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# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
this code is based on https://github.com/open-mmlab/mmpose
"""
import cv2
import numpy as np
import paddle.nn.functional as F
def get_affine_mat_kernel(h, w, s, inv=False):
if w < h:
w_ = s
h_ = int(np.ceil((s / w * h) / 64.) * 64)
scale_w = w
scale_h = h_ / w_ * w
else:
h_ = s
w_ = int(np.ceil((s / h * w) / 64.) * 64)
scale_h = h
scale_w = w_ / h_ * h
center = np.array([np.round(w / 2.), np.round(h / 2.)])
size_resized = (w_, h_)
trans = get_affine_transform(
center, np.array([scale_w, scale_h]), 0, size_resized, inv=inv)
return trans, size_resized
def get_affine_transform(center,
input_size,
rot,
output_size,
shift=(0., 0.),
inv=False):
"""Get the affine transform matrix, given the center/scale/rot/output_size.
Args:
center (np.ndarray[2, ]): Center of the bounding box (x, y).
input_size (np.ndarray[2, ]): Size of input feature (width, height).
rot (float): Rotation angle (degree).
output_size (np.ndarray[2, ]): Size of the destination heatmaps.
shift (0-100%): Shift translation ratio wrt the width/height.
Default (0., 0.).
inv (bool): Option to inverse the affine transform direction.
(inv=False: src->dst or inv=True: dst->src)
Returns:
np.ndarray: The transform matrix.
"""
assert len(center) == 2
assert len(output_size) == 2
assert len(shift) == 2
if not isinstance(input_size, (np.ndarray, list)):
input_size = np.array([input_size, input_size], dtype=np.float32)
scale_tmp = input_size
shift = np.array(shift)
src_w = scale_tmp[0]
dst_w = output_size[0]
dst_h = output_size[1]
rot_rad = np.pi * rot / 180
src_dir = rotate_point([0., src_w * -0.5], rot_rad)
dst_dir = np.array([0., dst_w * -0.5])
src = np.zeros((3, 2), dtype=np.float32)
src[0, :] = center + scale_tmp * shift
src[1, :] = center + src_dir + scale_tmp * shift
src[2, :] = _get_3rd_point(src[0, :], src[1, :])
dst = np.zeros((3, 2), dtype=np.float32)
dst[0, :] = [dst_w * 0.5, dst_h * 0.5]
dst[1, :] = np.array([dst_w * 0.5, dst_h * 0.5]) + dst_dir
dst[2, :] = _get_3rd_point(dst[0, :], dst[1, :])
if inv:
trans = cv2.getAffineTransform(np.float32(dst), np.float32(src))
else:
trans = cv2.getAffineTransform(np.float32(src), np.float32(dst))
return trans
def get_warp_matrix(theta, size_input, size_dst, size_target):
"""This code is based on
https://github.com/open-mmlab/mmpose/blob/master/mmpose/core/post_processing/post_transforms.py
Calculate the transformation matrix under the constraint of unbiased.
Paper ref: Huang et al. The Devil is in the Details: Delving into Unbiased
Data Processing for Human Pose Estimation (CVPR 2020).
Args:
theta (float): Rotation angle in degrees.
size_input (np.ndarray): Size of input image [w, h].
size_dst (np.ndarray): Size of output image [w, h].
size_target (np.ndarray): Size of ROI in input plane [w, h].
Returns:
matrix (np.ndarray): A matrix for transformation.
"""
theta = np.deg2rad(theta)
matrix = np.zeros((2, 3), dtype=np.float32)
scale_x = size_dst[0] / size_target[0]
scale_y = size_dst[1] / size_target[1]
matrix[0, 0] = np.cos(theta) * scale_x
matrix[0, 1] = -np.sin(theta) * scale_x
matrix[0, 2] = scale_x * (
-0.5 * size_input[0] * np.cos(theta) + 0.5 * size_input[1] *
np.sin(theta) + 0.5 * size_target[0])
matrix[1, 0] = np.sin(theta) * scale_y
matrix[1, 1] = np.cos(theta) * scale_y
matrix[1, 2] = scale_y * (
-0.5 * size_input[0] * np.sin(theta) - 0.5 * size_input[1] *
np.cos(theta) + 0.5 * size_target[1])
return matrix
def _get_3rd_point(a, b):
"""To calculate the affine matrix, three pairs of points are required. This
function is used to get the 3rd point, given 2D points a & b.
The 3rd point is defined by rotating vector `a - b` by 90 degrees
anticlockwise, using b as the rotation center.
Args:
a (np.ndarray): point(x,y)
b (np.ndarray): point(x,y)
Returns:
np.ndarray: The 3rd point.
"""
assert len(
a) == 2, 'input of _get_3rd_point should be point with length of 2'
assert len(
b) == 2, 'input of _get_3rd_point should be point with length of 2'
direction = a - b
third_pt = b + np.array([-direction[1], direction[0]], dtype=np.float32)
return third_pt
def rotate_point(pt, angle_rad):
"""Rotate a point by an angle.
Args:
pt (list[float]): 2 dimensional point to be rotated
angle_rad (float): rotation angle by radian
Returns:
list[float]: Rotated point.
"""
assert len(pt) == 2
sn, cs = np.sin(angle_rad), np.cos(angle_rad)
new_x = pt[0] * cs - pt[1] * sn
new_y = pt[0] * sn + pt[1] * cs
rotated_pt = [new_x, new_y]
return rotated_pt
def transpred(kpts, h, w, s):
trans, _ = get_affine_mat_kernel(h, w, s, inv=True)
return warp_affine_joints(kpts[..., :2].copy(), trans)
def warp_affine_joints(joints, mat):
"""Apply affine transformation defined by the transform matrix on the
joints.
Args:
joints (np.ndarray[..., 2]): Origin coordinate of joints.
mat (np.ndarray[3, 2]): The affine matrix.
Returns:
matrix (np.ndarray[..., 2]): Result coordinate of joints.
"""
joints = np.array(joints)
shape = joints.shape
joints = joints.reshape(-1, 2)
return np.dot(np.concatenate(
(joints, joints[:, 0:1] * 0 + 1), axis=1),
mat.T).reshape(shape)
def affine_transform(pt, t):
new_pt = np.array([pt[0], pt[1], 1.]).T
new_pt = np.dot(t, new_pt)
return new_pt[:2]
def transform_preds(coords, center, scale, output_size):
target_coords = np.zeros(coords.shape)
trans = get_affine_transform(center, scale * 200, 0, output_size, inv=1)
for p in range(coords.shape[0]):
target_coords[p, 0:2] = affine_transform(coords[p, 0:2], trans)
return target_coords
def oks_iou(g, d, a_g, a_d, sigmas=None, in_vis_thre=None):
if not isinstance(sigmas, np.ndarray):
sigmas = np.array([
.26, .25, .25, .35, .35, .79, .79, .72, .72, .62, .62, 1.07, 1.07,
.87, .87, .89, .89
]) / 10.0
vars = (sigmas * 2)**2
xg = g[0::3]
yg = g[1::3]
vg = g[2::3]
ious = np.zeros((d.shape[0]))
for n_d in range(0, d.shape[0]):
xd = d[n_d, 0::3]
yd = d[n_d, 1::3]
vd = d[n_d, 2::3]
dx = xd - xg
dy = yd - yg
e = (dx**2 + dy**2) / vars / ((a_g + a_d[n_d]) / 2 + np.spacing(1)) / 2
if in_vis_thre is not None:
ind = list(vg > in_vis_thre) and list(vd > in_vis_thre)
e = e[ind]
ious[n_d] = np.sum(np.exp(-e)) / e.shape[0] if e.shape[0] != 0 else 0.0
return ious
def oks_nms(kpts_db, thresh, sigmas=None, in_vis_thre=None):
"""greedily select boxes with high confidence and overlap with current maximum <= thresh
rule out overlap >= thresh
Args:
kpts_db (list): The predicted keypoints within the image
thresh (float): The threshold to select the boxes
sigmas (np.array): The variance to calculate the oks iou
Default: None
in_vis_thre (float): The threshold to select the high confidence boxes
Default: None
Return:
keep (list): indexes to keep
"""
if len(kpts_db) == 0:
return []
scores = np.array([kpts_db[i]['score'] for i in range(len(kpts_db))])
kpts = np.array(
[kpts_db[i]['keypoints'].flatten() for i in range(len(kpts_db))])
areas = np.array([kpts_db[i]['area'] for i in range(len(kpts_db))])
order = scores.argsort()[::-1]
keep = []
while order.size > 0:
i = order[0]
keep.append(i)
oks_ovr = oks_iou(kpts[i], kpts[order[1:]], areas[i], areas[order[1:]],
sigmas, in_vis_thre)
inds = np.where(oks_ovr <= thresh)[0]
order = order[inds + 1]
return keep
def rescore(overlap, scores, thresh, type='gaussian'):
assert overlap.shape[0] == scores.shape[0]
if type == 'linear':
inds = np.where(overlap >= thresh)[0]
scores[inds] = scores[inds] * (1 - overlap[inds])
else:
scores = scores * np.exp(-overlap**2 / thresh)
return scores
def soft_oks_nms(kpts_db, thresh, sigmas=None, in_vis_thre=None):
"""greedily select boxes with high confidence and overlap with current maximum <= thresh
rule out overlap >= thresh
Args:
kpts_db (list): The predicted keypoints within the image
thresh (float): The threshold to select the boxes
sigmas (np.array): The variance to calculate the oks iou
Default: None
in_vis_thre (float): The threshold to select the high confidence boxes
Default: None
Return:
keep (list): indexes to keep
"""
if len(kpts_db) == 0:
return []
scores = np.array([kpts_db[i]['score'] for i in range(len(kpts_db))])
kpts = np.array(
[kpts_db[i]['keypoints'].flatten() for i in range(len(kpts_db))])
areas = np.array([kpts_db[i]['area'] for i in range(len(kpts_db))])
order = scores.argsort()[::-1]
scores = scores[order]
# max_dets = order.size
max_dets = 20
keep = np.zeros(max_dets, dtype=np.intp)
keep_cnt = 0
while order.size > 0 and keep_cnt < max_dets:
i = order[0]
oks_ovr = oks_iou(kpts[i], kpts[order[1:]], areas[i], areas[order[1:]],
sigmas, in_vis_thre)
order = order[1:]
scores = rescore(oks_ovr, scores[1:], thresh)
tmp = scores.argsort()[::-1]
order = order[tmp]
scores = scores[tmp]
keep[keep_cnt] = i
keep_cnt += 1
keep = keep[:keep_cnt]
return keep
def resize(input,
size=None,
scale_factor=None,
mode='nearest',
align_corners=None,
warning=True):
if warning:
if size is not None and align_corners:
input_h, input_w = tuple(int(x) for x in input.shape[2:])
output_h, output_w = tuple(int(x) for x in size)
if output_h > input_h or output_w > output_h:
if ((output_h > 1 and output_w > 1 and input_h > 1 and
input_w > 1) and (output_h - 1) % (input_h - 1) and
(output_w - 1) % (input_w - 1)):
warnings.warn(
f'When align_corners={align_corners}, '
'the output would more aligned if '
f'input size {(input_h, input_w)} is `x+1` and '
f'out size {(output_h, output_w)} is `nx+1`')
return F.interpolate(input, size, scale_factor, mode, align_corners)
def flip_back(output_flipped, flip_pairs, target_type='GaussianHeatmap'):
"""Flip the flipped heatmaps back to the original form.
Note:
- batch_size: N
- num_keypoints: K
- heatmap height: H
- heatmap width: W
Args:
output_flipped (np.ndarray[N, K, H, W]): The output heatmaps obtained
from the flipped images.
flip_pairs (list[tuple()): Pairs of keypoints which are mirrored
(for example, left ear -- right ear).
target_type (str): GaussianHeatmap or CombinedTarget
Returns:
np.ndarray: heatmaps that flipped back to the original image
"""
assert len(output_flipped.shape) == 4, \
'output_flipped should be [batch_size, num_keypoints, height, width]'
shape_ori = output_flipped.shape
channels = 1
if target_type.lower() == 'CombinedTarget'.lower():
channels = 3
output_flipped[:, 1::3, ...] = -output_flipped[:, 1::3, ...]
output_flipped = output_flipped.reshape((shape_ori[0], -1, channels,
shape_ori[2], shape_ori[3]))
output_flipped_back = output_flipped.clone()
# Swap left-right parts
for left, right in flip_pairs:
output_flipped_back[:, left, ...] = output_flipped[:, right, ...]
output_flipped_back[:, right, ...] = output_flipped[:, left, ...]
output_flipped_back = output_flipped_back.reshape(shape_ori)
# Flip horizontally
output_flipped_back = output_flipped_back[..., ::-1]
return output_flipped_back
def _calc_distances(preds, targets, mask, normalize):
"""Calculate the normalized distances between preds and target.
Note:
batch_size: N
num_keypoints: K
dimension of keypoints: D (normally, D=2 or D=3)
Args:
preds (np.ndarray[N, K, D]): Predicted keypoint location.
targets (np.ndarray[N, K, D]): Groundtruth keypoint location.
mask (np.ndarray[N, K]): Visibility of the target. False for invisible
joints, and True for visible. Invisible joints will be ignored for
accuracy calculation.
normalize (np.ndarray[N, D]): Typical value is heatmap_size
Returns:
np.ndarray[K, N]: The normalized distances. \
If target keypoints are missing, the distance is -1.
"""
N, K, _ = preds.shape
# set mask=0 when normalize==0
_mask = mask.copy()
_mask[np.where((normalize == 0).sum(1))[0], :] = False
distances = np.full((N, K), -1, dtype=np.float32)
# handle invalid values
normalize[np.where(normalize <= 0)] = 1e6
distances[_mask] = np.linalg.norm(
((preds - targets) / normalize[:, None, :])[_mask], axis=-1)
return distances.T
def _distance_acc(distances, thr=0.5):
"""Return the percentage below the distance threshold, while ignoring
distances values with -1.
Note:
batch_size: N
Args:
distances (np.ndarray[N, ]): The normalized distances.
thr (float): Threshold of the distances.
Returns:
float: Percentage of distances below the threshold. \
If all target keypoints are missing, return -1.
"""
distance_valid = distances != -1
num_distance_valid = distance_valid.sum()
if num_distance_valid > 0:
return (distances[distance_valid] < thr).sum() / num_distance_valid
return -1
def keypoint_pck_accuracy(pred, gt, mask, thr, normalize):
"""Calculate the pose accuracy of PCK for each individual keypoint and the
averaged accuracy across all keypoints for coordinates.
Note:
PCK metric measures accuracy of the localization of the body joints.
The distances between predicted positions and the ground-truth ones
are typically normalized by the bounding box size.
The threshold (thr) of the normalized distance is commonly set
as 0.05, 0.1 or 0.2 etc.
- batch_size: N
- num_keypoints: K
Args:
pred (np.ndarray[N, K, 2]): Predicted keypoint location.
gt (np.ndarray[N, K, 2]): Groundtruth keypoint location.
mask (np.ndarray[N, K]): Visibility of the target. False for invisible
joints, and True for visible. Invisible joints will be ignored for
accuracy calculation.
thr (float): Threshold of PCK calculation.
normalize (np.ndarray[N, 2]): Normalization factor for H&W.
Returns:
tuple: A tuple containing keypoint accuracy.
- acc (np.ndarray[K]): Accuracy of each keypoint.
- avg_acc (float): Averaged accuracy across all keypoints.
- cnt (int): Number of valid keypoints.
"""
distances = _calc_distances(pred, gt, mask, normalize)
acc = np.array([_distance_acc(d, thr) for d in distances])
valid_acc = acc[acc >= 0]
cnt = len(valid_acc)
avg_acc = valid_acc.mean() if cnt > 0 else 0
return acc, avg_acc, cnt
def keypoint_auc(pred, gt, mask, normalize, num_step=20):
"""Calculate the pose accuracy of PCK for each individual keypoint and the
averaged accuracy across all keypoints for coordinates.
Note:
- batch_size: N
- num_keypoints: K
Args:
pred (np.ndarray[N, K, 2]): Predicted keypoint location.
gt (np.ndarray[N, K, 2]): Groundtruth keypoint location.
mask (np.ndarray[N, K]): Visibility of the target. False for invisible
joints, and True for visible. Invisible joints will be ignored for
accuracy calculation.
normalize (float): Normalization factor.
Returns:
float: Area under curve.
"""
nor = np.tile(np.array([[normalize, normalize]]), (pred.shape[0], 1))
x = [1.0 * i / num_step for i in range(num_step)]
y = []
for thr in x:
_, avg_acc, _ = keypoint_pck_accuracy(pred, gt, mask, thr, nor)
y.append(avg_acc)
auc = 0
for i in range(num_step):
auc += 1.0 / num_step * y[i]
return auc
def keypoint_epe(pred, gt, mask):
"""Calculate the end-point error.
Note:
- batch_size: N
- num_keypoints: K
Args:
pred (np.ndarray[N, K, 2]): Predicted keypoint location.
gt (np.ndarray[N, K, 2]): Groundtruth keypoint location.
mask (np.ndarray[N, K]): Visibility of the target. False for invisible
joints, and True for visible. Invisible joints will be ignored for
accuracy calculation.
Returns:
float: Average end-point error.
"""
normalize = np.ones((pred.shape[0], pred.shape[2]), dtype=np.float32)
distances = _calc_distances(pred, gt, mask, normalize)
distance_valid = distances[distances != -1]
return distance_valid.sum() / max(1, len(distance_valid))