It 's also possible that the original picture was blurry or grainy .
还有可能原始图片就模糊或有纹理。
Self realizes that he recognizes one of the guys in the grainy still image .
在模糊的静止图像中，赛尔夫认出了其中一个持卡人。
They also try to detect if noise-the overexposed pixels within the image that create a grainy effect-was present at the time the photograph was taken or has been added later .
他们还试图检测噪声图像中呈现粒状效果的过度曝光像素是产生于照片被摄制的时刻还是后来才被加上的。
However , if these pictures are not only flashed very briefly but are also hard to make out to begin with and have a grainy pattern displayed right after them , they often cannot be seen .
