这可能是一个愚蠢的问题，但我是机器学习和Tensorflow的新手。我尝试使用Tensorflow Lite在树莓派上运行对象检测API。我尝试在此示例的帮助下修改代码

https://github.com/freedomtan/tensorflow/blob/deeplab_tflite_python/tensorflow/contrib/lite/examples/python/object_detection.py

这段代码将从图像中检测物体。但我想通过Pi相机真实的检测物体，而不是图像。我试图修改这段代码，从相机而不是图像中读取输入。以下是我的代码-

import numpy as np
from tensorflow.contrib.lite.python import interpreter as interpreter_wrapper
import cv2

cap = cv2.VideoCapture(0)
ret, image_np = cap.read()

PATH_TO_MODEL = "ssd_mobilenet_v1_coco.tflite"

interpreter = tf.contrib.lite.Interpreter(model_path=PATH_TO_MODEL)
interpreter.allocate_tensors()

input_details = interpreter.get_input_details()
output_details = interpreter.get_output_details()

while True:
  # NxHxWxC, H:1, W:2
  height = input_details[0]['shape'][1]
  width = input_details[0]['shape'][2]
  ret, image_np = cap.read()

  image_np_expanded = np.expand_dims(image_np, axis=0)
  #if floating_model:
  image_np_expanded = (np.float32(image_np_expanded) - input_mean) / input_std

  #HERE I AM GETTING ERROR
  interpreter.set_tensor(input_details[0]['index'], image_np_expanded)

  if cv2.waitKey(25) & 0xFF == ord('q'):
    cv2.destroyAllWindows()
    break

但我得到了这个错误

Traceback (most recent call last):
  File "New_object_detection.py", line 257, in <module>
    interpreter.set_tensor(input_details[0]['index'], image_np_expanded)
  File "/home/saurabh/.local/lib/python3.6/site-packages/tensorflow/contrib/lite/python/interpreter.py", line 151, in set_tensor
    self._interpreter.SetTensor(tensor_index, value)
  File "/home/saurabh/.local/lib/python3.6/site-packages/tensorflow/contrib/lite/python/interpreter_wrapper/tensorflow_wrap_interpreter_wrapper.py", line 133, in SetTensor
    return _tensorflow_wrap_interpreter_wrapper.InterpreterWrapper_SetTensor(self, i, value)
ValueError: Cannot set tensor: Dimension mismatch

任何人都可以请告诉我如何修复这个错误或建议教程相同？