def build(step):
return BlockBitHider(
TransformHider(
SingleBitHider(ScanMapping(),
BinaryQuantizationIndexModulation(step)),
ImageTransform(
SeparableTransform(transform.TCHEBICHEF, transform.DCT2))))
def build(step, alpha, dimension=8):
CHARLIER = matrix.CharlierMatrix(dimension, alpha=alpha).get_values()
return BlockBitHider(
TransformHider(
SingleBitHider(ScanMapping(),
BinaryQuantizationIndexModulation(step)),
ImageTransform(SeparableTransform(CHARLIER, transform.DCT2))))
def build(step, a, q, dimension=8):
qc = QCharlierMatrix(dimension, a=a, q=q)
th = TchebichefMatrix(dimension, N=dimension)
transform = SeparableTransform(qc.get_values(), th.get_values())
return BlockBitHider(
TransformHider(
SingleBitHider(ScanMapping(),
BinaryQuantizationIndexModulation(step)),
ImageTransform(transform)))
def build(step, alpha, beta, gamma, dimension=8):
return BlockBitHider(
TransformHider(
SingleBitHider(ScanMapping(),
BinaryQuantizationIndexModulation(step)),
ImageTransform(
matrix.CharlierSobolevMatrix(dimension,
alpha=alpha,
beta=beta,
gamma=gamma))))
def test_set_coeficient(self):
'''
Test set coefficient with 8x8 row major scan
'''
block = np.array(range(0, 64)).reshape(8, 8)
scan = ScanMapping()
scanning = scan(block)
scanning[24] = 8
self.assertEqual(block[3, 0], 8)
def test_map_index_out_range(self):
block = np.array(range(0, 64)).reshape(8, 8)
scan = ScanMapping()
scanning = scan(block)
with self.assertRaises(IndexError, msg='scan index out of range'):
scanning[64]
with self.assertRaises(IndexError, msg='scan index out of range'):
scanning[64] = 9
def test_get_coeficient(self):
'''
Test get coefficient with 8x8 row major scan
'''
block = np.array(range(0, 64)).reshape(8, 8)
scan = ScanMapping()
scanning = scan(block)
self.assertEqual(scanning[0], 0)
self.assertEqual(scanning[18], 18)
self.assertEqual(scanning[63], 63)
def test_scanning(self):
'''
Test scanning with 8x8 row major scan
'''
block = np.array(range(0, 64)).reshape(8, 8)
exploration = list(range(0, 64))
scan = ScanMapping()
scanning = scan(block)
np.testing.assert_array_equal(list(scanning), exploration)
def test_block_index_out_range(self):
'''
Test raise condition when block has
less dimension than the map
'''
block = np.array([[0, 1, 5, 6], [2, 4, 7, 13], [3, 8, 12, 17],
[9, 11, 18, 24]])
scan = ScanMapping()
scanning = scan(block)
with self.assertRaises(IndexError, msg='block index out of range'):
scanning[63]
with self.assertRaises(IndexError, msg='block index out of range'):
scanning[63] = 8
def test_extract(self):
embedder = MagicMock()
embedder.extract = Mock(return_value=0.52259635)
cover = np.array([
[0.72104381, 0.3611912],
[0.54423469, 0.99351504],
])
scan = ScanMapping()
hider = hiders.SingleBitHider(scan, embedder)
amplitude = hider.extract(cover, index=0)
embedder.extract.assert_called_once_with(.72104381)
self.assertEqual(amplitude, .52259635)
def test_set_coeficient(self):
'''
Test set coefficient with 8x8 zig-zag scan
'''
block = np.array([[0, 1, 5, 6, 14, 15, 27, 28],
[2, 4, 7, 13, 16, 26, 29, 42],
[3, 8, 12, 17, 25, 30, 41, 43],
[9, 11, 18, 24, 31, 40, 44, 53],
[10, 19, 23, 32, 39, 45, 52, 54],
[20, 22, 33, 38, 46, 51, 55, 60],
[21, 34, 37, 47, 50, 56, 59, 61],
[35, 36, 48, 49, 57, 58, 62, 63]])
scan = ScanMapping(map=maps.ZIGZAG_8x8)
scanning = scan(block)
scanning[24] = 8
self.assertEqual(block[3, 3], 8)
def test_scanning(self):
'''
Test scanning with 8x8 zig-zag scan
'''
block = np.array([[0, 1, 5, 6, 14, 15, 27, 28],
[2, 4, 7, 13, 16, 26, 29, 42],
[3, 8, 12, 17, 25, 30, 41, 43],
[9, 11, 18, 24, 31, 40, 44, 53],
[10, 19, 23, 32, 39, 45, 52, 54],
[20, 22, 33, 38, 46, 51, 55, 60],
[21, 34, 37, 47, 50, 56, 59, 61],
[35, 36, 48, 49, 57, 58, 62, 63]])
exploration = list(range(0, 64))
scan = ScanMapping(map=maps.ZIGZAG_8x8)
scanning = scan(block)
np.testing.assert_array_equal(list(scanning), exploration)
def test_map_index_out_range(self):
block = np.array([[0, 1, 5, 6, 14, 15, 27, 28],
[2, 4, 7, 13, 16, 26, 29, 42],
[3, 8, 12, 17, 25, 30, 41, 43],
[9, 11, 18, 24, 31, 40, 44, 53],
[10, 19, 23, 32, 39, 45, 52, 54],
[20, 22, 33, 38, 46, 51, 55, 60],
[21, 34, 37, 47, 50, 56, 59, 61],
[35, 36, 48, 49, 57, 58, 62, 63]])
scan = ScanMapping(map=maps.ZIGZAG_8x8)
scanning = scan(block)
with self.assertRaises(IndexError, msg='scan index out of range'):
scanning[64]
with self.assertRaises(IndexError, msg='scan index out of range'):
scanning[64] = 9
def test_insert(self):
embedder = MagicMock()
embedder.embed = Mock(return_value=0.52259635)
cover_work = np.array([
[0.72104381, 0.3611912],
[0.54423469, 0.99351504],
])
ws_work_expected = np.array([
[0.52259635, 0.3611912],
[0.54423469, 0.99351504],
])
scan = ScanMapping()
hider = hiders.SingleBitHider(scan, embedder)
ws_work = hider.insert(cover_work, bit=1, index=0)
embedder.embed.assert_called_once_with(0.72104381, 1)
np.testing.assert_array_equal(ws_work, ws_work_expected)
def build(step):
return BlockBitHider(
TransformHider(
SingleBitHider(ScanMapping(),
BinaryQuantizationIndexModulation(step)),
ImageTransform(DCT())))
def build(step, p, q, dimensions=8):
return BlockBitHider(
TransformHider(
SingleBitHider(ScanMapping(),
BinaryQuantizationIndexModulation(step)),
ImageTransform(QKrawtchoukMatrix(dimensions, p=p, q=q))))