图片的信息熵计算

• Information Entropy: To maximize the density of meaningful content seen during training, we
filter out low-entropy images. This is achieved through two complementary methods: (1) analyzing
the variance of border pixels to detect images with large, uniform-color backgrounds or frames,
and (2) performing a transient JPEG re-encoding and using the resulting bytes-per-pixel (BPP) as a
proxy for image complexity

一种用边缘像素的方差, 一种用jpeg压缩后看每一个像素用多少bite来表示.