带有图像增强器的X射线实时成像系统检测磁性工件时,图像易发生畸变,进而影响评片的准确性.分析了图像增强器的工作过程和图像畸变产生的原因,针对工件产生的磁场引起X射线像增强器内部电子束发生偏转最终导致图像出现畸变的现象,提出采用了动态磁场补偿器来改变驱动电流的大小和方向.此方法是通过改变磁场强度和磁场极性,消除磁性工件对图像增强器内电子束运动的影响.该动态补偿器结构简单,操作简便,性能稳定可靠.实验验证,此方法有效改善了成像质量,消除了图像畸变,得到清晰准确的检测图像.%When X-ray real-time imaging system with image intensifier detects magnetic workpiece, it is easy to cause image distortion and then affect comments on the accuracy of film. This paper analyses working process of image intensifier and studys reasons of image distortion. According to the phenomenon that magnetic field deriving from workpiece deflects electron beam in the X-ray image intensifier and then directly image distortion is brought, a method is supposed that compensator with dynamic magnetic field is used to change magnitude and direction of driving current. By changing intensity and polarity of magnetic field, the influence of magnetic workpiece on motion of electron beam is counteracted. The instrument is simple in structure, easy for operation and stable in performance. The experiment shows that the method can improve imaging quality, eliminate image distortion, and finally clear and accurate detection picture is obtained.
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