def batch_map(cords):
y = ((cords[..., 0] + 1.0) / 2.0) * self.image_size[0]
x = ((cords[..., 1] + 1.0) / 2.0) * self.image_size[1]
y = ktf.reshape(y, (1, 1, -1))
x = ktf.reshape(x, (1, 1, -1))
return ktf.exp(-((self.yy - y)**2 + (self.xx - x)**2) /
(2 * self.sigma**2))
def _col_kernel(upsampled_region_size, upsample_factor, axis_offsets,
data_shape):
data_shape_float = tf.cast(data_shape, tf.float32)
col_constant = tf.cast(data_shape_float[2] * upsample_factor, tf.complex64)
col_constant = (-1j * 2 * np.pi / col_constant)
col_kernel_a = tf.range(0, data_shape_float[2], dtype=tf.float32)
col_kernel_a = fftshift1d(col_kernel_a)
col_kernel_a = tf.reshape(col_kernel_a, (-1, 1))
col_kernel_a -= tf.floor(data_shape_float[2] / 2.)
col_kernel_a = tf.reshape(col_kernel_a, (1, -1))
col_kernel_a = tf.tile(col_kernel_a, (data_shape[0], 1))
col_kernel_b = tf.range(0, upsampled_region_size, dtype=tf.float32)
col_kernel_b = tf.reshape(col_kernel_b, (1, -1))
col_kernel_b = tf.tile(col_kernel_b, (data_shape[0], 1))
col_kernel_b = tf.transpose(col_kernel_b)
col_kernel_b -= tf.transpose(axis_offsets[:, 1])
col_kernel_b = tf.transpose(col_kernel_b)
col_kernel_a = tf.expand_dims(col_kernel_a, 1)
col_kernel_b = tf.expand_dims(col_kernel_b, -1)
col_kernel = col_kernel_a * col_kernel_b
col_kernel = tf.transpose(col_kernel, perm=(0, 2, 1))
col_kernel = col_constant * tf.cast(col_kernel, tf.complex64)
col_kernel = tf.exp(col_kernel)
return col_kernel
def _row_kernel(upsampled_region_size, upsample_factor, axis_offsets,
data_shape):
data_shape_float = tf.cast(data_shape, tf.float32)
row_constant = tf.cast(data_shape_float[1] * upsample_factor, tf.complex64)
row_constant = (-1j * 2 * np.pi / row_constant)
row_kernel_a = tf.range(0, upsampled_region_size, dtype=tf.float32)
row_kernel_a = tf.reshape(row_kernel_a, (1, -1))
row_kernel_a = tf.tile(row_kernel_a, (data_shape[0], 1))
row_kernel_a = tf.transpose(row_kernel_a)
row_kernel_a = row_kernel_a - axis_offsets[:, 0]
row_kernel_b = tf.range(0, data_shape_float[1], dtype=tf.float32)
row_kernel_b = fftshift1d(row_kernel_b)
row_kernel_b = tf.reshape(row_kernel_b, (1, -1))
row_kernel_b = tf.tile(row_kernel_b, (data_shape[0], 1))
row_kernel_b = row_kernel_b - tf.floor(data_shape_float[1] / 2.)
row_kernel_a = tf.expand_dims(row_kernel_a, 1)
row_kernel_b = tf.expand_dims(row_kernel_b, -1)
row_kernel = tf.transpose(row_kernel_a) * row_kernel_b
row_kernel = tf.transpose(row_kernel, perm=(0, 2, 1))
row_kernel = row_constant * tf.cast(row_kernel, tf.complex64)
row_kernel = tf.exp(row_kernel)
return row_kernel
def gaussian_kernel_1d(size, sigma):
size = tf.constant(size, dtype=tf.float32)
sigma = tf.constant(sigma, dtype=tf.float32)
x = tf.range(-(size // 2), (size // 2) + 1, dtype=tf.float32)
kernel = 1 / (sigma * tf.sqrt(2 * np.pi))
kernel *= tf.exp(-0.5 * (x / sigma)**2)
return tf.expand_dims(kernel, axis=-1)