Ошибка при вычислении фазового угла с использованием графика углового угла. ⇐ Python

[Anonymous]

Я пытаюсь вычислить фазовый угол между двумя временными рядами по двум известным сигналам (две синусоидальные волны с фазой 24 градуса). Однако, когда я вычисляю фазовый угол между этими сигналами, я не получаю ожидаемого результата по кадрам (24 градуса). Вот мой сценарий:

Код: Выделить всё

 def coupling_angle_joints(x, y, epsilon=0.05, datatype="degs"):
"""
Calculate coupling angles between two joint angle signals.

Parameters:
x:              numpy array
First angle signal (e.g., proximal joint angle).
y:              numpy array
Second angle signal (e.g., distal joint angle).
epsilon:        float, optional (default=0.05)
Tolerance level. Values below this threshold are considered close to zero.
datatype:       str, optional (default="degs")
Specifies the unit of the input data: "degs" for degrees, "rads" for radians.

Returns:
phase_angles:   numpy array
Array of coupling phase angles (in degrees) between 'x' and 'y' signals.
"""

# Convert angles from radians to degrees if necessary
# This ensures that all angles are in degrees before processing
if datatype.lower().strip() == "rads":
x = np.degrees(x)
y = np.degrees(y)

# Compute the difference between consecutive elements in each signal
# This captures the rate of change in the proximal (x) and distal (y) angles
x_diff = np.diff(x)
y_diff = np.diff(y)

# Initialize an array to store the calculated phase angles
# The shape matches the number of computed differences (len(x) - 1)
phase_angles = np.zeros(x_diff.shape[0])

# Iterate over each pair of consecutive differences to calculate coupling angles
for idx in range(len(x_diff)):

xi_diff = x_diff[idx]  # Change in the proximal angle (x) between two consecutive points
yi_diff = y_diff[idx]  # Change in the distal angle (y) between two consecutive points

# Handle cases where both differences are close to zero, using the tolerance 'epsilon'
if np.abs(xi_diff) < epsilon and np.abs(yi_diff) < epsilon:
# If both changes are negligible, set the phase angle to NaN
phase_angle = np.nan

# Handle cases where only proximal change is negligible
elif np.abs(xi_diff) < epsilon:
# Proximal joint is essentially static; angle depends on distal joint movement
# If distal change is positive, set to 90 degrees; if negative, set to -90 degrees
phase_angle = 90 if yi_diff > 0 else -90

# Handle cases where only distal change is negligible
elif np.abs(yi_diff) < epsilon:
# Distal joint is essentially static; angle depends on proximal joint movement
# If proximal change is positive, set to 0 degrees; if negative, set to -180 degrees
phase_angle = 0 if xi_diff > 0 else 180

else:
# Calculate phase angle using arctan2, which handles the signs of both `yi_diff` and `xi_diff`
# to place the angle correctly within all four quadrants
phase_angle = np.degrees(np.arctan2(yi_diff, xi_diff))

# Ensure phase angle is within the range [0, 360) by adding 360 if it's negative
if phase_angle < 0:
phase_angle += 360

# Store the calculated phase angle in the output array
phase_angles[idx] = phase_angle

return phase_angles

Заранее благодарим за любую помощь.

Подробнее здесь: https://stackoverflow.com/questions/791 ... angle-plot