feat: cleaning the code removing dead part (#25)

bytetracker/basetrack.py

@@ -1,8 +1,3 @@
-from collections import OrderedDict
-
-import numpy as np
-
-
 class TrackState(object):
     New = 0
     Tracked = 1
@@ -17,16 +12,9 @@ class BaseTrack(object):
     is_activated = False
     state = TrackState.New
 
-    history = OrderedDict()
-    features = []
-    curr_feature = None
     score = 0
     start_frame = 0
     frame_id = 0
-    time_since_update = 0
-
-    # multi-camera
-    location = (np.inf, np.inf)
 
     @property
     def end_frame(self):

bytetracker/byte_tracker.py

@@ -36,7 +36,6 @@ def __init__(self, tlwh, score, cls):
         self.is_activated = False
 
         self.score = score
-        self.tracklet_len = 0
         self.cls = cls
 
     def predict(self):
@@ -66,7 +65,6 @@ def activate(self, kalman_filter, frame_id):
         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
         if frame_id == 1:
             self.is_activated = True
@@ -78,7 +76,6 @@ 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.tracklet_len = 0
         self.state = TrackState.Tracked
         self.is_activated = True
         self.frame_id = frame_id
@@ -96,7 +93,6 @@ def update(self, new_track, frame_id):
         :return:
         """
         self.frame_id = frame_id
-        self.tracklet_len += 1
         self.cls = new_track.cls
 
         new_tlwh = new_track.tlwh
@@ -142,23 +138,6 @@ def tlwh_to_xyah(tlwh):
         ret[2] /= ret[3]
         return ret
 
-    def to_xyah(self):
-        return self.tlwh_to_xyah(self.tlwh)
-
-    @staticmethod
-    # @jit(nopython=True)
-    def tlbr_to_tlwh(tlbr):
-        ret = np.asarray(tlbr).copy()
-        ret[2:] -= ret[:2]
-        return ret
-
-    @staticmethod
-    # @jit(nopython=True)
-    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)
 
@@ -262,7 +241,7 @@ def update(self, dets, frame_id):
             strack_pool[i] for i in u_track if strack_pool[i].state == TrackState.Tracked
         ]
         dists = matching.iou_distance(r_tracked_stracks, detections_second)
-        matches, u_track, u_detection_second = matching.linear_assignment(dists, thresh=0.5)
+        matches, u_track, _ = matching.linear_assignment(dists, thresh=0.5)
         for itracked, idet in matches:
             track = r_tracked_stracks[itracked]
             det = detections_second[idet]

bytetracker/kalman_filter.py

@@ -1,23 +1,6 @@
 import numpy as np
 import scipy.linalg
 
-"""
-Table for the 0.95 quantile of the chi-square distribution with N degrees of
-freedom (contains values for N=1, ..., 9). Taken from MATLAB/Octave's chi2inv
-function and used as Mahalanobis gating threshold.
-"""
-chi2inv95 = {
-    1: 3.8415,
-    2: 5.9915,
-    3: 7.8147,
-    4: 9.4877,
-    5: 11.070,
-    6: 12.592,
-    7: 14.067,
-    8: 15.507,
-    9: 16.919,
-}
-
 
 class KalmanFilter(object):
     """
@@ -229,46 +212,3 @@ def update(self, mean, covariance, measurement):
             (kalman_gain, projected_cov, kalman_gain.T)
         )
         return new_mean, new_covariance
-
-    def gating_distance(self, mean, covariance, measurements, only_position=False, metric="maha"):
-        """Compute gating distance between state distribution and measurements.
-        A suitable distance threshold can be obtained from `chi2inv95`. If
-        `only_position` is False, the chi-square distribution has 4 degrees of
-        freedom, otherwise 2.
-        Parameters
-        ----------
-        mean : ndarray
-            Mean vector over the state distribution (8 dimensional).
-        covariance : ndarray
-            Covariance of the state distribution (8x8 dimensional).
-        measurements : ndarray
-            An Nx4 dimensional matrix of N measurements, each in
-            format (x, y, a, h) where (x, y) is the bounding box center
-            position, a the aspect ratio, and h the height.
-        only_position : Optional[bool]
-            If True, distance computation is done with respect to the bounding
-            box center position only.
-        Returns
-        -------
-        ndarray
-            Returns an array of length N, where the i-th element contains the
-            squared Mahalanobis distance between (mean, covariance) and
-            `measurements[i]`.
-        """
-        mean, covariance = self.project(mean, covariance)
-        if only_position:
-            mean, covariance = mean[:2], covariance[:2, :2]
-            measurements = measurements[:, :2]
-
-        d = measurements - mean
-        if metric == "gaussian":
-            return np.sum(d * d, axis=1)
-        elif metric == "maha":
-            cholesky_factor = np.linalg.cholesky(covariance)
-            z = scipy.linalg.solve_triangular(
-                cholesky_factor, d.T, lower=True, check_finite=False, overwrite_b=True
-            )
-            squared_maha = np.sum(z * z, axis=0)
-            return squared_maha
-        else:
-            raise ValueError("invalid distance metric")

bytetracker/matching.py

@@ -1,37 +1,5 @@
 import lap
 import numpy as np
-import scipy
-from scipy.spatial.distance import cdist
-
-from bytetracker import kalman_filter
-
-
-def merge_matches(m1, m2, shape):
-    O, P, Q = shape
-    m1 = np.asarray(m1)
-    m2 = np.asarray(m2)
-
-    M1 = scipy.sparse.coo_matrix((np.ones(len(m1)), (m1[:, 0], m1[:, 1])), shape=(O, P))
-    M2 = scipy.sparse.coo_matrix((np.ones(len(m2)), (m2[:, 0], m2[:, 1])), shape=(P, Q))
-
-    mask = M1 * M2
-    match = mask.nonzero()
-    match = list(zip(match[0], match[1]))
-    unmatched_O = tuple(set(range(O)) - set([i for i, j in match]))
-    unmatched_Q = tuple(set(range(Q)) - set([j for i, j in match]))
-
-    return match, unmatched_O, unmatched_Q
-
-
-def _indices_to_matches(cost_matrix, indices, thresh):
-    matched_cost = cost_matrix[tuple(zip(*indices))]
-    matched_mask = matched_cost <= thresh
-
-    matches = indices[matched_mask]
-    unmatched_a = tuple(set(range(cost_matrix.shape[0])) - set(matches[:, 0]))
-    unmatched_b = tuple(set(range(cost_matrix.shape[1])) - set(matches[:, 1]))
-
-    return matches, unmatched_a, unmatched_b
 
 
 def linear_assignment(cost_matrix, thresh):
@@ -42,7 +10,7 @@ def linear_assignment(cost_matrix, thresh):
             tuple(range(cost_matrix.shape[1])),
         )
     matches, unmatched_a, unmatched_b = [], [], []
-    cost, x, y = lap.lapjv(cost_matrix, extend_cost=True, cost_limit=thresh)
+    _, x, y = lap.lapjv(cost_matrix, extend_cost=True, cost_limit=thresh)
     for ix, mx in enumerate(x):
         if mx >= 0:
             matches.append([ix, mx])
@@ -95,91 +63,6 @@ def iou_distance(atracks, btracks):
     return cost_matrix
 
 
-def v_iou_distance(atracks, btracks):
-    """
-    Compute cost based on IoU
-    :type atracks: list[STrack]
-    :type btracks: list[STrack]
-
-    :rtype cost_matrix np.ndarray
-    """
-
-    if (len(atracks) > 0 and isinstance(atracks[0], np.ndarray)) or (
-        len(btracks) > 0 and isinstance(btracks[0], np.ndarray)
-    ):
-        atlbrs = atracks
-        btlbrs = btracks
-    else:
-        atlbrs = [track.tlwh_to_tlbr(track.pred_bbox) for track in atracks]
-        btlbrs = [track.tlwh_to_tlbr(track.pred_bbox) for track in btracks]
-    _ious = ious(atlbrs, btlbrs)
-    cost_matrix = 1 - _ious
-
-    return cost_matrix
-
-
-def embedding_distance(tracks, detections, metric="cosine"):
-    """
-    :param tracks: list[STrack]
-    :param detections: list[BaseTrack]
-    :param metric:
-    :return: cost_matrix np.ndarray
-    """
-
-    cost_matrix = np.zeros((len(tracks), len(detections)), dtype=np.float32)
-    if cost_matrix.size == 0:
-        return cost_matrix
-    det_features = np.asarray([track.curr_feat for track in detections], dtype=np.float32)
-    # for i, track in enumerate(tracks):
-    # cost_matrix[i, :] = np.maximum(0.0, cdist(track.smooth_feat.reshape(1,-1), det_features, metric))
-    track_features = np.asarray([track.smooth_feat for track in tracks], dtype=np.float32)
-    cost_matrix = np.maximum(0.0, cdist(track_features, det_features, metric))  # Nomalized features
-    return cost_matrix
-
-
-def gate_cost_matrix(kf, cost_matrix, tracks, detections, only_position=False):
-    if cost_matrix.size == 0:
-        return cost_matrix
-    gating_dim = 2 if only_position else 4
-    gating_threshold = kalman_filter.chi2inv95[gating_dim]
-    measurements = np.asarray([det.to_xyah() for det in detections])
-    for row, track in enumerate(tracks):
-        gating_distance = kf.gating_distance(
-            track.mean, track.covariance, measurements, only_position
-        )
-        cost_matrix[row, gating_distance > gating_threshold] = np.inf
-    return cost_matrix
-
-
-def fuse_motion(kf, cost_matrix, tracks, detections, only_position=False, lambda_=0.98):
-    if cost_matrix.size == 0:
-        return cost_matrix
-    gating_dim = 2 if only_position else 4
-    gating_threshold = kalman_filter.chi2inv95[gating_dim]
-    measurements = np.asarray([det.to_xyah() for det in detections])
-    for row, track in enumerate(tracks):
-        gating_distance = kf.gating_distance(
-            track.mean, track.covariance, measurements, only_position, metric="maha"
-        )
-        cost_matrix[row, gating_distance > gating_threshold] = np.inf
-        cost_matrix[row] = lambda_ * cost_matrix[row] + (1 - lambda_) * gating_distance
-    return cost_matrix
-
-
-def fuse_iou(cost_matrix, tracks, detections):
-    if cost_matrix.size == 0:
-        return cost_matrix
-    reid_sim = 1 - cost_matrix
-    iou_dist = iou_distance(tracks, detections)
-    iou_sim = 1 - iou_dist
-    fuse_sim = reid_sim * (1 + iou_sim) / 2
-    det_scores = np.array([det.score for det in detections])
-    det_scores = np.expand_dims(det_scores, axis=0).repeat(cost_matrix.shape[0], axis=0)
-    # fuse_sim = fuse_sim * (1 + det_scores) / 2
-    fuse_cost = 1 - fuse_sim
-    return fuse_cost
-
-
 def fuse_score(cost_matrix, detections):
     if cost_matrix.size == 0:
         return cost_matrix