Sharpness of vision, especially as tested with a Snellen chart. Normal visual acuity based on the Snellen chart is 20/20.

视觉的敏锐程度，尤指经斯纳仑氏图表所测结果。在斯纳仑氏图表上测得的一般的视觉敏锐度为20/20。

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But besides noises, there are some other interference factors which weaken the vision effect of digital image greatly, like image contrast, image brightness and image sharpness, etc.

但是通常影响数字图像的视觉效果，除了噪声以外，还存在其它的因素，如图像对比度、图像亮度、图像清晰度等等。

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Other signs of concussion are stomach and head pain, muscle weakness and a loss in sharpness of vision.

脑震荡的其他症状有胃痛、痛，肌肉无力，视力下降。

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