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| class CognitiveDistractionDetector: """认知分心检测器""" def __init__(self, config: Dict): self.thresholds = { 'saccade_freq': config.get('saccade_freq', (2, 8)), 'blink_rate': config.get('blink_rate', (0.1, 0.5)), 'pupil_diameter': config.get('pupil_diameter', (3, 6)), 'fixation_duration': config.get('fixation_duration', (0.2, 1.0)) } self.window_size = config.get('window_size', 60) def extract_eye_metrics(self, eye_data: np.ndarray) -> Dict: """ 提取眼动指标 Args: eye_data: 眼动数据序列 (N, 8) [timestamp, gaze_x, gaze_y, pupil_left, pupil_right, blink_left, blink_right, confidence] Returns: metrics: 眼动指标 """ gaze_coords = eye_data[:, 1:3] saccade_freq = self._calculate_saccade_frequency(gaze_coords) blinks = eye_data[:, 5:7].mean(axis=1) blink_rate = self._calculate_blink_rate(blinks) pupil_diameter = eye_data[:, 3:5].mean(axis=1).mean() fixation_duration = self._calculate_fixation_duration(gaze_coords) gaze_entropy = self._calculate_gaze_entropy(gaze_coords) return { 'saccade_frequency': saccade_freq, 'blink_rate': blink_rate, 'pupil_diameter': pupil_diameter, 'fixation_duration': fixation_duration, 'gaze_entropy': gaze_entropy } def _calculate_saccade_frequency(self, gaze: np.ndarray) -> float: """计算扫视频率""" velocity = np.linalg.norm(np.diff(gaze, axis=0), axis=1) saccade_threshold = 0.05 saccades = velocity > saccade_threshold return np.sum(saccades) / len(velocity) * 30 def _calculate_blink_rate(self, blink_signal: np.ndarray) -> float: """计算眨眼频率""" blink_events = np.diff(blink_signal > 0.5).astype(int) blink_count = np.sum(blink_events == 1) return blink_count / len(blink_signal) * 30 def _calculate_fixation_duration(self, gaze: np.ndarray) -> float: """计算平均注视时长""" velocity = np.linalg.norm(np.diff(gaze, axis=0), axis=1) fixation_threshold = 0.01 is_fixation = velocity < fixation_threshold fixation_segments = self._find_segments(is_fixation) if not fixation_segments: return 0 durations = [seg[1] - seg[0] for seg in fixation_segments] return np.mean(durations) / 30 def _calculate_gaze_entropy(self, gaze: np.ndarray) -> float: """计算凝视熵(空间分布度量)""" grid_size = 10 x_bins = np.linspace(0, 1, grid_size + 1) y_bins = np.linspace(0, 1, grid_size + 1) hist, _, _ = np.histogram2d(gaze[:, 0], gaze[:, 1], bins=[x_bins, y_bins]) hist = hist.flatten() hist = hist / hist.sum() hist = hist[hist > 0] entropy = -np.sum(hist * np.log2(hist)) return entropy def _find_segments(self, condition: np.ndarray) -> List[Tuple[int, int]]: """找到连续段的起止索引""" segments = [] start = None for i, val in enumerate(condition): if val and start is None: start = i elif not val and start is not None: segments.append((start, i)) start = None if start is not None: segments.append((start, len(condition))) return segments def detect(self, eye_data: np.ndarray) -> Tuple[bool, float, Dict]: """ 检测认知分心 Args: eye_data: 眼动数据 Returns: is_distracted: 是否认知分心 confidence: 置信度 details: 详细指标 """ metrics = self.extract_eye_metrics(eye_data) anomaly_count = 0 anomaly_details = {} if not (self.thresholds['saccade_freq'][0] <= metrics['saccade_frequency'] <= self.thresholds['saccade_freq'][1]): anomaly_count += 1 anomaly_details['saccade'] = 'abnormal' if not (self.thresholds['blink_rate'][0] <= metrics['blink_rate'] <= self.thresholds['blink_rate'][1]): anomaly_count += 1 anomaly_details['blink'] = 'abnormal' if metrics['gaze_entropy'] < 3.0: anomaly_count += 1 anomaly_details['gaze_entropy'] = 'low' if metrics['fixation_duration'] > 2.0: anomaly_count += 1 anomaly_details['fixation'] = 'prolonged' is_distracted = anomaly_count >= 2 confidence = anomaly_count / 4.0 return is_distracted, confidence, { 'metrics': metrics, 'anomalies': anomaly_details, 'anomaly_count': anomaly_count }
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