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| 冰体内气泡缺陷特征的“机器视觉”无损检测方法 |
| "Machine Vision" nondestructive testing method for the defect characteristics of bubbles in ice |
| 投稿时间：2022-10-06 修订日期：2022-12-06 |
| DOI： |
| 中文关键词: 激光散射 冰体气泡 无损检测 |
| 英文关键词:Laser Scattering Ice Bubble Nondestructive Testing |
| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目）；科技部重点研发计划“科技冬奥”专项 |
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| 中文摘要: |
| 内部气泡对冰的力学性能影响较大，为深入了解气泡缺陷特征，通常采用切片的方式来观察冰体内部气泡分布，但需从整个冰体中进行切割。本文基于光的散射原理，发展了冰中缺陷特征的高效率定量识别方法。设计了可控移动片光源倾斜入射和垂直图像采集的光路系统。利用片光源入射和光的散射原理大幅度提升了气泡缺陷的对比度，提高检测精度。基于光折射定理，实现单相机图像采集准确得到冰中气泡三维空间位置。利用片光源的移动速度和气泡散射存在时长得到垂直冰面方向上气泡的尺寸。通过对透明亚克力材料中已标定形状和三维位置气泡缺陷的实验测量，验证了方法的可行性。对含气泡冰体进行测量，分析得到了冰体中气泡形状，位置分布，数量以及体积分数等信息。该实验方法为非接触式测量，不会对冰体造成破坏，因而不会对同一冰样的后续使用产生影响。该测试方法在冰的力学性能研究以及透明材料的无损检测等领域中都将有广泛的应用。 |
| 英文摘要: |
| The mechanical property of ice can be influenced by its bubbles inside. In order to further understand the defect characteristics of bubbles, conventional way to detect ice bubbles is to cut the ice sample into slices. In this way, the sample preparation has to separate from the ice. This paper develops an efficient quantitative identification method based on laser scattering theory to detect ice bubbles, which includes a movable slant laser sheet and a camera perpendicular to the testing sample. The laser can highlight the bubbles inside and improve the measurement accuracy. Starting from refraction theorem, 3D position of the bubbles can be easily acquired by a single camera. The deep dimension is determined according to the duration of bubbles being illuminated by the laser with uniform velocity. A series of experiments on transparent PMMA (polymethyl methacrylate) with certain holes or notches are conducted to verify the feasibility of this method. The shape, distribution, quantity and volume fraction of ice bubbles are obtained by further experiments on ice samples. This method causes no damage to ice, which ensures the further experiment on the same sample. This method has application potential in study of ice mechanical property and nondestructive testing field of transparent material. |
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