面部表情捕捉比动作捕捉更加困难，因为面部的动作要小得多。

Capturing facial expressions is harder than motion capture because the movements are much smaller.

youdao

其中一个问题是，《极地速递》中运用的面部表情捕捉系统无法捕捉眼睛的运动。

One problem was that the facial-capture system used in "the Polar Express" could not capture eye movements.

youdao

不同于“发光小球”，这些小点是直接绘在面部表皮组织上的，因而可以捕捉到更细微的表情。

Unlike marker beads, the dots were painted directly on surface tissue, which allowed more detailed expression capture.

youdao