How to remove the black border around rotated & masked image in result? OpenCv Python

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Hi,

How do I remove the black border around mainlogo.png in Result image?

import cv2
import numpy as np
import imutils

img1 = cv2.imread('ralph.jpg')
overlay_img1 = np.ones(img1.shape, np.uint8)*255

img2 = cv2.imread('mainlogo.png')
img2 = imutils.rotate_bound(img2, 10)
img2[np.where((img2==[0,0,0]).all(axis=2))] = [255,255,255]            

rows,cols,channels = img2.shape

overlay_img1[0:rows, 0:cols ] = img2

img2gray = cv2.cvtColor(overlay_img1,cv2.COLOR_BGR2GRAY)
ret, mask = cv2.threshold(img2gray, 220, 255, cv2.THRESH_BINARY_INV)
mask_inv = cv2.bitwise_not(mask)


temp1 = cv2.bitwise_and(img1,img1,mask = mask_inv)
temp2 = cv2.bitwise_and(overlay_img1, overlay_img1, mask = mask)
cv2.imshow('Temp2', temp2)
result = cv2.add(temp1,temp2)
cv2.imshow("Result",result)
cv2.imwrite("Result.jpg", result)
cv2.waitKey(0)    
cv2.destroyAllWindows()

ralph.jpg

mainlogo.png

Result: