The Extended Kalman Filter Data Fusion Algorithm Based on Discrete Stationary Wavelet Transformation     

LI Hong - lian  HUANG Ding - f  XIONG Yong - liang 《保鲜与加工》2006,(3):43

It is difficult to establish precise mathematical model in extended Kalman filter data fusion algorithm for GPS/ DR integrated vehicle navigation system, an improved extended Kalman filter data fusion algorithm is put forward based on Discrete stationary wavelet transformation. The simulation results show that the algorithm is better than the extended Kalman filter data fusion algorithm, and is available for GPS/DR integrated vehicle navigation system.  相似文献   

Neural network ensemble residual kriging application for spatial variability of soil properties   总被引：19，自引：0，他引：19  

SHEN Zhang-Quan  SHI Jie-Bin  WANG Ke  KONG Fan-Sheng  J. S. BAILEY 《土壤圈》2004,14(3):289-296

High quality, agricultural nutrient distribution maps are necessary for precision management, but depend on initial soil sample analyses and interpolation techniques. To examine the methodologies for and explore the capability of interpolating soil properties based on neural network ensemble residual kriging, a silage field at Hayes, Northern Ireland, UK, was selected for this study with all samples being split into independent training and validation data sets. The training data set, comprised of five soil properties: soil pH, soil available P, soil available K, soil available Mg and soil available S,was modeled for spatial variability using 1) neural network ensemble residual kriging, 2) neural network ensemble and 3) kriging with their accuracies being estimated by means of the validation data sets. Ordinary kriging of the residuals provided accurate local estimates, while final estimates were produced as a sum of the artificial neural network (ANN) ensemble estimates and the ordinary kriging estimates of the residuals. Compared to kriging and neural network ensemble,the neural network ensemble residual kriging achieved better or similar accuracy for predicting and estimating contour maps. Thus, the results demonstrated that ANN ensemble residual kriging was an efficient alternative to the conventional geo-statistical models that were usually used for interpolation of a data set in the soil science area.  相似文献   

基于拖拉机作业轨迹的农田面积测量   总被引：2，自引：1，他引：2  

鲁植雄  钟文军  刁秀永  梅士坤  周晶  程准 《农业工程学报》2015,31(19):169-176

为了精确测量拖拉机在农田作业时的作业面积,以评价拖拉机的作业效率。该文选用双星定位(GPS卫星和伽利略卫星)接收机采集定位数据,采用自适应卡尔曼滤波算法提高接收机单点定位精度,利用高斯投影算法将GPS接收机采集经纬度转化成平面坐标来计算面积。选用回耕法、梭形耕法、套耕法3种方法旋耕地块,利用安装拖拉机上的GPS识别出作业轨迹,利用图像处理计算3种方法的有效作业面积、实际作业面积和重漏耕面积。试验表明:卡尔曼滤波提高了GPS单点定位精度;面积测量相对误差为2.09%;地块1(回耕法)漏耕率为14.29%,重耕率为6.19%,地块2(梭形耕法)漏耕率为10.72%,重耕率为5.54%,地块3(套耕法)漏耕率为1.80%,重耕率为6.82%。随测量面积增加,测量精度越高;套耕法效率最高,梭形耕法其次;回耕法的漏耕率最大,作业效率最低。  相似文献   

Image denoising using HMT in PDTDFB domain     

SHANG Zhao wei  ZHANG Feng  LANG Fang nian  YUAN Bo  LI Jian 《保鲜与加工》2011,(6):105-109

Based on the dependency of the PDTDFB coefficients across the interscale and interdirection and the statistical properties of HMT for the correlation properties, a new HMT in PDTDFB domain was put forward. Compared with the other typical denoising methods, the experimental results demonstrate that the proposed method shows better performance in image denoising, especially in edge maintenance.  相似文献   

Substrate integrated waveguide bandpass filter based on butterfly radial slot     

CHEN Shi yong  CHEN Kai rang 《保鲜与加工》2011,(6):127-131

A novel broadband substrate integrated waveguide bandpass filter was presented based on the highpass characteristics of substrate integrated waveguide(SIW) and the bandstop performance of butterfly radial slot photonic band gap(PBG) structure. In order to verify this idea,a wideband bandpass filter with 4.65 GHz center frequency and 40% fractional bandwidth was designed. The electromagnetic simulation results show good passband characteristics from 3.71 to 5.6 GHz, while the maximun insertion loss is about 0.40dB. An experimental filter prototype was fabricated with standard PCB process and measured by the vector network analyzer. The measured results show that, for the filter prototype, the passband is from 3.78 GHz to 5.76GHz, the fractional bandwidth is about 41%, the minimal insertion loss is about 0.72 dB and the maximun insertion loss is 1.65.dB The measured results are in good agreement with the simulated results.  相似文献   

滤膜过滤器新的理论模型初步探讨     

张桂芳  汤广发  李念平  任承钦  黄宇 《湖南农业大学学报(自然科学版)》2001,28(1)

通过对滤膜过滤器的过滤机理进行分析，认为过滤器在使用期间，滤膜中每个毛细管的过滤性能随时间和空间位置的变化而变化，因而对过滤器性能的评价还应从系统的、全面的、宏观统计的观点来综合反映，由此可根据多孔介质流体动力学理论模型来准确地反映滤膜过滤器的性能变化。  相似文献   

人工湿地植物的选择及湿地植物对污染河水的净化能力   总被引：22，自引：0，他引：22  

张雨葵  杨扬  刘涛 《农业环境科学学报》2006,25(5):1318-1323

阐述了在人工湿地中植物的作用和选择人工湿地植物的原则，分析比较了4种常用于人工湿地的植物的生长特性、环境适应性，并进行了潜流人工湿地和生物滤床作为人工湿地的对照试验）对污染河水处理效果的比较。结果表明，在湿地床中，美人蕉（C．flaccida）和香根草（Vetiveria zizanioides）长速较快，较适合于需快速启动的湿地系统；风车草（Cyperus slternifolius）长势良好，覆盖度接近100％；纸莎草（Cyperus papyrus）长势较差，环境适应性差。在HRT为13h的运行条件下，系统稳定运行后植物对CODMn，TP、TN、NH4^＋-N的平均去除率分别为3．1％、2．0％、12．7％、5．2％，植物对浊度没有明显的改善作用。人工湿地有较强的耐冲击负荷能力，在HRT为13h条件下系统的处理能力还有较大的提升空间。  相似文献   

小波变换用于抑制干扰信号几种方法的比较研究     

杨春玲  戴景民  刘超 《湖南农业大学学报(自然科学版)》2002,29(6)

对小波变换抑制干扰信号提取真实信号的3种方法，即小波滤波器消噪法；软、硬阈值消噪法；基于模极大值的小波去噪方法，进行了比较研究。给出了每种方法的适用范围及具体的算法、仿真结果，对于选用小波变换工具进行信号处理具有一定的理论意义和实用价值。  相似文献   

基于机器视觉印品缺陷检测的滤波算法     

谢勇 王耀南彭涛  龙永红 《湖南农业大学学报(自然科学版)》2005,32(4)

彩色印刷品是经过多色印刷后形成的，各色之间不可避免地存在一定程度的套印位置偏差等工艺缺陷．针对这个问题，提出了一种从印刷品差分图像中滤掉边缘噪声的算法．基于印刷工艺因素的影响及标准图像的自身结构特征，设计了滤波算法由图像乘、全局亮度门限和腐蚀／膨胀等部分组成．实验证明该算法能有效地降低边缘噪声。  相似文献   

喷油助燃再生DPF过滤体入口废气温度条件研究   总被引：1，自引：0，他引：1  

伏军  龚金科  吴钢  余明果  吁璇  张文强 《农业机械学报》2011,42(3):1-5,10

阐述了DPF喷油助燃再生的工作原理,在考虑过滤体内沉积微粒氧化反应次模型的基础上,以壁流式蜂窝陶瓷过滤体为研究对象,建立柴油机稳态工况下过滤体入口孔道的再生简化模型。考虑到柴油机中小负荷排气富氧条件,通过无量纲化,结合DPF的排气背压模型,得到了喷油助燃再生DPF时过滤体入口端所需的温度条件。试验表明,以该条件获得的理论过滤体入口废气温度所对应的喷油率来调节燃烧器功率可顺利实现DPF的再生过程,为DPF喷油助燃再生系统的设计提供了一定的理论依据。  相似文献