watermark_invisiable.py 文件源码

def _extract_svd_sig(self,vec,siglen):
        Q = 32
        ext_sig=[]

        for i in range(0,vec.shape[0],8):  #128*128
            for j in range(0,vec.shape[1],8):
                u,s,v = np.linalg.svd(np.mat(vec[i:i+8,j:j+8]))
                z = s[0] % Q
                if z>=Q/2 :
                    ext_sig.append(1)                    
                else:
                    ext_sig.append(0)

        if siglen >len(ext_sig):
            logging.warning('extract svd sig is {},small  than needed {}'.format(len(ext_sig),siglen))
            ext_sig.extend([0] * (siglen - len(ext_sig)))
        else:
            ext_sig = ext_sig[:siglen]

        return [ext_sig]


##################################################################################################################################