Leffa / densepose /structures /chart_result.py
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init code
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# Copyright (c) Facebook, Inc. and its affiliates.
from dataclasses import dataclass
from typing import Any, Optional, Tuple
import torch
@dataclass
class DensePoseChartResult:
"""
DensePose results for chart-based methods represented by labels and inner
coordinates (U, V) of individual charts. Each chart is a 2D manifold
that has an associated label and is parameterized by two coordinates U and V.
Both U and V take values in [0, 1].
Thus the results are represented by two tensors:
- labels (tensor [H, W] of long): contains estimated label for each pixel of
the detection bounding box of size (H, W)
- uv (tensor [2, H, W] of float): contains estimated U and V coordinates
for each pixel of the detection bounding box of size (H, W)
"""
labels: torch.Tensor
uv: torch.Tensor
def to(self, device: torch.device):
"""
Transfers all tensors to the given device
"""
labels = self.labels.to(device)
uv = self.uv.to(device)
return DensePoseChartResult(labels=labels, uv=uv)
@dataclass
class DensePoseChartResultWithConfidences:
"""
We add confidence values to DensePoseChartResult
Thus the results are represented by two tensors:
- labels (tensor [H, W] of long): contains estimated label for each pixel of
the detection bounding box of size (H, W)
- uv (tensor [2, H, W] of float): contains estimated U and V coordinates
for each pixel of the detection bounding box of size (H, W)
Plus one [H, W] tensor of float for each confidence type
"""
labels: torch.Tensor
uv: torch.Tensor
sigma_1: Optional[torch.Tensor] = None
sigma_2: Optional[torch.Tensor] = None
kappa_u: Optional[torch.Tensor] = None
kappa_v: Optional[torch.Tensor] = None
fine_segm_confidence: Optional[torch.Tensor] = None
coarse_segm_confidence: Optional[torch.Tensor] = None
def to(self, device: torch.device):
"""
Transfers all tensors to the given device, except if their value is None
"""
def to_device_if_tensor(var: Any):
if isinstance(var, torch.Tensor):
return var.to(device)
return var
return DensePoseChartResultWithConfidences(
labels=self.labels.to(device),
uv=self.uv.to(device),
sigma_1=to_device_if_tensor(self.sigma_1),
sigma_2=to_device_if_tensor(self.sigma_2),
kappa_u=to_device_if_tensor(self.kappa_u),
kappa_v=to_device_if_tensor(self.kappa_v),
fine_segm_confidence=to_device_if_tensor(self.fine_segm_confidence),
coarse_segm_confidence=to_device_if_tensor(self.coarse_segm_confidence),
)
@dataclass
class DensePoseChartResultQuantized:
"""
DensePose results for chart-based methods represented by labels and quantized
inner coordinates (U, V) of individual charts. Each chart is a 2D manifold
that has an associated label and is parameterized by two coordinates U and V.
Both U and V take values in [0, 1].
Quantized coordinates Uq and Vq have uint8 values which are obtained as:
Uq = U * 255 (hence 0 <= Uq <= 255)
Vq = V * 255 (hence 0 <= Vq <= 255)
Thus the results are represented by one tensor:
- labels_uv_uint8 (tensor [3, H, W] of uint8): contains estimated label
and quantized coordinates Uq and Vq for each pixel of the detection
bounding box of size (H, W)
"""
labels_uv_uint8: torch.Tensor
def to(self, device: torch.device):
"""
Transfers all tensors to the given device
"""
labels_uv_uint8 = self.labels_uv_uint8.to(device)
return DensePoseChartResultQuantized(labels_uv_uint8=labels_uv_uint8)
@dataclass
class DensePoseChartResultCompressed:
"""
DensePose results for chart-based methods represented by a PNG-encoded string.
The tensor of quantized DensePose results of size [3, H, W] is considered
as an image with 3 color channels. PNG compression is applied and the result
is stored as a Base64-encoded string. The following attributes are defined:
- shape_chw (tuple of 3 int): contains shape of the result tensor
(number of channels, height, width)
- labels_uv_str (str): contains Base64-encoded results tensor of size
[3, H, W] compressed with PNG compression methods
"""
shape_chw: Tuple[int, int, int]
labels_uv_str: str
def quantize_densepose_chart_result(result: DensePoseChartResult) -> DensePoseChartResultQuantized:
"""
Applies quantization to DensePose chart-based result.
Args:
result (DensePoseChartResult): DensePose chart-based result
Return:
Quantized DensePose chart-based result (DensePoseChartResultQuantized)
"""
h, w = result.labels.shape
labels_uv_uint8 = torch.zeros([3, h, w], dtype=torch.uint8, device=result.labels.device)
labels_uv_uint8[0] = result.labels
labels_uv_uint8[1:] = (result.uv * 255).clamp(0, 255).byte()
return DensePoseChartResultQuantized(labels_uv_uint8=labels_uv_uint8)
def compress_quantized_densepose_chart_result(
result: DensePoseChartResultQuantized,
) -> DensePoseChartResultCompressed:
"""
Compresses quantized DensePose chart-based result
Args:
result (DensePoseChartResultQuantized): quantized DensePose chart-based result
Return:
Compressed DensePose chart-based result (DensePoseChartResultCompressed)
"""
import base64
import numpy as np
from io import BytesIO
from PIL import Image
labels_uv_uint8_np_chw = result.labels_uv_uint8.cpu().numpy()
labels_uv_uint8_np_hwc = np.moveaxis(labels_uv_uint8_np_chw, 0, -1)
im = Image.fromarray(labels_uv_uint8_np_hwc)
fstream = BytesIO()
im.save(fstream, format="png", optimize=True)
labels_uv_str = base64.encodebytes(fstream.getvalue()).decode()
shape_chw = labels_uv_uint8_np_chw.shape
return DensePoseChartResultCompressed(labels_uv_str=labels_uv_str, shape_chw=shape_chw)
def decompress_compressed_densepose_chart_result(
result: DensePoseChartResultCompressed,
) -> DensePoseChartResultQuantized:
"""
Decompresses DensePose chart-based result encoded into a base64 string
Args:
result (DensePoseChartResultCompressed): compressed DensePose chart result
Return:
Quantized DensePose chart-based result (DensePoseChartResultQuantized)
"""
import base64
import numpy as np
from io import BytesIO
from PIL import Image
fstream = BytesIO(base64.decodebytes(result.labels_uv_str.encode()))
im = Image.open(fstream)
labels_uv_uint8_np_chw = np.moveaxis(np.array(im, dtype=np.uint8), -1, 0)
return DensePoseChartResultQuantized(
labels_uv_uint8=torch.from_numpy(labels_uv_uint8_np_chw.reshape(result.shape_chw))
)