我最近问了一个关于将数据嵌入图像的问题。在其他论坛的帮助下，我立即解决了该问题。我遇到了一个新问题：我的程序适用于所有拉丁字符，甚至带有变音（重音）标记的字符。我的程序无法处理其他 unicode 字符，例如西里尔文、希腊文和阿拉伯文等脚本中的字符。
这是我当前程序的代码，无法执行 unicode。
def embed_text(self, image_path, text, output_path):
# Convert text message to binary format
binary_message = ''.join(format(ord(char), '08b') for char in text) #aligning the bytes for embedding the message
# Load the image
image = Image.open(image_path)
w, h = image.size
# Calculate the number of embedding characters (eN)
eN = (h * w * 3) // 8
if len(text) > eN:
raise ValueError("Message too long to fit in the image")
# Embedding loop
message_index = 0
for i in range(h):
for j in range(w):
pixel = list(image.getpixel((j, i)))
for k in range(3): # For R, G, B components
if message_index < len(binary_message):
M = int(binary_message[message_index])
# Perform XOR operation with the 7th bit of the RGB component
pixel[k] = (pixel[k] & 0xFE) | (((pixel[k] >> 1) & 1) ^ M)
message_index += 1
else:
break # No more message bits to embed
image.putpixel((j, i), tuple(pixel))
# Save the Stego Image
image.save(output_path)
def xor_substitution(self, component, bit):
# Perform XOR on the least significant bit of the component with the bit
return (component & 0xFE) | (component & 1) ^ bit
def extract_text(self, image_path):
stego_image = Image.open(image_path)
w, h = stego_image.size
binary_message = ""
for i in range(h):
for j in range(w):
pixel = stego_image.getpixel((j, i))
for k in range(3):
binary_message += str(pixel[k] & 1)
# Extract only up to the NULL character
end = binary_message.find('00000000')
if end != -1:
binary_message = binary_message[:end]
return self.binary_to_string(binary_message)
def binary_to_string(self, binary_message):
text = ""
for i in range(0, len(binary_message), 8):
byte = binary_message[i:i+8]
text += chr(int(byte, 2))
return text
正如我所说，这些方法在从我扔给它的图像中嵌入和提取拉丁文本方面做得很好。当我尝试嵌入诸如
之类的东西时το
قili
8
我得到类似的东西
ñ;
ÈY♣
[]
为了解决此问题，我已将表示“08b”的行中的 8 位值更改为“16b”。我发现该程序仍然能够将内容嵌入到图像中，但会取出日语汉字或汉字。
Heere是我更改的代码：
def embed_text(self, image_path, text, output_path):
# Convert text message to binary format
binary_message = ''.join(format(ord(char), '16b') for char in text)
# Load the image
image = Image.open(image_path)
w, h = image.size
# Calculate the number of embedding characters (eN)
eN = (h * w * 3) // 16
if len(text) > eN:
raise ValueError("Message too long to fit in the image")
binary_message = binary_message.ljust(eN * 16, '0')
# Embedding loop
message_index = 0
for i in range(h):
for j in range(w):
pixel = list(image.getpixel((j, i)))
for k in range(3): # For R, G, B components
if message_index < len(binary_message):
M = int(binary_message[message_index:message_index+16], 2)
# Perform XOR operation with the 7th bit of the RGB component
pixel[k] = (pixel[k] & 0xFFFE) | (((pixel[k] >> 1) & 1) ^ M)
message_index += 16
else:
break # No more message bits to embed
image.putpixel((j, i), tuple(pixel))
# Save the Stego Image
image.save(output_path)
def xor_substitution(self, component, bit):
# Perform XOR on the least significant bit of the component with the bit
return (component & 0xFE) | (component & 1) ^ bit
def extract_text(self, image_path):
stego_image = Image.open(image_path)
w, h = stego_image.size
binary_message = ""
for i in range(h):
for j in range(w):
pixel = stego_image.getpixel((j, i))
for k in range(3):
binary_message += format(pixel[k] & 1, 'b').zfill(16)[-1]
# Extract only up to the NULL character
end = binary_message.find('00000000')
if end != -1:
binary_message = binary_message[:end]
return self.binary_to_string(binary_message)
def binary_to_string(self, binary_message):
text = ""
for i in range(0, len(binary_message), 16):
byte = binary_message[i:i+16]
text += chr(int(byte, 2))
return text
我想知道如何解决我的程序存在的这些问题，因为我需要在 12 月 5 日之前完成此实施。预先感谢您的帮助！
对原始代码进行最小程度的更改以使其正常工作，并带有注释：
# Added missing import
from PIL import Image
# removed "self" from arguments.
def embed_text(image_path, text, output_path):
# encode the message in UTF-8 and add a null.
message = text.encode() + b'\x00'
binary_message = ''.join(format(byte, '08b') for byte in message)
image = Image.open(image_path)
w, h = image.size
# Calculate the number of embedding characters (eN)
eN = (h * w * 3) // 8
# Check that encoded message has enough space in image
if len(message) > eN:
raise ValueError("Message too long to fit in the image")
message_index = 0
for i in range(h):
for j in range(w):
pixel = list(image.getpixel((j, i)))
for k in range(3): # For R, G, B components
if message_index < len(binary_message):
M = int(binary_message[message_index])
# Set bit 0 of the RGB component to the message bit
pixel[k] = (pixel[k] & 0xFE) | M
message_index += 1
else:
break
image.putpixel((j, i), tuple(pixel))
image.save(output_path)
def extract_text(image_path):
stego_image = Image.open(image_path)
w, h = stego_image.size
binary_message = ""
for i in range(h):
for j in range(w):
pixel = stego_image.getpixel((j, i))
for k in range(3):
binary_message += str(pixel[k] & 1)
# The NULL find here could false locate 8 zero bits that are parts of two bytes so removed.
# removed "self." from function call.
return binary_to_string(binary_message)
# removed "self" parameter.
def binary_to_string(binary_message):
# Use a byte array to store extracted bytes
text = bytearray()
for i in range(0, len(binary_message), 8):
byte = binary_message[i:i+8]
# stop on NULL byte
if byte == '00000000': break
# add extracted byte
text.append(int(byte, 2))
# decode the message
return text.decode()
# testing. Use appropriate input PNG file.
embed_text('in.png', 'Hello, world! 世界您好！', 'out.png')
print(extract_text('out.png'))
更高效的算法，删除 int/str/int 转换，只处理输入文件直到 null:
from PIL import Image
def embed_text(image_path, text, output_path):
# Convert text message to bytes format and add null
message_bytes = text.encode() + b'\x00'
# Load the image and extract the bytes into a mutable array
image = Image.open(image_path)
image_bytes = bytearray(image.tobytes())
# Need 8 bytes of image to store 8 bits of a message byte
if len(message_bytes) * 8 > len(image_bytes):
raise ValueError("Message too long to fit in the image")
# Embedding loop:
# 1. Clear the image byte MSB.
# 2. Compute the message_byte/bit indices.
# 3. Compute the message bit and set the image byte LSB.
for i in range(len(message_bytes) * 8):
image_bytes[i] &= 0xFE
message_index, bit_index = divmod(i, 8)
image_bytes[i] |= (message_bytes[message_index] >> bit_index) & 1
# Load the updated bytes into the image and save
image.frombytes(image_bytes)
image.save(output_path)
def extract_text(image_path):
stego_image = Image.open(image_path)
image_bytes = stego_image.tobytes()
message_bytes = bytearray()
message_byte = 0
# Extraction loop:
# 1. Extract LSB and store in message_byte at the correct index
# 2. Once 8 bits are extracted (indices 0-7):
# IF message_byte is not null:
# append message byte to message and clear message byte
# ELSE stop processing image bytes.
for i, byte in enumerate(image_bytes):
bit_index = i % 8
message_byte |= (byte & 1) << bit_index
if bit_index == 7:
if message_byte: # if not null
message_bytes.append(message_byte)
message_byte = 0
else:
break
try:
return message_bytes.decode()
except UnicodeDecodeError:
return 'No valid message found.'
embed_text('in.png', 'Hello, world! 世界您好！', 'out.png')
print(extract_text('out.png'))