---
tags: Data Hiding, Python
disqus: HackMD
---
資料隱藏 Homework #3
===
```python=
import os
import cv2
import numpy as np
import copy
import pywt
from PIL import Image
from scipy.fftpack import dct
from scipy.fftpack import idct
```
```python=
base_path = '/content/drive/MyDrive/H.成大上課講義/資料隱藏技術/作業/作業三/'
file_path = base_path + 'images/'
coverImage = file_path + 'Lenna256.png'
watermarkimgA = file_path + 'watermarkA.jpg'
watermarkimgB = file_path + 'watermarkB.jpg'
```
LsbWatermark
---
```python=
class LSBSteg:
def __init__(self, im):
self.image = im
self.height, self.width, self.nbchannels = im.shape
self.size = self.width * self.height
self.maskONEValues = [1, 2, 4, 8, 16, 32, 64, 128]
# Mask used to put one ex:1->00000001, 2->00000010 .. associated with OR bitwise
self.maskONE = self.maskONEValues.pop(0) # Will be used to do bitwise operations
self.maskZEROValues = [254, 253, 251, 247, 239, 223, 191, 127]
# Mak used to put zero ex:254->11111110, 253->11111101 .. associated with AND bitwise
self.maskZERO = self.maskZEROValues.pop(0)
self.curwidth = 0 # Current width position
self.curheight = 0 # Current height position
self.curchan = 0 # Current channel position
def put_binary_value(self, bits): # Put the bits in the image
for c in bits:
val = list(self.image[self.curheight, self.curwidth]) # Get the pixel value as a list
if int(c) == 1:
val[self.curchan] = int(val[self.curchan]) | self.maskONE # OR with maskONE
else:
val[self.curchan] = int(val[self.curchan]) & self.maskZERO # AND with maskZERO
self.image[self.curheight, self.curwidth] = tuple(val)
self.next_slot() # Move "cursor" to the next space
def next_slot(self): # Move to the next slot were information can be taken or put
if self.curchan == self.nbchannels - 1: # Next Space is the following channel
self.curchan = 0
if self.curwidth == self.width - 1: # Or the first channel of the next pixel of the same line
self.curwidth = 0
if self.curheight == self.height - 1: # Or the first channel of the first pixel of the next line
self.curheight = 0
if self.maskONE == 128: # Mask 1000000, so the last mask
raise SteganographyException("No available slot remaining (image filled)")
else: # Or instead of using the first bit start using the second and so on..
self.maskONE = self.maskONEValues.pop(0)
self.maskZERO = self.maskZEROValues.pop(0)
else:
self.curheight += 1
else:
self.curwidth += 1
else:
self.curchan += 1
def read_bit(self): # Read a single bit int the image
val = self.image[self.curheight, self.curwidth][self.curchan]
val = int(val) & self.maskONE
self.next_slot()
if val > 0:
return "1"
else:
return "0"
def read_byte(self):
return self.read_bits(8)
def read_bits(self, nb): # Read the given number of bits
bits = ""
for i in range(nb):
bits += self.read_bit()
return bits
def byteValue(self, val):
return self.binary_value(val, 8)
def binary_value(self, val, bitsize): # Return the binary value of an int as a byte
binval = bin(val)[2:]
if len(binval) > bitsize:
raise SteganographyException("binary value larger than the expected size")
while len(binval) < bitsize:
binval = "0" + binval
return binval
def encode_text(self, txt):
l = len(txt)
binl = self.binary_value(l, 16) # Length coded on 2 bytes so the text size can be up to 65536 bytes long
self.put_binary_value(binl) # Put text length coded on 4 bytes
for char in txt: # And put all the chars
c = ord(char)
self.put_binary_value(self.byteValue(c))
return self.image
def decode_text(self):
ls = self.read_bits(16) # Read the text size in bytes
l = int(ls, 2)
i = 0
unhideTxt = ""
while i < l: # Read all bytes of the text
tmp = self.read_byte() # So one byte
i += 1
unhideTxt += chr(int(tmp, 2)) # Every chars concatenated to str
return unhideTxt
def encode_image(self, imtohide):
height = imtohide.shape[0]
width = imtohide.shape[1]
channels = imtohide.shape[2]
if self.width * self.height * self.nbchannels < width * height * channels:
raise SteganographyException("Carrier image not big enough to hold all the datas to steganography")
binw = self.binary_value(width, 16) # Width coded on to byte so width up to 65536
binh = self.binary_value(height, 16)
self.put_binary_value(binw) # Put width
self.put_binary_value(binh) # Put height
for h in range(height): # Iterate the hole image to put every pixel values
for w in range(width):
for chan in range(channels):
val = imtohide[h, w][chan]
self.put_binary_value(self.byteValue(int(val)))
return self.image
def decode_image(self):
width = int(self.read_bits(16), 2) # Read 16bits and convert it in int
height = int(self.read_bits(16), 2)
channels = self.nbchannels
unhideimg = np.zeros((width, height, 3), np.uint8) # Create an image in which we will put all the pixels read
for h in range(height):
for w in range(width):
for chan in range(channels):
val = list(unhideimg[w, h])
val[chan] = int(self.read_byte(), 2) # Read the value
unhideimg[w, h] = tuple(val)
return unhideimg
def encode_binary(self, data):
l = len(data)
if self.width * self.height * self.nbchannels < l + 64:
raise SteganographyException("Carrier image not big enough to hold all the datas to steganography")
self.put_binary_value(self.binary_value(l, 64))
for byte in data:
byte = byte if isinstance(byte, int) else ord(byte) # Compat py2/py3
self.put_binary_value(self.byteValue(byte))
return self.image
def decode_binary(self):
l = int(self.read_bits(64), 2)
output = b""
for i in range(l):
output += bytearray([int(self.read_byte(), 2)])
return output
```
DctWatermark
---
```python=
class DCTSteg:
def __init__(self):
self.path = os.path.join("images")
self.image = ""
self.watermark = ""
pass
def resizeImage(self, filename, size):
img = Image.open(os.path.join(self.path, filename))
img = img.resize((size, size), Image.ANTIALIAS)
img.save(os.path.join(self.path, filename))
def resizeImage2(self, filename, width, height):
img = Image.open(os.path.join(self.path, filename))
img = img.resize((width, height), Image.ANTIALIAS)
img.save(os.path.join(self.path, filename))
def convertImage(self, imageName, size, imName):
img = Image.open(imageName)
img = img.resize((size, size), Image.ANTIALIAS)
# Convert RGB image to gray scale
img = img.convert('L')
# Storing the gray scale image
img.save(os.path.join(self.path, 'processedInputImage/' + imName))
imageArray = np.array(img.getdata(), dtype=np.float).reshape((size, size))
return imageArray
def embedWatermark(self, watermarkArray, originalImage):
watermarkFlat = watermarkArray.ravel()
ind = 0
for x in range(0, len(originalImage), 8):
for y in range(0, len(originalImage), 8):
if ind < len(watermarkFlat):
subdct = originalImage[x:x+8, y:y+8]
subdct[5][5] = watermarkFlat[ind]
originalImage[x:x+8, y:y+8] = subdct
ind+= 1
return originalImage
def applyDCT(self, imageArray):
size = len(imageArray[0])
allSubdct = np.empty((size, size))
for i in range(0, size, 8):
for j in range(0, size, 8):
subpixels = imageArray[i:i+8, j:j+8]
subdct = dct(dct(subpixels.T, norm="ortho").T, norm="ortho")
allSubdct[i:i+8, j:j+8] = subdct
return allSubdct
def inverseDCT(self, allSubdct):
size = len(allSubdct[0])
allSubidct = np.empty((size, size))
for i in range(0, size, 8):
for j in range(0, size, 8):
subidct = idct(idct(allSubdct[i:i+8, j:j+8].T, norm="ortho").T, norm="ortho")
allSubidct[i:i+8, j:j+8] = subidct
return allSubidct
def getWatermark(self, dctWatermarkedCoeff, watermarkSize):
subwatermarks = []
for x in range(0, len(dctWatermarkedCoeff), 8):
for y in range(0, len(dctWatermarkedCoeff), 8):
coeffSlice = dctWatermarkedCoeff[x:x+8, y:y+8]
subwatermarks.append(coeffSlice[5][5])
watermark = np.array(subwatermarks).reshape(watermarkSize, watermarkSize)
return watermark
def recoverWatermark(self, imageArray, newpath, model='haar', level=1):
coeffsWatermarkedImage=list(pywt.wavedec2(data=imageArray, wavelet=model, level=level))
dctWatermarkedCoeff = self.applyDCT(coeffsWatermarkedImage[0])
watermarkArray = self.getWatermark(dctWatermarkedCoeff, 128)
watermarkArray = np.uint8(watermarkArray)
# Save result
img = Image.fromarray(watermarkArray)
img.save(os.path.join(self.path, newpath))
def printImage(self, imageArray, name):
imageArrayCopy = imageArray.clip(0, 255)
imageArrayCopy = imageArrayCopy.astype("uint8")
img = Image.fromarray(imageArrayCopy)
img.save(os.path.join(self.path, 'result/' + name))
def watermarkImage(self, img1, img2):
self.image = img1
self.watermark = img2
model = 'haar'
level = 1
imageArray = self.convertImage(self.image, 2048, "1.jpg")
watermarkArray = self.convertImage(self.watermark, 128, "2.png")
coeffsImage = list(pywt.wavedec2(data=imageArray, wavelet=model, level=level))
# coeffs_image = process_coefficients(image_array, model, level=level)
dctArray = self.applyDCT(coeffsImage[0])
dctArray = self.embedWatermark(watermarkArray, dctArray)
coeffsImage[0] = self.inverseDCT(dctArray)
# Watermark reconstruction
imageArrayH = pywt.waverec2(coeffsImage, model)
self.printImage(imageArrayH, 'watermarkedImage.jpg')
# recover images
# self.recoverWatermark(imageArray=imageArrayH, newpath='result/recoveredWatermark.jpg', model=model, level=level)
def decodeWatermark(self, img, newpath):
model = 'haar'
level = 1
imageArray = self.convertImage(img, 2048, "3.jpg")
self.recoverWatermark(imageArray=imageArray, newpath=newpath, model=model, level=level)
```
圖片處理方法
---
```python=
class ImgUtility:
def __init__(self):
pass
def greenCover(self, xmin, ymin, xmax, ymax):
img = self
cv2.rectangle(img, (xmin, ymin), (xmax, ymax), (104, 255, 88), 16*8, 8*8)
return img
def colorCover(self, x, y):
img = self
height = img.shape[0]
width = img.shape[1]
for h in range(height):
for w in range(width):
if w >= x and h >= y:
img[w, h] = 0
return img
def colorCover2(self, xmin, ymin, xmax, ymax):
img = self
height = img.shape[0]
width = img.shape[1]
for h in range(height):
for w in range(width):
if (w >= xmin) and (h >= ymin) and (w <= xmin + xmax) and (h <= ymin + ymax):
img[w, h] = 0
return img
```
主程式開始
---
* 建立資料夾
```python=
if not os.path.isdir('images'):
os.mkdir('images')
if not os.path.isdir('images/result'):
os.mkdir('images/result')
if not os.path.isdir('images/processedInputImage'):
os.mkdir('images/processedInputImage')
```
* coverImage空間域藏入watermark
```python=
LsbWatermark = LSBSteg(cv2.imread(coverImage))
new_imgC = LsbWatermark.encode_image(cv2.imread(watermarkimgA)) # 嵌入空間域浮水印
cv2.imwrite('images/result/new_image_C.png', new_imgC) # 儲存C圖(已嵌入空間域浮水印)
LsbWatermark = LSBSteg(cv2.imread('images/result/new_image_C.png')) # 取得空間域浮水印
decodeLsbWatermark = LsbWatermark.decode_image() # 第一張浮水印
img90 = np.rot90(cv2.flip(decodeLsbWatermark, 0), -1) # 轉正浮水印
cv2.imwrite('images/result/decodeLsbWatermark.png', img90) # 儲存空間域浮水印
```
* coverImage頻率域藏入watermark
```python=
"""第一題嵌入浮水印得到D圖, image/result/watermarkedImage.jpg"""
DctWatermark = DCTSteg()
DctWatermark.watermarkImage('images/result/new_image_C.png', watermarkimgB) # 嵌入頻率域浮水印
```
```python=
"""第二題取出浮水印, image/result/Watermark_decode.jpg"""
DctWatermark.decodeWatermark(os.path.join('images/result/watermarkedImage.jpg')
, newpath='result/Watermark_decode.jpg')
imgD = cv2.imread(os.path.join('images/result/watermarkedImage.jpg'))
watermark_decode = cv2.imread(os.path.join('images/result/Watermark_decode.jpg'))
watermark_decode97x195 = cv2.resize(watermark_decode, (97, 195), interpolation=cv2.INTER_CUBIC)
cv2.imwrite(os.path.join('images/result/watermarkedImage97x195.jpg'), watermark_decode97x195)
```
```python=
"""第三題將D圖之右下角的四分之一裁掉，然後取出剩下部分內部之 watermark"""
tmp = copy.copy(imgD)
cropimg = ImgUtility.colorCover(tmp, 128*8, 128*8)
cv2.imwrite(os.path.join('images/result/cropImage.jpg'), cropimg)
DctWatermark.decodeWatermark(os.path.join('images/result/cropImage.jpg')
, newpath='result/cropImage_decode.jpg')
DctWatermark.resizeImage2('result/cropImage_decode.jpg', 97, 195)
```
```python=
"""第四題將中間32*32，64*64，128*128正方形分別裁掉，然後分別取出剩下部分內部之watermark。"""
tmp = copy.copy(imgD)
cropimg32x32 = ImgUtility.colorCover2(tmp, 112*8, 112*8, 32*8, 32*8)
cv2.imwrite(os.path.join('images/result/cropImage32x32.jpg'), cropimg32x32)
DctWatermark.decodeWatermark(os.path.join('images/result/cropImage32x32.jpg')
, newpath='result/cropImage32x32_decode.jpg')
DctWatermark.resizeImage2('result/cropImage32x32_decode.jpg', 97, 195)
tmp = copy.copy(imgD)
cropimg64x64 = ImgUtility.colorCover2(tmp, 96*8, 96*8, 64*8, 64*8)
cv2.imwrite(os.path.join('images/result/cropImage64x64.jpg'), cropimg64x64)
DctWatermark.decodeWatermark(os.path.join('images/result/cropImage64x64.jpg')
, newpath='result/cropImage64x64_decode.jpg')
DctWatermark.resizeImage2('result/cropImage64x64_decode.jpg', 97, 195)
tmp = copy.copy(imgD)
cropimg128x128 = ImgUtility.colorCover2(tmp, 64*8, 64*8, 128*8, 128*8)
cv2.imwrite(os.path.join('images/result/cropImage128x128.jpg'), cropimg128x128)
DctWatermark.decodeWatermark(os.path.join('images/result/cropImage128x128.jpg')
, newpath='result/cropImage128x128_decode.jpg')
DctWatermark.resizeImage2('result/cropImage128x128_decode.jpg', 97, 195)
```
```python=
"""第五題將 D 圖截去如下圖中之兩圈綠色部分(兩圈實際位置請自行決定，但須說明 你做的選擇)，
綠色部分的寬度均為 16 pixels，然後取出剩下部分內部之 watermark。"""
tmp = copy.copy(imgD)
img256x256 = cv2.resize(tmp, (256, 256))
cv2.imwrite('images/result/watermarkedImage256x256.jpg', img256x256)
green1 = ImgUtility.greenCover(imgD, 10*8, 10*8, 220*8, 220*8)
green2 = ImgUtility.greenCover(green1, 90*8, 90*8, 140*8, 140*8)
tmp2 = copy.copy(green2)
green256x256 = cv2.resize(green2, (256, 256))
cv2.imwrite(os.path.join('images/result/greenCoverImage256x256.jpg'), green256x256)
cv2.imwrite(os.path.join('images/result/greenCoverImage.jpg'), tmp2)
DctWatermark.decodeWatermark(os.path.join('images/result/greenCoverImage.jpg')
, newpath='result/greenCoverImageWatermark_decode.jpg')
DctWatermark.resizeImage2('result/greenCoverImageWatermark_decode.jpg', 97, 195)
```
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