cv2.error: OpenCV(4.6.0) D:aopencv-pythonopencv-pythonopencvmodulesimgprocsrccolor.cpp:182

调用OpenCV模块的cvtColor处理图片：

img_rgb = r'G:手机照片2022IMG_122440.jpg'
img_gray = cv2.cvtColor(img_rgb, cv2.COLOR_BGR2GRAY)

发生了报错，报错内容为：

[ WARN:0@0.011] global D:aopencv-pythonopencv-pythonopencvmodulesimgcodecssrcloadsave.cpp (239) cv::findDecoder imread_('G:手机照片2022IMG_122440.jpg'): can't open/read file: check file path/integrity
Traceback (most recent call last):
  File "G:Test39.py", line 26, in <module>
    control_to_sketch(image, to_image)
  File "G:Test39.py", line 10, in control_to_sketch
    img_gray = cv2.cvtColor(img_rgb, cv2.COLOR_BGR2GRAY)
cv2.error: OpenCV(4.6.0) D:aopencv-pythonopencv-pythonopencvmodulesimgprocsrccolor.cpp:182: error: (-215:Assertion failed) !_src.empty() in function 'cv::cvtColor'

报错原因：第1行的警告其实有给出了答案，就是路径问题，不能打开或读取文件，需要改一下路径（can't open/read file: check file path/integrity）。
解决方法：

• 方法1：把路径中涉及到中文的文件夹的名称改为非中文名称，如：

img_rgb = r'G:mobile_photo_2022IMG_122440.jpg'
img_gray = cv2.cvtColor(img_rgb, cv2.COLOR_BGR2GRAY)

• 方法2：重新建一个英文名称的文件夹，将文件放到该文件夹中测试。