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| import numpy as np from typing import Dict, List, Tuple from dataclasses import dataclass
@dataclass class VitalSigns: """生命体征""" heart_rate: float breathing_rate: float confidence: float
class CPDDetector: """儿童存在检测器""" def __init__(self, radar_config: Dict): """ 初始化检测器 Args: radar_config: 雷达配置 """ self.config = radar_config self.fft_size = 256 self.range_bins = 64 self.movement_threshold = 0.1 self.heart_rate_range = (60, 180) self.breathing_rate_range = (20, 60) def process_frame(self, radar_data: np.ndarray) -> Dict: """ 处理单帧雷达数据 Args: radar_data: 雷达ADC数据 (num_chirps, num_rx, num_samples) Returns: result: { "presence_detected": bool, "vital_signs": VitalSigns, "distance": float, "confidence": float } """ range_fft = self._range_fft(radar_data) doppler_fft = self._doppler_fft(range_fft) targets = self._detect_targets(doppler_fft) vital_signs = self._extract_vital_signs(range_fft, targets) presence_detected = len(targets) > 0 or vital_signs.confidence > 0.7 return { "presence_detected": presence_detected, "vital_signs": vital_signs, "targets": targets, "confidence": vital_signs.confidence } def _range_fft(self, radar_data: np.ndarray) -> np.ndarray: """ 距离维FFT Args: radar_data: (num_chirps, num_rx, num_samples) Returns: range_fft: (num_chirps, num_rx, range_bins) """ range_fft = np.fft.fft(radar_data, n=self.range_bins, axis=2) range_fft = np.abs(range_fft) return range_fft def _doppler_fft(self, range_fft: np.ndarray) -> np.ndarray: """ 速度维FFT Args: range_fft: (num_chirps, num_rx, range_bins) Returns: doppler_fft: (doppler_bins, num_rx, range_bins) """ doppler_fft = np.fft.fft(range_fft, axis=0) doppler_fft = np.fft.fftshift(doppler_fft, axes=0) doppler_fft = np.abs(doppler_fft) return doppler_fft def _detect_targets(self, doppler_fft: np.ndarray) -> List[Dict]: """ CFAR目标检测 Args: doppler_fft: 多普勒FFT结果 Returns: targets: 检测到的目标列表 """ targets = [] max_val = np.max(doppler_fft) if max_val > 0.1: peak_idx = np.unravel_index(np.argmax(doppler_fft), doppler_fft.shape) distance = peak_idx[2] * 0.5 velocity = peak_idx[0] * 0.1 targets.append({ "distance": distance, "velocity": velocity, "intensity": max_val }) return targets def _extract_vital_signs(self, range_fft: np.ndarray, targets: List[Dict]) -> VitalSigns: """ 提取生命体征 心跳和呼吸引起的胸部微动(<1mm)会产生相位调制 Args: range_fft: 距离FFT结果 targets: 检测到的目标 Returns: vital_signs: 生命体征 """ if not targets: return VitalSigns(0, 0, 0) phase_sequence = self._extract_phase_sequence(range_fft, targets[0]) heart_rate = self._detect_heart_rate(phase_sequence) breathing_rate = self._detect_breathing_rate(phase_sequence) confidence = self._calculate_confidence(heart_rate, breathing_rate) return VitalSigns(heart_rate, breathing_rate, confidence) def _extract_phase_sequence(self, range_fft: np.ndarray, target: Dict) -> np.ndarray: """提取相位序列""" return np.angle(range_fft[:, 0, int(target['distance'] * 2)]) def _detect_heart_rate(self, phase_sequence: np.ndarray) -> float: """检测心率""" fft = np.fft.fft(phase_sequence) freqs = np.fft.fftfreq(len(phase_sequence), d=0.05) heart_band = (freqs >= 0.8) & (freqs <= 3.0) if np.any(heart_band): peak_freq = freqs[heart_band][np.argmax(np.abs(fft[heart_band]))] heart_rate = peak_freq * 60 else: heart_rate = 80 return np.clip(heart_rate, self.heart_rate_range[0], self.heart_rate_range[1]) def _detect_breathing_rate(self, phase_sequence: np.ndarray) -> float: """检测呼吸率""" fft = np.fft.fft(phase_sequence) freqs = np.fft.fftfreq(len(phase_sequence), d=0.05) breath_band = (freqs >= 0.2) & (freqs <= 1.0) if np.any(breath_band): peak_freq = freqs[breath_band][np.argmax(np.abs(fft[breath_band]))] breathing_rate = peak_freq * 60 else: breathing_rate = 30 return np.clip(breathing_rate, self.breathing_rate_range[0], self.breathing_rate_range[1]) def _calculate_confidence(self, heart_rate: float, breathing_rate: float) -> float: """计算置信度""" if heart_rate > 0 and breathing_rate > 0: return 0.85 elif heart_rate > 0 or breathing_rate > 0: return 0.6 else: return 0.3
if __name__ == "__main__": radar_config = { "fft_size": 256, "range_bins": 64, "chirps_per_frame": 128 } detector = CPDDetector(radar_config) radar_data = np.random.randn(128, 2, 256) * 0.01 result = detector.process_frame(radar_data) print(f"儿童存在: {result['presence_detected']}") print(f"心率: {result['vital_signs'].heart_rate:.1f} bpm") print(f"呼吸率: {result['vital_signs'].breathing_rate:.1f} bpm") print(f"置信度: {result['vital_signs'].confidence:.2f}")
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