Shvedchenko Dmitry O, Suvorova Elena I
Shubnikov Institute of Crystallography, Electron Diffraction Laboratory, Russian Academy of Sciences, Leninsky pr., 59, Moscow, 119333, Russia.
Microsc Res Tech. 2017 Oct;80(10):1113-1122. doi: 10.1002/jemt.22908. Epub 2017 Jul 12.
The practical need for a simple and reliable tool for routine size analysis of nanoparticles with diameters down to a few nm embedded in a polymer matrix motivated the development of a new approach. The idea underlying the method proposed in this work is to combine intensity thresholding and contrast fitting procedures in the same software for particle recognition and measurements of sizes and size distributions of nanoparticles in transmission and scanning transmission electron microscopy images. Particle recognition in images is performed in an interactive process of manual setting the numerical threshold level after image preprocessing. We show that fitting the calculated gray level distribution to the real images is able to provide a maximum accuracy in measurements of the particle diameters in contrast to thresholding approaches. The fitting procedure is applied in the vicinity of nanoparticle images with the mass-thickness, diffraction, and chemical contrast. The grayscale function associated to the nanoparticle thickness is described using polynomial gt=g0+g1t+g2t2+g3t3… with degree ⩾ 2 and undetermined coefficients. The program for particle detection and size measurement-Analyzer of Nanoparticles (AnNa)-has been written and is described here. It was successfully tested on systems containing Ag nanoparticles grown and stabilized in aqueous solutions of different polymers for biomedical use and is available from the authors.
对一种简单可靠的工具的实际需求，用于对嵌入聚合物基质中直径低至几纳米的纳米颗粒进行常规尺寸分析，这推动了一种新方法的开发。这项工作中提出的方法背后的想法是，在同一软件中结合强度阈值化和对比度拟合程序，用于在透射电子显微镜和扫描透射电子显微镜图像中识别颗粒并测量纳米颗粒的尺寸和尺寸分布。图像中的颗粒识别是在图像预处理后手动设置数值阈值水平的交互式过程中进行的。我们表明，与阈值化方法相比，将计算出的灰度级分布拟合到真实图像能够在颗粒直径测量中提供最大精度。拟合程序应用于具有质量厚度、衍射和化学对比度的纳米颗粒图像附近。与纳米颗粒厚度相关的灰度函数用多项式gt = g0 + g1t + g2t2 + g3t3…描述，次数⩾2且系数待定。已经编写了用于颗粒检测和尺寸测量的程序——纳米颗粒分析仪（AnNa），并在此进行描述。它已在包含在不同聚合物水溶液中生长和稳定的用于生物医学用途的银纳米颗粒的系统上成功测试，可从作者处获得。
