电力系统管道漏磁检测异常数据高度采集仿真

所需采集的电力系统管道漏磁异常数据需要持续不断上传至检测系统上,数据量大。传统的等时间间隔数据采集方式没有考虑到所采样数据的变化,存在数据大量冗余、难以准确反映当前漏磁异常数据变化等缺点,提出基于稀疏采样的电力系统管道漏磁检测异常数据高效采集方法。采用双重判断方法,判断漏磁检测扰动信号的波动程度,剔除其对漏磁检测数据采集时间间隔调整的干扰。再依据数据采集间隔与数据变化量之间的比例关系,动态调整数据采集时间间隔变化尺度,以实现短暂、瞬时变化下漏磁检测异常数据的高效采集。实验结果表明,所提方法可在保证采集漏磁检测异常数据质量的同时减少采集量,且相比等时间间隔数据采集方法的拟合曲线失真度较小,可为管道漏磁检测与诊断等研究工作提供有效数据保障。

清晰表达沥青路面纹理构造特性的图像采集方法

采用工业相机和遮光暗箱,开发了沥青路面路表图像采集装置,提出基于矩形分区和OTSU相结合的路表图像纹理构造分割方法,并研究外界因素对路表纹理图像采集效果的影响。结果表明:路表图像采集装置可以规范采集高度和光照条件,避免外界因素干扰给原始图像带来的信息误差。改进的阈值分割算法可以有效地将纹理构造同沥青胶浆和集料颗粒分割开来。采集高度对沥青路面路表宏观构造宽度的计算具有显著影响。当光照条件达到一定强度后,可以忽略光照强度对路表图像宏观构造宽度的影响。基于路表图像进行沥青路面集料分布均匀性评价时,推荐图像采集的最佳高度为50~70 cm,LED光源功率设为5 W以上。

基于无人机图像以及不同机器学习和深度学习模型的小麦倒伏率检测

小麦在生长过程中发生倒伏会严重影响其产量,因此实时且准确地对小麦倒伏状况监测有很重要的意义。传统的方法采用手工方式生成数据集,不仅效率低、易出错,而且生成的数据集不准确。针对这一问题,本研究提出了一种基于图像处理的自动数据集生成方法。首先利用无人机在15、46和91 m三个高度采集图像数据;采集完数据后,根据无倒伏、倒伏面积<50%和倒伏面积>50%的标准对每一块地的小麦倒伏情况进行人工评估;采用三种机器学习(支持向量机、随机森林、K近邻)和三种深度学习(ResNet101、GoogLeNet、VGG16)算法对小麦倒伏检测情况进行分类。结果显示,ResNet101的分类结果优于随机森林,并且在91 m高度采集的数据分类精度并不低于在15 m高度采集的数据。本研究证明了针对在91 m高度采集的无人机图像,采用ResNet101对小麦倒伏率检测是一种有效的替代人工检测的方法,其检测精度达到了75%。

采集高度对香蜂花叶及全草中精油含量和质量的影响

香蜂花 Melissa officinalis L.cv.Citra具有镇静、解痉、抗菌和抗病毒作用,精油是其主要活性组分。作者研究了不同的采集高度对该植物叶和全株中精油含量和质量的影响。于开花前对培育3年且平均高度达到80 cm 的植株的采摘高度分别距地面15 cm(全株)、40 cm(该植物的上1/2～1/3)。

Thermal contact conductance estimation and experimental validation in hot stamping process

The variation in temperature of the blank would make major contribution to the mechanical properties of final component in hot stamping of ultra high strength steel(UHSS).It is important to use accurate thermal contact conductance(TCC) to carry out finite element simulation of hot stamping for reliable caculation results.In this paper,a flat compression test was performanced on a servo press.A fast response temperature measurement and data acquisition system was designed to obtain the temperature history of blank and die under different pressures.The thermal contact conductance between blank and die was got using an optimization algorithm.The error between the temperature curves using calculated thermal contact conductance and the curves of measurement temperature was analyzed.Result shows that reliable simulation results of temperature can be got through accurate thermal contact conductance.

Design and analysis for a high-accuracy CCD

In order to improve the test accuracy of CCD,a new type of CCD device is proposed.Several columns(rows) of photoelectric diodes(PDs) are combined together,and staggered with the distance of H1=H/N,where H is the space between two adjacent PDs,and N is the number of columns(rows).The photoelectric signals are collected simultaneously by multi-channel A/D,and the accurate measurement result is obtained through appropriate signal processing.Without changing the size or space of PDs,more photographic pixels are arranged in the given direction within a finite length.Diameters of three standard poles are measured by a single CCD and two staggered CCDs,respectively with length of 30 mm and diameters of 5 mm,8 mm and 12 mm,respectively.The results show that the accuracy of double staggered CCDs is two times of that of single CCD.The new type of CCDs can avoid the impact of PD space theoretically and higher measurement accuracy can be obtained.