def benchmark_extract_step(self, path, image, attack_name, attacked, attacked_path, watermark_file):
wmark, gamma = self.extract_specific(numpy.array(Image.open(image)),
attacked_path)
wmark = wmark.clip(0,255)
wmark = wmark.astype('uint8')
gamma = Metrics.gamma(wmark.ravel(), numpy.array(Image.open(watermark_file)).ravel())
wmark = Image.fromarray(wmark)
wmark.save(os.path.join(path, attack_name + "-extracted-wm-" + os.path.split(image)[1]))
return wmark, gamma
def extract_specific(self, image, watermark):
f_dct = TwoDimensionalDCT.forward(image)
w = self.load_watermark(watermark)
xi = []
xo = []
for entry in w:
xo.append( entry[self.INSERTED_WATERMARK_VALUE_KEY] )
xi.append( (f_dct[tuple(entry[self.INDEX_KEY])] - entry[self.ORIGINAL_VALUE_KEY]) /\
(self.alpha))
return None, Metrics.gamma(xi, xo)
