Data processing method of time-of-flight 3D imaging camera

飞行时间法三维成像摄像机测量结果存在中心点偏移、距离歧义性和混合像素等问题,且易受曝光时间和主动光源影响.为提高测量结果的有效性和准确性,对测量数据进行了如下处理:对摄像机进行校正,减小了球面距离到三维坐标转换过程中引入的误差;采用2个不同光源调制频率交替进行测量,根据2次测量结果差值消除距离歧义性;过度曝光时测量幅值随曝光时间增大而减小,据此提出了一种基于感兴趣区域的快速自动曝光控制方法;边界混合像素以单点或单线形式出现,根据某像素邻域内各像素位置分布情况判定该像素是否为混合像素;由测量幅值判定噪声大小,根据对主动光源成像时测量幅值很大、偏移值很小的特点辨别主动光源.实验结果表明:以上方法能有效提高数据可靠性和准确性.Measurement results of time-of-flight 3D imaging camera have problems of center offset,range ambiguity and mixed-pixel,and they are sensitive to exposure time and vulnerable to active light source.The measurement data were processed to improve the effectiveness and accuracy of measurement results.The camera was calibrated so that the error was decreased thanks to the transformation from spherical distances to Cartesian coordinates.The ambiguity was eliminated according to the difference between two measurements taken with two different light modulation frequencies alternately.The amplitude decreases with increasing exposure time due to excessive exposure,accordingly,a rapid auto-exposure control method based on region of interest was proposed.Boundary mixed pixels are in form of a single point or a single line,accordingly,the location distribution of each pixel in its neighborhood was a used to determine whether the pixel was a mixed pixel.Noise was determined according to the amplitude,meanwhile,the active light source was identified according to the characteristics that the amplitude was very small and the offset was very big when the active light source was measured.The experimental results showed that the data reliability and accuracy were improved with the above methods.国家自然科学基金重点资助项目(60534070);国家自然科学基金资助项目(60302013

第十八届美国理论与应用力学大会总结

1会议概况2018年6月5—9日,第18届美国理论与应用力学大会(18th U.S. National Congress of Theoretical and Applied Mechanics, USNCTAM2018)在美国芝加哥召开.本次大会由美国力学国家委员会和中国力学学会联合主办,旨在探讨和交流近四年世界范围内在理论和应用力学领域的基础研究、创新技术的最新进展,吸引了来自世界各地的近千名专家学

2010-2011 Forecast and Analysis of China's Macroeconomy

“中国季度宏观经济模型(CQMM)“课题组于2010年2月6日在北京举行了中国季度宏观经济模型第八次预测发布。课题组利用最新发表的宏观经济季度数据估计模型(CQMM),对2010年和2011年共八个季度的中国宏观经济主要指标数据进行了预测。预测结果表明,2010年中国gdP预计可增长9.13%,复苏迹象明显。但在投资刺激和出口回归正常后,未来数年,我国经济可能难以继续保持之前两位数增长,预期增长9%左右。课题组还模拟了不同货币调整力度对宏观经济的影响,以及居民可分配收入变化对宏观经济运行的影响。依据预测和政策模拟的结果,课题组对2010年我国宏观经济调控提出相关政策建议,即适度控制经济增长速度,调整国民收入支出结构必须多方着手、多方努力。On February 6,2010,Beijing,the eighth quarterly macroeconomic forecast was released by the China's Quarterly Macroeconomic Model(CQMM) project team.The project team used the newly released CQMM to forecast China's major macroeconomic indicators for 2010 and 2011,eight quarters in total.The forecast assumes a 9.13% growth of China's GDP in 2010,a significant indication of economic recovery.However,after measures for investment stimulation have been taken and exportation returns to normal,China's GDP growth will be less likely to rise above 10% as it did in the past but remain at about 9% in the next few years.The team has also simulated the impacts on the macroeconomy of different monetary adjustment policies and different disposable income distributions.Based on the forecast and policy simulation results,the team recommends the following policies:that China's GDP growth must be kept at a moderate rate and that the adjustment of the income expenditure structure must be approached by efforts from various sectors and institutions.教育部文科重点研究基地重大研究项目“我国宏观经济运行的微观基础研究”(08JJD790134);教育部文科重点研究基地重大研究项目“‘十一五’期间我国宏观调控方式转变的问题研究”(07JJD630226);教育部文科重点研究基地重大研究项目“经济全球化条件下中国经济增长的动态效率研究”(06JJD790029);教育部文科重点研究基地重大研究项目“中国宏观季度模型与宏观预测”(05JJD790093);国家社科基金重大项目“扩大国内内需的宏观经济政策”(08&ZD034

不同产地甘草主要有效成分与生态因子的相关性研究/Study on correlation between the main active ingredient of different habitats of Licorice and environmental factors[J]

本文研究了不同产地甘草有效成分与生态因子之间的相关性.利用高效液相(HPLC)色谱法,测定了新疆、甘肃、宁夏、内蒙古、山西、吉林不同产地甘草样品中主要有效成分的含量;并利用基于数字高程模型(digital eleva-tion model,DEM)的多元线性回归插值方法,应用Arcgis软件包进行空间插值,获得采样区域10个生态因子(包括活动积温X1、年平均气温X2、海拔X3、年相对湿度X4、年日照时数X5、年均降水量X6、7月最高气温X7、7月平均气温X8、1月最低气温X9、1月平均气温X10)数据,采用回归分析法分析了这些生态因子与甘草药材主要有效成分之间的相关性和变量投影重要性分析,并构建了偏最小二乘回归模型.结果表明,内蒙古武川(NHW)、山西右玉(SSY)、山西大同(SDD)、山西天镇(SDT)和山西阳高(SDY)的甘草样品6种有效成分总和最高,可以认为这几个产地野生甘草品质较优.生态因子中年平均气温、7月最高气温、7月平均气温、1月最低气温、1月平均气温与甘草酸、甘草苷和异甘草苷呈负相关关系,海拔、年均降水量与三种有效成分呈正相关关系

新疆艾丁湖区中全新世以来孢粉记录与古环境/POLLEN RECORDS AND PALEOENVIRONMENT SINCE MID-HOLOCENE IN THE AYDINGKOL LAKE OF XINJIANG[J]

内陆干旱、半干旱封闭湖泊对气候变化的响应十分敏感,是较为理想的古环境研究场所.艾丁湖位于新疆维吾尔自治区吐鲁番盆地南部,湖面海拔-154.4m,是全国最低的洼地,故艾丁湖特殊的地理位置与独特的地质环境,使其在西北干旱区环境变化研究中有着重要的意义.取自艾丁湖湖区东北方向中全新世以来两个剖面共计88个沉积物样品,通过对该剖面进行年代测定、粒度分析与孢粉鉴定统计后,根据其孢粉组合与粒度特征,发现艾丁湖中全新世的环境演变经历了两个干-湿的变化过程,并且艾丁湖地区受西风带影响明显,即中晚全新世以来气候相对比较湿润,尤其在小冰期时期受西风带影响降水增加,从而进一步揭示了西北干旱区生态演化过程以及干旱区湖泊的演化过程