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Get pixel's RGB using PIL

Posted by: admin November 29, 2017 Leave a comment

Questions:

Is it possible to get the RGB color of a pixel using PIL?
I’m using this code:

im = Image.open("image.gif")
pix = im.load()
print(pix[1,1])

However, it only outputs a number (e.g. 0 or 1) and not three numbers (e.g. 60,60,60 for R,G,B). I guess I’m not understanding something about the function. I’d love some explanation.

Thanks a lot.

Answers:

Yes, this way:

im = Image.open('image.gif')
rgb_im = im.convert('RGB')
r, g, b = rgb_im.getpixel((1, 1))

print(r, g, b)
(65, 100, 137)

The reason you were getting a single value before with pix[1, 1] is because GIF pixels refer to one of the 256 values in the GIF color palette.

See also this SO post: Python and PIL pixel values different for GIF and JPEG and this PIL Reference page contains more information on the convert() function.

By the way, your code would work just fine for .jpg images.

Questions:
Answers:

GIFs store colors as one of x number of possible colors in a palette. Read about the gif limited color palette. So PIL is giving you the palette index, rather than the color information of that palette color.

Edit: Removed link to a blog post solution that had a typo. Other answers do the same thing without the typo.

Questions:
Answers:

Not PIL, but scipy.misc.imread might still be interesting:

import scipy.misc
im = scipy.misc.imread('um_000000.png', flatten=False, mode='RGB')
print(im.shape)

gives

(480, 640, 3)

so it is (height, width, channels). So the pixel at position (x, y) is

color = tuple(im[y][x])
r, g, b = color

Questions:
Answers:

An alternative to converting the image is to create an RGB index from the palette.

from PIL import Image

def chunk(seq, size, groupByList=True):
    """Returns list of lists/tuples broken up by size input"""
    func = tuple
    if groupByList:
        func = list
    return [func(seq[i:i + size]) for i in range(0, len(seq), size)]


def getPaletteInRgb(img):
    """
    Returns list of RGB tuples found in the image palette
    :type img: Image.Image
    :rtype: list[tuple]
    """
    assert img.mode == 'P', "image should be palette mode"
    pal = img.getpalette()
    colors = chunk(pal, 3, False)
    return colors

# Usage
im = Image.open("image.gif")
pal = getPalletteInRgb(im)