def quad_qual(coords):
vec = np.array([coords[i] - coords[i - 1] for i in range(len(coords))])
a = np.array([angle(vec[i], vec[(i - 1)]) for i in range(len(vec))])
length = np.array([np.linalg.norm([v]) for v in vec])
qual = 1 - np.sum([
np.abs(a - np.pi / 2) /
(np.pi / 2) + np.abs(length - np.mean(length)) / np.mean(length)
]) / 8
return qual
def directionality_error(nodes, polygon):
angles = []
for i in range(len(nodes)):
#edge as vector
v1 = nodes[i - 1] - nodes[i]
#get vector of two closest boundary points to each node
v2 = nearest_points(polygon,Point(nodes[i][0], nodes[i][1]))[0] -\
nearest_points(polygon,Point(nodes[i-1][0], nodes[i-1][1]))[0]
angles.append((angle(v1, v2) % (0.5 * np.pi)))
return 1 - (np.mean(angles) / (0.5 * np.pi))
def geometric_irregularity(nodes, mode="std-angle"):
if mode == "std-edges":
dist = [
np.sqrt((nodes[i - 1][0] - nodes[i][0])**2 +
(nodes[i - 1][1] - nodes[i][1])**2)
for i in range(len(nodes))
]
result = 1 - np.std(dist) / np.mean(dist)
if mode == "std-angle":
angles = []
for i in range(len(nodes)):
# edge as vector
v1 = nodes[i - 1] - nodes[i]
v2 = nodes[i] - nodes[(i + 1) % len(nodes)]
angles.append(angle(v1, v2))
result = 1 - np.std(angles) / np.pi
#if angles don't add up to 360 degrees (only for quads) that means their dot product has a different sign somewhere
#so it is non-convex --> avoid this quad
if len(nodes) == 4 and not np.isclose(np.sum(angles), 2 * np.pi):
return 0
return result
def dft_analysis(_input, window, N):
"""
Analysis of a signal using the discrete Fourier transform
inputs:
_input: tensor of shape [batch_size, N]
window: analysis window, tensor of shape [N]
N: FFT size
returns:
Tensors m, p: magnitude and phase spectrum of _input
m of shape [batch_size, num_coefficients]
p of shape [batch_size, num_coefficients]
"""
if not (is_power2(N)):
raise ValueError("FFT size is not a power of 2")
_, input_length = _input.get_shape()
_input_shape = tf.shape(_input)
if (int(input_length) > N):
raise ValueError("Input length is greater than FFT size")
if (int(window.get_shape()[0]) != N):
raise ValueError("Window length is different from FFT size")
if int(input_length) < N:
with tf.name_scope('DFT_Zero_padding'):
zeros_left = tf.zeros(_input_shape)[:, :int((N -
(int(input_length)) +
1) / 2)]
zeros_right = tf.zeros(_input_shape)[:, :int(
(N - (int(input_length))) / 2)]
_input = tf.concat([zeros_left, _input, zeros_right], axis=1)
assert (int(_input.get_shape()[1]) == N)
positive_spectrum_size = int(N / 2) + 1
with tf.name_scope('Windowing'):
window_norm = tf.div(window, tf.reduce_sum(window))
# window the input
windowed_input = tf.multiply(_input, window_norm)
with tf.name_scope('Zero_phase_padding'):
# zero-phase window in fftbuffer
fftbuffer_left = tf.slice(windowed_input, [0, int(N / 2)], [-1, -1])
fftbuffer_right = tf.slice(windowed_input, [0, 0], [-1, int(N / 2)])
fftbuffer = tf.concat([fftbuffer_left, fftbuffer_right], axis=1)
fft = tf.spectral.rfft(fftbuffer)
with tf.name_scope('Slice_positive_side'):
sliced_fft = tf.slice(fft, [0, 0], [-1, positive_spectrum_size])
with tf.name_scope('Magnitude'):
# compute absolute value of positive side
abs_fft = tf.abs(sliced_fft)
# magnitude spectrum of positive frequencies in dB
magnitude = 20 * log10(tf.maximum(abs_fft, 1E-06))
with tf.name_scope('Phase'):
# phase of positive frequencies
phase = angle(sliced_fft)
return magnitude, phase
