修改心率部分，减小其负荷

reproject/HeartRateMonitor.py

@@ -14,11 +14,17 @@ class HeartRateMonitor:
         self.b_buffer = collections.deque(maxlen=window_size)
         
         # 滤波器状态
-        self.bp_b, self.bp_a = self._create_bandpass_filter(0.75, 2.5, fps) # 45-150 BPM
+        # 修改: 将最低频率从 0.75(45 BPM) 提高到 0.9(54 BPM) 以过滤低频噪声
+        self.bp_b, self.bp_a = self._create_bandpass_filter(0.9, 2.5, fps) # 54-150 BPM
         
         # 平滑结果用的
         self.bpm_history = collections.deque(maxlen=10)
 
+        # 优化: 降频计算
+        self.frame_counter = 0
+        self.process_interval = 15  # 每15帧(约0.5s)计算一次，其他时间收集数据
+        self.last_bpm = None
+
     def _create_bandpass_filter(self, lowcut, highcut, fs, order=5):
         """创建巴特沃斯带通滤波器"""
         nyq = 0.5 * fs
@@ -92,6 +98,12 @@ class HeartRateMonitor:
             progress = int(len(self.r_buffer) / self.buffer_size * 100)
             return None # 或者返回 progress 表示进度
 
+        # [优化] 降频计算策略
+        # 我们每帧都需要收集数据(Buffer append)，但不需要每帧都做 FFT
+        self.frame_counter += 1
+        if self.frame_counter % self.process_interval != 0:
+            return self.last_bpm
+
         # --- 3. 信号处理 (核心升级部分) ---
         r = np.array(self.r_buffer)
         g = np.array(self.g_buffer)
@@ -119,13 +131,13 @@ class HeartRateMonitor:
         mag = np.abs(fft_res)
         
         # D. 寻找峰值
-        # 限制频率范围 (45 BPM - 180 BPM)
-        interest_idx = np.where((freqs >= 0.75) & (freqs <= 3.0))
+        # 限制频率范围 (54 BPM - 180 BPM)
+        interest_idx = np.where((freqs >= 0.9) & (freqs <= 3.0))
         valid_freqs = freqs[interest_idx]
         valid_mags = mag[interest_idx]
         
         if len(valid_mags) == 0:
-            return None
+            return self.last_bpm
 
         max_idx = np.argmax(valid_mags)
         peak_freq = valid_freqs[max_idx]
@@ -136,4 +148,5 @@ class HeartRateMonitor:
         self.bpm_history.append(bpm)
         avg_bpm = np.mean(self.bpm_history)
         
+        self.last_bpm = int(avg_bpm)
         return int(avg_bpm)