How to prevent INPAINTING blocks and improve coloring-CodePudding

I wanted to Remove all the texts USING INPAINTING from this I've managed to get this new better result by noticing that my threshold is the best mask I can get. After doing this I performed the masking process 3 different times with variable masks and inversions. I did the inpainting algorithm 3 times, it basically the other times inverse the mask, because in some cases required mask is the inversed mask. Still I think it needs improvement, If I chose a different image the results are not so good.

CodePudding user response：

Python/OpenCV inpaint methods, generally, are not appropriate to your type of image. They work best on thin (scratch-like) regions, not large blocks. You really need an exemplar type method such as

Read the input
Threshold on the green sign
Apply morphology to close it up and keep as mask1
Apply the mask to the image to blacken out the outside of the sign
Threshold on the white in this new image and keep as mask2
Apply morphology dilate to enlarge it slightly and save as mask3
Do the inpaint
Save the results

import cv2
import numpy as np

# read input
img = cv2.imread('airport_sign.jpg')

# threshold on green sign
lower = (30,80,0)
upper = (70,120,20)
thresh = cv2.inRange(img, lower, upper)

# apply morphology close
kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (135,135))
mask1 = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel)

# apply mask to img
img2 = img.copy()
img2[mask1==0] = (0,0,0)

# threshold on white
#gray = cv2.cvtColor(img2, cv2.COLOR_BGR2GRAY)
#mask2 = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY cv2.THRESH_OTSU)[1]
lower = (120,120,120)
upper = (255,255,255)
mask2 = cv2.inRange(img2, lower, upper)

# apply morphology dilate
kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (5,5))
mask3 = cv2.morphologyEx(mask2, cv2.MORPH_DILATE, kernel)


# do inpainting
result1 = cv2.inpaint(img,mask3,11,cv2.INPAINT_TELEA)
result2 = cv2.inpaint(img,mask3,11,cv2.INPAINT_NS)

# save results
cv2.imwrite('airport_sign_mask.png', mask3)
cv2.imwrite('airport_sign_inpainted1.png', result1)
cv2.imwrite('airport_sign_inpainted2.png', result1)

# show results
cv2.imshow('thresh',thresh)
cv2.imshow('mask1',mask1)
cv2.imshow('img2',img2)
cv2.imshow('mask2',mask2)
cv2.imshow('mask3',mask3)
cv2.imshow('result1',result1)
cv2.imshow('result2',result2)
cv2.waitKey(0)
cv2.destroyAllWindows()

Mask 3:

Inpaint 1 (Telea):

Inpaint 2 (NS):