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# Copyright (c) Facebook, Inc. and its affiliates.
import math
from typing import Any, List
import torch
from torch import nn
from torch.nn import functional as F
from detectron2.config import CfgNode
from detectron2.structures import Instances
from .. import DensePoseConfidenceModelConfig, DensePoseUVConfidenceType
from .chart import DensePoseChartLoss
from .registry import DENSEPOSE_LOSS_REGISTRY
from .utils import BilinearInterpolationHelper, LossDict
@DENSEPOSE_LOSS_REGISTRY.register()
class DensePoseChartWithConfidenceLoss(DensePoseChartLoss):
""" """
def __init__(self, cfg: CfgNode):
super().__init__(cfg)
self.confidence_model_cfg = DensePoseConfidenceModelConfig.from_cfg(cfg)
if self.confidence_model_cfg.uv_confidence.type == DensePoseUVConfidenceType.IID_ISO:
self.uv_loss_with_confidences = IIDIsotropicGaussianUVLoss(
self.confidence_model_cfg.uv_confidence.epsilon
)
elif self.confidence_model_cfg.uv_confidence.type == DensePoseUVConfidenceType.INDEP_ANISO:
self.uv_loss_with_confidences = IndepAnisotropicGaussianUVLoss(
self.confidence_model_cfg.uv_confidence.epsilon
)
def produce_fake_densepose_losses_uv(self, densepose_predictor_outputs: Any) -> LossDict:
"""
Overrides fake losses for fine segmentation and U/V coordinates to
include computation graphs for additional confidence parameters.
These are used when no suitable ground truth data was found in a batch.
The loss has a value 0 and is primarily used to construct the computation graph,
so that `DistributedDataParallel` has similar graphs on all GPUs and can
perform reduction properly.
Args:
densepose_predictor_outputs: DensePose predictor outputs, an object
of a dataclass that is assumed to have the following attributes:
* fine_segm - fine segmentation estimates, tensor of shape [N, C, S, S]
* u - U coordinate estimates per fine labels, tensor of shape [N, C, S, S]
* v - V coordinate estimates per fine labels, tensor of shape [N, C, S, S]
Return:
dict: str -> tensor: dict of losses with the following entries:
* `loss_densepose_U`: has value 0
* `loss_densepose_V`: has value 0
* `loss_densepose_I`: has value 0
"""
conf_type = self.confidence_model_cfg.uv_confidence.type
if self.confidence_model_cfg.uv_confidence.enabled:
loss_uv = (
densepose_predictor_outputs.u.sum() + densepose_predictor_outputs.v.sum()
) * 0
if conf_type == DensePoseUVConfidenceType.IID_ISO:
loss_uv += densepose_predictor_outputs.sigma_2.sum() * 0
elif conf_type == DensePoseUVConfidenceType.INDEP_ANISO:
loss_uv += (
densepose_predictor_outputs.sigma_2.sum()
+ densepose_predictor_outputs.kappa_u.sum()
+ densepose_predictor_outputs.kappa_v.sum()
) * 0
return {"loss_densepose_UV": loss_uv}
else:
return super().produce_fake_densepose_losses_uv(densepose_predictor_outputs)
def produce_densepose_losses_uv(
self,
proposals_with_gt: List[Instances],
densepose_predictor_outputs: Any,
packed_annotations: Any,
interpolator: BilinearInterpolationHelper,
j_valid_fg: torch.Tensor,
) -> LossDict:
conf_type = self.confidence_model_cfg.uv_confidence.type
if self.confidence_model_cfg.uv_confidence.enabled:
u_gt = packed_annotations.u_gt[j_valid_fg]
u_est = interpolator.extract_at_points(densepose_predictor_outputs.u)[j_valid_fg]
v_gt = packed_annotations.v_gt[j_valid_fg]
v_est = interpolator.extract_at_points(densepose_predictor_outputs.v)[j_valid_fg]
sigma_2_est = interpolator.extract_at_points(densepose_predictor_outputs.sigma_2)[
j_valid_fg
]
if conf_type == DensePoseUVConfidenceType.IID_ISO:
return {
"loss_densepose_UV": (
self.uv_loss_with_confidences(u_est, v_est, sigma_2_est, u_gt, v_gt)
* self.w_points
)
}
elif conf_type in [DensePoseUVConfidenceType.INDEP_ANISO]:
kappa_u_est = interpolator.extract_at_points(densepose_predictor_outputs.kappa_u)[
j_valid_fg
]
kappa_v_est = interpolator.extract_at_points(densepose_predictor_outputs.kappa_v)[
j_valid_fg
]
return {
"loss_densepose_UV": (
self.uv_loss_with_confidences(
u_est, v_est, sigma_2_est, kappa_u_est, kappa_v_est, u_gt, v_gt
)
* self.w_points
)
}
return super().produce_densepose_losses_uv(
proposals_with_gt,
densepose_predictor_outputs,
packed_annotations,
interpolator,
j_valid_fg,
)
class IIDIsotropicGaussianUVLoss(nn.Module):
"""
Loss for the case of iid residuals with isotropic covariance:
$Sigma_i = sigma_i^2 I$
The loss (negative log likelihood) is then:
$1/2 sum_{i=1}^n (log(2 pi) + 2 log sigma_i^2 + ||delta_i||^2 / sigma_i^2)$,
where $delta_i=(u - u', v - v')$ is a 2D vector containing UV coordinates
difference between estimated and ground truth UV values
For details, see:
N. Neverova, D. Novotny, A. Vedaldi "Correlated Uncertainty for Learning
Dense Correspondences from Noisy Labels", p. 918--926, in Proc. NIPS 2019
"""
def __init__(self, sigma_lower_bound: float):
super(IIDIsotropicGaussianUVLoss, self).__init__()
self.sigma_lower_bound = sigma_lower_bound
self.log2pi = math.log(2 * math.pi)
def forward(
self,
u: torch.Tensor,
v: torch.Tensor,
sigma_u: torch.Tensor,
target_u: torch.Tensor,
target_v: torch.Tensor,
):
# compute $\sigma_i^2$
# use sigma_lower_bound to avoid degenerate solution for variance
# (sigma -> 0)
sigma2 = F.softplus(sigma_u) + self.sigma_lower_bound
# compute \|delta_i\|^2
# pyre-fixme[58]: `**` is not supported for operand types `Tensor` and `int`.
delta_t_delta = (u - target_u) ** 2 + (v - target_v) ** 2
# the total loss from the formula above:
loss = 0.5 * (self.log2pi + 2 * torch.log(sigma2) + delta_t_delta / sigma2)
return loss.sum()
class IndepAnisotropicGaussianUVLoss(nn.Module):
"""
Loss for the case of independent residuals with anisotropic covariances:
$Sigma_i = sigma_i^2 I + r_i r_i^T$
The loss (negative log likelihood) is then:
$1/2 sum_{i=1}^n (log(2 pi)
+ log sigma_i^2 (sigma_i^2 + ||r_i||^2)
+ ||delta_i||^2 / sigma_i^2
- <delta_i, r_i>^2 / (sigma_i^2 * (sigma_i^2 + ||r_i||^2)))$,
where $delta_i=(u - u', v - v')$ is a 2D vector containing UV coordinates
difference between estimated and ground truth UV values
For details, see:
N. Neverova, D. Novotny, A. Vedaldi "Correlated Uncertainty for Learning
Dense Correspondences from Noisy Labels", p. 918--926, in Proc. NIPS 2019
"""
def __init__(self, sigma_lower_bound: float):
super(IndepAnisotropicGaussianUVLoss, self).__init__()
self.sigma_lower_bound = sigma_lower_bound
self.log2pi = math.log(2 * math.pi)
def forward(
self,
u: torch.Tensor,
v: torch.Tensor,
sigma_u: torch.Tensor,
kappa_u_est: torch.Tensor,
kappa_v_est: torch.Tensor,
target_u: torch.Tensor,
target_v: torch.Tensor,
):
# compute $\sigma_i^2$
sigma2 = F.softplus(sigma_u) + self.sigma_lower_bound
# compute \|r_i\|^2
# pyre-fixme[58]: `**` is not supported for operand types `Tensor` and `int`.
r_sqnorm2 = kappa_u_est**2 + kappa_v_est**2
delta_u = u - target_u
delta_v = v - target_v
# compute \|delta_i\|^2
# pyre-fixme[58]: `**` is not supported for operand types `Tensor` and `int`.
delta_sqnorm = delta_u**2 + delta_v**2
delta_u_r_u = delta_u * kappa_u_est
delta_v_r_v = delta_v * kappa_v_est
# compute the scalar product <delta_i, r_i>
delta_r = delta_u_r_u + delta_v_r_v
# compute squared scalar product <delta_i, r_i>^2
# pyre-fixme[58]: `**` is not supported for operand types `Tensor` and `int`.
delta_r_sqnorm = delta_r**2
denom2 = sigma2 * (sigma2 + r_sqnorm2)
loss = 0.5 * (
self.log2pi + torch.log(denom2) + delta_sqnorm / sigma2 - delta_r_sqnorm / denom2
)
return loss.sum()
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