imaginAIry/imaginairy/vendored/facexlib/tracking/kalman_tracker.py
Bryce 5bbb09f69e build: vendorize facexlib
had too many unused sub-dependencies

also monkeypatch the download mechanism to use our standard download function
2024-01-06 17:23:27 -08:00

109 lines
3.8 KiB
Python

import numpy as np
from filterpy.kalman import KalmanFilter
def convert_bbox_to_z(bbox):
"""Takes a bounding box in the form [x1,y1,x2,y2] and returns z in the form
[x,y,s,r] where x,y is the centre of the box and s is the scale/area and
r is the aspect ratio
"""
w = bbox[2] - bbox[0]
h = bbox[3] - bbox[1]
x = bbox[0] + w / 2.
y = bbox[1] + h / 2.
s = w * h # scale is just area
r = w / float(h)
return np.array([x, y, s, r]).reshape((4, 1))
def convert_x_to_bbox(x, score=None):
"""Takes a bounding box in the centre form [x,y,s,r] and returns it in
the form [x1,y1,x2,y2] where x1,y1 is the top left and x2,y2 is the bottom
right
"""
w = np.sqrt(x[2] * x[3])
h = x[2] / w
if score is None:
return np.array([x[0] - w / 2., x[1] - h / 2., x[0] + w / 2., x[1] + h / 2.]).reshape((1, 4))
else:
return np.array([x[0] - w / 2., x[1] - h / 2., x[0] + w / 2., x[1] + h / 2., score]).reshape((1, 5))
class KalmanBoxTracker(object):
"""This class represents the internal state of individual tracked objects
observed as bbox.
doc: https://filterpy.readthedocs.io/en/latest/kalman/KalmanFilter.html
"""
count = 0
def __init__(self, bbox):
"""Initialize a tracker using initial bounding box.
"""
# define constant velocity model
# TODO: x: what is the meanning of x[4:7], v?
self.kf = KalmanFilter(dim_x=7, dim_z=4)
# F (dim_x, dim_x): state transition matrix
self.kf.F = np.array([[1, 0, 0, 0, 1, 0, 0], [0, 1, 0, 0, 0, 1, 0], [0, 0, 1, 0, 0, 0,
1], [0, 0, 0, 1, 0, 0, 0],
[0, 0, 0, 0, 1, 0, 0], [0, 0, 0, 0, 0, 1, 0], [0, 0, 0, 0, 0, 0, 1]])
# H (dim_z, dim_x): measurement function
self.kf.H = np.array([[1, 0, 0, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0],
[0, 0, 0, 1, 0, 0, 0]])
# R (dim_z, dim_z): measurement uncertainty/noise
self.kf.R[2:, 2:] *= 10.
# P (dim_x, dim_x): covariance matrix
# give high uncertainty to the unobservable initial velocities
self.kf.P[4:, 4:] *= 1000.
self.kf.P *= 10.
# Q (dim_x, dim_x): Process uncertainty/noise
self.kf.Q[-1, -1] *= 0.01
self.kf.Q[4:, 4:] *= 0.01
# x (dim_x, 1): filter state estimate
self.kf.x[:4] = convert_bbox_to_z(bbox)
self.time_since_update = 0
self.id = KalmanBoxTracker.count
KalmanBoxTracker.count += 1
self.history = []
self.hits = 0
self.hit_streak = 0
self.age = 0
# 解决画面中无人脸检测到时而导致的原有追踪器人像预测的漂移bug
self.predict_num = 0 # 连续预测的数目
# additional fields
self.face_attributes = []
def update(self, bbox):
"""Updates the state vector with observed bbox.
"""
self.time_since_update = 0
self.history = []
self.hits += 1
self.hit_streak += 1 # 连续命中
if bbox != []:
self.kf.update(convert_bbox_to_z(bbox))
self.predict_num = 0
else:
self.predict_num += 1
def predict(self):
"""Advances the state vector and returns the predicted bounding box
estimate.
"""
if (self.kf.x[6] + self.kf.x[2]) <= 0:
self.kf.x[6] *= 0.0
self.kf.predict()
self.age += 1
if self.time_since_update > 0:
self.hit_streak = 0
self.time_since_update += 1
self.history.append(convert_x_to_bbox(self.kf.x))
return self.history[-1][0]
def get_state(self):
"""Returns the current bounding box estimate."""
return convert_x_to_bbox(self.kf.x)[0]