| import numpy as np | |
| import copy | |
| import cv2 | |
| import pywt | |
| import math | |
| import pprint | |
| pp = pprint.PrettyPrinter(indent=2) | |
| class EmbedDwtDctSvd(object): | |
| def __init__(self, watermarks=[], wmLen=8, scales=[0,36,0], block=4): | |
| self._watermarks = watermarks | |
| self._wmLen = wmLen | |
| self._scales = scales | |
| self._block = block | |
| def encode(self, bgr): | |
| (row, col, channels) = bgr.shape | |
| yuv = cv2.cvtColor(bgr, cv2.COLOR_BGR2YUV) | |
| for channel in range(2): | |
| if self._scales[channel] <= 0: | |
| continue | |
| ca1,(h1,v1,d1) = pywt.dwt2(yuv[:row//4*4,:col//4*4,channel], 'haar') | |
| self.encode_frame(ca1, self._scales[channel]) | |
| yuv[:row//4*4,:col//4*4,channel] = pywt.idwt2((ca1, (v1,h1,d1)), 'haar') | |
| bgr_encoded = cv2.cvtColor(yuv, cv2.COLOR_YUV2BGR) | |
| return bgr_encoded | |
| def decode(self, bgr): | |
| (row, col, channels) = bgr.shape | |
| yuv = cv2.cvtColor(bgr, cv2.COLOR_BGR2YUV) | |
| scores = [[] for i in range(self._wmLen)] | |
| for channel in range(2): | |
| if self._scales[channel] <= 0: | |
| continue | |
| ca1,(h1,v1,d1) = pywt.dwt2(yuv[:row//4*4,:col//4*4,channel], 'haar') | |
| scores = self.decode_frame(ca1, self._scales[channel], scores) | |
| avgScores = list(map(lambda l: np.array(l).mean(), scores)) | |
| bits = (np.array(avgScores) * 255 > 127) | |
| return bits | |
| def decode_frame(self, frame, scale, scores): | |
| (row, col) = frame.shape | |
| num = 0 | |
| for i in range(row//self._block): | |
| for j in range(col//self._block): | |
| block = frame[i*self._block : i*self._block + self._block, | |
| j*self._block : j*self._block + self._block] | |
| score = self.infer_dct_svd(block, scale) | |
| wmBit = num % self._wmLen | |
| scores[wmBit].append(score) | |
| num = num + 1 | |
| return scores | |
| def diffuse_dct_svd(self, block, wmBit, scale): | |
| u,s,v = np.linalg.svd(cv2.dct(block)) | |
| s[0] = (s[0] // scale + 0.25 + 0.5 * wmBit) * scale | |
| return cv2.idct(np.dot(u, np.dot(np.diag(s), v))) | |
| def infer_dct_svd(self, block, scale): | |
| u,s,v = np.linalg.svd(cv2.dct(block)) | |
| score = 0 | |
| score = int ((s[0] % scale) > scale * 0.5) | |
| return score | |
| if score >= 0.5: | |
| return 1.0 | |
| else: | |
| return 0.0 | |
| def encode_frame(self, frame, scale): | |
| ''' | |
| frame is a matrix (M, N) | |
| we get K (watermark bits size) blocks (self._block x self._block) | |
| For i-th block, we encode watermark[i] bit into it | |
| ''' | |
| (row, col) = frame.shape | |
| num = 0 | |
| for i in range(row//self._block): | |
| for j in range(col//self._block): | |
| block = frame[i*self._block : i*self._block + self._block, | |
| j*self._block : j*self._block + self._block] | |
| wmBit = self._watermarks[(num % self._wmLen)] | |
| diffusedBlock = self.diffuse_dct_svd(block, wmBit, scale) | |
| frame[i*self._block : i*self._block + self._block, | |
| j*self._block : j*self._block + self._block] = diffusedBlock | |
| num = num+1 | |