中文摘要：

针对传统的反投影算法中,假定声速均匀和延时补偿固定往往使得图像在特定的深度聚焦,在其他深度出现伪影的情况。本文分析了这种假定造成图像质量下降的原因并提出了一种改进的拟合延时补偿（FDC）重建算法,该方法利用拟合的延时补偿代替单一的延时补偿,采用变化的延时补偿进行光声重建。实验对比表明,相比传统的重建算法,该算法明显改善了聚焦效果,能够有效地消除伪影,提高图像质量。

英文摘要：

When we apply constant values of SOS and DC in reconstruction, the in-focus region will be in a certain depth, causing artifacts and displacement at other depths which deteriorates the image quality seriously. In this paper, the detailed reasons are analyzed for this phenomenon and. Furthermore, a reconstruction approach based on Fitted Delay Compensation（FDC） is proposed. It uses the various fitted delay compensation in image reconstruction, other than apply fixed delay and can significantly reduce the artifact. The experiment is carried out to validate its efficiency, which proves that, compared with the traditional reconstruction algorithm like delay and sum back projection（DNSBP）, it shows pretty good effect in improving the image quality.