PulseFocusPlatform/deploy/python/keypoint_postprocess.py

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2022-06-01 11:18:00 +08:00
# 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.
from scipy.optimize import linear_sum_assignment
from collections import defaultdict
import numpy as np
import math
from keypoint_preprocess import get_affine_mat_kernel, get_affine_transform
class HrHRNetPostProcess(object):
'''
HrHRNet postprocess contain:
1) get topk keypoints in the output heatmap
2) sample the tagmap's value corresponding to each of the topk coordinate
3) match different joints to combine to some people with Hungary algorithm
4) adjust the coordinate by +-0.25 to decrease error std
5) salvage missing joints by check positivity of heatmap - tagdiff_norm
Args:
max_num_people (int): max number of people support in postprocess
heat_thresh (float): value of topk below this threshhold will be ignored
tag_thresh (float): coord's value sampled in tagmap below this threshold belong to same people for init
inputs(list[heatmap]): the output list of modle, [heatmap, heatmap_maxpool, tagmap], heatmap_maxpool used to get topk
original_height, original_width (float): the original image size
'''
def __init__(self, max_num_people=30, heat_thresh=0.2, tag_thresh=1.):
self.max_num_people = max_num_people
self.heat_thresh = heat_thresh
self.tag_thresh = tag_thresh
def lerp(self, j, y, x, heatmap):
H, W = heatmap.shape[-2:]
left = np.clip(x - 1, 0, W - 1)
right = np.clip(x + 1, 0, W - 1)
up = np.clip(y - 1, 0, H - 1)
down = np.clip(y + 1, 0, H - 1)
offset_y = np.where(heatmap[j, down, x] > heatmap[j, up, x], 0.25,
-0.25)
offset_x = np.where(heatmap[j, y, right] > heatmap[j, y, left], 0.25,
-0.25)
return offset_y + 0.5, offset_x + 0.5
def __call__(self, heatmap, tagmap, heat_k, inds_k, original_height,
original_width):
N, J, H, W = heatmap.shape
assert N == 1, "only support batch size 1"
heatmap = heatmap[0]
tagmap = tagmap[0]
heats = heat_k[0]
inds_np = inds_k[0]
y = inds_np // W
x = inds_np % W
tags = tagmap[np.arange(J)[None, :].repeat(self.max_num_people),
y.flatten(), x.flatten()].reshape(J, -1, tagmap.shape[-1])
coords = np.stack((y, x), axis=2)
# threshold
mask = heats > self.heat_thresh
# cluster
cluster = defaultdict(lambda: {
'coords': np.zeros((J, 2), dtype=np.float32),
'scores': np.zeros(J, dtype=np.float32),
'tags': []
})
for jid, m in enumerate(mask):
num_valid = m.sum()
if num_valid == 0:
continue
valid_inds = np.where(m)[0]
valid_tags = tags[jid, m, :]
if len(cluster) == 0: # initialize
for i in valid_inds:
tag = tags[jid, i]
key = tag[0]
cluster[key]['tags'].append(tag)
cluster[key]['scores'][jid] = heats[jid, i]
cluster[key]['coords'][jid] = coords[jid, i]
continue
candidates = list(cluster.keys())[:self.max_num_people]
centroids = [
np.mean(
cluster[k]['tags'], axis=0) for k in candidates
]
num_clusters = len(centroids)
# shape is (num_valid, num_clusters, tag_dim)
dist = valid_tags[:, None, :] - np.array(centroids)[None, ...]
l2_dist = np.linalg.norm(dist, ord=2, axis=2)
# modulate dist with heat value, see `use_detection_val`
cost = np.round(l2_dist) * 100 - heats[jid, m, None]
# pad the cost matrix, otherwise new pose are ignored
if num_valid > num_clusters:
cost = np.pad(cost, ((0, 0), (0, num_valid - num_clusters)),
constant_values=((0, 0), (0, 1e-10)))
rows, cols = linear_sum_assignment(cost)
for y, x in zip(rows, cols):
tag = tags[jid, y]
if y < num_valid and x < num_clusters and \
l2_dist[y, x] < self.tag_thresh:
key = candidates[x] # merge to cluster
else:
key = tag[0] # initialize new cluster
cluster[key]['tags'].append(tag)
cluster[key]['scores'][jid] = heats[jid, y]
cluster[key]['coords'][jid] = coords[jid, y]
# shape is [k, J, 2] and [k, J]
pose_tags = np.array([cluster[k]['tags'] for k in cluster])
pose_coords = np.array([cluster[k]['coords'] for k in cluster])
pose_scores = np.array([cluster[k]['scores'] for k in cluster])
valid = pose_scores > 0
pose_kpts = np.zeros((pose_scores.shape[0], J, 3), dtype=np.float32)
if valid.sum() == 0:
return pose_kpts, pose_kpts
# refine coords
valid_coords = pose_coords[valid].astype(np.int32)
y = valid_coords[..., 0].flatten()
x = valid_coords[..., 1].flatten()
_, j = np.nonzero(valid)
offsets = self.lerp(j, y, x, heatmap)
pose_coords[valid, 0] += offsets[0]
pose_coords[valid, 1] += offsets[1]
# mean score before salvage
mean_score = pose_scores.mean(axis=1)
pose_kpts[valid, 2] = pose_scores[valid]
# salvage missing joints
if True:
for pid, coords in enumerate(pose_coords):
tag_mean = np.array(pose_tags[pid]).mean(axis=0)
norm = np.sum((tagmap - tag_mean)**2, axis=3)**0.5
score = heatmap - np.round(norm) # (J, H, W)
flat_score = score.reshape(J, -1)
max_inds = np.argmax(flat_score, axis=1)
max_scores = np.max(flat_score, axis=1)
salvage_joints = (pose_scores[pid] == 0) & (max_scores > 0)
if salvage_joints.sum() == 0:
continue
y = max_inds[salvage_joints] // W
x = max_inds[salvage_joints] % W
offsets = self.lerp(salvage_joints.nonzero()[0], y, x, heatmap)
y = y.astype(np.float32) + offsets[0]
x = x.astype(np.float32) + offsets[1]
pose_coords[pid][salvage_joints, 0] = y
pose_coords[pid][salvage_joints, 1] = x
pose_kpts[pid][salvage_joints, 2] = max_scores[salvage_joints]
pose_kpts[..., :2] = transpred(pose_coords[..., :2][..., ::-1],
original_height, original_width,
min(H, W))
return pose_kpts, mean_score
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)
class HRNetPostProcess(object):
def flip_back(self, output_flipped, matched_parts):
assert output_flipped.ndim == 4,\
'output_flipped should be [batch_size, num_joints, height, width]'
output_flipped = output_flipped[:, :, :, ::-1]
for pair in matched_parts:
tmp = output_flipped[:, pair[0], :, :].copy()
output_flipped[:, pair[0], :, :] = output_flipped[:, pair[1], :, :]
output_flipped[:, pair[1], :, :] = tmp
return output_flipped
def get_max_preds(self, heatmaps):
'''get predictions from score maps
Args:
heatmaps: numpy.ndarray([batch_size, num_joints, height, width])
Returns:
preds: numpy.ndarray([batch_size, num_joints, 2]), keypoints coords
maxvals: numpy.ndarray([batch_size, num_joints, 2]), the maximum confidence of the keypoints
'''
assert isinstance(heatmaps,
np.ndarray), 'heatmaps should be numpy.ndarray'
assert heatmaps.ndim == 4, 'batch_images should be 4-ndim'
batch_size = heatmaps.shape[0]
num_joints = heatmaps.shape[1]
width = heatmaps.shape[3]
heatmaps_reshaped = heatmaps.reshape((batch_size, num_joints, -1))
idx = np.argmax(heatmaps_reshaped, 2)
maxvals = np.amax(heatmaps_reshaped, 2)
maxvals = maxvals.reshape((batch_size, num_joints, 1))
idx = idx.reshape((batch_size, num_joints, 1))
preds = np.tile(idx, (1, 1, 2)).astype(np.float32)
preds[:, :, 0] = (preds[:, :, 0]) % width
preds[:, :, 1] = np.floor((preds[:, :, 1]) / width)
pred_mask = np.tile(np.greater(maxvals, 0.0), (1, 1, 2))
pred_mask = pred_mask.astype(np.float32)
preds *= pred_mask
return preds, maxvals
def get_final_preds(self, heatmaps, center, scale):
"""the highest heatvalue location with a quarter offset in the
direction from the highest response to the second highest response.
Args:
heatmaps (numpy.ndarray): The predicted heatmaps
center (numpy.ndarray): The boxes center
scale (numpy.ndarray): The scale factor
Returns:
preds: numpy.ndarray([batch_size, num_joints, 2]), keypoints coords
maxvals: numpy.ndarray([batch_size, num_joints, 1]), the maximum confidence of the keypoints
"""
coords, maxvals = self.get_max_preds(heatmaps)
heatmap_height = heatmaps.shape[2]
heatmap_width = heatmaps.shape[3]
for n in range(coords.shape[0]):
for p in range(coords.shape[1]):
hm = heatmaps[n][p]
px = int(math.floor(coords[n][p][0] + 0.5))
py = int(math.floor(coords[n][p][1] + 0.5))
if 1 < px < heatmap_width - 1 and 1 < py < heatmap_height - 1:
diff = np.array([
hm[py][px + 1] - hm[py][px - 1],
hm[py + 1][px] - hm[py - 1][px]
])
coords[n][p] += np.sign(diff) * .25
preds = coords.copy()
# Transform back
for i in range(coords.shape[0]):
preds[i] = transform_preds(coords[i], center[i], scale[i],
[heatmap_width, heatmap_height])
return preds, maxvals
def __call__(self, output, center, scale):
preds, maxvals = self.get_final_preds(output, center, scale)
return np.concatenate(
(preds, maxvals), axis=-1), np.mean(
maxvals, axis=1)
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 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]