improved stability of FPS display

ocv_rpicam.py

@@ -38,7 +38,7 @@ picam2 = Picamera2()
 pprint(picam2.sensor_modes)
 settings = {'NoiseReductionMode': 0, 'AeExposureMode': 0, 'ExposureTime': 10000, 'AnalogueGain': 1, 'FrameRate': picam2.sensor_modes[0]['fps']}
 caps = {"FrameRate": (1, picam2.sensor_modes[0]['fps'], None)}
-timer = None
+fps = 0
 
 
 def load_settings():
@@ -78,16 +78,10 @@ def get_value(item: str):
     return picam2.camera_controls[item]
     
 def process(request):
-    global timer
-    fps = 0
+    global fps
 
     timestamp = time.strftime("%Y-%m-%d %X")
 
-    # Calculate Frames per second (FPS)
-    if timer is not None:
-        fps = cv2.getTickFrequency() / (cv2.getTickCount() - timer)
-
-
     with MappedArray(request, "main") as m:
         # Display timestamp on frame
         cv2.putText(m.array, timestamp, (0, 30), cv2.FONT_HERSHEY_SIMPLEX, 1, (0, 255, 0), 2)
@@ -95,8 +89,6 @@ def process(request):
         # Display FPS on frame
         cv2.putText(m.array, "FPS : " + str(int(fps)), (20, m.array.shape[0] - 20), cv2.FONT_HERSHEY_SIMPLEX, 1, (0, 240, 0), 2)
 
-    # Start timer
-    timer = cv2.getTickCount()
 
 if __name__ == '__main__':
     for item in items:
@@ -126,6 +118,9 @@ if __name__ == '__main__':
     picam2.start()
     
     while True:
+        # Start timer
+        timer = cv2.getTickCount()
+
         rgb = picam2.capture_array("main")
         frame = cv2.cvtColor(rgb, cv2.COLOR_RGB2BGR)
 
@@ -193,7 +188,10 @@ if __name__ == '__main__':
             fps = set_value('FrameRate', fps)
             print(f"FPS: {fps}")
 
-            
+    # Calculate Frames per second (FPS)
+    fps = cv2.getTickFrequency() / (cv2.getTickCount() - timer)
+
+
     # Release the capture and close windows
     save_settings(settings)
     cv2.destroyAllWindows()

settings.json

@@ -1,7 +1,7 @@
 {
 "NoiseReductionMode": 0,
 "AeExposureMode": 0,
-"ExposureTime": 12829,
-"AnalogueGain": 5.0,
-"FrameRate": 10.380000000000003
+"ExposureTime": 13929,
+"AnalogueGain": 1.0,
+"FrameRate": 60.38
 }