利用线列CCD像机交汇测量弹丸攻角

提出了一种新的测量弹丸攻角的方法。利用线列CCD像机交汇形成一光靶 ,测量弹丸通过光靶的瞬时位置 ,将获得的位置信息按时间序列进行排列后即可获得弹丸的攻角。首先分析了利用线列CCD像机交汇测量弹丸攻角的测量原理及可行性 ,在此基础上提出了实现这一目标的测量系统的组成与功能 ,然后对测量系统的攻角测量精度进行了分析和讨论。结果表明 ,在目前CCD狭缝像机还不具备实际应用条件的前提下 ,利用此方法可以解决狭缝像机不能实时测量的问题     

二维弥散介质温度场的快速重建

提出了一种利用电荷耦合器件摄像机获取的辐射信息进行二维弥散介质温度场快速重建的新模型. 与现有的温度场重建模型相比,该模型是以逆向Monte Carlo方法为基础,重建速度更快、效率更高,能更好地描述散射介质. 采用了一个精确的二维温度场作为重建对象,结果表明,即使在存在测量误差的情况下,利用此模型重建出的温度场仍能重现原有精确温度场的特征. 关键词： 温度场重建 逆向Monte Carlo 电荷耦合器件摄像机 反问题     

Application of CCD cameras in spectral analysis

Smolensk Pedagogical Institute, 4 Przhevalskii Str., Smolensk, 214000, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 6, pp. 166–169, November–December, 1995.     

CCD比色测温中工作波长与带宽的选择

介绍了CCD比色测温原理,分析了影响波长和带宽选择的因素,讨论了它们的选择过程,针对给定的被测温度范围,建立了比色波长及带宽选择的精确方法,对水泥篦冷机熟料温度场测量的实验表明,该方法选择的波长及带宽合理,满足温度场测量的要求。     

Full-field optical coherence tomography by two-dimensional heterodyne detection with a pair of CCD cameras

A two-dimensional heterodyne detection technique based on the frequency-synchronous detection method [Jpn. J. Appl. Phys. 39, 1194 (2000)] is demonstrated for full-field optical coherence tomography. This technique, which employs a pair of CCD cameras to detect the in-phase and quadrature components of the heterodyne signal simultaneously, offers the advantage of phase-drift suppression in interferometric measurement. Horizontal cross-sectional images are acquired at the rate of 100 frames/s in a single longitudinal scan, with a depth interval of 6 microm, making the rapid reconstruction of three-dimensional images possible.     

Noncontact all-optical measurement of corneal elasticity

We report on a noninvasive and noncontact all-optical method to measure the elasticity of the cornea. We use a pulsed laser to excite surface acoustic waves (SAW) that propagate on the corneal surface, then use a phase-sensitive optical coherence tomography system to remotely record the SAWs from which the corneal elasticity is estimated. In addition, the system is able to provide real-time tomographic images of the cornea being examined, an important consideration for clinical studies. While precisely maintaining a range of intraocular pressures (IOP), a series of measurements is performed on ex vivo intact primate eyes. The measurement results not only demonstrate the feasibility of the proposed system to remotely measure the corneal elasticity, but also suggest a strong correlation between the corneal stiffness and the true IOP.     

Noncontact measurement of the thermal diffusivity of IR semi-transparent and semiconducting n-CdMgSe mixed crystals by means of the photothermal radiometry

In this paper we present results of noncontact measurements of the thermal diffusivity of infrared semi-transparent n-CdMgSe mixed semiconductor crystals by means of the photothermal radiometry (PTR) in a transmission configuration. In order to overcome an influence of the infrared semi-transparency and plasma waves on the PTR signal from n-CdMgSe mixed crystals the samples were covered by thin aluminum foils on both sides. The thermal diffusivities of n-CdMgSe mixed crystals were estimated from PTR phase frequency characteristics using a well-known formula. It was found that the obtained results are underestimated in comparison to thermal diffusivities estimated from the PPE (photopyro-electric) measurements. A three layer model of a PTR signal was applied in order to estimate an error in determination of the thermal diffusivity of a sample caused by aluminum foils.     

三维燃烧介质和壁面温度的非接触联合重建研究

温度分布在线实时测量对于燃烧过程优化和污染物控制具有重要意义, 针对以往非接触三维温度分布重建过程的耗时性问题和忽略壁面辐射的不足, 本文提出了一种新的离散重建模型, 用于三维吸收、 发射和散射性高温燃烧介质以及壁面温度的快速联合非接触测量. 该模型以四个CCD(Charge Coupled Device) 为测量传感器, 通过构建辐射逆问题求解方程, 从CCD输出的辐射投影图像重建温度分布. 介质中不同投影方向内的辐射传递过程通过离散传递法来描述, 介质的散射和壁面反射则通过离散坐标法来近似. 离散后计算局部辐射强度的病态方程通过最小二乘余量法来求解, 论文对其计算速度进行了优化. 通过非对称温度分布测量算例分析了该模型的有效性, 讨论了测量噪音、 介质和壁面辐射特性对重建精度的影响, 并与其他方法对比分析了模型的重建速度. 计算结果表明本文提出的离散模型可以有效地用于大型高温燃烧介质和壁面温度分布的联合非接触测量. 即使在有噪声的情况下, 该模型也能获得准确的测量结果, 与其他计算方法相比, 采用改进的最小二乘余量法, 能有效地提高温度分布的重建计算速度.     

三线阵CCD相机安装支架分析及检测

为了满足三线阵CCD相机对刚度和稳定性的要求,提高相机测绘精度,本文在有限元优化分析的基础上完成了相机测绘基座的结构设计。对测绘基座的模态以及承受载荷情况下的自重变形以及自重变形引起的各相机光轴的变化量进行了分析。基于得到的测绘基座关键技术指标,研制了测绘基座专用的垂直度检测工具。对加工过程中测绘基座进行了跟踪检测,验证了该检测工具的可用性,确保测绘基座的几何精度。     

Efficient inverse radiation analysis of temperature distribution in participating medium based on backward Monte Carlo method

An efficient numerical inverse radiation analysis based on the backward Monte Carlo (BMC) method is presented to determine the three-dimensional (3-D) temperature distribution in a large rectangular enclosure containing the participating medium, using radiative intensities in the visible range received by charge-coupled device (CCD) cameras. For large radiative sources and small detectors, when the radiation onto a small spot and onto a small direction cone is desired, the BMC method is more efficient than the forward Monte Carlo (FMC) method. Because the temperature reconstruction from the measured radiative intensities is an ill-posed inverse problem, least-square QR decomposition (LSQR) method is introduced to determine the meaningful temperature distribution. In order to gain insight into the effects on the accuracy of temperature distribution reconstruction, the detailed analyses are made using numerical simulations. The results show that the temperature distribution can be reconstructed accurately for the exact and noisy data.     

Retrieval of spatial shot-noise in the full dynamic range of calibrated CCD cameras

The pixel by pixel calibration of a scientific CCD camera allows Poissonian statistics of the spatial fluctuations of an uniform enlightening to be retrieved in the full range of the camera dynamic. The procedure works efficiently for thermal as well as for laser sources, provided that the wavelength and the coherence properties of the source are chosen in order to avoid the formation of equal thickness fringes in the chip (etaloning effect). Calibration allows also the comparison at the shot noise level of images recorded at different places on the chip. Received 9 September 2002 / Received in final form 16 October 2002 Published online 21 January 2003     

Determination of the gas temperature in a plasmatron channel by means of a known electron temperature distribution

An analytic method is proposed that permits computation of the heavy particle temperature distribution in a plasmatron channel according to a known electron temperature distribution. The results obtained can be useful for a number of model computations in the determination of the most efficient conditions for propelling a gas through a plasmatron in order to heat the heavy component. This approach permits comprehension of the specifics of heating a cold gas penetrating the plasma and correctly estimating the gas temperature distribution within the channel.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 85–88, August, 1989.     

Ratcheting up energy by means of measurement

The destruction of quantum coherence can pump energy into a system. For our examples this is paradoxical because the destroyed correlations are ordinarily considered negligible. Mathematically the explanation is straightforward and physically one can identify the degrees of freedom supplying this energy. Nevertheless, the energy input can be calculated without specific reference to those degrees of freedom.     

CCD相机对14 MeV和2.5 MeV中子瞬态响应特性

从理论上分析了中子在CCD相机拍摄图像中引起的瞬态干扰噪声的机理,并针对两种不同类型的CCD相机,在能量为14 MeV和2.5 MeV的低强度稳态中子源上开展了实验研究,分析了噪声特征与入射中子能量、入射角度、注量及CCD相机结构的关系。实验结果表明中子瞬态干扰噪声主要表现为脉冲噪声,且出现斑点现象,与理论分析结果相吻合。研究得出了噪声特征随入射中子注量变化的规律,比较了不同能量及不同入射角条件下的噪声特性,并分析了两种不同结构的CCD相机响应特性的差别。     

CCD相机对14MeV和2.5MeV中子瞬态响应特性

从理论上分析了中子在CCD相机拍摄图像中引起的瞬态干扰噪声的机理,并针对两种不同类型的CCD相机,在能量为14MeV和2.5MeV的低强度稳态中子源上开展了实验研究,分析了噪声特征与入射中子能量、入射角度、注量及CCD相机结构的关系。实验结果表明中子瞬态干扰噪声主要表现为脉冲噪声,且出现斑点现象,与理论分析结果相吻合。研究得出了噪声特征随入射中子注量变化的规律,比较了不同能量及不同入射角条件下的噪声特性,并分析了两种不同结构的CCD相机响应特性的差别。     

Noncontact measurement of nerve displacement during action potential with a dual-beam low-coherence interferometer

We have used a novel phase-referenced heterodyne dual-beam low-coherence interferometer to perform what we believe are the first noncontact measurements of surface motion in a nerve bundle during the action potential. Nerve displacements of approximately 5-nm amplitude and approximately 10-ms duration are measured without signal averaging. This interferometer may find general application in measurement of small motion in cells and other weakly scattering samples.     

Colored conical emission by means of second harmonic generation in a quadratically nonlinear medium

Colored conical emission was observed experimentally in a thick beta-barium borate crystal as a result of spatiotemporal modulational instability. In the presence of both dispersion and diffraction, colored conical emission showed specific features that were characteristic of the nonlinear dynamics of the strongly coupled fundamental and harmonic fields. Experimental observation directly demonstrated that beam angular spectra were substantially modified as a result of exponential growth of perturbations by means of parametric wave mixing. Seeded amplification of colored conical emission was demonstrated to support ultrabroadband up-conversion.     

PLIF法定量测量甲烷-空气火焰二维温度场分布

利用平面激光诱导荧光(PLIF)技术,通过选择适合的OH自由基激励线,定量测量了甲烷-空气燃烧火焰的二维温度场分布。给出炉面中心上方火焰温度随离炉面高度的变化和距炉面12 mm高处沿炉面水平方向变化的实验测量结果并进行了讨论与分析。与利用相干反斯托克斯喇曼散射（CARS）技术进行测温的实验结果相比,该测量的相对不确定度优于5％。     

PLIF法定量测量甲烷-空气火焰二维温度场分布

利用平面激光诱导荧光(PLIF)技术,通过选择适合的OH自由基激励线,定量测量了甲烷-空气燃烧火焰的二维温度场分布。给出炉面中心上方火焰温度随离炉面高度的变化和距炉面12 mm高处沿炉面水平方向变化的实验测量结果并进行了讨论与分析。与利用相干反斯托克斯喇曼散射（CARS）技术进行测温的实验结果相比,该测量的相对不确定度优于5％。