Vandel Egert, Vaasma Tiit, Sugita Shinya
Institute of Ecology, Tallinn University, Tallinn, Estonia.
MethodsX. 2020 Jul 2;7:100981. doi: 10.1016/j.mex.2020.100981. eCollection 2020.
This paper provides a methodological protocol for measuring diameter and other properties of mineral sand grains using an image analysis technique. The aeolian sand influx (ASI) from coastal bogs has been used to reconstruct changes in the past storminess. However, concentrations of sand grains in peat deposits, from which the ASI is calculated, tend to be low, and sieving and laser diffractometry cannot be applied. Manual counting of sands under microscope is time-consuming and less efficient because of possible human errors. This paper describes a protocol for an image analysis method used in our recent paper (Vandel et al. 2019) that overcomes those issues in sand grain measurements. After preliminary sample preparations, including loss-on-ignition and chemical pretreatments, this study uses - a semi-automated image processing program - to analyze images captured under microscope. With proper sample size selection, pre-treatment, image capturing and image analysis settings in described in this paper, the approach proved to be:•objective and efficient for analysing grain-size distribution even with low concentrations of sands in samples,•increasing reliability of the measurement and providing reproducible results by avoiding manual measuring processes, and•non-destructive and enabling further analyses on mineral composition and other properties of sand grains.
本文提供了一种使用图像分析技术测量矿砂颗粒直径及其他特性的方法方案。来自沿海沼泽的风成砂流入量（ASI）已被用于重建过去风暴活动的变化。然而，用于计算ASI的泥炭沉积物中的砂粒浓度往往较低，且无法应用筛分法和激光衍射法。由于可能存在人为误差，在显微镜下人工计数砂粒既耗时又效率低下。本文描述了一种在我们最近的论文（万德尔等人，2019年）中使用的图像分析方法方案，该方案克服了砂粒测量中的这些问题。经过初步的样品制备，包括烧失量和化学预处理后，本研究使用一种半自动图像处理程序来分析在显微镜下拍摄的图像。通过本文所述的适当样品大小选择、预处理、图像采集和图像分析设置，该方法被证明：•即使样品中的砂浓度较低，对于分析粒度分布也是客观且高效的；•通过避免人工测量过程提高了测量的可靠性并提供了可重复的结果；•无损且能够对砂粒的矿物成分和其他特性进行进一步分析。
