Trim whitespace using PIL

Question

Is there a simple solution to trim whitespace on the image in PIL?

ImageMagick has easy support for it in the following way:

convert test.jpeg -fuzz 7% -trim test_trimmed.jpeg

I found a solution for PIL:

from PIL import Image, ImageChops

def trim(im, border):
    bg = Image.new(im.mode, im.size, border)
    diff = ImageChops.difference(im, bg)
    bbox = diff.getbbox()
    if bbox:
        return im.crop(bbox)

But this solution has disadvantages:

I need to define border color, it is not a big deal for me, my images has a white background
And the most disadvantage, This PIL solution doesn’t support ImageMagick’s -fuzz key. To add some fuzzy cropping. as I can have some jpeg compression artifacts and unneeded huge shadows.

Maybe PIL has some built-in functions for it?
Or there is some fast solution?

Asked By: Eugene Nagorny

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Source

Answer 1

I don’t think there is anything built in to PIL that can do this. But I’ve modified your code so it will do it.

It gets the border colour from the top left pixel, using getpixel, so you don’t need to pass the colour.
Subtracts a scalar from the differenced image, this is a quick way of saturating all values under 100, 100, 100 (in my example) to zero. So is a neat way to remove any ‘wobble’ resulting from compression.

Code:

from PIL import Image, ImageChops

def trim(im):
    bg = Image.new(im.mode, im.size, im.getpixel((0,0)))
    diff = ImageChops.difference(im, bg)
    diff = ImageChops.add(diff, diff, 2.0, -100)
    bbox = diff.getbbox()
    if bbox:
        return im.crop(bbox)

im = Image.open("bord3.jpg")
im = trim(im)
im.show()

Heavily compressed jpeg:

enter image description here Cropped:

Noisy jpeg:

enter image description here Cropped:

Answered By: fraxel

Answer 2

Use wand http://docs.wand-py.org/en/0.3-maintenance/wand/image.html

trim(color=None, fuzz=0)
Remove solid border from image. Uses top left pixel as a guide by default, or you can also specify the color to remove.

Answered By: Jie Bao

Answer 3

using trim function at ufp.image module.

import ufp.image
import PIL
im = PIL.Image.open('test.jpg', 'r')
trimed = ufp.image.trim(im, fuzz=13.3)
trimed.save('trimed.jpg')

Answered By: c2o93y50

Answer 4

The answer by fraxel works, but as pointed by Matt Pitkin sometimes the image should be converted to "RGB", otherwise the borders are not detected:

from PIL import Image, ImageChops
def trim(im):
    bg = Image.new(im.mode, im.size, im.getpixel((0,0)))
    diff = ImageChops.difference(im, bg)
    diff = ImageChops.add(diff, diff, 2.0, -100)
    bbox = diff.getbbox()
    if bbox:
        return im.crop(bbox)
    else: 
        # Failed to find the borders, convert to "RGB"        
        return trim(im.convert('RGB'))

Answered By: Victor

Trim whitespace using PIL

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