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# Copyright (c) Facebook, Inc. and its affiliates. | |
import random | |
from typing import Optional, Tuple | |
import torch | |
from torch.nn import functional as F | |
from detectron2.config import CfgNode | |
from detectron2.structures import Instances | |
from densepose.converters.base import IntTupleBox | |
from .densepose_cse_base import DensePoseCSEBaseSampler | |
class DensePoseCSEConfidenceBasedSampler(DensePoseCSEBaseSampler): | |
""" | |
Samples DensePose data from DensePose predictions. | |
Samples for each class are drawn using confidence value estimates. | |
""" | |
def __init__( | |
self, | |
cfg: CfgNode, | |
use_gt_categories: bool, | |
embedder: torch.nn.Module, | |
confidence_channel: str, | |
count_per_class: int = 8, | |
search_count_multiplier: Optional[float] = None, | |
search_proportion: Optional[float] = None, | |
): | |
""" | |
Constructor | |
Args: | |
cfg (CfgNode): the config of the model | |
embedder (torch.nn.Module): necessary to compute mesh vertex embeddings | |
confidence_channel (str): confidence channel to use for sampling; | |
possible values: | |
"coarse_segm_confidence": confidences for coarse segmentation | |
(default: "coarse_segm_confidence") | |
count_per_class (int): the sampler produces at most `count_per_class` | |
samples for each category (default: 8) | |
search_count_multiplier (float or None): if not None, the total number | |
of the most confident estimates of a given class to consider is | |
defined as `min(search_count_multiplier * count_per_class, N)`, | |
where `N` is the total number of estimates of the class; cannot be | |
specified together with `search_proportion` (default: None) | |
search_proportion (float or None): if not None, the total number of the | |
of the most confident estimates of a given class to consider is | |
defined as `min(max(search_proportion * N, count_per_class), N)`, | |
where `N` is the total number of estimates of the class; cannot be | |
specified together with `search_count_multiplier` (default: None) | |
""" | |
super().__init__(cfg, use_gt_categories, embedder, count_per_class) | |
self.confidence_channel = confidence_channel | |
self.search_count_multiplier = search_count_multiplier | |
self.search_proportion = search_proportion | |
assert (search_count_multiplier is None) or (search_proportion is None), ( | |
f"Cannot specify both search_count_multiplier (={search_count_multiplier})" | |
f"and search_proportion (={search_proportion})" | |
) | |
def _produce_index_sample(self, values: torch.Tensor, count: int): | |
""" | |
Produce a sample of indices to select data based on confidences | |
Args: | |
values (torch.Tensor): a tensor of length k that contains confidences | |
k: number of points labeled with part_id | |
count (int): number of samples to produce, should be positive and <= k | |
Return: | |
list(int): indices of values (along axis 1) selected as a sample | |
""" | |
k = values.shape[1] | |
if k == count: | |
index_sample = list(range(k)) | |
else: | |
# take the best count * search_count_multiplier pixels, | |
# sample from them uniformly | |
# (here best = smallest variance) | |
_, sorted_confidence_indices = torch.sort(values[0]) | |
if self.search_count_multiplier is not None: | |
search_count = min(int(count * self.search_count_multiplier), k) | |
elif self.search_proportion is not None: | |
search_count = min(max(int(k * self.search_proportion), count), k) | |
else: | |
search_count = min(count, k) | |
sample_from_top = random.sample(range(search_count), count) | |
index_sample = sorted_confidence_indices[-search_count:][sample_from_top] | |
return index_sample | |
def _produce_mask_and_results( | |
self, instance: Instances, bbox_xywh: IntTupleBox | |
) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor]: | |
""" | |
Method to get labels and DensePose results from an instance | |
Args: | |
instance (Instances): an instance of | |
`DensePoseEmbeddingPredictorOutputWithConfidences` | |
bbox_xywh (IntTupleBox): the corresponding bounding box | |
Return: | |
mask (torch.Tensor): shape [H, W], DensePose segmentation mask | |
embeddings (Tuple[torch.Tensor]): a tensor of shape [D, H, W] | |
DensePose CSE Embeddings | |
other_values: a tensor of shape [1, H, W], DensePose CSE confidence | |
""" | |
_, _, w, h = bbox_xywh | |
densepose_output = instance.pred_densepose | |
mask, embeddings, _ = super()._produce_mask_and_results(instance, bbox_xywh) | |
other_values = F.interpolate( | |
getattr(densepose_output, self.confidence_channel), | |
size=(h, w), | |
mode="bilinear", | |
)[0].cpu() | |
return mask, embeddings, other_values | |