Calibration of the Cloud Particle Imager Probes Using Calibration Beads and Ice Crystal Analogs: The Depth of Field
Calibration of the Cloud Particle Imager Probes Using Calibration Beads and Ice Crystal Analogs: The Depth of Field
复制标题
使用校准珠和冰晶类似物校准云粒子成像仪探头：景深
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
K. Bower
中科院分区：
文献类型：
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作者：
P. Connolly;M. Flynn;Z. Ulanowski;T. Choularton;M. Gallagher;K. Bower
摘要本文介绍并发展了一种与Stratton Park Engineering Company，Inc.合作的云粒子尺寸分布测量的修正算法，云粒子成像仪（CPI）。当从CPI拍摄的图像中推断出云的颗粒大小时，相对于它们的“真实”大小，云的颗粒大小将过大。此外，如果粒子与物平面的距离大于景深，则它们将停止在图像帧中被“接受”。通过考虑不透明圆盘对光的衍射的标量理论的元素，设计了一种校准方法来克服这两个问题。该方法减少了从CPI数据推断颗粒尺寸的误差，并且还能够确定颗粒与物平面的距离，从而确定它们的景深。这两个量是至关重要的，使定量测量云粒子大小分布（直方图的颗粒大小，按比例缩放到粒子的总数浓度）在大气中。
Abstract This paper explains and develops a correction algorithm for measurement of cloud particle size distributions with the Stratton Park Engineering Company, Inc., Cloud Particle Imager (CPI). Cloud particle sizes, when inferred from images taken with the CPI, will be oversized relative to their “true” size. Furthermore, particles will cease to be “accepted” in the image frame if they lie a distance greater than the depth of field from the object plane. By considering elements of the scalar theory for diffraction of light by an opaque circular disc, a calibration method is devised to overcome these two problems. The method reduces the error in inferring particle size from the CPI data and also enables the determination of the particles distance from the object plane and hence their depth of field. These two quantities are vital to enable quantitative measurements of cloud particle size distributions (histograms of particle size that are scaled to the total number concentration of particles) in the atm...