How to count number of objects

Python
,
1

I am trying to count the number of cars within a video, but for some reason the count keeps resetting to zero and when I put cars_count = 0 outside of def annotate_image it says that I am referencing a variable before assignment, I also tried putting it above the annotated_img = annotate_image(frame) line too and it’s the same error referencing variable before assignment


def annotate_image(image):
    # perform precidtion
    image_rgb = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
    results = model(image_rgb)
    cars_count = 0
    for i in range(len(results.pandas().xyxy[0].name)):
      
      name = results.pandas().xyxy[0].name[i]
      startX = int(results.pandas().xyxy[0].xmin[i])
      startY = int(results.pandas().xyxy[0].ymin[i])
      endX = int(results.pandas().xyxy[0].xmax[i])
      endY = int(results.pandas().xyxy[0].ymax[i])
      confidence = results.pandas().xyxy[0].confidence[i]
      label = "{}: {:.2f}%".format(name, confidence * 100)
      
      if confidence > 0.6:
        cv2.rectangle(image, (startX, startY), (endX, endY),
                  (255,0,0), 2)
        y = startY - 15 if startY - 15 > 15 else startY + 15
        cv2.putText(image, label, (startX, y),
            cv2.FONT_HERSHEY_SIMPLEX, 0.5, (255,255,255), 2)
        if name == "car":
          cars_count = cars_count + 1
      
    cars_count_label = "{}:".format(cars_count) 
    cv2.putText(image, cars_count_label, (400, 100), cv2.FONT_HERSHEY_SIMPLEX, 0.5, (255,255,255), 2)

    return image

video_in_file = "/content/drive/MyDrive/Colab_Notebooks/data/toycars.mp4"
video_out_file = "/content/drive/MyDrive/Colab_Notebooks/data/out.mp4"

print("[INFO] accessing video stream...")
v_out = None

v_in = cv2.VideoCapture(video_in_file)
total_frame = int(v_in.get(cv2.CAP_PROP_FRAME_COUNT ))

for frame_no in tqdm(range(total_frame), desc="Processing Video..."):
  (grabbed, frame) = v_in.read()

  # if the frame was not grabbed then we've reached the end of
  # the video stream so exit the script
  if not grabbed:
      print("[INFO] no frame read from stream - exiting")
      break
  
  annotated_img = annotate_image(frame)

  # check if the video writer is None
  if v_out is None:
      # initialize our video writer
      fourcc = cv2.VideoWriter_fourcc(*"mp4v")
      v_out = cv2.VideoWriter(video_out_file, fourcc,
                  int(v_in.get(cv2.CAP_PROP_FPS)),
                  (frame.shape[1], frame.shape[0]), True)

  # write the output frame to disk
  v_out.write(annotated_img)

# release the file pointers
print("\n[INFO] cleaning up...")
v_out.release()
v_in.release()