问题
I'm trying to identify the colors of the used color palette of an image with PIL/pillow. I've tried the following:
image[x,y]: this will only give me the index number of the corresponding pixel (i.e.1)image.getpixel((x,y)): again, this will only give me the index number of the corresponding pixel (i.e.1)image.getcolors(): This will give me the number of pixels and their corresponding index number (i.e.[(2, 1), (2, 0)])image.palette: Returns a "PIL.ImagePalette.ImagePalette object"image.getpalette(): Returns a large array of (to me seemingly) unrelated integers (i.e.[0, 0, 255, 255, 0, 0, 2, 2, 2, 3, 3 ,3 ...])
As an absolute fallback, I could convert the image mode and then get the color values, but I'd rather not if possible.
With this example image (2x2 pixel image, indexed mode with 2 colors created with GIMP, the top two pixels are red (255,0,0) the bottom two are blue (0,0,255)), I was expecting something like:
image.getpalette()
1: (255,0,0)
0: (0,0,255)
Edit: The closest I have is:
image.palette.getdata(): This gives me ('RGB;L', b'\x00\x00\xff\xff\x00\x00'). Is there any way to have this mapped to the index number. Here each three bytes would map to one index number, I'd reckon.
回答1:
You can get and arrange the palette like this:
import numpy as np
from PIL import Image
# Open image
im = Image.open('a.png')
# Get palette and reshape into 3 columns
palette = np.array(im.getpalette(),dtype=np.uint8).reshape((256,3))
Then just print palette.
[[ 0 0 255] <--- first entry is blue
[255 0 0] <--- second is red
[ 2 2 2] <--- grey padding to end
[ 3 3 3]
[ 4 4 4]
[ 5 5 5]
[ 6 6 6]
...
...
[253 253 253]
[254 254 254]
[255 255 255]]
If you want to count the colours and how many of each there are, do this:
# Convert Image to RGB and make into Numpy array
na = np.array(im.convert('RGB'))
# Get used colours and counts of each
colours, counts = np.unique(na.reshape(-1,3), axis=0, return_counts=1)
That gives colours as:
array([[ 0, 0, 255],
[255, 0, 0]], dtype=uint8)
and counts as:
array([2, 2])
来源：https://stackoverflow.com/questions/60539888/identify-the-color-values-of-an-image-with-a-color-palette-using-pil-pillow