“…In the SPOT-7 test image, when a block size of 22 22 occurs, an extracted-bit error of 1 bit occurs in the block position y (3,12). Based on the fluctuation calculation results, at the position of block y (3,12), the proposed fluctuation function extracts the wrong information bit, "0," while only the Zhang fluctuation function correctly extracts the embedded information bit into the image, which is bit "1." In the Pleiades-1A test image, when a block size is 21 21, there is an extracted-bit error of 1 bit in the block position y (4,8).…”