我正在尝试使用python将图像转换为二进制，但有些东西无法正常工作。以下是我的代码：

def binarize_image(filename):
    filename = MEDIA_ROOT + "\\" + filename
    img = cv2.imread(filename)
    greyscale_img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    binary_img = cv2.threshold(greyscale_img, 127, 64, cv2.THRESH_BINARY,)
    resized_name = f"binary_{filename[:len(filename) - 4]}.png"
    cv2.imwrite(resized_name, binary_img)
    return resized_name

它在写入图像时崩溃，回溯如下：

Traceback (most recent call last):
  File "D:\Python\proj\venv\lib\site-packages\django\core\handlers\exception.py", line 56, in inner
    response = get_response(request)
  File "D:\Python\proj\venv\lib\site-packages\django\core\handlers\base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "D:\Python\proj\src\core\views.py", line 48, in create_binary_image
    binarize_image(url)
  File "D:\Python\proj\src\core\utils\image_binarize.py", line 17, in binarize_image
    cv2.imwrite(resized_name, binary_img)
cv2.error: OpenCV(4.7.0) :-1: error: (-5:Bad argument) in function 'imwrite'
> Overload resolution failed:
>  - img is not a numerical tuple
>  - Expected Ptr<cv::UMat> for argument 'img'

你知道我做错了什么吗？我将非常感谢你的建议！