边缘保持是保持边缘区域的梯度；

The edge preservation is to preserve the gradient of edge areas.

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这就意味着，这些不断生长的牙齿，可以有规律地脱落磨损部分，以保持边缘锋利。

This means the teeth, which grow continuously, can regularly shed damaged areas to keep a well-honed edge.

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实验结果证明，这种方法不但能有效地滤除椒盐噪声，而且能够很好地保持边缘。

The experiment shows that this method can powerfully denoise salt-and-pepper noise with good edge-preserving.

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