Removing borders from an image in Python

Question

Some videos have frames that have black strips like borders. I have to remove them from the frames. I came up with a crude solution:

import sys, cv2, numpy
i         


        

Answer 1

I think that you will find that the problem goes away if you work from the other side of the image, as you are checking the first column (col[0] - it's black so you delete it and the black col[1] becomes col[0] then you check the col[1] - skipping the new col[0]....

If you start from the max it would work or if you stay on any given col once you have deleted it. Alternatively you can make a list of which to delete, reverse it and then do the deletions.

Answer 2

using opencv and numpy as in your attempt how about something like this:

im = cv2.imread(filename)
h,w,d = im.shape
#left limit
for i in range(w):
    if np.sum(im[:,i,:]) > 0:
        break
#right limit
for j in xrange(w-1,0,-1):
    if np.sum(im[:,j,:]) > 0:
        break

cropped = im[:,i:j+1,:].copy() # deep copy to get byte-aligned array needed for opencv 

Answer 3

Why not calculate the frame and use PIL

from PIL import Image

img = Image.open('myImage.jpeg')
box = (50, 50, 100, 100)
area = img.crop(box)

Answer 4

This problem was already solved in this answer.

In [1]: from PIL import Image, ImageChops

In [3]: im = Image.open('iI3ZE.jpg')

In [4]: 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)
   ...:

In [5]: trim(im).show()

I used Pillow instead of PIL:

pip install pillow

Results in: