PIL rotate image colors (BGR -> RGB)

Question

I have an image where the colors are BGR. How can I transform my PIL image to swap the B and R elements of each pixel in an efficient manner?

Answer 1

Just to add a more up to date answer:

With the new cv2 interface images loaded are now numpy arrays automatically.
But openCV cv2.imread() loads images as BGR while numpy.imread() loads them as RGB.

The easiest way to convert is to use openCV cvtColor.

import cv2
srcBGR = cv2.imread("sample.png")
destRGB = cv2.cvtColor(srcBGR, cv2.COLOR_BGR2RGB)

Answer 2

You should be able to do this with the ImageMath module.

Edit:

Joe's solution is even better, I was overthinking it. :)

Answer 3

I know it's an old question, but I had the same problem and solved it with:

img = img[:,:,::-1]

Answer 4

This was my best answer. This does, by the way, work with Alpha too.

from PIL import Image
import numpy as np
import sys 

sub = Image.open(sys.argv[1])
sub = sub.convert("RGBA")
data = np.array(sub) 
red, green, blue, alpha = data.T 
data = np.array([blue, green, red, alpha])
data = data.transpose()
sub = Image.fromarray(data)

Answer 5

import cv2
srcBGR = cv2.imread("sample.png")
destRGB = cv2.cvtColor(srcBGR,cv2.COLOR_BGR2RGB)

Just to clarify Martin Beckets solution, as I am unable to comment. You need cv2. in front of the color constant.