Using high energy X-ray defocus phase contrast imaging on polystyrene(PS) microspheres, the contrast of the edge of tiny bubbles (about a few micrometers in diameter) in the sphere's wall are effectively enhanced, where the density gradi ent is relatively larger, and thus the bubbles will be highlighted on the image of microsphere which has overall smooth gray scale. The contrast causing and related factors are analyzed and discussed. The experiments conducted use micro-focal spot X-ray tube and CCD as the light source and detector, the derived image resolution is better than 2 μm, and the rapid defect detection of PS shells is achieved at the X-ray energy of 20 to 30 keV, providing a fast and effective means for monitoring of microspheres prepa ration process.%利用较高能量的X射线对聚苯乙烯(PS)微球进行离焦相衬成像,球壁内密度变化较大的微小气泡的边缘衬度得到有效增强,从而在灰度变化较平滑的微球整体图像中凸显出来,分析了衬度来源及相关因素.实验采用微焦斑的X射线管及CCD作为光源及探测器,图像分辨力约为2μm,在能量为20～30 keV时,实现了PS微球缺陷快速检测,为微球制备工艺的改善和提高提供了快速有效的监测手段.
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