pythonopencv

Remove white space from an image using python


There are multiple images that have white spaces that I need to remove. Simply crop the image so as to get rid of the white spaces Here's the code I tried so far (this is a result of search)

import numpy as np
import cv2

img = cv2.imread('Sample.png')
img = img[:-5,:-5] 
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
gray = 255*(gray < 128).astype(np.uint8)
gray = cv2.morphologyEx(gray, cv2.MORPH_OPEN, np.ones((2, 2), dtype=np.uint8))
coords = cv2.findNonZero(gray)
x, y, w, h = cv2.boundingRect(coords)
rect = img[y:y+h, x:x+w] 
cv2.imshow("Cropped", rect)
cv2.waitKey(0)
cv2.destroyAllWindows()
cv2.imwrite("Output.png", rect)

Here's the sample image

enter image description here

And this is the desired output

enter image description here


Solution

  • The code is almost perfect. It just can't crop on the right side because of the scrollbar. And it does not consider some padding (which you liked according the comments).

    The thing I removed is the topology modification.

    import numpy as np
    import cv2
    
    img = cv2.imread('cropwhitefromimage.png')
    scrollbarright = 20
    img = img[:, :-scrollbarright]
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    gray = 255*(gray < 128).astype(np.uint8)
    coords = cv2.findNonZero(gray)
    x, y, w, h = cv2.boundingRect(coords)
    padding = 10
    rect = img[y-padding:y+h+padding, x-padding:x+w+padding]
    cv2.imshow("Cropped", rect)
    cv2.waitKey(0)
    cv2.destroyAllWindows()
    cv2.imwrite("cropwhitefromimage_result.png", rect)