基于DM642的香烟小包装外观检测系统

本文设计与实现了一种基于TMS320DM642的香烟小包装外观质量检测系统,详细阐述了该系统的硬件构成、软件流程、检测算法以及针对DSP处理器进行的系统优化。系统以TMS320DM642处理器为核心建立硬件平台,通过摄像头获取香烟小包装图像,采用改进的模板匹配算法对当前图像进行质量检测,最终在监视器上显示检测结果并将检测结果送执行单元进行处理。实验结果表明基于TMS320DM642的香烟小包装检测系统,检测效果快速、准确、有效,应用前景广泛。

复杂离散制造过程建模与性能评价方法研究

离散制造系统是制造业中最为复杂的制造系统之一，其生产特点表现在：生产方式的异步、并行；生产柔性强；调度复杂性高等方面。要实现对复杂离散制造系统的控制，首先必须对其建模。随着制造系统自动化程度提高，规模的增大，组成因素的复杂化，性能评价问题变得日益复杂并越来越受到人们的重视。提供直观的模型描述方法、有效的数学理论工具和模型分析方法及分析软件，是制造系统性能评价迫切需要解决的问题。为此本文进行了以下工作： 首先，提出了一种支持性能评价的制造过程模型框架。该框架体现了车间生产闭环控制机制，全面描述了车间制造过程相关组成要素之间的关系，可用于指导制造过程的建模和基于性能评价的优化控制。模型框架核心部分是生产过程模型、过程控制模型和过程性能模型，这三部分构成了制造过程模型。该过程模型在工厂模型的支持下，由事件模型驱动，受策略模型约束，通过一些过程准则和方法进行测量和监视，对性能相关数据进行统计、分析和评估，反映在性能指标上。 第二，确定了离散车间性能评价指标体系。该指标体系建立了不同性能指标与不同层次、不同类型的制造过程以及不同性能评价主体之间的关联，为选择评价方法奠定了基础。该指标体系按照车间目标将性能指标分为三大类，即时间、质量、成本；每一类细化为三个层次，分别是基本性能指标、扩展性能指标和综合性能指标。 第三，基于随机Petri网建立了具有随机机器故障的制造过程性能模型。该模型包含两个基本的状态转换环，将正常状态和异常情况分别描述；基于故障的随机特征，设置了服从泊松分布的故障发生模块；根据不同的故障发现模式，衍生出若干状态转换环，清晰地将故障发生、发现分离；还考虑了中断作业的处理，使模型更接近实际系统动态行为特征。另外，本文设计了考虑成本信息的作业优先级调度规则，并基于随机高级Petri网（SHLPN）应用到混流装配线动态调度问题中；针对流水线上存在的一类共享资源—维修工人，建立了考虑系统状态的维修排序规则SHLPN模型。通过数学分析和仿真方法结合实现了对以上制造过程模型的性能评价，验证了模型的有效性。 第四，针对性能评价的需求和Petri网在制造过程成本分析方面存在的不足，提出了一种适合制造过程成本分析的价格时间Petri网，并给出了相应的状态空间化简方法。通过对装配生产线多目标工人指派问题的求解，验证了模型和方法的有效性。 最后，根据管理控制过程和生产过程的特点以及它们之间的关系，提出了基于进程代数与Petri网的分层生产控制方法。采用Petri网和进程代数相结合的方法将物流和信息流集成在一个模型中，Petri网描述基于状态的与生产过程有关的过程流，进程代数描述计划、调度等与控制有关的推理过程，构成了两层分布式的车间生产控制结构。 综上可见，本文提出的制造过程建模、性能评价和控制方法，可以支持复杂离散制造系统的分析和综合；基于过程模型实现了复杂离散制造系统的生产过程模拟和性能分析；能够发现影响系统性能的瓶颈环节；为制造过程的改进和制造系统性能的提高提供了依据；进而实现了制造系统自主闭环自适应的优化控制。本文的研究工作具有重要的理论意义和实际应用价值。

Characterization of a Laser-Discrete Quenched Steel Substrate/Chromium System by Dissolving Coatings

A laser-discrete quenched steel (LDQS) substrate/as-deposited chromium (top high-contraction (HC) and underlying low-contraction (LC) chromium) system was investigated by dissolving coatings in order to reveal the mechanism that the service life of the coated parts is largely improved using the hybrid technique of laser pre-quenching plus chromium post-depositing. It was found that the surface characteristics of the substrate, LC and HC chromium layer can be simultaneously revealed owing to the dissolution edge effect of chromium coatings. Moreover, the periodical gradient morphologies of the LDQS substrate are clearly shown: the surfaces of laser transformation-hardened regions are rather smooth; a lot of fine micro-holes exist in the transition zones; there are many micro-dimples in the original substrate. Furthermore, the novel method of dissolving coatings with sharp interfaces may be used to reveal the structural features of a substrate/coating system, explore the effect of the substrate on the initial microstructure and morphologies of coatings, and check the quality of the coated-parts.

A time domain computation method for dynamic behavior of mooring system

A quasi-steady time domain method is developed for the prediction of dynamic behavior of a mooring system under the environmental disturbances, such as regular or irregular waves, winds and currents. The mooring forces are obtained in a static sense at each instant. The dynamic feature of the mooring cables can be obtained by incorporating the extended 3-D lumped-mass method with the known ship motion history. Some nonlinear effects, such as the influence of the instantaneous change of the wetted hull surface on the hydrostatic restoring forces and Froude-Krylov forces, are included. The computational results show a satisfactory agreement with the experimental ones.

Time domain synthesis of electro-optical birefringent system for optical waveform generation

In this paper is described a novel technique for producing an electro-optical intensity synthesizer which can generate different periodic time domain waveforms through only sine or cosine wave applied-voltages. The synthesizer presented here consists of a series of stages between two polarizers, with each stage consisting of an electro-optic element and a compensator. Every electro-optical element has the same applied-voltage function but different azimuth angles and ratios between the longitudinal and transverse lengths. The main principle is the synthesis of an electro-optic effect and a polarization interference effect in the time domain. This technique is based on an expanded Fourier positive-direction searching algorithm, which can not only simplify the calculation process but also produces many choices of structural parameters for different waveforms generation. A three-stage synthesis of an electro-optical birefringent system for continuous square waveform is undertaken to prove the principle.

Detection of Brillouin scattering temperature signal in Brillouin optical time-domain reflectometer sensing system based on instantaneous frequency measurement technology

We present a simple and practical method for the single-ended distributed fiber temperature measurements using microwave (11-GHz) coherent detection and the instantaneous frequency measurement (IFM) technique to detect spontaneous Brillouin backscattered signal in which a specially designed rf bandpass filter at 11 GHz is used as a frequency discriminator to transform frequency shift to intensity fluctuation. A Brillouin temperature signal can be obtained at 11 GHz over a sensing length of 10 km. The power sensitivity dependence on temperature induced by frequency shift is measured as 2.66%/K. (c) 2007 Society of Photo-Optical Instrumentation Engineers.

Detection of Brillouin scattering temperature signal in Brillouin optical time-domain reflectometer sensing system based on instantaneous frequency measurement technology

abstract {We present a simple and practical method for the single-ended distributed fiber temperature measurements using microwave (11-GHz) coherent detection and the instantaneous frequency measurement (IFM) technique to detect spontaneous Brillouin backscattered signal in which a specially designed rf bandpass filter at 11 GHz is used as a frequency discriminator to transform frequency shift to intensity fluctuation. A Brillouin temperature signal can be obtained at 11 GHz over a sensing length of 10 km. The power sensitivity dependence on temperature induced by frequency shift is measured as 2.66%/K. © 2007 Society of Photo-Optical Instrumentation Engineers.}

Spin dynamics in the second subband of a quasi-two-dimensional system studied in a single-barrier heterostructure by time-resolved Kerr rotation

Spin dynamics in the first and second subbands have been examined simultaneously by time resolved Kerr rotation in a single-barrier heterostructure of a 500 nm thick GaAs absorption layer. By scanning the wavelengths of the probe and pump beams towards the short wavelength in the zero magnetic field, the spin coherent time T-2(1)* in the 1st subband E-1 decreases in accordance with the D'yakonov-Perel' (DP) spin decoherence mechanism. Meanwhile, the spin coherence time T-2(2)* in the 2nd subband E-2 remains very low at wavelengths longer than 810 nm, and then is dramatically enhanced afterwards. At 803 nm, T-2(2)* (450 ps) becomes ten times longer than T-2(1)* (50 ps). A new feature has been discovered at the wavelength of 811nm under the bias of -0.3V (807nm under the bias of -0.6V) that the spin coherence times (T-2(1)* and T-2(2)*) and the effective g* factors (vertical bar g*(E-1)vertical bar and vertical bar g*(E-2)vertical bar) all display a sudden change, presumably due to the "resonant" spin exchange coupling between two spin opposite bands. Copyright (C) EPLA, 2008.

Pipeline Architecture and Parallel Computation-Based Real-Time Stereovision Tracking System for Surgical Navigation

This paper studies the development of a real-time stereovision system to track multiple infrared markers attached to a surgical instrument. Multiple stages of pipeline in field-programmable gate array (FPGA) are developed to recognize the targets in both left and right image planes and to give each target a unique label. The pipeline architecture includes a smoothing filter, an adaptive threshold module, a connected component labeling operation, and a centroid extraction process. A parallel distortion correction method is proposed and implemented in a dual-core DSP. A suitable kinematic model is established for the moving targets, and a novel set of parallel and interactive computation mechanisms is proposed to position and track the targets, which are carried out by a cross-computation method in a dual-core DSP. The proposed tracking system can track the 3-D coordinate, velocity, and acceleration of four infrared markers with a delay of 9.18 ms. Furthermore, it is capable of tracking a maximum of 110 infrared markers without frame dropping at a frame rate of 60 f/s. The accuracy of the proposed system can reach the scale of 0.37 mm RMS along the x- and y-directions and 0.45 mm RMS along the depth direction (the depth is from 0.8 to 0.45 m). The performance of the proposed system can meet the requirements of applications such as surgical navigation, which needs high real time and accuracy capability.

Pipeline Architecture and Parallel Computation-Based Real-Time Stereovision Tracking System for Surgical Navigation

This paper studies the development of a real-time stereovision system to track multiple infrared markers attached to a surgical instrument. Multiple stages of pipeline in field-programmable gate array (FPGA) are developed to recognize the targets in both left and right image planes and to give each target a unique label. The pipeline architecture includes a smoothing filter, an adaptive threshold module, a connected component labeling operation, and a centroid extraction process. A parallel distortion correction method is proposed and implemented in a dual-core DSP. A suitable kinematic model is established for the moving targets, and a novel set of parallel and interactive computation mechanisms is proposed to position and track the targets, which are carried out by a cross-computation method in a dual-core DSP. The proposed tracking system can track the 3-D coordinate, velocity, and acceleration of four infrared markers with a delay of 9.18 ms. Furthermore, it is capable of tracking a maximum of 110 infrared markers without frame dropping at a frame rate of 60 f/s. The accuracy of the proposed system can reach the scale of 0.37 mm RMS along the x- and y-directions and 0.45 mm RMS along the depth direction (the depth is from 0.8 to 0.45 m). The performance of the proposed system can meet the requirements of applications such as surgical navigation, which needs high real time and accuracy capability.

Real-time counting of single electron tunneling through a T-shaped double quantum dot system

Real-time detection of single electron tunneling through a T-shaped double quantum dot is simulated, based on a Monte Carlo scheme. The double dot is embedded in a dissipative environment and the presence of electrons on the double dot is detected with a nearby quantum point contact. We demonstrate directly the bunching behavior in electron transport, which leads eventually to a super-Poissonian noise. Particularly, in the context of full counting statistics, we investigate the essential difference between the dephasing mechanisms induced by the quantum point contact detection and the coupling to the external phonon bath. A number of intriguing noise features associated with various transport mechanisms are revealed.

Note: A time-resolved Kerr rotation system with a rotatable in-plane magnetic field

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Real-time far distance micro-vibration measurement using an external cavity semiconductor laser interferometer with a feedback control system

An external cavity semiconductor laser interferometer used to measure far distance micro-vibration in real time is proposed. In the interferometer, a single longitudinal mode and excellent coherent characteristic grating external cavity semiconductor laser is constructed and acted as a light source and a phase compensator. Its coherent length exceeds 200 meters. The angle between normal and incidence beam of the far object is allowed to change in definite range during the measurement with this interferometer, and this makes the far distance interference measurement easier and more convenient. Also, it is not required to keep the amplitudes of the first and second harmonic components equal, and then the dynamic range is increased. A feedback control system is used to compensate the phase disturbance between the two interference beams introduced by environmental vibration.

A discrete square global grid system based on the parallels plane projection

Knowledge Innovation Project of Chinese Academy of Sciences [KZCX3-SW-347]; National Science Fund for Distinguished Young Scholar [40225004]

A discrete square global grid system based on the parallels plane projection

We developed a direct partitioning method to construct a seamless discrete global grid system (DGGS) with any resolution based on a two-dimensional projected plane and the earth ellipsoid. This DGGS is composed of congruent square grids over the projected plane and irregular ellipsoidal quadrilaterals on the ellipsoidal surface. A new equal area projection named the parallels plane (PP) projection derived from the expansion of the central meridian and parallels has been employed to perform the transformation between the planar squares and the corresponding ellipsoidal grids. The horizontal sides of the grids are parts of the parallel circles and the vertical sides are complex ellipsoidal curves, which can be obtained by the inverse expression of the PP projection. The partition strategies, transformation equations, geometric characteristics and distortions for this DGGS have been discussed. Our analysis proves that the DGGS is area-preserving while length distortions only occur on the vertical sides off the central meridian. Angular and length distortions positively correlate to the increase in latitudes and the spanning of longitudes away from a chosen central meridian. This direct partition only generates a small number of broken grids that can be treated individually.