生成隐形水印，提取隐形水印

extract.py

from PIL import Image
import numpy as np
import sys
import os

def extract_watermark(input_image_path):
    # 打开带有隐形水印的图片
    watermarked_image = Image.open(input_image_path)
    watermarked_pixels = np.array(watermarked_image)

    # 提取红色通道
    red_channel = watermarked_pixels[:, :, 0]
    
    # 根据红色通道的奇偶性创建二进制水印图像
    # 偶数表示白色（255），奇数表示黑色（0）
    binary_watermark = (red_channel % 2 == 0).astype(np.uint8) * 255

    # 将二进制水印图像保存为新图像
    extracted_watermark_image = Image.fromarray(binary_watermark)
    extracted_watermark_path = os.path.join(os.path.dirname(input_image_path), 'watermark.png')
    extracted_watermark_image.save(extracted_watermark_path, format='PNG')
    print(f"Extracted watermark image saved to {extracted_watermark_path}")

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Usage: python script.py <path_to_watermarked_image>")
        sys.exit(1)

    input_image_path = os.path.abspath(sys.argv[1])  # 支持相对路径
    extract_watermark(input_image_path)

generate.py

from PIL import Image, ImageDraw, ImageFont
import numpy as np
import sys
import os

def add_watermark(input_image_path, watermark_text):
    # 打开原始图片
    original_image = Image.open(input_image_path)
    original_pixels = np.array(original_image)

    # 创建水印文字图片
    watermark_image = Image.new('L', original_image.size, 255)  # 白色背景
    draw = ImageDraw.Draw(watermark_image)
    font_size = 50
    font_path = "/System/Library/Fonts/Helvetica.ttc"  # macOS 上的 Helvetica 字体路径
    font = ImageFont.truetype(font_path, font_size)
    text_width, text_height = draw.textsize(watermark_text, font=font)
    
    # 添加边距
    margin = 20
    text_width += margin * 2
    text_height += margin * 2

    # 以重复平铺的方式绘制水印文字
    for y in range(0, watermark_image.height, text_height):
        for x in range(0, watermark_image.width, text_width):
            draw.text((x + margin, y + margin), watermark_text, font=font, fill=0)  # 使用黑色填充文字，添加边距

    watermark_pixels = np.array(watermark_image)

    # 将原始图片的红色通道每个像素值向上加1或向下减1，根据水印文字的黑色和白色部分
    height, width, _ = original_pixels.shape
    for i in range(height):
        for j in range(width):            
            # 检查水印像素是否是白色
            if watermark_pixels[i, j] == 255:
                # 如果原始红色通道值是奇数，则需要将其变为偶数
                if original_pixels[i, j, 0] % 2 == 1:
                    # 检查是否可以增加 1 而不超出 RGB 范围
                    if original_pixels[i, j, 0] < 255:
                        original_pixels[i, j, 0] += 1
                    else:
                        original_pixels[i, j, 0] -= 1
            else:
                # 水印像素是黑色，需要将原始红色通道值变为奇数
                if original_pixels[i, j, 0] % 2 == 0:
                    # 检查是否可以增加 1 而不超出 RGB 范围
                    if original_pixels[i, j, 0] < 255:
                        original_pixels[i, j, 0] += 1
                    else:
                        original_pixels[i, j, 0] -= 1

    # 保存修改后的图片
    output_image = Image.fromarray(original_pixels)
    output_image_path = os.path.join(os.path.dirname(input_image_path), 'output.png')
    output_image.save(output_image_path, format='PNG')
    print(f"Watermarked image saved to {output_image_path}")

if __name__ == "__main__":
    if len(sys.argv) != 3:
        print("Usage: python script.py <path_to_image> <watermark_text>")
        sys.exit(1)
    
    input_image_path = os.path.abspath(sys.argv[1])  # 支持相对路径
    watermark_text = sys.argv[2]
    add_watermark(input_image_path, watermark_text)