Question :
I have the following code and it fails, because it cannot read the file from disk. The image is always None.
# -*- coding: utf-8 -*-
import cv2
import numpy
bgrImage = cv2.imread(u'D:\ö\handschuh.jpg')
Note: my file is already saved as UTF-8 with BOM. I verified with Notepad++.
In Process Monitor, I see that Python is acccessing the file from a wrong path:
I have read about:
- Open file with unicode filename, which is about the
open()function and not related to OpenCV. - How do I read an image file using Python, but that’s unrelated to Unicode issues.
Answer #1:
It can be done by
- opening the file using
open(), which supports Unicode as in the linked answer, - read the contents as a byte array,
- convert the byte array to a NumPy array,
- decode the image
# -*- coding: utf-8 -*-
import cv2
import numpy
stream = open(u'D:\ö\handschuh.jpg', "rb")
bytes = bytearray(stream.read())
numpyarray = numpy.asarray(bytes, dtype=numpy.uint8)
bgrImage = cv2.imdecode(numpyarray, cv2.IMREAD_UNCHANGED)
Answer #2:
Inspired by Thomas Weller’s answer, you can also use np.fromfile() to read the image and convert it to ndarray and then use cv2.imdecode() to decode the array into a three-dimensional numpy ndarray (suppose this is a color image without alpha channel):
import numpy as np
# img is in BGR format if the underlying image is a color image
img = cv2.imdecode(np.fromfile('????/test.jpg', dtype=np.uint8), cv2.IMREAD_UNCHANGED)
np.fromfile() will convert the image on disk to numpy 1-dimensional ndarray representation. cv2.imdecode can decode this format and convert to the normal 3-dimensional image representation. cv2.IMREAD_UNCHANGED is a flag for decoding. Complete list of flags can be found here.
PS. For how to write image to a path with unicode characters, see here.
Answer #3:
My problem is similar to you, however, my program will terminate at the
image = cv2.imread(filename)statement.
I solved this problem by first encode the file name into utf-8 and then decode it as
image = cv2.imread(filename.encode('utf-8', 'surrogateescape').decode('utf-8', 'surrogateescape'))
Answer #4:
bgrImage = cv2.imread(filename.encode('utf-8'))
encode file full path to utf-8
