An optical sensor for hydrogen sulfide detection in open path using WMS-2f/1f technique

An optical hydrogen sulfide (H2S) sensor based on wavelength modulation spectroscopy with the second harmonic (2f) corrected by the first harmonic (1f) signal (WMS-2f/1f) is developed using a distributed feedback (DFB) laser emitting at 1.578 µm and a homemade gas cell with 1-m-long optical path length. The novel sensor is constructed by an electrical cabinet and an optical reflecting and receiving end. The DFB laser is employed for targeting a strong H2S line at 6 336.62 cm-1 in the fundamental absorption band of H2S. The sensor performance, including the minimum detection limit and the stability, can be improved by reducing the laser intensity drift and common mode noise by means of the WMS-2f/1f technique. The experimental results indicate that the linearity and response time of the sensor are 0.999 26 and 6 s (in concentration range of 15.2—45.6 mg/m3), respectively. The maximum relative deviation for continuous detection (60 min) of 30.4 mg/m3 H2S is 0.48% and the minimum detection limit obtained by Allan variance is 79 μg/m3 with optimal integration time of 32 s. The optical H2S sensor can be applied to environmental monitoring and industrial production, and it has significance for real-time online detection in many fields.     

消除水分对化学发光测量氮氧化物干扰的方法

采用了抽真空法和卡尔曼滤波器数据处理,设计一种减少水分对化学发光法测量氮氧化物干扰的方法.该方法利用了真空度越高、水分沸点越低的原理,水分进入分析仪反应室会出现“闪蒸”现象,从而减少了水分对测量过程的干扰,同时采用了卡尔曼滤波器进行数据处理,使得该方法能获得较高的测量精度,对于测量工业中产生气体的方法研究,具有一定的借鉴价值.     

基于离散度和EBFNN的指纹分类方法

针对指纹图像中的较大平移和旋转,提出了一种基于离散度和EBFNN的指纹分类方法.首先,对指纹图像进行离散小波变换获得特征空间.然后,对特征空间进行搜索得到不同维数下的优化特征组合,通过研究这些优化特征组合的散度值随维数的变化趋势,最终确定特征向量的构成.最后,以此特征向量训练EBFNN,完成指纹纹型分类,并在FVC2000和FVC2002-DB1上作了测试.实验结果表明,当隐层节点为11时 ,总的纹型辨识正确率可达91.45%,而且对指纹图像中的平移和旋转具有良好的鲁棒性,具有一定的实用价值.     

BL-30K雷达液位仪常见故障及排除方法

本文详细介绍了BL-30K雷达液位仪常见故障及详细的处理方法,对用户正确使用雷达液位仪具有一定的指导意义,本文具有一定的参考价值.     

基于三维光学信息的人体姿态快速测量

汽车中人体姿态三维测量对汽车座椅设计的舒适性评价具有重要的意义。为了快速准确地获取车内人体三维数据,文中采用一种基于双目视觉的立体三维数据获取方法,该方法将结构光与标记点相结合,实现了人体三维点云快速重建以及三维姿态(距离、角度)自动快速测量。实验结果表明,该方法在距离2 m以上,测量范围1.5 m×2 m时,人体姿态测量精度可以达到0.03 mm,满足了汽车人体姿态高精度三维数据采集的需求。与传统的汽车人体姿态三维测量方法相比,文中所使用的三维自动测量方法不仅自动化程度高,而且具有测量精度高、速度快、鲁棒性强的优点。     

基于计算机视觉的车架号采集系统

在车架号管理系统中,车架号的获取目前还主要通过人工拓印来完成。这种方法提取速度慢、人员操作不方便、消耗大量人力,在车辆众多的情况下,花费时间太长,严重影响办公效率。针对这种情况,介绍了一种新的车架号采集方法,该方法利用计算机图像识别技术和机器视觉检测技术从图片中定位并恢复出原始车架号信息,与拓印方法相比,不仅可节省时间,提高办公效率,而且易于实现车架号的数字化和网络化管理。经天津车管所的样机试验和使用,效果良好。     

基于伺服控制的自动快速图像拼接算法

针对目前图像拼接中计算量大、精度低两大难题,本算法应用高精度伺服控制平台、边缘信息阈值分割和模板匹配图像处理方法,实现了PCB图像的快速拼接。由于高精度伺服控制平台的引入,使得图像重合区域的参数获取变得容易。实验表明：应用伺服控制平台以后,提高了算法的实时性,达到较高的精度。     

Quantitative analysis of multicomponent mud logging gas based on infrared spectra

This work deals with quantitative analysis of multicomponent mud logging gas based on infrared spectra. An accurate analysis method is proposed by combining a genetic algorithm (GA) and a radial basis function neural network (RBFNN). The GA is used to screen the infrared spectrum of the mixed gas, while the selected spectral region is used as the input of the RBFNN to establish a calibration model to quantitatively analyze the components of logging gas. The analysis results demonstrate that the proposed GA-RBFNN performs better than FS-RBFNN and ES-RBFNN, and our proposed method is feasible.     

单幅图像形貌恢复在三维数字加工中的应用

仅仅根据一幅照片,就可得到照片内物体每个像素点的三维形貌数据.并可将这些三维数据应用到三维数字加工中,拓宽了数字加工的范围.     

Fast 3D reconstruction of dental cast model based on structured light

To quickly obtain accurate 3D data of dental cast model, this paper proposes a 3D reconstruction method for dental cast model based on structured light. This method combines the structured light with the motor turntable to obtain a group of 3D data for the dental cast model from multiple angles, and automatically registers the dental 3D data from multiple angles through the ball calibration of turntable. Compared with the real data of the dental cast model, the maximum error of the 3D reconstruction results in this paper is 0.115 mm. The reconstruction time of this process is about 130 s. The experimental results show that the method has high precision and high scanning speed for the 3D reconstruction of the dental cast model.