PIL, CV2: Image quality breaks after converting from PIL to Numpy

Question

I have this image and I read as a PIL file. Then, I save it back using save method in PIL and imwrite method in cv2. Saving the image with imwrite downgrades the image quality (it becomes black and white and text can't be read).

image = Image.open("image.png")

cv2_image = numpy.asarray(image)

image.save("pil.png")
cv2.imwrite("opencv.png", cv2_image)

Here are the output files:

pil.png
opencv.png

Answer 1

The input image is a palette image - see here. So, you need to convert it to RGB otherwise you just pass OpenCV the palette indices but without the palette.

So, you need:

image = Image.open(...).convert('RGB')

Now make it into a Numpy array:

cv2image = np.array(image)

But that will be in RGB order, so you need to reverse the channel order:

cv2image = cv2image[..., ::-1]