blakeblackshear.frigate/frigate/track/norfair_tracker.py
Blake Blackshear d81dd60fef
Improve motion detection and region selection (#6741)
* refactor existing motion detector

* implement and use cnt bgsub

* pass fps to motion detector

* create a simplified motion detector

* lightning detection

* update default motion config

* lint imports

* use estimated boxes for regions

* use improved motion detector

* update test

* use a different strategy for clustering motion and object boxes

* increase alpha during calibration

* simplify object consolidation

* add some reasonable constraints to the estimated box

* adjust cluster boundary to 10%

* refactor

* add disabled debug code

* fix variable scope
2023-06-11 08:45:11 -05:00

302 lines
11 KiB
Python

import random
import string
import numpy as np
from norfair import Detection, Drawable, Tracker, draw_boxes
from norfair.drawing.drawer import Drawer
from frigate.config import DetectConfig
from frigate.track import ObjectTracker
from frigate.util import intersection_over_union
# Normalizes distance from estimate relative to object size
# Other ideas:
# - if estimates are inaccurate for first N detections, compare with last_detection (may be fine)
# - could be variable based on time since last_detection
# - include estimated velocity in the distance (car driving by of a parked car)
# - include some visual similarity factor in the distance for occlusions
def distance(detection: np.array, estimate: np.array) -> float:
# ultimately, this should try and estimate distance in 3-dimensional space
# consider change in location, width, and height
estimate_dim = np.diff(estimate, axis=0).flatten()
detection_dim = np.diff(detection, axis=0).flatten()
# get bottom center positions
detection_position = np.array(
[np.average(detection[:, 0]), np.max(detection[:, 1])]
)
estimate_position = np.array([np.average(estimate[:, 0]), np.max(estimate[:, 1])])
distance = (detection_position - estimate_position).astype(float)
# change in x relative to w
distance[0] /= estimate_dim[0]
# change in y relative to h
distance[1] /= estimate_dim[1]
# get ratio of widths and heights
# normalize to 1
widths = np.sort([estimate_dim[0], detection_dim[0]])
heights = np.sort([estimate_dim[1], detection_dim[1]])
width_ratio = widths[1] / widths[0] - 1.0
height_ratio = heights[1] / heights[0] - 1.0
# change vector is relative x,y change and w,h ratio
change = np.append(distance, np.array([width_ratio, height_ratio]))
# calculate euclidean distance of the change vector
return np.linalg.norm(change)
def frigate_distance(detection: Detection, tracked_object) -> float:
return distance(detection.points, tracked_object.estimate)
class NorfairTracker(ObjectTracker):
def __init__(self, config: DetectConfig):
self.tracked_objects = {}
self.disappeared = {}
self.positions = {}
self.max_disappeared = config.max_disappeared
self.detect_config = config
self.track_id_map = {}
# TODO: could also initialize a tracker per object class if there
# was a good reason to have different distance calculations
self.tracker = Tracker(
distance_function=frigate_distance,
distance_threshold=2.5,
initialization_delay=0,
hit_counter_max=self.max_disappeared,
)
def register(self, track_id, obj):
rand_id = "".join(random.choices(string.ascii_lowercase + string.digits, k=6))
id = f"{obj['frame_time']}-{rand_id}"
self.track_id_map[track_id] = id
obj["id"] = id
obj["start_time"] = obj["frame_time"]
obj["motionless_count"] = 0
obj["position_changes"] = 0
self.tracked_objects[id] = obj
self.disappeared[id] = 0
self.positions[id] = {
"xmins": [],
"ymins": [],
"xmaxs": [],
"ymaxs": [],
"xmin": 0,
"ymin": 0,
"xmax": self.detect_config.width,
"ymax": self.detect_config.height,
}
def deregister(self, id):
del self.tracked_objects[id]
del self.disappeared[id]
# tracks the current position of the object based on the last N bounding boxes
# returns False if the object has moved outside its previous position
def update_position(self, id, box):
position = self.positions[id]
position_box = (
position["xmin"],
position["ymin"],
position["xmax"],
position["ymax"],
)
xmin, ymin, xmax, ymax = box
iou = intersection_over_union(position_box, box)
# if the iou drops below the threshold
# assume the object has moved to a new position and reset the computed box
if iou < 0.6:
self.positions[id] = {
"xmins": [xmin],
"ymins": [ymin],
"xmaxs": [xmax],
"ymaxs": [ymax],
"xmin": xmin,
"ymin": ymin,
"xmax": xmax,
"ymax": ymax,
}
return False
# if there are less than 10 entries for the position, add the bounding box
# and recompute the position box
if len(position["xmins"]) < 10:
position["xmins"].append(xmin)
position["ymins"].append(ymin)
position["xmaxs"].append(xmax)
position["ymaxs"].append(ymax)
# by using percentiles here, we hopefully remove outliers
position["xmin"] = np.percentile(position["xmins"], 15)
position["ymin"] = np.percentile(position["ymins"], 15)
position["xmax"] = np.percentile(position["xmaxs"], 85)
position["ymax"] = np.percentile(position["ymaxs"], 85)
return True
def is_expired(self, id):
obj = self.tracked_objects[id]
# get the max frames for this label type or the default
max_frames = self.detect_config.stationary.max_frames.objects.get(
obj["label"], self.detect_config.stationary.max_frames.default
)
# if there is no max_frames for this label type, continue
if max_frames is None:
return False
# if the object has exceeded the max_frames setting, deregister
if (
obj["motionless_count"] - self.detect_config.stationary.threshold
> max_frames
):
return True
return False
def update(self, track_id, obj):
id = self.track_id_map[track_id]
self.disappeared[id] = 0
# update the motionless count if the object has not moved to a new position
if self.update_position(id, obj["box"]):
self.tracked_objects[id]["motionless_count"] += 1
if self.is_expired(id):
self.deregister(id)
return
else:
# register the first position change and then only increment if
# the object was previously stationary
if (
self.tracked_objects[id]["position_changes"] == 0
or self.tracked_objects[id]["motionless_count"]
>= self.detect_config.stationary.threshold
):
self.tracked_objects[id]["position_changes"] += 1
self.tracked_objects[id]["motionless_count"] = 0
self.tracked_objects[id].update(obj)
def update_frame_times(self, frame_time):
# if the object was there in the last frame, assume it's still there
detections = [
(
obj["label"],
obj["score"],
obj["box"],
obj["area"],
obj["ratio"],
obj["region"],
)
for id, obj in self.tracked_objects.items()
if self.disappeared[id] == 0
]
self.match_and_update(frame_time, detections=detections)
def match_and_update(self, frame_time, detections):
norfair_detections = []
for obj in detections:
# centroid is used for other things downstream
centroid_x = int((obj[2][0] + obj[2][2]) / 2.0)
centroid_y = int((obj[2][1] + obj[2][3]) / 2.0)
# track based on top,left and bottom,right corners instead of centroid
points = np.array([[obj[2][0], obj[2][1]], [obj[2][2], obj[2][3]]])
norfair_detections.append(
Detection(
points=points,
label=obj[0],
data={
"label": obj[0],
"score": obj[1],
"box": obj[2],
"area": obj[3],
"ratio": obj[4],
"region": obj[5],
"frame_time": frame_time,
"centroid": (centroid_x, centroid_y),
},
)
)
tracked_objects = self.tracker.update(detections=norfair_detections)
# update or create new tracks
active_ids = []
for t in tracked_objects:
estimate = tuple(t.estimate.flatten().astype(int))
# keep the estimate within the bounds of the image
estimate = (
max(0, estimate[0]),
max(0, estimate[1]),
min(self.detect_config.width - 1, estimate[2]),
min(self.detect_config.height - 1, estimate[3]),
)
obj = {
**t.last_detection.data,
"estimate": estimate,
}
active_ids.append(t.global_id)
if t.global_id not in self.track_id_map:
self.register(t.global_id, obj)
# if there wasn't a detection in this frame, increment disappeared
elif t.last_detection.data["frame_time"] != frame_time:
id = self.track_id_map[t.global_id]
self.disappeared[id] += 1
# sometimes the estimate gets way off
# only update if the upper left corner is actually upper left
if estimate[0] < estimate[2] and estimate[1] < estimate[3]:
self.tracked_objects[id]["estimate"] = obj["estimate"]
# else update it
else:
self.update(t.global_id, obj)
# clear expired tracks
expired_ids = [k for k in self.track_id_map.keys() if k not in active_ids]
for e_id in expired_ids:
self.deregister(self.track_id_map[e_id])
del self.track_id_map[e_id]
def debug_draw(self, frame, frame_time):
active_detections = [
Drawable(id=obj.id, points=obj.last_detection.points, label=obj.label)
for obj in self.tracker.tracked_objects
if obj.last_detection.data["frame_time"] == frame_time
]
missing_detections = [
Drawable(id=obj.id, points=obj.last_detection.points, label=obj.label)
for obj in self.tracker.tracked_objects
if obj.last_detection.data["frame_time"] != frame_time
]
# draw the estimated bounding box
draw_boxes(frame, self.tracker.tracked_objects, color="green", draw_ids=True)
# draw the detections that were detected in the current frame
draw_boxes(frame, active_detections, color="blue", draw_ids=True)
# draw the detections that are missing in the current frame
draw_boxes(frame, missing_detections, color="red", draw_ids=True)
# draw the distance calculation for the last detection
# estimate vs detection
for obj in self.tracker.tracked_objects:
ld = obj.last_detection
# bottom right
text_anchor = (
ld.points[1, 0],
ld.points[1, 1],
)
frame = Drawer.text(
frame,
f"{obj.id}: {str(obj.last_distance)}",
position=text_anchor,
size=None,
color=(255, 0, 0),
thickness=None,
)