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cvpr_2023/smpl/smpl_torch.py
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2023-05-22 23:19:39 +02:00

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Python

# based on https://github.com/CalciferZh/SMPL/blob/master/smpl_torch_batch.py
import os
import sys
import pickle
import torch
import numpy as np
import scipy.io as sio
from time import time
from torch.nn import Module
class SMPL(Module):
def __init__(self, device=None, path='', orig_smpl=False, is_skirt=False):
super(SMPL, self).__init__()
self.J_regressor = []
self.v_template = []
self.shapedirs = []
self.posedirs = []
self.weights = []
self.is_skirt = is_skirt
# Load SMPL models
# path = os.path.abspath(os.path.dirname(__file__))
with open(os.path.join(path, 'super_model_f.pkl'), 'rb') as f:
female = pickle.load(f, encoding="latin1")
self.J_regressor.append(torch.tensor(np.array(female['J_regressor'].todense(), dtype=np.float32)))
self.v_template.append(torch.tensor(female['v_template'], dtype=torch.float32))
self.posedirs.append(torch.tensor(female['posedirs'], dtype=torch.float32))
self.shapedirs.append(torch.tensor(female['shapedirs'], dtype=torch.float32))
self.weights.append(torch.tensor(female['weights'], dtype=torch.float32))
with open(os.path.join(path, 'super_model_m.pkl'), 'rb') as f:
male = pickle.load(f, encoding="latin1")
self.J_regressor.append(torch.tensor(np.array(male['J_regressor'].todense(), dtype=np.float32)))
self.v_template.append(torch.tensor(male['v_template'], dtype=torch.float32))
self.posedirs.append(torch.tensor(male['posedirs'], dtype=torch.float32))
self.shapedirs.append(torch.tensor(male['shapedirs'], dtype=torch.float32))
self.weights.append(torch.tensor(male['weights'], dtype=torch.float32))
kintree_table = male['kintree_table']
id_to_col = {kintree_table[1, i]: i for i in range(kintree_table.shape[1])}
self.parent = {i: id_to_col[kintree_table[0, i]] for i in range(1, kintree_table.shape[1])}
self.J_regressor = torch.stack(self.J_regressor, axis=0).to(device)
self.v_template = torch.stack(self.v_template, axis=0).to(device)
self.shapedirs = torch.stack(self.shapedirs, axis=0).to(device)
self.posedirs = torch.stack(self.posedirs, axis=0).to(device)
self.weights = torch.stack(self.weights, axis=0).to(device)
# Topology no head/hands/feet
F = sio.loadmat(os.path.join(path, 'ssmpl_faces.mat'))
self.f = np.array(F['faces_default'])
self.f_skirt = np.array(F['faces_skirt'])
self.nn = np.array(sio.loadmat(os.path.join(path, 'NN.mat')))
self.to_keep = sio.loadmat(os.path.join(path, 'keep_remove.mat'))['keep'].reshape(-1)
self.weights_all = self.weights
self.weights = self.weights[:,self.to_keep,:]
self.shape = (1,27578,3)
self.device = device
if orig_smpl:
self.to_keep = self.to_keep[self.to_keep < 6890]
self.J_regressor = self.J_regressor[:,:,:6890]
self.v_template = self.v_template[:,:6890,:]
self.shapedirs = self.shapedirs[:,:6890,:,:]
self.posedirs = self.posedirs[:,:6890,:,:]
self.weights_all = self.weights_all[:,:6890,:]
self.weights = self.weights_all[:,self.to_keep,:]
self.shape = (1, 6890, 3)
@staticmethod
def rodrigues(r):
"""
Rodrigues' rotation formula that turns axis-angle tensor into rotation
matrix in a batch-ed manner.
Parameter:
----------
r: Axis-angle rotation tensor of shape [batch_size * angle_num, 1, 3].
Return:
-------
Rotation matrix of shape [batch_size * angle_num, 3, 3].
"""
# eps = r.clone().normal_(std=1e-8)
# theta = torch.norm(r + eps, dim=(1, 2), keepdim=True) # dim cannot be tuple
theta = torch.norm(r, dim=(1, 2), keepdim=True)
theta = torch.maximum(theta, torch.ones_like(theta) * np.finfo(np.float32).eps)
theta_dim = theta.shape[0]
r_hat = r / theta
# cos = torch.cos(theta)
z_stick = torch.zeros(theta_dim, dtype=torch.float32).to(r.device)
m = torch.stack(
(z_stick, -r_hat[:, 0, 2], r_hat[:, 0, 1], r_hat[:, 0, 2], z_stick,
-r_hat[:, 0, 0], -r_hat[:, 0, 1], r_hat[:, 0, 0], z_stick), dim=1)
m = torch.reshape(m, (-1, 3, 3))
i_cube = (torch.eye(3, dtype=torch.float32).unsqueeze(dim=0) \
+ torch.zeros((theta_dim, 3, 3), dtype=torch.float32)).to(r.device)
A = r_hat.permute(0, 2, 1)
# dot = torch.matmul(A, r_hat)
# R = cos * i_cube + (1 - cos) * dot + torch.sin(theta) * m
R = i_cube + m * torch.sin(theta) + torch.matmul(m, m) * (1 - torch.cos(theta))
return R
@staticmethod
def with_zeros(x):
"""
Append a [0, 0, 0, 1] tensor to a [3, 4] tensor.
Parameter:
---------
x: Tensor to be appended.
Return:
------
Tensor after appending of shape [4,4]
"""
ones = torch.tensor(
[[[0.0, 0.0, 0.0, 1.0]]], dtype=torch.float32
).expand(x.shape[0],-1,-1).to(x.device)
ret = torch.cat((x, ones), dim=1)
return ret
@staticmethod
def pack(x):
"""
Append zero tensors of shape [4, 3] to a batch of [4, 1] shape tensor.
Parameter:
----------
x: A tensor of shape [batch_size, 4, 1]
Return:
------
A tensor of shape [batch_size, 4, 4] after appending.
"""
zeros43 = torch.zeros(
(x.shape[0], x.shape[1], 4, 3), dtype=torch.float32).to(x.device)
ret = torch.cat((zeros43, x), dim=3)
return ret
def forward(self, pose, betas, verts: torch.Tensor = None, remove: bool = True):
"""
Construct a compute graph that takes in parameters and outputs a tensor as
model vertices. Face indices are also returned as a numpy ndarray.
20190128: Add batch support.
Parameters:
---------
pose: Also known as 'theta', an [N, 24, 3] tensor indicating child joint rotation
relative to parent joint. For root joint it's global orientation.
Represented in a axis-angle format.
betas: Parameter for model shape. A tensor of shape [N, 10] as coefficients of
PCA components. Only 10 components were released by SMPL author.
trans: Global translation tensor of shape [N, 3].
Return:
------
A 3-D tensor of [N * 6890 * 3] for vertices,
and the corresponding [N * 19 * 3] joint positions.
"""
batch_num = betas.shape[0]
# v_shaped = torch.tensordot(betas, self.shapedirs, dims=([1], [2])) + self.v_template
v_shaped = []
v_shaped.append(torch.tensordot(betas[:,:10], self.shapedirs[0], dims=[[1], [2]]) + torch.reshape(self.v_template[0], shape=self.shape)) # female
v_shaped.append(torch.tensordot(betas[:,:10], self.shapedirs[1], dims=[[1], [2]]) + torch.reshape(self.v_template[1], shape=self.shape)) # male
v_shaped = torch.stack(v_shaped, axis=-1)
# J = torch.matmul(self.J_regressor, v_shaped)
J = torch.stack([torch.matmul(self.J_regressor[torch.greater(g, 0.5).to(torch.long)], v_shaped[i, :, :, torch.greater(g, 0.5).to(torch.long)]) for i, g in enumerate(betas[:,-1])])
J0 = torch.reshape(J[:,0,:], (-1, 1, 3))
J = J - J0
R_cube_big = self.rodrigues(pose.reshape(-1, 1, 3)).reshape(batch_num, -1, 3, 3)
if verts is not None:
v_posed = verts
else:
R_cube = R_cube_big[:, 1:, :, :]
I_cube = (torch.eye(3, dtype=torch.float32).unsqueeze(dim=0) + \
torch.zeros((batch_num, R_cube.shape[1], 3, 3), dtype=torch.float32)).to(self.device)
lrotmin = (R_cube - I_cube).reshape(batch_num, -1, 1).squeeze(dim=2)
v_posed = torch.stack([v_shaped[i, :, :, torch.greater(g, 0.5).to(torch.long)] + torch.tensordot(lrotmin[i], self.posedirs[torch.greater(g, 0.5).to(torch.long)], dims=([0], [2])) for i, g in enumerate(betas[:,-1])])
results = []
results.append(
self.with_zeros(torch.cat((R_cube_big[:, 0], torch.reshape(J[:, 0, :], (-1, 3, 1))), dim=2))
)
for i in range(1, 24):
results.append(
torch.matmul(
results[self.parent[i]],
self.with_zeros(
torch.cat(
(R_cube_big[:, i], torch.reshape(J[:, i, :] - J[:, self.parent[i], :], (-1, 3, 1))),
dim=2
)
)
)
)
stacked = torch.stack(results, dim=1)
results = stacked - \
self.pack(
torch.matmul(
stacked,
torch.reshape(
torch.cat((J, torch.zeros((batch_num, 24, 1), dtype=torch.float32).to(self.device)), dim=2),
(batch_num, 24, 4, 1)
)
)
)
joints = torch.matmul(results, torch.transpose(torch.concat([J, torch.ones((J.shape[0], 24, 1), dtype=torch.float32, device=J.get_device())], axis=-1)[:,:,None,:],2,3))[:,:,:3,0]
T = torch.stack([torch.tensordot(results[i], self.weights[torch.greater(g, 0.5).to(torch.long)], dims=([0], [1])).permute(2, 0, 1) for i, g in enumerate(betas[:,-1])])
rest_shape_h = torch.cat(
(v_posed, torch.ones((batch_num, v_posed.shape[1], 1), dtype=torch.float32).to(self.device)), dim=2
)
v = torch.matmul(T, torch.reshape(rest_shape_h, (batch_num, -1, 4, 1)))
v = torch.reshape(v, (batch_num, -1, 4))[:, :, :3]
result = v
root_joint = torch.reshape(joints[:,0,:], (-1, 1, 3))
result = result - root_joint
joints = joints - root_joint
# # plut result as a plotly 3d mesh
# import plotly.graph_objects as go
# fig = go.Figure(data=[go.Mesh3d(x=result[0,:,0].cpu().numpy(), y=result[0,:,2].cpu().numpy(), z=result[0,:,1].cpu().numpy(), color='lightpink', opacity=0.50, i=self.f[:,0], j=self.f[:,1], k=self.f[:,2], name='body')])
# # plot the joints as spheres
# fig.add_trace(go.Scatter3d(x=joints[0,:,0].cpu().numpy(), y=joints[0,:,2].cpu().numpy(), z=joints[0,:,1].cpu().numpy(), mode='markers', marker=dict(size=5, color='red'), name='joints'))
# fig.show()
if remove and verts is None:
result = result[:,self.to_keep,:]
return result, joints, v_shaped, v_posed