encode.py

# coding=utf-8
import cv2
import numpy as np
import random
import os
from argparse import ArgumentParser
ALPHA = 5


def build_parser():
    parser = ArgumentParser()
    parser.add_argument('--image', dest='img', required=True)
    parser.add_argument('--watermark', dest='wm', required=True)
    parser.add_argument('--result', dest='res', required=True)
    parser.add_argument('--alpha', dest='alpha', default=ALPHA)
    return parser


def main():
    parser = build_parser()
    options = parser.parse_args()
    img = options.img
    wm = options.wm
    res = options.res
    alpha = options.alpha
    if not os.path.isfile(img):
        parser.error("image %s does not exist." % img)
    if not os.path.isfile(wm):
        parser.error("watermark %s does not exist." % wm)
    encode(img, wm, res, alpha)


def encode(img_path, wm_path, res_path, alpha):
    img = cv2.imread(img_path)
    img_f = np.fft.fft2(img)
    height, width, channel = np.shape(img)
    watermark = cv2.imread(wm_path)
    wm_height, wm_width = watermark.shape[0], watermark.shape[1]
    x, y = range(height / 2), range(width)
    random.seed(height + width)
    random.shuffle(x)
    random.shuffle(y)
    tmp = np.zeros(img.shape)
    for i in range(height / 2):
        for j in range(width):
            if x[i] < wm_height and y[j] < wm_width:
                tmp[i][j] = watermark[x[i]][y[j]]
                tmp[height - 1 - i][width - 1 - j] = tmp[i][j]
    res_f = img_f + alpha * tmp
    res = np.fft.ifft2(res_f)
    res = np.real(res)
    cv2.imwrite(res_path, res, [int(cv2.IMWRITE_JPEG_QUALITY), 100])
if __name__ == '__main__':
    main()