基于LSB与量化处理的盲提取实现

水印实现的思路为：

先将水印图像W二值化，当水印图像W=255时，若载体图像I对应位像素值为奇数，则I对应位值不变，若为偶数，I对应位值加一；当水印图像W=0时，若载体图像I对应位像素值为偶数，则I对应位值不变，若为奇数，I对应位值减一。

提取时只要判断对应位像素值的奇偶性，二值化赋值就可以提取出水印。

 

二值化

import cv2
from PIL import Image
import numpy as np

Img_path = 'C:\\User\\logo.bmp'

Img = Image.open(Img_path)
Img = Img.convert('L')

# 设定阈值
threshold = 180
table = []
for i in range(256):
    if i < threshold:
        table.append(0)
    else:
        table.append(255)

waterImg = Img.point(table, '1')
waterImg.save('C:\\Users\\2value.bmp')

为确保健壮性，后面的代码仍采用了阈值进行判断，而非0，255二值

水印嵌入部分

import cv2
import numpy as np
from PIL import Image

Img_path = 'C:\\Users\\20_2.bmp' # 载体图像
waterImg_path = 'C:\\Users\\2value.bmp' # 水印图像

Img = cv2.imread(Img_path)

waterImg = cv2.imread(waterImg_path, 0)

H = Img.shape[0]
W = Img.shape[1]
Img = cv2.resize(Img, (W, H))
waterImg = cv2.resize(waterImg, (W, H))
b = np.zeros((H, W), dtype=Img.dtype)
g = np.zeros((H, W), dtype=Img.dtype)
r = np.zeros((H, W), dtype=Img.dtype)
Img_new = np.zeros((H, W), dtype=Img.dtype)

b[:, :] = Img[:, :, 0]
g[:, :] = Img[:, :, 1]
r[:, :] = Img[:, :, 2]

for h in range(H):
    for w in range(W):
        if int(waterImg[h, w]) >= 180 and int(r[h, w]) % 2 == 0:
            Img_new[h, w] = int(r[h, w]) + 1
        elif int(waterImg[h, w]) < 180 and int(r[h, w]) % 2 == 1:
            Img_new[h, w] = int(r[h, w]) - 1
        else:
            Img_new[h, w] = int(r[h, w])


watermarkedImg = cv2.merge([Img_new, g, b])
watermarkedImg = Image.fromarray(watermarkedImg)
watermarkedImg = watermarkedImg.resize((W, H), Image.ANTIALIAS)
watermarkedImg.save('C:\\Users\\2value_new.bmp')

水印提取部分

import cv2
import numpy as np
from PIL import Image

extract_path = 'C:\\Users\\2value_new.bmp'
extract = cv2.imread(extract_path)

H = extract.shape[0]
W = extract.shape[1]

B = np.zeros((H, W), dtype=extract.dtype)
G = np.zeros((H, W), dtype=extract.dtype)
R = np.zeros((H, W), dtype=extract.dtype)
extract_new = np.zeros((H, W), dtype=extract.dtype)

B[:, :] = extract[:, :, 0]
G[:, :] = extract[:, :, 1]
R[:, :] = extract[:, :, 2]

for h in range(H):
    for w in range(W):
        if int(R[h, w]) % 2 == 0:
            extract_new[h, w] = 0
        elif int(R[h, w]) % 2 == 1:
            extract_new[h, w] = 255

waterImg = Image.fromarray(extract_new)
waterImg = waterImg.resize((100, 100), Image.ANTIALIAS)
waterImg.save('C:\\Users\\logonew.bmp')

最终结果

 

 

 提取结果也没有问题。