EasyMocap/easymocap/mytools/reconstruction.py
linyu0219 6475cbec41 fix repro_smpl projectN3 error
when vis repro_smpl, the kpts3d shape is [x,x,3], it has no visibility,it has xyz only, use z maybe lost some point in repro_smpl.
2022-09-22 16:37:39 +00:00

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'''
* @ Date: 2020-09-14 11:01:52
* @ Author: Qing Shuai
@ LastEditors: Qing Shuai
@ LastEditTime: 2021-04-13 20:31:34
@ FilePath: /EasyMocapRelease/media/qing/Project/mirror/EasyMocap/easymocap/mytools/reconstruction.py
'''
import numpy as np
def solveZ(A):
u, s, v = np.linalg.svd(A)
X = v[-1, :]
X = X / X[3]
return X[:3]
def projectN3(kpts3d, Pall):
# kpts3d: (N, 3)
nViews = len(Pall)
kp3d = np.hstack((kpts3d[:, :3], np.ones((kpts3d.shape[0], 1))))
kp2ds = []
for nv in range(nViews):
kp2d = Pall[nv] @ kp3d.T
kp2d[:2, :] /= kp2d[2:, :]
kp2ds.append(kp2d.T[None, :, :])
kp2ds = np.vstack(kp2ds)
if kpts3d.shape[-1] == 4:
kp2ds[..., -1] = kp2ds[..., -1] * (kpts3d[None, :, -1] > 0.)
return kp2ds
def simple_reprojection_error(kpts1, kpts1_proj):
# (N, 3)
error = np.mean((kpts1[:, :2] - kpts1_proj[:, :2])**2)
return error
def simple_triangulate(kpts, Pall):
# kpts: (nViews, 3)
# Pall: (nViews, 3, 4)
# return: kpts3d(3,), conf: float
nViews = len(kpts)
A = np.zeros((nViews*2, 4), dtype=np.float)
result = np.zeros(4)
result[3] = kpts[:, 2].sum()/(kpts[:, 2]>0).sum()
for i in range(nViews):
P = Pall[i]
A[i*2, :] = kpts[i, 2]*(kpts[i, 0]*P[2:3,:] - P[0:1,:])
A[i*2 + 1, :] = kpts[i, 2]*(kpts[i, 1]*P[2:3,:] - P[1:2,:])
result[:3] = solveZ(A)
return result
def batch_triangulate(keypoints_, Pall, keypoints_pre=None, lamb=1e3):
# keypoints: (nViews, nJoints, 3)
# Pall: (nViews, 3, 4)
# A: (nJoints, nViewsx2, 4), x: (nJoints, 4, 1); b: (nJoints, nViewsx2, 1)
v = (keypoints_[:, :, -1]>0).sum(axis=0)
valid_joint = np.where(v > 1)[0]
keypoints = keypoints_[:, valid_joint]
conf3d = keypoints[:, :, -1].sum(axis=0)/v[valid_joint]
# P2: P矩阵的最后一行(1, nViews, 1, 4)
P0 = Pall[None, :, 0, :]
P1 = Pall[None, :, 1, :]
P2 = Pall[None, :, 2, :]
# uP2: x坐标乘上P2: (nJoints, nViews, 1, 4)
uP2 = keypoints[:, :, 0].T[:, :, None] * P2
vP2 = keypoints[:, :, 1].T[:, :, None] * P2
conf = keypoints[:, :, 2].T[:, :, None]
Au = conf * (uP2 - P0)
Av = conf * (vP2 - P1)
A = np.hstack([Au, Av])
if keypoints_pre is not None:
# keypoints_pre: (nJoints, 4)
B = np.eye(4)[None, :, :].repeat(A.shape[0], axis=0)
B[:, :3, 3] = -keypoints_pre[valid_joint, :3]
confpre = lamb * keypoints_pre[valid_joint, 3]
# 1, 0, 0, -x0
# 0, 1, 0, -y0
# 0, 0, 1, -z0
# 0, 0, 0, 0
B[:, 3, 3] = 0
B = B * confpre[:, None, None]
A = np.hstack((A, B))
u, s, v = np.linalg.svd(A)
X = v[:, -1, :]
X = X / X[:, 3:]
# out: (nJoints, 4)
result = np.zeros((keypoints_.shape[1], 4))
result[valid_joint, :3] = X[:, :3]
result[valid_joint, 3] = conf3d
return result
eps = 0.01
def simple_recon_person(keypoints_use, Puse):
out = batch_triangulate(keypoints_use, Puse)
# compute reprojection error
kpts_repro = projectN3(out, Puse)
square_diff = (keypoints_use[:, :, :2] - kpts_repro[:, :, :2])**2
conf = np.repeat(out[None, :, -1:], len(Puse), 0)
kpts_repro = np.concatenate((kpts_repro, conf), axis=2)
return out, kpts_repro
def check_limb(keypoints3d, limb_means, thres=0.5):
# keypoints3d: (nJ, 4)
valid = True
cnt = 0
for (src, dst), val in limb_means.items():
if not (keypoints3d[src, 3] > 0 and keypoints3d[dst, 3] > 0):
continue
cnt += 1
# 计算骨长
l_est = np.linalg.norm(keypoints3d[src, :3] - keypoints3d[dst, :3])
if abs(l_est - val['mean'])/val['mean']/val['std'] > thres:
valid = False
break
# 至少两段骨头可以使用
valid = valid and cnt > 2
return valid