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yingshiyun/analysis/fall_detector.py
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yuming b3608f534e feat: 新增视频分析流水线、Web界面、孤儿清理工具;修复健壮性问题
- 新增 analysis/ 模块:MOG2活动检测、YOLO人物跟踪、MediaPipe摔倒检测、Ollama活动打标、缩略图抽取
- 新增 webapp/:Flask事件浏览界面,按需HEVC→H264转码缓存
- 新增 analyze.py:7阶段状态机流水线(scan→backfill→motion→person→fall→activity→thumbnail)
- 新增 cleanup_orphans.py:清理文件已删除的数据库孤儿记录
- 修复:motion/person/activity三阶段加单视频异常兜底,避免批次中断
- 修复:ollama_client加健康检查和3次重试,num_ctx从8192降到2048
- 修复:transcode_cache加fcntl文件锁,防止并发转码同一视频
- 修复:SQLite开WAL模式+busy_timeout,支持读写并发
- 修复:sync.py ffmpeg路径改为shutil.which查找,删除automate.py死代码PYTHON
- 修复:thumbnail失败加3次重试上限,避免无限重试损坏文件
- 新增:requirements.lock锁定版本、README文档
- 更新:.gitignore排除.playwright-mcp、截图、备份文件
2026-09-18 15:52:49 +08:00

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"""在 person_tracker 已确认"有人"的时间段内跑 MediaPipe Pose 关键点估计,
用确定性规则引擎判断是否摔倒,写入 events 表(event_type='fall')。
不用VLM做摔倒检测:这是安全信号,需要可解释、可调阈值、宁可多报不漏报的确定性
规则,而不是模型的"感觉"。规则:短时间内从"直立"骤变为"横躺",且"横躺"状态
持续一段时间——单独判断"是否躺平"分不清摔倒和弯腰/坐下,必须叠加"骤变"和
"持续"两个时间条件。
"""
import json
import math
from datetime import datetime, timedelta
import cv2
import mediapipe as mp
import numpy as np
from mediapipe.tasks import python as mp_python
from mediapipe.tasks.python import vision
from analysis.config import (
FALL_MODEL_PATH,
FALL_SAMPLE_STRIDE,
FALL_MIN_VISIBILITY,
FALL_ASPECT_RATIO_THRESH,
FALL_TORSO_ANGLE_UPRIGHT,
FALL_TORSO_ANGLE_PRONE,
FALL_TRANSITION_MAX_SEC,
FALL_SUSTAIN_MIN_SEC,
FALL_GAP_TOLERANCE_SEC,
PROJECT_ROOT,
)
from analysis.db import get_all_videos, get_events, insert_event, update_video_status
LEFT_SHOULDER, RIGHT_SHOULDER = 11, 12
LEFT_HIP, RIGHT_HIP = 23, 24
def _make_landmarker():
base_options = mp_python.BaseOptions(model_asset_path=str(FALL_MODEL_PATH))
options = vision.PoseLandmarkerOptions(
base_options=base_options,
running_mode=vision.RunningMode.VIDEO,
num_poses=1,
)
return vision.PoseLandmarker.create_from_options(options)
def _classify_pose(landmarks, width, height):
"""返回 'upright' / 'prone' / 'unknown'(关键点不足或角度介于两者之间)。"""
visible = [lm for lm in landmarks if lm.visibility >= FALL_MIN_VISIBILITY]
if len(visible) < 4:
return "unknown"
xs = [lm.x * width for lm in visible]
ys = [lm.y * height for lm in visible]
bbox_w = max(xs) - min(xs)
bbox_h = max(ys) - min(ys)
if bbox_h <= 0:
return "unknown"
aspect_ratio = bbox_w / bbox_h
shoulders = [landmarks[i] for i in (LEFT_SHOULDER, RIGHT_SHOULDER) if landmarks[i].visibility >= FALL_MIN_VISIBILITY]
hips = [landmarks[i] for i in (LEFT_HIP, RIGHT_HIP) if landmarks[i].visibility >= FALL_MIN_VISIBILITY]
if not shoulders or not hips:
return "unknown"
shoulder_mid = (sum(lm.x for lm in shoulders) / len(shoulders) * width,
sum(lm.y for lm in shoulders) / len(shoulders) * height)
hip_mid = (sum(lm.x for lm in hips) / len(hips) * width,
sum(lm.y for lm in hips) / len(hips) * height)
dx = abs(hip_mid[0] - shoulder_mid[0])
dy = abs(hip_mid[1] - shoulder_mid[1])
torso_angle = math.degrees(math.atan2(dx, dy + 1e-6)) # 0°=垂直直立,90°=水平躺平
if aspect_ratio >= FALL_ASPECT_RATIO_THRESH and torso_angle >= FALL_TORSO_ANGLE_PRONE:
return "prone"
if aspect_ratio < 1.0 and torso_angle <= FALL_TORSO_ANGLE_UPRIGHT:
return "upright"
return "unknown"
def _extract_pose_states(landmarker, cap, fps, width, height, start_sec, end_sec):
"""在给定时间段内采样跑姿态估计,返回 [(t, state), ...]。"""
start_frame = int(start_sec * fps)
end_frame = int(end_sec * fps)
cap.set(cv2.CAP_PROP_POS_FRAMES, start_frame)
states = []
frame_idx = start_frame
while frame_idx <= end_frame:
ret, frame = cap.read()
if not ret:
break
if (frame_idx - start_frame) % FALL_SAMPLE_STRIDE == 0:
t = frame_idx / fps
rgb = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
mp_image = mp.Image(image_format=mp.ImageFormat.SRGB, data=np.ascontiguousarray(rgb))
result = landmarker.detect_for_video(mp_image, int(t * 1000))
if result.pose_landmarks:
state = _classify_pose(result.pose_landmarks[0], width, height)
else:
state = "unknown"
states.append((t, state))
frame_idx += 1
return states
def _find_fall_windows(states):
"""从时序姿态状态里找出"直立→骤变→横躺并持续"的片段,返回 [(start_sec, end_sec), ...]。
用"疑似摔倒事件"(episode)建模:只有真正观察到"直立"样本才会结束当前事件的计时;
事件进行期间即使长时间检测不到姿态(真实摔倒后人体角度/遮挡经常导致关键点大面积
漏检,不代表已经爬起来),也继续算同一次事件,直到确认恢复直立,或者长时间
(超过 FALL_GAP_TOLERANCE_SEC)连"横躺"样本都等不到才判定事件已经结束/跟丢。
"""
windows = []
last_upright_t = None
episode_start = None
episode_last_prone = None
def close_episode():
nonlocal episode_start, episode_last_prone
if episode_start is not None and (episode_last_prone - episode_start) >= FALL_SUSTAIN_MIN_SEC:
windows.append((episode_start, episode_last_prone))
episode_start = None
episode_last_prone = None
for t, state in states:
if state == "upright":
close_episode()
last_upright_t = t
elif state == "prone":
if episode_start is None:
# 只有紧接在"直立"之后、且间隔够短,才算一次骤变
if last_upright_t is not None and (t - last_upright_t) <= FALL_TRANSITION_MAX_SEC:
episode_start = t
episode_last_prone = t
# 否则忽略:不是从直立状态骤变而来(比如视频开头就是横躺,或者是缓慢躺下)
elif (t - episode_last_prone) <= FALL_GAP_TOLERANCE_SEC:
episode_last_prone = t
else:
# 距离上一次确认"横躺"太久,且中途也没等到"直立"信号,视为跟丢,结算当前事件
close_episode()
# state == "unknown" 不改变状态机,只是跳过这一帧(容忍短暂遮挡/漏检)
close_episode()
return windows
def _merge_windows(events):
"""合并人物track的时间区间(有重叠或紧邻就合并成一段)。
同一个人有时会被 ByteTrack 拆成多个track_id(跟踪中途丢失又重新编号),
这些track的时间区间往往高度重叠——如果按track各自跑一遍姿态估计,
同一次摔倒会被重复检测、重复插入,所以要先合并再处理,保证同一段画面只处理一次。
"""
spans = sorted((e["start_offset_sec"], e["end_offset_sec"]) for e in events)
merged = []
for start, end in spans:
if merged and start <= merged[-1][1]:
merged[-1] = (merged[-1][0], max(merged[-1][1], end))
else:
merged.append((start, end))
return merged
def process_video(video, person_events):
if not person_events:
update_video_status(video["id"], "fall_done")
return 0
cap = cv2.VideoCapture(str(PROJECT_ROOT / video["file_path"]))
if not cap.isOpened():
update_video_status(video["id"], "fall_done")
return 0
fps = video["fps"] or 15.0
width, height = video["width"], video["height"]
start_time = None
if video["start_time"]:
try:
start_time = datetime.strptime(video["start_time"], "%Y-%m-%d %H:%M:%S")
except ValueError:
pass
fall_count = 0
# landmarker 实例按需复用:VIDEO 模式要求时间戳在同一实例内严格递增,只有当下一个
# 事件的起始时间会比当前实例已处理到的时间更早(多人同时/交替出现导致事件时间重叠)
# 时才换新实例。之前"每个事件都新建一个实例"的写法在批量跑千级视频时会持续新建
# GPU/Metal 上下文,资源迟迟未完全释放,最终在某个看似无关的帧读取操作上引发底层崩溃
landmarker = _make_landmarker()
last_t = -1.0
try:
# 先合并所有track的时间区间再处理:同一个人有时会被拆成多个重叠的track_id,
# 按原始track各自跑一遍会导致同一次摔倒被重复检测、重复插入
for merged_start, merged_end in _merge_windows(person_events):
start_frame_t = int(merged_start * fps) / fps
if start_frame_t <= last_t:
landmarker.close()
landmarker = _make_landmarker()
states = _extract_pose_states(
landmarker, cap, fps, width, height,
merged_start, merged_end,
)
if states:
last_t = states[-1][0]
for start_sec, end_sec in _find_fall_windows(states):
timestamp_abs = (start_time + timedelta(seconds=start_sec)).isoformat() if start_time else None
insert_event({
"video_id": video["id"],
"event_type": "fall",
"label": None,
"start_offset_sec": start_sec,
"end_offset_sec": end_sec,
"timestamp_abs": timestamp_abs,
"confidence": None,
"track_id": None,
"thumbnail_path": None,
"extra_json": None,
"created_at": datetime.now().isoformat(),
})
fall_count += 1
except Exception as e:
# 兜底:单条视频处理异常不应中断整个批次,标记失败并继续下一条。
# 异常本身可能就是底层解码/GPU上下文已经出问题,close()也可能再报错,不能让它盖过原始异常
try:
landmarker.close()
except Exception:
pass
cap.release()
update_video_status(video["id"], "fall_failed", error_message=str(e))
return fall_count
landmarker.close()
cap.release()
update_video_status(video["id"], "fall_done")
return fall_count
def process_all(limit=None):
videos = get_all_videos(status="person_done")
if limit:
videos = videos[:limit]
events_by_video = {}
for e in get_events("person_presence"):
events_by_video.setdefault(e["video_id"], []).append(e)
processed = 0
total_falls = 0
for video in videos:
total_falls += process_video(video, events_by_video.get(video["id"], []))
processed += 1
return {"processed": processed, "total_falls": total_falls}
if __name__ == "__main__":
print("===== 开始检测摔倒事件 =====")
result = process_all()
print(f"→ 处理 {result['processed']} 个视频,检测到 {result['total_falls']} 次疑似摔倒")
print("===== 检测完成 =====")