The simulations prove that not only the PSNR improved, but also the visible blocking effect is effectively decreased by using adaptive threshold and pointwise variance method.

• 仿真结果表明：采用自适应阈值并结合具有更强自适应性的逐点噪声方差法不仅能提高医学图像的峰值信噪比，还能有效地降低由传统阈值所带来的方块效应。