为了解水果的光学特性及其与可溶性固形物含量和含水率的关系,本实验采用单积分球技术搭建光学特性测量系统,并对系统进行了验证;进而以‘红颜’、‘甜香’和‘章姬’草莓为对象,测定950~1650 nm波长范围内草莓的光吸收系数μa和约化散...为了解水果的光学特性及其与可溶性固形物含量和含水率的关系,本实验采用单积分球技术搭建光学特性测量系统,并对系统进行了验证;进而以‘红颜’、‘甜香’和‘章姬’草莓为对象,测定950~1650 nm波长范围内草莓的光吸收系数μa和约化散射系数μ’s,分析光学参数与草莓可溶性固形物含量和含水率间的关系;建立基于光学参数谱预测草莓可溶性固形物含量和含水率的偏最小二乘模型。结果表明,该系统测量μa和μ’s的平均相对误差分别为8.23%和3.71%;整个波长范围内,μa在975、1197 nm和1411 nm波长处存在峰值,而μ’s基本随波长的增大而减小;草莓的μa与可溶性固形物含量呈负相关,而与含水率呈正相关,且吸收峰处出现相关系数极值;基于μa谱所构建模型具有最好的预测可溶性固形物含量(rp=0.815、预测集均方根误差(root mean squares error of prediction,RMSEP)=1.153%)和含水率(rp=0.757、RMSEP=1.280%)的能力,说明可溶性固形物含量和含水率主要影响草莓的吸收特性,基于吸收特性可以更好地预测草莓的内部品质。展开更多
The accuracy of parameter estimation is critical when digitally modeling a ship. A parameter estimation method with constraints was developed, based on the variational method. Performance functions and constraint equa...The accuracy of parameter estimation is critical when digitally modeling a ship. A parameter estimation method with constraints was developed, based on the variational method. Performance functions and constraint equations in the variational method are constructed by analyzing input and output equations of the system. The problem of parameter estimation was transformed into a problem of least squares estimation. The parameter estimation equation was analyzed in order to get an optimized estimation of parameters based on the Lagrange multiplication operator. Simulation results showed that this method is better than the traditional least squares estimation, producing a higher precision when identifying parameters. It has very important practical value in areas of application such as system identification and parameter estimation.展开更多
文摘为了解水果的光学特性及其与可溶性固形物含量和含水率的关系,本实验采用单积分球技术搭建光学特性测量系统,并对系统进行了验证;进而以‘红颜’、‘甜香’和‘章姬’草莓为对象,测定950~1650 nm波长范围内草莓的光吸收系数μa和约化散射系数μ’s,分析光学参数与草莓可溶性固形物含量和含水率间的关系;建立基于光学参数谱预测草莓可溶性固形物含量和含水率的偏最小二乘模型。结果表明,该系统测量μa和μ’s的平均相对误差分别为8.23%和3.71%;整个波长范围内,μa在975、1197 nm和1411 nm波长处存在峰值,而μ’s基本随波长的增大而减小;草莓的μa与可溶性固形物含量呈负相关,而与含水率呈正相关,且吸收峰处出现相关系数极值;基于μa谱所构建模型具有最好的预测可溶性固形物含量(rp=0.815、预测集均方根误差(root mean squares error of prediction,RMSEP)=1.153%)和含水率(rp=0.757、RMSEP=1.280%)的能力,说明可溶性固形物含量和含水率主要影响草莓的吸收特性,基于吸收特性可以更好地预测草莓的内部品质。
基金Supported by the Navy Equipment Department Foundation under Grant No. 2009(189)
文摘The accuracy of parameter estimation is critical when digitally modeling a ship. A parameter estimation method with constraints was developed, based on the variational method. Performance functions and constraint equations in the variational method are constructed by analyzing input and output equations of the system. The problem of parameter estimation was transformed into a problem of least squares estimation. The parameter estimation equation was analyzed in order to get an optimized estimation of parameters based on the Lagrange multiplication operator. Simulation results showed that this method is better than the traditional least squares estimation, producing a higher precision when identifying parameters. It has very important practical value in areas of application such as system identification and parameter estimation.
