python上使用新函数应该更快

classes, scores, boxes = model.detect(frames, conf_thd, nms_thd)

其中model这个是来自：
`net = cv2.dnn.readNetFromDarknet(CONFIG_FILE, WEIGHT_FILE)  # 读取权重与配置文件`

`net.setPreferableBackend(cv2.dnn.DNN_BACKEND_CUDA)`
`net.setPreferableTarget(cv2.dnn.DNN_TARGET_CUDA)`
`model = cv2.dnn_DetectionModel(net)`
`model.setInputParams(size=(side_width, side_height), scale=1/255, swapRB=True)`
