Berdnik Vladimir V, Loiko Valery A
Técnicas de Investigacion Hidrogeolologica S.A., Bolshaja Krasnaja Street, 64, Kazan, Russia.
Appl Opt. 2009 Nov 10;48(32):6178-87. doi: 10.1364/AO.48.006178.
A method to retrieve the radius and the relative refractive index of spherical homogeneous nonabsorbing particles by multiangle scattering is proposed. It is based on the formation of noise-resistant functionals of the scattered intensity, which are invariant with respect to the linear homogeneous transformations of an intensity-based signal and approximation of the retrieved parameters' dependence on the functionals by a feed-forward neural network. The neural network was trained by minimization of the mean squared relative error in the range of particle radii from 0.6 mkm up to 13.6 mkm and relative refractive index from 1.015 up to 1.28. In comparison with training on a minimum of the mean squared error, this method enables one to increase the accuracy of the radius retrieval in the range of radii from 0.6 to 2 microm and refractive index in the range from 1.015 to 1.1. The values of intensity of light scattered in the interval of angles 10 degrees-60 degrees are used as input data. If the measurement error is 20%, the mean errors of the radius and relative refractive index are 0.8% and 7%, respectively. The results obtained by the proposed method and by the trial and error method with published experimental data (measured with a scanning flow cytometer) are compared. The maximal difference in the retrieval results of radius and the relative refractive index of particles obtained by both methods is under 5%.
提出了一种通过多角度散射来获取球形均匀非吸收性颗粒半径和相对折射率的方法。该方法基于散射强度的抗噪声泛函的形成，这些泛函对于基于强度的信号的线性均匀变换是不变的，并且通过前馈神经网络来近似所检索参数对泛函的依赖性。神经网络通过最小化平均平方相对误差进行训练，颗粒半径范围为0.6微米至13.6微米，相对折射率范围为1.015至1.28。与基于最小均方误差的训练相比，该方法能够提高半径在0.6至2微米范围内以及折射率在1.015至1.1范围内的检索精度。在10度至60度角度区间内散射光的强度值用作输入数据。如果测量误差为20%，半径和相对折射率的平均误差分别为0.8%和7%。将所提出的方法与试错法以及已发表的实验数据（用扫描流式细胞仪测量）所得到的结果进行了比较。两种方法所获得的颗粒半径和相对折射率检索结果的最大差异在5%以内。
