X射线TICT在复合材料工件检测中的射束硬化拟合校正研究

X射线TICT中,X射线透射物质时,发生了能谱硬化现象.使图像重建时出现伪影.因此必须进行修正.文中对X射线硬化现象进行了分析,探讨了X射线TICT在检测复合材料工件中,X射线射束和与透射厚度的关系,并根据Beer定律和X射线与物质作用的特点,通过获取X射线射束和数据,首先拟合出射束和与透射厚度的关系式,然后推导出X射线射束和校正为单色射线射束和的等效厚度与透射厚度的关系及其等效方法,最终得出X射线TICT在检测复合材料工件中X射线等效单色射线的衰减系数的射束硬化拟合值,再对此衰减系数拟合值进行卷积反投影重构,即可有效消除X射线TICT在检测复合材料工件中射束硬化造成的影响.

Beam Hardening Simulated Correction Research for X-Ray TICT in Testing Composites Workpiece

In X-ray TICT,when X-ray is transmitted in the materal,the phenomenon of energy spectrum hardening takes place,resulting in artifacts.Thus,hardening correction has to be done.In the present paper,the phenomenon of X-ray beam hardening resulting in analyized,and the relation between the X-ray beam sum and the transmission thickness in testing composites workpiece is discussed.According to the Beer law and the characteristics of the interaction between X-ray and the material,and getting the data of X-ray beam sum,the relation equation between the beam sum and transmission thickness is simulated firstly,and testing composites workpiece.Then,the relation and the method of equivalence are carried out between the equivalent transmission thickness and the transmission thickness for X-ray beam sum being corrected for monochromatic ray beam.Finally, the attenuation coefficient beam hardening simulated value for X-ray equivalent monochromatic is reasoned out in testing composites workpiece.Then,the attenuation coefficient simulated value that has been corrected is used for product back-projection reconstruction.Thus,the effect caused by X-ray beam hardening is wipped off effectively in testing composites workpiece.