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唐磊  邱泽华  阚宝祥 《大地测量与地球动力学》2008,28(2):56-60

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High-accuracy photogrammetric technique for human spine measurement     

Albert K.  Chong  Peter  Milburn  Richard  Newsham-West  Marieketer  Voert 《The Photogrammetric Record》2009,24(127):264-279

Close range photogrammetry has been recognised as an essential tool for the capture of high-accuracy spatial data for medical applications, in particular work involving dynamic human body parts such as limbs. Offline and online photogrammetric systems are readily available for a number of common applications. However, off-the-shelf systems are not always appropriate because of project site conditions. To achieve high measurement accuracy in a field environment, a modified field camera calibration technique was introduced. The technique is particularly important where each camera is limited to one captured image during calibration, as the camera and the calibration testfield are in fixed positions. In this paper a custom-built imaging system designed for the study of the human spine in an outdoor environment is introduced. The discussion addresses: (1) imaging system design; (2) modified field calibration techniques; and (3) a case study on human spines. Two field camera calibration techniques were evaluated, both of which improved the accuracy of the prototype system, the use of a detachable target board offering the best results. This modified camera calibration procedure has improved the 3D measurement accuracy from 1·25 ± 0·3 mm to 0·43 ± 0·1 mm. The improvement is at a level achievable in the laboratory. The technique is considered to provide accurate and reliable anthropometric landmark measurement at low cost. This was evaluated in a clinical setting where diurnal changes in spine length and contour were measured in a cohort of 30 university students. The capability of the technique to measure sagittal and frontal angular changes provides a novel way of examining changes in spine shape.  相似文献   

土壤有机质光谱特征研究(英文)   总被引：1，自引：0，他引：1  

何挺  王静  林宗坚  程烨 《地球空间信息科学学报》2009,12(1):33-40

The study on soil spectral reflectance features is the physical basis for soil remote sensing. Soil organic matter content influences the soil spectral reflectance dramatically. This paper studied the spectral curves between 400 nm∼2500 nm of 174 soil samples which were collected in Hengshan county and Yixing county. Fourteen types of transformations were applied to the soil reflectance R to remove the noise and to linearize the correlation between reflectance (independent variable) and soil organic matter (SOM) content (dependent variable). Then, the methods such as derivative spectrum technology and stepwise regression analysis, were applied to study the relationship between these soil spectral features and soil organic matter content. It shows that order 1 derivative of the logarithm of reflectance (O1DLA) is the most sensitive to SOM among the various transform types of reflectance in consideration. The regression model whose coefficient of determination reaches 0.885 is built. It predicted the soil organic matter content with higher effect. Supported by the National Natural Science Foundation of China (No. 40271007).  相似文献   

地震计时域标定的噪声数据处理   总被引：2，自引：1，他引：1  

周云耀 《大地测量与地球动力学》2004,24(4):123-127

分析了在甚宽频带地震计的时域标定中存在的各种噪声，探讨了相应的处理方法，重点阐述了对阶跃标定影响最大的长周期漂移噪声的处理方法——漂移曲线拟合法。  相似文献   

Distinguishing Carbonate Reservoir Pore Facies with Nuclear Magnetic Resonance Measurements   总被引：1，自引：0，他引：1  

Coralie Genty  Jerry L. Jensen  Wayne M. Ahr 《Natural Resources Research》2007,16(1):45-54

  Characterization of carbonate rocks may involve identifying the important pore types which are present. In the past, this task has required detailed petrographic analysis of many core samples. Here, we describe a method which uses nuclear magnetic resonance (NMR) measurements to reduce the amount of petrographic analysis needed for porosity typing of carbonate reservoir rocks. For a rock sample which has been measured with NMR, our method decomposes the log(T₂) spectrum into at most three Gaussian-shaped components and gives a set of nine parameters. Two characteristic quantities having geological significance are extracted from the nine parameters. Values of the two quantities are compared with a reference set, established from samples having both NMR and petrographic evaluations of porosity types. We use a Bayesian approach to the classification of the dominant porosity type. Tests of our method on 103 samples show a correct prediction in 60 to 90 percent of the samples. The lower success rate was obtained for samples with five porosity types from three fields; the higher success rate obtained with samples with three porosity types from one well. The use of geologically significant quantities extracted from the decomposition gives comparable success rate to those obtained using a standard, non-geological approach such as canonical variates.  相似文献   

黄壁庄水库水质参数遥感反演研究   总被引：6，自引：0，他引：6  

赵旭阳  刘征  贺军亮  张文宗 《地理与地理信息科学》2007,23(6):46-49

以石家庄市黄壁庄水库为研究对象,利用ASD FieldSpec Pro野外光谱辐射计进行反射光谱测量和同步水质采样分析,应用高光谱技术阐释了水质参数(SS、COD、TN、TP)与光谱反射率的关系,为今后利用星载高光谱传感器对黄壁庄水库乃至我国北方内陆水体水质参数进行大面积反演提供理论基础。在分析水库水体反射光谱特征的基础上,运用微分光谱技术和统计相关方法直接分析、诊断各水质参数的敏感波段,并建立线性估算模型,确定研究区SS、COD、TN、TP的敏感波段分别为715 nm7、04 nm、595 nm8、73 nm。  相似文献   

系列14C样品贝叶斯法日历年龄校正研究进展     

尹金辉  郑勇刚  刘粤霞  卢演俦 《地球科学进展》2007,22(3):297-304

系列14C样品贝叶斯法日历年龄校正研究已成为当前14C年代学中一个热点,系统综述了时序已知、时序间隔已知和时序间隔近似已知系列14C样品日历年龄校正研究的历史、原理、计算方法及其在树轮、泥炭、地层等领域上应用进展,对影响系列样品贝叶斯分析获得14C日历年龄区间的主要因素以及未来发展方向作了归纳.大量事例研究结果表明系列样品贝叶斯分析的实质在于贝叶斯方法从统计的角度灵活地把地层信息以概率方式加入到14C日历年龄校正过程中,获得比单个14C年代校正精度更高的日历年龄.  相似文献   

成都经济区土壤光谱特征及其意义     

张艳彬  王玉  杨忠芳  陈岳龙 《世界地质》2007,26(1):118-123

对成都经济区内的根系土壤样品进行了光谱测试分析。针对不同土壤类型和不同成土母质，总结了光谱特征，并对土壤分类做了初步的研究。结果表明：①violet（紫光）、blue（蓝光）光谱与根系土壤CA含量都成正相关；②yellcw（黄光）、orange（橙光）、redness（红光）波段光谱与根系土壤CA含量呈负相关；③可以通过紫光、橙光的组合初步判断出土壤类型。  相似文献   

废光谱感光板中银的提取     

王洪波 《岩矿测试》2007,26(6):505-506

废光谱感光板用自来水浸泡，剥离的乳胶经氢氧化钠和双氧水溶解后，在微酸性溶液中加入锌粉置换出银，银沉淀经过滤和硼砂与碳酸钠的混合熔剂熔炼后得到成品银锭。采用建立的方案提取废光谱感光板中成品银的纯度达到95．4％，工艺操作简便，成本低、环境污染小。  相似文献   

Improving resolution of gravity data with wavelet analysis and spectral method     

Qiu Ning  He Zhanxiang  Chang Yanjun 《Frontiers of Earth Science》2007,1(3):380-387

Gravity data are the results of gravity force field interaction from all the underground sources. The objects of detection are always submerged in the background field, and thus one of the crucial problems for gravity data interpretation is how to improve the resolution of observed information. The wavelet transform operator has recently been introduced into the domain fields both as a filter and as a powerful source analysis tool. This paper studied the effects of improving resolution of gravity data with wavelet analysis and spectral method, and revealed the geometric characteristics of density heterogeneities described by simple shaped sources. First, the basic theory of the multiscale wavelet analysis and its lifting scheme and spectral method were introduced. With the experimental study on forward simulation of anomalies given by the superposition of six objects and measured data in Songliao plain, Northeast China, the shape, size and depth of the buried objects were estimated in the study. Also, the results were compared with those obtained by conventional techniques, which demonstrated that this method greatly improves the resolution of gravity anomalies. Translated from Progress in Geophysics, 2007, 22(1): 112–120 [译自: 地球物理学进展]  相似文献