为了修复X射线投影图像中闪烁体缺陷引起的图像伪影,提高X射线投影图像的三维重构质量,结合X射线成像过程中闪烁体缺陷的结构特点,提出了一种改进的BSCB修复算法(IBSCB)。利用Kirsch算子对本底图像进行处理,获得标记出闪烁体缺陷像素的掩膜图像。进而对样品投影图像中相应的缺陷区域按照由外及内的顺序迭代进行修复和扩散,在对外层缺陷区域修复完成后,利用修复后的信息修复内部缺陷区域,并且根据周围缺陷像素的个数确定修复和扩散过程中的迭代系数和迭代次数;对于其中的修复过程,采用log算子滤波,并将滤波后的信息沿等照度线方向扩散实现图像修复。从主观视觉和客观数据两方面对BSCB和IBSCB修复算法进行评价。不同放大倍率下X射线投影图像的修复结果表明:IBSCB不但提高了修复质量,而且其修复速度也比BSCB算法提高了5~6倍。比较修复前后X射线投影图像的三维重构图像,进一步验证了本文算法的有效性。
To eliminate the artifacts in X-ray projection images and improve the quality of the three-dimensional reconstruction images using X-ray projection images,a modified BSCB inpainting algorithm is proposed based on the characteristics of scintillation defects in the projected images.The Kirsch operator is operated on a normal image for extracting the mask image,on which the defective pixels of the image are marked.On this basis,corresponding defective pixels in the projection images are inpainted and diffused from outer to inner layer.After the inpainting of the outer region is accomplished,the inner region will be inpainted by using the information of the outer region which has been inpainted.And the iteration times and coefficient are determined by the defective pixels around.The inpainting process is accomplished by using log operator and the filtered information is diffused along the isolux line.BSCB and IBSCB algorithms are evaluated from both subjective vision and objective data.Numerical results show that under the different magnifications,the IBSCB algorithm provides an improvement in inpainting quality.Also,the IBSCB algorithm is five to six times faster than the BSCB algorithm.Three-dimensional reconstruction images using X-ray projection images before and after restoration are compared,which further verifies the effectiveness of the proposed algorithm.