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为增强γ辐射编码成像系统中最大似然期望最大化(Maximum Likelihood Expectation Maximization,MLEM)算法对噪声的抑制,提高算法重建质量,基于互补编码板成像相减去除噪声的思想,对原有MLEM算法进行改进,提出了MLEM互补算法,并引入修正因子?对MLEM互补算法的收敛程度进行控制。通过模拟及实验方式验证了MLEM互补算法的有效性,给出了不同情况下MLEM互补算法达到最优值时修正因子?的拟合曲线。结果表明,MLEM互补算法可有效抑制噪声,提高重建图像质量。修正因子?的拟合曲线可以有效确定MLEM算法的最佳?值。
In order to enhance the reconstruction quality of MLEM algorithm and improve the quality of MLEM algorithm, based on the idea of subtracting noises by complementary coded plate subtraction, the original MLEM algorithm The MLEM complementary algorithm is proposed and a correction factor is introduced to control the degree of convergence of MLEM complementary algorithm. The validity of the MLEM complementary algorithm was verified by simulation and experiment, and the fitting curve of the correction factor? Was obtained when MLEM complementary algorithm reached the optimal value under different conditions. The results show that MLEM complementary algorithm can effectively suppress the noise and improve the quality of the reconstructed image. The fitting factor of the correction factor can effectively determine the best value of the MLEM algorithm.