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import torch | |
import numpy as np | |
def mpjpe(predicted, target): | |
""" | |
Mean per-joint position error (i.e. mean Euclidean distance), | |
often referred to as "Protocol #1" in many papers. | |
""" | |
assert predicted.shape == target.shape | |
return torch.mean(torch.norm(predicted - target, dim=len(target.shape) - 1)) | |
def p_mpjpe(predicted, target): | |
""" | |
Pose error: MPJPE after rigid alignment (scale, rotation, and translation), | |
often referred to as "Protocol #2" in many papers. | |
""" | |
assert predicted.shape == target.shape | |
muX = np.mean(target, axis=1, keepdims=True) | |
muY = np.mean(predicted, axis=1, keepdims=True) | |
X0 = target - muX | |
Y0 = predicted - muY | |
normX = np.sqrt(np.sum(X0 ** 2, axis=(1, 2), keepdims=True)) | |
normY = np.sqrt(np.sum(Y0 ** 2, axis=(1, 2), keepdims=True)) | |
X0 /= normX | |
Y0 /= normY | |
H = np.matmul(X0.transpose(0, 2, 1), Y0) | |
U, s, Vt = np.linalg.svd(H) | |
V = Vt.transpose(0, 2, 1) | |
R = np.matmul(V, U.transpose(0, 2, 1)) | |
# Avoid improper rotations (reflections), i.e. rotations with det(R) = -1 | |
sign_detR = np.sign(np.expand_dims(np.linalg.det(R), axis=1)) | |
V[:, :, -1] *= sign_detR | |
s[:, -1] *= sign_detR.flatten() | |
R = np.matmul(V, U.transpose(0, 2, 1)) # Rotation | |
tr = np.expand_dims(np.sum(s, axis=1, keepdims=True), axis=2) | |
a = tr * normX / normY # Scale | |
t = muX - a * np.matmul(muY, R) # Translation | |
# Perform rigid transformation on the input | |
predicted_aligned = a * np.matmul(predicted, R) + t | |
# Return MPJPE | |
return np.mean(np.linalg.norm(predicted_aligned - target, axis=len(target.shape) - 1)) | |
def euclidean_losses(actual, target): | |
"""Calculate the average Euclidean loss for multi-point samples. | |
Each sample must contain `n` points, each with `d` dimensions. For example, | |
in the MPII human pose estimation task n=16 (16 joint locations) and | |
d=2 (locations are 2D). | |
Args: | |
actual (Tensor): Predictions (B x L x D) | |
target (Tensor): Ground truth target (B x L x D) | |
""" | |
assert actual.size() == target.size(), 'input tensors must have the same size' | |
# Calculate Euclidean distances between actual and target locations | |
diff = actual - target | |
dist_sq = diff.pow(2).sum(-1, keepdim=False) | |
dist = dist_sq.sqrt() | |
return dist | |
def pck(actual, expected, threshold=150): | |
dists = euclidean_losses(actual, expected) | |
return (dists < threshold).double().mean().item() | |
def auc(actual, expected): | |
# This range of thresholds mimics `mpii_compute_3d_pck.m`, which is provided as part of the | |
# MPI-INF-3DHP test data release. | |
thresholds = torch.linspace(0, 150, 31).tolist() | |
pck_values = torch.DoubleTensor(len(thresholds)) | |
for i, threshold in enumerate(thresholds): | |
pck_values[i] = pck(actual, expected, threshold=threshold) | |
return pck_values.mean().item() | |