Patent ID: 7792377

Claim:
A method for performing image authentication and restoration comprising: converting a selected image into YCbCr color space; setting YCbCr coefficients (Yε{15, 17, . . . , 235}, Cb,Crε{16, 17, . . . , 240}); dividing the selected image into a plurality of non-overlapping 8×8 blocks; performing a DCT (Discrete Cosine Transform) on each block; calculating DC (Direct Current) and AC (Alternating Current) feature bits of a selected block respectively; generating a coefficient set; determining whether the coefficient set corresponds to a predetermined rule; determining that the selected block is not a tampered image if the coefficient set corresponds to the predetermined rule; executing the following steps if the coefficient set does not correspond to the predetermined rule: calculating horizontal and vertical flatness indexes of each block; sorting the DCT-converted blocks; acquiring restoration information of the DC and AC coefficients; storing quantified coefficients via DPCM (Differential Pulse Code Modulation); encrypting the restoration information of the DC and AC coefficients; and embedding the encrypted restoration information into the selected block.