Enabling foreground and background blur increases rendering time but gives more realistic results.

开启前景和背景模糊，虽然会增加渲染时间，但会得到更加真实的效果。

youdao

As you can see the background of the photo studio was kind of dirty, so in order to remove the stains I applied some Surface Blur.

就像你看到的，照片工作室的地面有点脏，所以为了移除污渍，我使用了一些表面模糊。

youdao

Notice how the foreground blur overlaps with the rest while the background doesn't.

可以看到前景的模糊区域会蔓延，并与其他部分重叠，而背景模糊则不会。

youdao

You stare so intently at the road ahead--a wide but constant curve--that nothing registers peripherally but a background blur.

FORBES: One Lamborghini, One Man, 200 MPH

The aim is to freeze the runners, but at the same time blur the background with a streaky effect to show speed.

BBC: Picture power: Running for gold

Such hopeful features have helped promote fresh interest among young Polish Jews and quite a few Gentiles in Poland's Jewish history since the communist era, when many Poles of Jewish background thought it wise to blur their ancestry.

ECONOMIST: Poland and Jews