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This paper presents a novel structured light approach for the 3D reconstruction of specular surface. The binary shifting strip is adopted as structured light pattern instead of conventional sinusoidal pattern. Based on the framework of conventional High Dynamic Range (HDR) imaging technique, an efficient means is first introduced to estimate the camera response function. And then, dynamic range of the generated radiance map is compressed in the gradient domain by introducing an attenuation function. Subject to the change of lighting conditions caused by projecting different structured light patterns, the structure light image with middle exposure level is selected as the reference image and used for the slight adjustment of the primary fused image. Finally, the regenerated structured light images with well exposing condition are used for 3D reconstruction of the specular surface. To evaluate performance of the method, some stainless stamping parts with strong reflectivity are used for the experiments. And the results showed that, different specular targets with various shapes can be precisely reconstructed by the proposed method. 相似文献
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基于圆结构光照明和LED照明相结合的三维检测技术 总被引:1,自引:0,他引:1
针对孔内表面的检测问题,提出了一种新的基于结构光照明和LED照明相结合的三维检测技术。该方法主要包括三个步骤:首先通过圆结构光照明获取孔内表面的截面轮廓图像,并通过图像处理和系统标定得到当前截面上局部区域的深度值;然后通过平面光照明得到孔内表面的平面图像,并在分析成像关系的前提下,在对平面图像进行坐标变换后得到孔内表面的展开图像,结合图像处理算法,提取展开图像的局部区域的平面尺寸信息;最后将圆结构光数据和LED光源数据变换到同一全局坐标系下,得到内表面的三维信息。 相似文献
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The magnitudes and azimuthal anisotropies of 4 keV Ne+ scattered ion fractions from the Si(1 0 0)-(2×1) two-domain surface have been measured by means of time-of-flight scattering and recoiling spectrometry. The absolute values of these ion fractions as well as their dependence on surface structure and electron density have been determined. By investigating the trajectories of the scattered Ne+, a clear correlation is demonstrated between these experimentally observed surviving ion fractions of Ne+ and the fraction of ions that scatters from the topmost layer of the surface. This is interpreted in terms of a model in which the neutralization probability of Ne+ is proportional to the local substrate electronic charge density. 相似文献
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The wavelet analysis method has been extensively employed to analyze the surface structures and evaluate the surface roughness. In this work, however, the wavelet analysis method was introduced to decompose and reconstruct the sampled surface profile signals in the cutting direction that achieved by SPDT (single point diamond turning) operation, and the surface profile signals in tool feeding direction were reconstructed with the approximate harmonic functions directly. And moreover, the orthogonal design method, i.e. the combination design of general rotary method, was resorted to model the variations of the independent frequency and amplitude of different simulated harmonic signals in the cutting and tool feeding directions. As expected resultantly, a novel 3D surface topography modeling solution was established, which aims to predict and modify the finished KDP (potassium dihydrogen phosphate or KH2PO4) crystal surfaces. The validation tests were carried out finally under different cutting conditions, and the collected average surface roughness in any case was compared with the corresponding value as predicted. The results indicated the experimental data were well consistent with the predictions, and only an average relative error of 11.4% occurred in predicting the average surface roughness. 相似文献
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为满足某地面实验中视觉测量系统的研制需求,研究了一种基于单幅图像的大尺寸实际平面上光点的定位方法。通过建立关于实际平面上光点3D坐标的数学模型,结合利用图像确定的通过光点的空间光束,实现了由单幅图像确定光点的3D坐标。依据具体特点,把实际平面分为高阶曲面型、分块平面型和分块曲面型3种类型,并分别给出了相应类型的光点定位方法。仿真实验验证了所提出方法的正确性,并比较分析了方法的精确性;实际试验数据表明,所提出方法可以满足尺寸为8000mm×8000mm的大型实际平面上光点的定位需求,定位误差小于1mm。 相似文献
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Si-Jie Yu Sreenivas R. Sukumar Andreas F. Koschan David L. Page Mongi A. Abidi 《Optics and Lasers in Engineering》2007,45(7):808-818
In this paper, we present our experience in building a mobile imaging system that incorporates multi-modality sensors for road surface mapping and inspection applications. Our proposed system leverages 3D laser-range sensors, video cameras, global positioning systems (GPS) and inertial measurement units (IMU) towards the generation of photo-realistic, geometrically accurate, geo-referenced 3D models of road surfaces. Based on our summary of the state-of-the-art systems for a road distress survey, we identify several challenges in the real-time deployment, integration and visualization of the multi-sensor data. Then, we present our data acquisition and processing algorithms as a novel two-stage automation procedure that can meet the accuracy requirements with real-time performance. We provide algorithms for 3D surface reconstruction to process the raw data and deliver detail preserving 3D models that possess accurate depth information for characterization and visualization of cracks as a significant improvement over contemporary commercial video-based vision systems. 相似文献
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A 3D HSQC-HSQMBC experiment is proposed for increasing the separation of proton–carbon long-range correlation cross peaks, the lack of which is occasionally seen in corresponding 2D experiments. It is aimed at complex molecules with many protonated carbons exhibiting a narrow spread of 13C chemical shifts e.g., complex carbohydrates. It does not yield long-range correlation of quaternary carbons. An extra indirectly detected 1H dimension of this experiment provides additional separation of long-range correlation cross peaks by utilising the chemical shifts of protons directly attached to 13C. Evolution of single-quantum coherences throughout the entire pulse sequence ensures that the cross peaks are inphase pure absorption singlets in both indirectly detected dimensions, thus maximising the resolution and sensitivity of the experiment. Partial signal cancellation can be expected due to the antiphase character of peaks in the directly detected dimension. The intensity of cross peaks depends on the length of a single long-range evolution interval and values of both active and passive long-range coupling constants of each carbon. The 3D HSQC-HSQMBC experiment provided high quality long-range correlation spectra of a 2 mg pentasaccharide sample in 27 h. The technique can also be used for measurement of long-range heteronuclear coupling constants from pure antiphase multiplets in the directly detected dimension. 相似文献
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All relevant low-energy transition amplitudes for the D(d,n)3He and D(d,p)3H reactions were determined from a fit to Legendre expansion coefficients of the available experimental data. A simple barrier penetrability model was used. Quintet S-wave transitions are found to contribute strongly thus obliterating the idea of neutron-lean “polarized” fusion energy production. The D+D interaction radius was determined with good accuracy for both reactions individually. The astrophysical S functions show a small S-wave enhancement and P-wave suppression of the D(d,p)3H branch. 相似文献
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针对提高室内三维空间的定位精度和速度的问题,从减少节点数量、建立特定坐标系的角度提出了一种基于四节点和特定坐标系的三维空间定位算法。该算法引入位置相对固定的四个节点,提高解算速度;充分考虑有效反射区对衰减指数影响,根据伯鲁斯特角将天线辐射场区分为叠加加强区和叠加减弱区,建立三维坐标系进行定位,结合信号强度指示(Received Signal Strength Indicator, RSSI)衰减模型,在叠加减弱区定位,把三维空间问题转化到二维空间,降低定位算法的复杂度。文中分别阐述方法的原理与验证,结果表明,四节点定位算法的解算速度比降低复杂度(Complexity-Reduced Trilateration Approach , COLA)定位算法有较大提高,该算法平均定位误差小于2米。 相似文献
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In this work, the quantitative conditions for the lift height for imaging of the magnetic field using magnetic force microscopy (MFM) were optimized. A thin cobalt film deposited on a monocrystalline silicon (1 0 0) substrate with a thickness of 55 nm and a thin nickel film deposited on a glass with a thickness of 600 nm were used as samples. The topography of the surface was acquired by tapping mode atomic force microscopy (AFM), while MFM imaging was performed in the lift mode for various lift heights. It was determined that the sensitivity of the measurements was about 10% higher for images obtained at a scan angle of 90° compared to a scan angle of 0°. Therefore, the three-dimensional surface texture parameters, i.e., average roughness, skewness, kurtosis and the bearing ratio, were determined in dependence on the lift height for a scan angle of 90°. The results of the analyses of the surface parameters showed that the influence of the substrate and its texture on the magnetic force image could be neglected for lift heights above 40 nm and that the upper lift height limit is 100 nm. It was determined that the optimal values of the lift heights were in the range from 60 to 80 nm, depending on the nature of the sample and on the type of the tip used. 相似文献
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The electron-stimulated desorption (ESD) of D+ from microporous D2O ice films condensed on Pt(111) has been investigated. The total D+ yield as a function of temperature from 90–180 K depends sensitively on the film roughness, surface temperature and ice phase. In particular, we observe an irreversible increase in the cation yield as the microporous thin film is heated from 90–120 K, which we associate with a decrease in surface roughness as the micropores collapse. We present evidence which suggests that the number of surface sites available for emission, the surface roughness, and reneutralization or reactive scattering of the D+ desorbate play major roles in determining the ion yield. A simple model which qualitatively addresses the role of surface roughening on ESD ion yields shows good agreement with the data. 相似文献
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Image potential resonances on the Sn/Ge(1 1 1) α-phase are investigated by two closely related methods: specular electron reflection and so-called selective electron scattering. Electrons from image resonances are detected on this surface at 120 and 300 K, i.e. below and above the phase transition at about 200 K. The dispersion of the image resonances reveals at these two temperatures equivalent effective electron masses, which are characteristic for this type of electronic surface states. The results of the two methods are consistent according to the similarity of the scattering processes. Changes in the loss peak intensity with the annealing temperature are assigned to the surface quality and are reflected by characteristic photoemission intensities. 相似文献
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ZHUJian-Yang YANGZhan-Ru 《理论物理通讯》2001,35(4):469-474
A single-spin transition critical dynamics is used to investigate the three-dimensional kinetic Ising model on an anisotropic cubic lattice,We first derive the fundamental dynamical equations.and then linearize them by a cutoff approximation.We obtain the approximate solutions of the local magnetization and equal-time pair correlation function approximation.We obtain the approximate solutions of the local magnetization and equal-time pair correlation function in zero field.In which the axial-decoupling terms γ1γ2,γ2γ3and γ1γ3as higher infinitesimal quantity are ignored,where γα=tanh(2k0633)=tanh(2Jα/kβT)(α=1,2,3,)We think that it is reasonable as the temperature of the system is very high.The result of what we obtain in this paper can go back to the one-dimensional Glauber‘s theory as long as k2=k3=0. 相似文献
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Contrary to conventional light emitting diodes for visible and very near infrared utilizing interband (ω>Eg) luminescence, the longer infrared emitting diodes (LIREDs) we describe here utilize intraband (ω<Eg) electron transitions and emit beyond the fundamental absorption range of the material used. Made of indirect band gap semiconductors (like Ge, Si) and, therefore, free from the Auger recombination impact, LIREDs efficiently operate at higher temperatures (T>300 K) in the longer wavelength atmospheric window (8–12 μm). Electrically modulated power emitted is comparable to that for black body sources whereas shorter rise–fall times are due to recombination processes (200 μs) and not dependent on pixel thermal mass and thermal conduction. LIREDs can be made of different semiconductor structures provided the controllable modulation of free carrier concentration in the device base is achieved. The main parameters of Ge based LIREDs under injection mode are reported. 相似文献