “最新研究发现，激光诱导荧光辅助激光诱导击穿光谱技术能有效提高合金结构钢中钼元素定量分析的准确性。”摘要：The content of molybdenum （Mo） element in alloy structural steel has significant effects on its performance， making the detection of Mo content in alloy structural steel of great significance. However， the spectral interference and self-absorption effects of matrix element （Fe） in alloy structural steel severely affect the accuracy of laser-induced breakdown spectroscopy （LIBS） for quantitative analysis of Mo element. In this work， we employed laser-induced fluorescence-assisted laser-induced breakdown spectroscopy （LIBS-LIF） to address these issues. We selected three spectral lines， Mo I 379.83 nm， Mo I 386.41 nm， and Mo I 390.30 nm， as the analysis lines. The results showed that LIBS-LIF enhanced the spectral intensities of the three analysis lines， eliminating spectral interferences. As the Mo content increased from 0.019 wt. % to 1.4 wt. %， the spectral intensities of Mo element lines also significantly increased. Compared to the traditional LIBS technique， the self-absorption factor of the Mo I 386.41 nm line decreased by 99.99% in LIBS-LIF， the root mean square error of cross-validation decreased by 65.37%， the average relative deviation decreased by 85.69%， and the average relative standard deviation decreased by 20.20%. Therefore， LIBS-LIF can effectively reduce spectral interferences and self-absorption effects， improving the accuracy of quantitative analysis.关键词：laser-induced breakdown spectroscopy;laser-induced fluorescence;alloy structure steel;molybdenum element
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发布时间：2024-12-18 - “最新研究突破，采用太赫兹融合光谱和改进Fused Lasso模型，有效鉴别转基因与非转基因菜籽油，准确率超95%。”摘要：Existing classification and identification models for transgenic rapeseed oil based on single-spectrum analysis suffer from limited information and high data dimensionality， leading to low operational efficiency and inaccurate detection results. To address these issues， a novel classification method for transgenic rapeseed oil was proposed， leveraging terahertz fusion spectroscopy combined with an improved Fused Lasso model. Using two types of transgenic rapeseed oil and two types of non-transgenic rapeseed oil as research subjects， the terahertz time-domain spectroscopy （THz-TDS） system was employed to obtain the terahertz absorption spectra of the four rapeseed oil samples in the frequency range of 0.2 to 1.6 THz. Features were extracted from the absorption and derivative spectra using the successive projections algorithm （SPA）， and then fused. Introducing a regularization sparse model， Fused Lasso， which integrates feature selection and classification. This model was improved into a multi-class model using the one-vs-one （OVO） method， and Bayesian optimization （BO） was employed to optimize its regularization parameters. The results demonstrated that the BO-Fused Lasso model， based on fusion spectra， significantly outperformed the traditional Fused Lasso model based on a single absorption spectrum in classifying the four types of rapeseed oil. The accuracy rates for the training and testing sets were 96.88% and 95.00%， respectively. This study， therefore， presents a novel approach for accurately identifying transgenic and non-transgenic rapeseed oils and provides a valuable reference for the detection of other transgenic substances.关键词：terahertz;transgenic rapeseed oil;fusion spectrum;regularized sparse model;Bayesian optimization
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发布时间：2024-12-18
Modern Applied Optics
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Research on factors influencing the pointing accuracy of large telescopes and the correction model AI导读
“在望远镜领域，专家建立了指向精度修正模型，有效提高大型望远镜指向精度。”摘要：Pointing accuracy is an important index to measure the performance of a telescope system. With the increasing of the aperture， structure size and weight of the telescope， it is more and more difficult to maintain and improve the pointing accuracy. Therefore， it is necessary to make a theoretical analysis of the factors affecting the errors of large telescopes， establish a mathematical model， and correct the pointing errors. In this paper， based on the structural characteristics of large aperture telescope， various factors affecting the pointing accuracy of the telescope were analyzed， and a method of setting up a pointing model to correct the pointing accuracy of the telescope was proposed. The modified model proposed in this paper had clear physical meaning and little correlation of parameters. The model proposed in this paper was used to correct the pointing accuracy of a large telescope， and the root-mean-square error of the azimuth pointing accuracy was 20.6 " before correction and 4.1" after correction， and the root-mean-square error of the elevation pointing accuracy was 5.1 " before correction and 2.8" after correction. Experimental results show that by using the model proposed in this paper， It can effectively correct the systematic errors of the telescope and improve the pointing accuracy.关键词：large aperture telescope;pointing accuracy;star calibration;error correction- 8
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发布时间：2024-12-18 - “在精密测量领域，专家设计了一种新型绝对式平面二维时栅位移传感器，通过多频磁场耦合技术，实现了无需找零的一体式二维绝对位移测量与定位。”摘要：Aiming at the problem that incremental planar two-dimensional （2-D） time-grating displacement sensors need to be zeroed when they are powered up， an absolute planar 2-D time-grating displacement sensor based on multi-frequency magnetic field coupling was designed， which adopts time-driven excitation signals of different frequencies to reduce the power consumption of the sensor circuit and at the same time make the decoupling of signals in the X and Y directions and the 2-D absolute position solving simpler and more reliable. Firstly， a mathematical model of magnetic field distribution of the excitation coil was established， and the relationship between the width of the excitation coil and the height of the coupled air gap was analyzed according to the characteristics of the spatial magnetic field distribution； based on the incremental 2-D time-grating displacement sensor structure of the differential structure， an absolute planar 2-D time-grating measurement model of the opposite poles reciprocal structure was established， and a new scheme for the 2-D absolute position solution based on the look-up table method was proposed， which avoided the influence of the measurement error on the solution result in the practical application； the feasibility of this solution was verified by electromagnetic field simulation， and the optimal installation gap of the sensor was determined to be 0.8 mm； finally， the sensor prototype was fabricated， and the 2-D precision experimental platform was constructed for performance testing. The experimental results show that the sensor prototype in the effective measuring range of 147 mm ×147 mm， the original measurement errors in the X and Y directions are ±20.4 μm and ±21.1 μm， respectively， and it has the advantages of no need to find the zero point on power-on， which realizes the all-in-one 2-D absolute displacement measurement and positioning.关键词：multifrequency magnetic field;antipolar prime;absolute two-dimensional;time-grating displacement sensor
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发布时间：2024-12-18 - “在微装配领域，专家提出了一种端对端去模糊模型，有效恢复多重模糊的显微图像，判别准确率达0.94，PSNR指标平均提升了6.3。”摘要：The measurement of microscopic vision is commonly used in micro-assembly and other fields. However， due to limitations such as depth of field in microscopic imaging， the image may appear blurred and affect the accuracy of measurement. Although the technology of auto-focusing in optical microscopy can alleviate defocusing problems， it will be too time-consuming to adapt to the requirements of efficient production. Herein， an end-to-end deblurring model that integrates blurring discrimination and multi-branch recovery was presented， in which a divide-and-conquer strategy of chunking， discrimination， deblurring， and fusion was established. Firstly， the image was divided into sub-images， which were then simultaneously processed by a discriminator and a recovery network. The discriminator employed the Fourier transform to obtain the frequency-domain map of the sub-images. From the frequency domain map， the Vision Transformer network extracted deep blur features with global correlation. The output of the blurring degree was then discriminated. The multi-branch recovery network was used to directionally recover sub-images with different blurring degrees based on the discriminative output. Finally， the spliced sub-images were fused to obtain high-resolution images. The experimental results indicate that the model can effectively restore multi-blurred microscopic images， with a discriminator accuracy reaching 0.94. Moreover， after undergoing processing by the multi-branch restoration network， the PSNR metric shows an average improvement of 6.3.关键词：micro-assembly;microscopic vision;blur classification;frequency domain processing
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发布时间：2024-12-18 - “在MEMS速率陀螺仪领域，专家构建了包含相位误差的FTR速率控制回路模型，分析了相位误差对动静态性能的影响，为提升陀螺仪性能提供解决方案。”摘要：In order to clarify the influence of phase error on the static and dynamic performance of MEMS rate gyroscopes based on the force to rebalance （FTR） measurement mode， the model of FTR rate control loop with phase error was constructed to analyze the influence of different phase errors on the dynamic and static performance. Firstly， the basic principle of the gyroscope using FTR rate mode was introduced， and the effect of phase error on the driving modes was briefly analyzed. Secondly， the model of FTR rate control loop containing phase errors in the feedback and forward channels was proposed， and an equivalent transformation of the model was performed. Thirdly， the effects of different types of phase errors on the dynamic and static performance of the gyroscope were analyzed according to the above model. Finally， the corresponding experimental validation was conducted. Experimental results indicate that the stability of the two-hourly measured value of the phase error in the feedback channel is 0.094 9， and the error only changes the value of scale factor； the bias and bias drift values before and after the compensation of the phase error in the forward channel are reduced by 4.8 and 2.9 times， respectively， and the bias instability and angular random walking are improved by 0.8 and 0.9 times， respectively. The phase error in the feedback channel can be compensated by the calibration， and this error only affects the value of the scale factor， and does not affect the bias and bandwidth performance； the phase error in the forward channel seriously restricts the static performance， but does not affect the dynamic performance at room temperature.关键词：MEMS rate gyroscope;force-to-rebalance control;phase error;bias performance;scale factor;bandwidth
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发布时间：2024-12-18
Micro/Nano Technology and Fine Mechanics
- “在遥感图像配准领域，专家提出了基于变分近似解算KL散度的红外/可见光遥感图像配准方法，具有较强的鲁棒性和运算效率。”摘要：To solve the problem of poor robustness of distance-based metrics in multi-sensor remote sensing image registration methods， an image registration algorithm based on Kullback-Leibler divergence using variational approximation was proposed. First， edge features were extracted from the infrared image and visible image， respectively. Second， the infrared image features were orthorectified using imaging poses， and Gaussian Mixture Models （GMMs） were constructed for the feature point sets of the infrared and visible images， respectively. Third， the Kullback-Leibler divergence between the two GMMs was calculated using the variational approximation method， in which variational parameters were introduced and the Lagrange multiplier was utilized. Finally， the Particle Swarm Optimization （PSO） algorithm was applied to search for the optimal registration parameters. In the remote sensing image registration experiments， the proposed method’s average Root Mean Square Error of registration parameters is 2.5， and the average runtime is 1.5 seconds. Additionally， the proposed method still achieves correct registration when the variance of Gaussian noise and the salt-and-pepper noise coefficient is 0.07， respectively. These results validate the robustness and high computational efficiency of our method.关键词：variational approximation;kullback-leibler divergence;image registration;Remote sensing
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发布时间：2024-12-18 - “在光学遥感图像飞机目标检测领域，研究者基于YOLOv8n模型，提出了一种融合全局信息与双域注意力机制的检测算法，有效提升了检测精度和模型效率。”摘要：To address the problem of insufficient detection accuracy of aircraft targets in optical remote sensing images due to complex backgrounds， small targets， and similar appearances among aircraft， an aircraft target detection algorithm was proposed in this paper based on the YOLOv8n model that integrated the global information and the dual-domain attention mechanism in optical remote sensing images. Firstly， the SPPF_Global module was designed to provide a global feature overview through the global maximum pooling layer， which helped the model better distinguish objects from the background in complex environments. Secondly， a dual-domain attention mechanism was proposed to improve the attention to important areas such as wing shape and other distinctive structures through the information guidance of space domain and channel domain， and enhanced the ability to distinguish the nuances of different aircraft models. Finally， the parallel path downsampling method and the Powerful-IoU loss function was introduced， and the adaptive penalty factor was used to accelerate the convergence of the model， which improved the recognition ability of the model for small target aircraft and the regression efficiency of the prediction frame. The experimental results show that compared with the original YOLOv8n， the accuracy rate， recall rate， mAP50 and MAP50-95 of the proposed model on the open data set MAR20 are increased by 3.3%， 2.6%， 3.2% and 2.6% respectively. On the NWPU VHR-10 dataset， the parameters are increased by 5%， 5.1%， 2.5% and 0.3% respectively， while the number of parameters and the calculation amount are decreased by 6.6% and 3.7% respectively， which proves the efficiency and superiority of the proposed model， and effectively improves the application value of the aircraft target detection algorithm in optical remote sensing images.关键词：optical remote sensing image;aircraft target detection;YOLOv8;attention mechanism;Powerful-IoU
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发布时间：2024-12-18 - “在低光照图像目标检测领域，专家提出了一种新方法，有效提升了目标检测性能。”摘要：A low-light target detection method was proposed to overcome the problem of low overall brightness， contrast and limited edge features in low-light images， which lead to poor recognition and localization of target detection algorithms. Firstly， a low-light enhancement network was designed to utilize the advantages of image Gaussian pyramid， Retinex and dark-channel defogging in low-light image enhancement， and edge contour features were added to the dark-channel defogging algorithm to enhance the overall luminance contrast while highlighting the edge features of the target. Secondly， to improve the accuracy of feature extraction in the feature extraction section of RTDETR， a lightweight self correcting feature extraction network was designed to generate and correct the feature maps generated by the backbone feature extraction network with smaller computational complexity， thereby improving the accuracy of object detection. The experimental results on the ExDark dataset shows that compared with the benchmark RTDETR， the mAP improves by 2.34%， the recall improves by 2.09%， the parameter amount reduces by 4.95 M， the model size reduces by 13.31 MB， and the proposed method is able to effectively improve the performance of the target detection in the low-light scene.关键词：object detection;dark targets;low-light intensity enhancement;gaussian pyramid;self correcting network
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发布时间：2024-12-18 - “在弹载遥测电台低带宽传输领域，专家提出了一种压缩性能优异的图像压缩算法，为引信天线罩形变图像传输提供解决方案。”摘要：To realize the transmission of fuze radome deformation images under low bandwidth condition of the missile-borne telemetry radio， an image compression algorithm with high-quality compressed images， low algorithmic complexity and easy to implement in hardware was proposed. The 9/7M wavelet basis recommended by the Consultative Committee for Space Data Systems （CCSDS） was used to decompose the image at four levels， thereby reducing data redundancy. The traditional weight allocation strategy was improved according to the image characteristics to reduce the distortion information， ensuring the quality of the reconstructed image. A parallel pixel scanning approach was adopted， which significantly reduced the time associated with the multi-resolution tree-structured partitioning in Set Partitioning In Hierarchical Trees （SPIHT）. Furthermore， for the specific features of the images， an enhanced Run-Length Encoding （RLE） algorithm was introduced， the image data classification method was optimized， achieving increased overall compression ratios without compromising image quality. Experimental results show that in comparison with SPIHT and CCSDS standards， the proposed algorithm achieves 6.92%， 16.45% and 11.12%， 22.56% increases in Structural Similarity Index （SSIM） and Peak Signal-to-Noise Ratio （PSNR）， respectively， while the compression time increases by only 0.06 s compared with SPIHT， and the increase in algorithmic complexity is not much. Compared with the mainstream image compression algorithms， under the same compression multiplier， this algorithm compresses the fuze radome deformation images with similar compressed image quality as the JPEG2000 algorithm， but the compression time saving is up to 35.35%. In summary， the algorithm has the characteristics of low complexity， its compression performance can meet the compression requirements of the ballistic system， and the decompression image quality reaches the level of mainstream algorithms.关键词：image compression;fuze radome deformation images;Set Partitioning in Hierarchical Trees （SPIHT）;Run-Length Encoding （RLE）;low-bandwidth transmission
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发布时间：2024-12-18
Information Sciences
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