baoshi-measure-cargo/api.py

import os
import time
import threading

import numpy as np
from fastapi import FastAPI, HTTPException
import uvicorn

from depth_common import (
    Settings,
    TemporalFilter,
    compute_roi_bounds,
    extract_depth_data,
    init_depth_pipeline,
    nearest_distance_in_roi,
)

# 采样参数
SAMPLE_COUNT = 10
FRAME_TIMEOUT_MS = 200
SAMPLE_TIMEOUT_SEC = 8
# 从环境变量加载测量配置
SETTINGS = Settings.from_env()

app = FastAPI(title="Cargo Height API")


# 相机相关的全局状态（由锁保护）
_pipeline = None
_depth_intrinsics = None
_temporal_filter = None
_lock = threading.Lock()


def _init_camera():
    # 延迟初始化相机，避免重复启动
    global _pipeline, _depth_intrinsics, _temporal_filter
    if _pipeline is not None:
        return
    try:
        pipeline, depth_intrinsics, _ = init_depth_pipeline()
    except Exception as exc:
        raise RuntimeError(f"Failed to init depth camera: {exc}") from exc
    _pipeline = pipeline
    _depth_intrinsics = depth_intrinsics
    _temporal_filter = TemporalFilter(alpha=0.5)


def _shutdown_camera():
    # 关闭相机资源
    global _pipeline
    if _pipeline is None:
        return
    _pipeline.stop()
    _pipeline = None


def _measure_once():
    # 单次采样：获取一帧并在 ROI 内计算最近距离
    frames = _pipeline.wait_for_frames(FRAME_TIMEOUT_MS)
    if frames is None:
        return None
    depth_frame = frames.get_depth_frame()
    depth_data = extract_depth_data(depth_frame, SETTINGS, _temporal_filter)
    if depth_data is None:
        return None
    bounds = compute_roi_bounds(depth_data, _depth_intrinsics, SETTINGS)
    if bounds is None:
        return None
    x_start, x_end, y_start, y_end, _ = bounds
    roi = depth_data[y_start:y_end, x_start:x_end]
    return nearest_distance_in_roi(roi, SETTINGS)


@app.on_event("startup")
def on_startup():
    # 服务启动时初始化相机
    _init_camera()


@app.on_event("shutdown")
def on_shutdown():
    # 服务关闭时释放相机
    _shutdown_camera()


@app.get("/height")
def get_height():
    # 采集多次样本并返回中位数高度
    start_time = time.time()
    samples = []
    with _lock:
        while len(samples) < SAMPLE_COUNT and (time.time() - start_time) < SAMPLE_TIMEOUT_SEC:
            value = _measure_once()
            if value is not None:
                samples.append(value)
    if len(samples) < SAMPLE_COUNT:
        raise HTTPException(status_code=503, detail="Insufficient valid samples from depth camera")
    median_value = int(np.median(np.array(samples, dtype=np.int32)))
    return {
        "height_mm": median_value,
        "samples": samples,
        "unit": "mm",
        "sample_count": SAMPLE_COUNT,
    }


@app.get("/health")
def health():
    # 健康检查接口
    return {"status": "ok"}


def main():
    # 读取监听地址并启动 API 服务
    host = os.getenv("API_HOST", "127.0.0.1")
    port = int(os.getenv("API_PORT", "8080"))
    uvicorn.run("api:app", host=host, port=port, log_level="info")


if __name__ == "__main__":
    main()