液晶数显仪表的缺字自动识别

数显仪表的自动识别技术对提高其使用效率,拓展使用环境等方面具有重要意义。本文针对液晶数显仪表在图像采集过程中的笔画缺失(缺字),提出了一种数字自动识别算法。引入二维熵阈值对待识别的图像进行二值化分割,减小照度过低或照明不均匀的影响,同时采用多次分割、编码匹配的方式对缺字数字进行识别。经过多种仪表的识别实验,结果表明该方法满足仪表数字识别的速度和准确率要求,且对图像倾斜、缩放等均有较好的适应性。     

基于特征检测的数字仪表数码快速识别算法

为对数显类仪表的显示数据进行自动识别与监测,提高该类仪表的自动化水平,需要研究仪表数码快速识别算法。该文提出一种基于特征提取的数字仪表数码快速直接识别算法。将图像进行预处理后,对数显屏幕进行定位。通过列切实现单个数码字符切割,对单个数码字符进行七段特征检测和五线相交检测,实现对正体数码和斜体数码的快速直接识别。实验表明,算法基本可以满足各种仪表数码的识别需求,识别速度快、准度高。     

基于机器视觉的仪表示值识别算法研究

针对常见的7段LED数码管显示仪表,提出了基于机器视觉技术的仪表示值识别方法。该方法通过计算机控制摄像头实时采集仪表示值图像,对图像进行分析区域选取、二值化等预处理操作之后采用投影变换的方法对数字图像进行分割、编码,进而实现了对该类仪表示值的自动读取。实验结果表明,该算法具有较理想的鲁棒性,能够满足长时间、大数据量的数据读取记录操作需求。     

基于Internet的数字仪表测试系统

本文提出了一个基于Internet的数字仪表测试系统。文章从总体上阐述了基于Web Services技术的系统架构,采用UML建模技术对系统各主要部件间的消息交互过程进行了分析,并介绍了系统中应用的数字仪表识别技术,最后以应用实例介绍了此系统。     

基于ELSD的指针式仪表自动识别算法研究

为实现指针式仪表自动识别,本文提出一种基于直线椭圆检测器(ELSD)的指针仪表自动识别策略。整个策略包括刻度线粗识别、仪表圆弧边界拟合、刻度线重识别和排序、仪表指针识别以及仪表示数计算等5个模块。首先,使用本文设计的自动迭代算法将检测到的线段匹配成对,并结合K-means聚类算法得到粗识别的刻度线;接着,根据粗识别出的刻度线与检测出的仪表圆弧位置关系确定仪表圆弧边界;然后,根据仪表刻度线与圆弧边界相交重新确定刻度线并进行插值补全、排序,构建出整个仪表刻度线坐标系;最后,根据仪表指针自身结构特征得到指针在坐标系中的位置并计算出仪表示数。通过实验结果可知,本文提出的算法可减少对模板图像和人工标定的依赖,在保证准确率的情况下能简化并加快整个仪表自动识别过程。     

船用指针式仪表自动识别方法研究

指针式仪表的自动识别为船舶设备的实时监控和信息化管理提供了有效的技术手段。本文通过计算机视觉技术对指针式表盘自动判读方法进行了研究。实现了对多种指针式仪表的同时识别,识别过程分为表盘分割、刻度识别、指针识别和仪表类型识别等几个部分,运用中心投影法和图集分类比较法等确定了仪表刻度、指针位置和仪表类别,实现了船用指针式仪表示值的自动识别,并通过试验和误差分析验证了识别方法的有效性。     

工业用数字显示仪表的允许误差计算方法解析

数字显示仪表的校验是一项很常规的工作，但长期以来，工业用数字显示仪表的允许误差计算方法缺少统一规定，使用者方法各异。据此，本文从实际应用出发，思索探讨出操作性强又比较实用的允许误差计算公式。     

基于加权硬度特征的仪表数字识别

仪表数字识别是智能仪表应用的关键,针对现有方法对角度倾斜、半字识别效率低的问题,引入硬度特征参数来衡量数字图像目标区域在某方向上的抵抗变形的能力,提出了一种结合数字结构特征和统计特征的识别方法。通过对仪表盘上采集的数字进行分析,建立数字自上而下及自下而上的硬度特征库。并依据每个特征重要程度的不同,引入权重,采用加权特征匹配的方法进行数字识别。实验表明,算法不仅简单高效,对于整字和半字都能够取得很好的分割和识别效果,而且对旋转和畸变有较强的容错。     

基于C8051的射频导纳长线料位仪的研制

本文介绍一种基于射频导纳技术长杆探极为测量探测器的仪表,并对仪表测量原理、工艺结构、软硬件设计进行分析。该仪表具有数字显示,限位报警的特点,并在现场得到应用,取得预期效果。     

数字电压表性能浅析

随着电子技术的发展,数字式电测仪表将逐步代替长期使用的指针式仪表,数字电压表又是构成其他型式数字电测仪表的主体。数字电压表是采用数字化的测量技术,将被测物理量由模拟量转换为数字量,再经过数显单元直接加以显示的仪表。数字式电压表有着广泛的应用,已经逐渐成为了当前便携式数字测量仪表中最主要的测量仪表之一。     

数字电能表的校验方法研究

为解决因数字电能表工作原理和接口方式都发生的根本性改变而导致的传统检定设备和技术已不能满足其检定要求这一难题,根据数字电能表的特点提出一种数字电能表的误差校验方法。通过分析,该方法不仅能向下校验低等级的数字电能表,也能向上通过更高等级模拟电能表溯源到国家基准,解决了量值传递问题。     

A Novel System for Recognizing Recording Devices from Recorded Speech Signals

The field of digital audio forensics aims to detect threats and fraud in audio signals. Contemporary audio forensic techniques use digital signal processing to detect the authenticity of recorded speech, recognize speakers, and recognize recording devices. User-generated audio recordings from mobile phones are very helpful in a number of forensic applications. This article proposed a novel method for recognizing recording devices based on recorded audio signals. First, a database of the features of various recording devices was constructed using 32 recording devices (20 mobile phones of different brands and 12 kinds of recording pens) in various environments. Second, the audio features of each recording device, such as the Mel-frequency cepstral coefficients (MFCC), were extracted from the audio signals and used as model inputs. Finally, support vector machines (SVM) with fractional Gaussian kernel were used to recognize the recording devices from their audio features. Experiments demonstrated that the proposed method had a 93.4% accuracy in recognizing recording devices.     

可实现听觉场景匹配的智能数字助听器算法

听觉场景匹配是当前智能数字助听器研究的热点问题,目前匹配精度大都较为理想,然而过高的计算量还是影响了硬件处理实时性的实现。此外,各类研究中所涉及的听觉场景类型和数量与人们实际接触较多的听觉场景也有差别。为此,首先对日常听觉场景类型进行分析统计,在此基础上提出了一种简单高效的智能数字助听器听觉场景匹配方法,以临界带能量比例为特征,以最小距离为分类算法,计算量较小、精度高,更适合数字助听器对计算量的苛刻要求。最后,通过主观测听,证明该方法与人耳的识别效果类似。     

远程测量系统中被测零件的重建

坐标测量机（CMM）与测量者分离进行远程测量时，掌握被测零件的位置与形状信息具有重要意义。提出一种对被测零件进行三维重建和定位的方法，根据双目视觉原理，利用从测量现场获取被测零件的图像及机械零件的规则性较强采用体积表示方法进行被测零件的三维重建，详细阐述了准确识别组成被测零件基本几何体的方法，展示了应用该系统三维重建和定位示例。     

Parametric identification of unsteady heat fluxes using thin-disc heat meters

A unified procedure for measuring unsteady heat fluxes based on one-dimensional receivers is proposed. A digital Kalman filter algorithm is used to obtain optimum estimates. The results of investigations of heat meters, the operating principle of which is based on the thin-disc method, are presented. __________ Translated from Izmeritel’naya Tekhnika, No. 7, pp. 46–49, July, 2006.     

Reference phase shifter for testing electronic phase meters type ÉF-1 (F2-1)

Conclusions It will be seen from analyzing (2') that the above methods of testing electronic phase meters can also be applied for testing digital phase meters (from 0 to 180°) by using more precise and higher-quality capacitance standards (for instance, capacitance boxes ME-1, ME-3 [5] KVM-4S [6], etc.), and a nonreactive resistance box type R-58, whose range extends to 5000 Hz, or a box consisting of nonreactive resistors UNU [7]. In the latter case the actual values of the resistors should be used, thus extending the frequency error testing range up to radio frequencies (without taking into consideration the shunting effect of the tested phase meter's input circuit).The reference phase shifter can be fed from Soviet-made oscillators (for instance, GZ-33, GZ-4A, etc.) by checking their frequency against a crystal oscillator type KG-A by means of an oscilloscope (for instance, ÉO-7 etc.) or a digital frequency meter (for instance, Ch3-3A, Ch3-4A, etc.).The testing will then be correct, provided that the input impedance of the tested digital phase meters retains a value of not less than Z_in=5 M.The value of Z_in drops with frequency, and this limits the phase meter's testing range.The electronic phase meters type ÉF-1 (F2-1) tested by this method at the plants which use them have all without exception subsequently passed their state testing at the VNIIM.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 74–76, April, 1970.     

Digital multitariff remote-sensing power supply meters

A new approach is presented to designing and using digital multitariff remote-sensing energy meters. Translated from Izmeritel’naya Tekhnika, No. 7, pp. 44–46, July, 1999.     

智能数显测微仪与质量控制系统

本文开发了一个微机数据采集与质量控制系统,可以将数显测微仪测量的数据直接送入计算机。根据PC总线计算系统硬件,对数据采集与质量控制系统的硬件进行了总体设计。主要内容包括:接口电路板的硬件设计,I/O口地址的译码方法及数据转换原理。质量控制与数据采集系统可以实现生产过程的在线测量和自动监控。     

Advanced Instrument For Field Calibration of Electrical Energy Meters

Calibration of electrical energy meters is coming up as a metrological concern. The latest European Union (EU) directives about measuring instruments adopted for commercial transactions state that their accuracy has to be verified in actual operating conditions. This requirement is leaving all laboratories involved in energy meter calibration in serious difficulty because this kind of metrological verification is, at the moment, still not fully developed or even clarified in all involved aspects. In this paper, a measurement equipment for the calibration of energy meters is presented. Its structure and metrological characterization are discussed. To improve its performances without increasing its costs, two online digital compensation procedures have been realized and are shown: one increases the spectral purity of test signals and one corrects the transducer frequency response. Experimental results relating metrological characterization have shown that the so-realized calibrator is suitable for the onsite calibration of energy meters.