bytetrack / tutorials /jde /tracker.py
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from collections import deque
import torch
import numpy as np
from utils.kalman_filter import KalmanFilter
from utils.log import logger
from models import *
from tracker import matching
from .basetrack import BaseTrack, TrackState
class STrack(BaseTrack):
def __init__(self, tlwh, score, temp_feat, buffer_size=30):
# wait activate
self._tlwh = np.asarray(tlwh, dtype=np.float)
self.kalman_filter = None
self.mean, self.covariance = None, None
self.is_activated = False
self.score = score
self.tracklet_len = 0
self.smooth_feat = None
self.update_features(temp_feat)
self.features = deque([], maxlen=buffer_size)
self.alpha = 0.9
def update_features(self, feat):
feat /= np.linalg.norm(feat)
self.curr_feat = feat
if self.smooth_feat is None:
self.smooth_feat = feat
else:
self.smooth_feat = self.alpha *self.smooth_feat + (1-self.alpha) * feat
self.features.append(feat)
self.smooth_feat /= np.linalg.norm(self.smooth_feat)
def predict(self):
mean_state = self.mean.copy()
if self.state != TrackState.Tracked:
mean_state[7] = 0
self.mean, self.covariance = self.kalman_filter.predict(mean_state, self.covariance)
@staticmethod
def multi_predict(stracks, kalman_filter):
if len(stracks) > 0:
multi_mean = np.asarray([st.mean.copy() for st in stracks])
multi_covariance = np.asarray([st.covariance for st in stracks])
for i, st in enumerate(stracks):
if st.state != TrackState.Tracked:
multi_mean[i][7] = 0
# multi_mean, multi_covariance = STrack.kalman_filter.multi_predict(multi_mean, multi_covariance)
multi_mean, multi_covariance = kalman_filter.multi_predict(multi_mean, multi_covariance)
for i, (mean, cov) in enumerate(zip(multi_mean, multi_covariance)):
stracks[i].mean = mean
stracks[i].covariance = cov
def activate(self, kalman_filter, frame_id):
"""Start a new tracklet"""
self.kalman_filter = kalman_filter
self.track_id = self.next_id()
self.mean, self.covariance = self.kalman_filter.initiate(self.tlwh_to_xyah(self._tlwh))
self.tracklet_len = 0
self.state = TrackState.Tracked
#self.is_activated = True
self.frame_id = frame_id
self.start_frame = frame_id
def re_activate(self, new_track, frame_id, new_id=False):
self.mean, self.covariance = self.kalman_filter.update(
self.mean, self.covariance, self.tlwh_to_xyah(new_track.tlwh)
)
self.update_features(new_track.curr_feat)
self.tracklet_len = 0
self.state = TrackState.Tracked
self.is_activated = True
self.frame_id = frame_id
if new_id:
self.track_id = self.next_id()
def update(self, new_track, frame_id, update_feature=True):
"""
Update a matched track
:type new_track: STrack
:type frame_id: int
:type update_feature: bool
:return:
"""
self.frame_id = frame_id
self.tracklet_len += 1
new_tlwh = new_track.tlwh
self.mean, self.covariance = self.kalman_filter.update(
self.mean, self.covariance, self.tlwh_to_xyah(new_tlwh))
self.state = TrackState.Tracked
self.is_activated = True
self.score = new_track.score
if update_feature:
self.update_features(new_track.curr_feat)
@property
def tlwh(self):
"""Get current position in bounding box format `(top left x, top left y,
width, height)`.
"""
if self.mean is None:
return self._tlwh.copy()
ret = self.mean[:4].copy()
ret[2] *= ret[3]
ret[:2] -= ret[2:] / 2
return ret
@property
def tlbr(self):
"""Convert bounding box to format `(min x, min y, max x, max y)`, i.e.,
`(top left, bottom right)`.
"""
ret = self.tlwh.copy()
ret[2:] += ret[:2]
return ret
@staticmethod
def tlwh_to_xyah(tlwh):
"""Convert bounding box to format `(center x, center y, aspect ratio,
height)`, where the aspect ratio is `width / height`.
"""
ret = np.asarray(tlwh).copy()
ret[:2] += ret[2:] / 2
ret[2] /= ret[3]
return ret
def to_xyah(self):
return self.tlwh_to_xyah(self.tlwh)
@staticmethod
def tlbr_to_tlwh(tlbr):
ret = np.asarray(tlbr).copy()
ret[2:] -= ret[:2]
return ret
@staticmethod
def tlwh_to_tlbr(tlwh):
ret = np.asarray(tlwh).copy()
ret[2:] += ret[:2]
return ret
def __repr__(self):
return 'OT_{}_({}-{})'.format(self.track_id, self.start_frame, self.end_frame)
class JDETracker(object):
def __init__(self, opt, frame_rate=30):
self.opt = opt
self.model = Darknet(opt.cfg, nID=14455)
# load_darknet_weights(self.model, opt.weights)
self.model.load_state_dict(torch.load(opt.weights, map_location='cpu')['model'], strict=False)
self.model.cuda().eval()
self.tracked_stracks = [] # type: list[STrack]
self.lost_stracks = [] # type: list[STrack]
self.removed_stracks = [] # type: list[STrack]
self.frame_id = 0
self.det_thresh = opt.conf_thres
self.init_thresh = self.det_thresh + 0.2
self.low_thresh = 0.4
self.buffer_size = int(frame_rate / 30.0 * opt.track_buffer)
self.max_time_lost = self.buffer_size
self.kalman_filter = KalmanFilter()
def update(self, im_blob, img0):
"""
Processes the image frame and finds bounding box(detections).
Associates the detection with corresponding tracklets and also handles lost, removed, refound and active tracklets
Parameters
----------
im_blob : torch.float32
Tensor of shape depending upon the size of image. By default, shape of this tensor is [1, 3, 608, 1088]
img0 : ndarray
ndarray of shape depending on the input image sequence. By default, shape is [608, 1080, 3]
Returns
-------
output_stracks : list of Strack(instances)
The list contains information regarding the online_tracklets for the recieved image tensor.
"""
self.frame_id += 1
activated_starcks = [] # for storing active tracks, for the current frame
refind_stracks = [] # Lost Tracks whose detections are obtained in the current frame
lost_stracks = [] # The tracks which are not obtained in the current frame but are not removed.(Lost for some time lesser than the threshold for removing)
removed_stracks = []
t1 = time.time()
''' Step 1: Network forward, get detections & embeddings'''
with torch.no_grad():
pred = self.model(im_blob)
# pred is tensor of all the proposals (default number of proposals: 54264). Proposals have information associated with the bounding box and embeddings
pred = pred[pred[:, :, 4] > self.low_thresh]
# pred now has lesser number of proposals. Proposals rejected on basis of object confidence score
if len(pred) > 0:
dets = non_max_suppression(pred.unsqueeze(0), self.low_thresh, self.opt.nms_thres)[0].cpu()
# Final proposals are obtained in dets. Information of bounding box and embeddings also included
# Next step changes the detection scales
scale_coords(self.opt.img_size, dets[:, :4], img0.shape).round()
'''Detections is list of (x1, y1, x2, y2, object_conf, class_score, class_pred)'''
# class_pred is the embeddings.
dets = dets.numpy()
remain_inds = dets[:, 4] > self.det_thresh
inds_low = dets[:, 4] > self.low_thresh
inds_high = dets[:, 4] < self.det_thresh
inds_second = np.logical_and(inds_low, inds_high)
dets_second = dets[inds_second]
dets = dets[remain_inds]
detections = [STrack(STrack.tlbr_to_tlwh(tlbrs[:4]), tlbrs[4], f, 30) for
(tlbrs, f) in zip(dets[:, :5], dets[:, 6:])]
else:
detections = []
dets_second = []
t2 = time.time()
# print('Forward: {} s'.format(t2-t1))
''' Add newly detected tracklets to tracked_stracks'''
unconfirmed = []
tracked_stracks = [] # type: list[STrack]
for track in self.tracked_stracks:
if not track.is_activated:
# previous tracks which are not active in the current frame are added in unconfirmed list
unconfirmed.append(track)
# print("Should not be here, in unconfirmed")
else:
# Active tracks are added to the local list 'tracked_stracks'
tracked_stracks.append(track)
''' Step 2: First association, with embedding'''
# Combining currently tracked_stracks and lost_stracks
strack_pool = joint_stracks(tracked_stracks, self.lost_stracks)
# Predict the current location with KF
STrack.multi_predict(strack_pool, self.kalman_filter)
dists = matching.embedding_distance(strack_pool, detections)
dists = matching.fuse_motion(self.kalman_filter, dists, strack_pool, detections)
#dists = matching.iou_distance(strack_pool, detections)
# The dists is the list of distances of the detection with the tracks in strack_pool
matches, u_track, u_detection = matching.linear_assignment(dists, thresh=0.7)
# The matches is the array for corresponding matches of the detection with the corresponding strack_pool
for itracked, idet in matches:
# itracked is the id of the track and idet is the detection
track = strack_pool[itracked]
det = detections[idet]
if track.state == TrackState.Tracked:
# If the track is active, add the detection to the track
track.update(detections[idet], self.frame_id)
activated_starcks.append(track)
else:
# We have obtained a detection from a track which is not active, hence put the track in refind_stracks list
track.re_activate(det, self.frame_id, new_id=False)
refind_stracks.append(track)
# None of the steps below happen if there are no undetected tracks.
''' Step 3: Second association, with IOU'''
detections = [detections[i] for i in u_detection]
# detections is now a list of the unmatched detections
r_tracked_stracks = [] # This is container for stracks which were tracked till the
# previous frame but no detection was found for it in the current frame
for i in u_track:
if strack_pool[i].state == TrackState.Tracked:
r_tracked_stracks.append(strack_pool[i])
dists = matching.iou_distance(r_tracked_stracks, detections)
matches, u_track, u_detection = matching.linear_assignment(dists, thresh=0.5)
# matches is the list of detections which matched with corresponding tracks by IOU distance method
for itracked, idet in matches:
track = r_tracked_stracks[itracked]
det = detections[idet]
if track.state == TrackState.Tracked:
track.update(det, self.frame_id)
activated_starcks.append(track)
else:
track.re_activate(det, self.frame_id, new_id=False)
refind_stracks.append(track)
# Same process done for some unmatched detections, but now considering IOU_distance as measure
# association the untrack to the low score detections
if len(dets_second) > 0:
detections_second = [STrack(STrack.tlbr_to_tlwh(tlbrs[:4]), tlbrs[4], f, 30) for
(tlbrs, f) in zip(dets_second[:, :5], dets_second[:, 6:])]
else:
detections_second = []
second_tracked_stracks = [r_tracked_stracks[i] for i in u_track if r_tracked_stracks[i].state == TrackState.Tracked]
dists = matching.iou_distance(second_tracked_stracks, detections_second)
matches, u_track, u_detection_second = matching.linear_assignment(dists, thresh=0.4)
for itracked, idet in matches:
track = second_tracked_stracks[itracked]
det = detections_second[idet]
if track.state == TrackState.Tracked:
track.update(det, self.frame_id)
activated_starcks.append(track)
else:
track.re_activate(det, self.frame_id, new_id=False)
refind_stracks.append(track)
for it in u_track:
track = second_tracked_stracks[it]
if not track.state == TrackState.Lost:
track.mark_lost()
lost_stracks.append(track)
# If no detections are obtained for tracks (u_track), the tracks are added to lost_tracks list and are marked lost
'''Deal with unconfirmed tracks, usually tracks with only one beginning frame'''
detections = [detections[i] for i in u_detection]
dists = matching.iou_distance(unconfirmed, detections)
matches, u_unconfirmed, u_detection = matching.linear_assignment(dists, thresh=0.7)
for itracked, idet in matches:
unconfirmed[itracked].update(detections[idet], self.frame_id)
activated_starcks.append(unconfirmed[itracked])
# The tracks which are yet not matched
for it in u_unconfirmed:
track = unconfirmed[it]
track.mark_removed()
removed_stracks.append(track)
# after all these confirmation steps, if a new detection is found, it is initialized for a new track
""" Step 4: Init new stracks"""
for inew in u_detection:
track = detections[inew]
if track.score < self.init_thresh:
continue
track.activate(self.kalman_filter, self.frame_id)
activated_starcks.append(track)
""" Step 5: Update state"""
# If the tracks are lost for more frames than the threshold number, the tracks are removed.
for track in self.lost_stracks:
if self.frame_id - track.end_frame > self.max_time_lost:
track.mark_removed()
removed_stracks.append(track)
# print('Remained match {} s'.format(t4-t3))
# Update the self.tracked_stracks and self.lost_stracks using the updates in this step.
self.tracked_stracks = [t for t in self.tracked_stracks if t.state == TrackState.Tracked]
self.tracked_stracks = joint_stracks(self.tracked_stracks, activated_starcks)
self.tracked_stracks = joint_stracks(self.tracked_stracks, refind_stracks)
# self.lost_stracks = [t for t in self.lost_stracks if t.state == TrackState.Lost] # type: list[STrack]
self.lost_stracks = sub_stracks(self.lost_stracks, self.tracked_stracks)
self.lost_stracks.extend(lost_stracks)
self.lost_stracks = sub_stracks(self.lost_stracks, self.removed_stracks)
self.removed_stracks.extend(removed_stracks)
self.tracked_stracks, self.lost_stracks = remove_duplicate_stracks(self.tracked_stracks, self.lost_stracks)
# get scores of lost tracks
output_stracks = [track for track in self.tracked_stracks if track.is_activated]
logger.debug('===========Frame {}=========='.format(self.frame_id))
logger.debug('Activated: {}'.format([track.track_id for track in activated_starcks]))
logger.debug('Refind: {}'.format([track.track_id for track in refind_stracks]))
logger.debug('Lost: {}'.format([track.track_id for track in lost_stracks]))
logger.debug('Removed: {}'.format([track.track_id for track in removed_stracks]))
# print('Final {} s'.format(t5-t4))
return output_stracks
def joint_stracks(tlista, tlistb):
exists = {}
res = []
for t in tlista:
exists[t.track_id] = 1
res.append(t)
for t in tlistb:
tid = t.track_id
if not exists.get(tid, 0):
exists[tid] = 1
res.append(t)
return res
def sub_stracks(tlista, tlistb):
stracks = {}
for t in tlista:
stracks[t.track_id] = t
for t in tlistb:
tid = t.track_id
if stracks.get(tid, 0):
del stracks[tid]
return list(stracks.values())
def remove_duplicate_stracks(stracksa, stracksb):
pdist = matching.iou_distance(stracksa, stracksb)
pairs = np.where(pdist<0.15)
dupa, dupb = list(), list()
for p,q in zip(*pairs):
timep = stracksa[p].frame_id - stracksa[p].start_frame
timeq = stracksb[q].frame_id - stracksb[q].start_frame
if timep > timeq:
dupb.append(q)
else:
dupa.append(p)
resa = [t for i,t in enumerate(stracksa) if not i in dupa]
resb = [t for i,t in enumerate(stracksb) if not i in dupb]
return resa, resb