将一个512×512的lena.bmp图像进行DCT变换，对得到的DCT系数按8×8块进行分层（分三层），重组填充得到新的系数矩阵，结果发现原图像的能量集中在了新图像的左上角低频部分。-The lena.bmp an image of 512 × 512 is subjected to DCT transform, the DCT coefficients obtained by layering 8 × 8 block (of three), to obtain a new recombinant filling coefficient matrix, the energy of the original image is found concentrated in upper left corner of the low-frequency part of the new image.