def test_invalid_binary_data(self):
# Watermark inserted
iwatermark = ewatermark = 'asd45621'
with self.assertRaises(ValueError):
metrics.ber(iwatermark, ewatermark)
iwatermark = ewatermark = '45621'
with self.assertRaises(ValueError):
metrics.ber(iwatermark, ewatermark)
def pnsr_ber_index(
hider_factory, cover_work, data,
index, step, *args, attacks=None, reference_psnr=44, **kwargs):
def get_extractor(extractor, index):
def wrapper(ws_work):
return extractor(ws_work, index=index)
return wrapper
index = int(round(index))
step = int(round(step))
data = utils.char2bin(data)
hider = hider_factory.build(step, *args, **kwargs)
ws_work = hider.insert(cover_work, data, index=index)
psnr = imperceptibility.psnr(cover_work, ws_work)
watermark = hider.extract(ws_work, index=index)
if attacks:
extract = get_extractor(hider.extract, index)
ber = ber_mean(extract, ws_work, watermark, attacks)
else:
ber = robustness.ber(watermark, data)
return psnr, ber
def test_watermarks_same_length(self):
# Watermark inserted
iwatermark = '1011001010'
# Watermark extracted
ewatermark = '1111000111'
ber = metrics.ber(iwatermark, ewatermark)
self.assertEqual(ber, 0.4)
def ber_mean(extract, ws_work, watermark, attacks):
return np.mean(
[
robustness.ber(
extract(attack(ws_work)),
watermark
)
for attack in attacks
]
)
def test_watermark_zero_length(self):
# Watermark inserted
iwatermark = ewatermark = ''
with self.assertRaises(ValueError):
metrics.ber(iwatermark, ewatermark)