OpenCV - Remove blemishes using Sobel Filter and Seamless Cloning

blemish-removal.py

# Author : Rajathithan Rajasekar
# Blemish removal using sobel filter


# selected blemish patch from mouse click
def selectedBlemish(x,y,r):
    global i
    crop_img = source[y:(y+2*r), x:(x+2*r)]     
    #i = i + 1
    #cv2.imwrite("blemish-"+ str(i) +".png",crop_img)
    return identifybestPatch(x,y,r)

# get the best gradient patch around the blemish
def identifybestPatch(x,y,r):
    #Nearby Patches in all 8 directions
    patches={}

    key1tup = appendDictionary(x+2*r,y)
    patches['Key1'] = (x+2*r,y,key1tup[0],key1tup[1])

    key2tup = appendDictionary(x+2*r,y+r)
    patches['Key2'] = (x+2*r,y+r,key2tup[0],key2tup[1])

    key3tup = appendDictionary(x-2*r,y)
    patches['Key3'] = (x-2*r,y,key3tup[0],key3tup[1])

    key4tup = appendDictionary(x-2*r,y-r)
    patches['Key4'] = (x-2*r,y-r,key4tup[0],key4tup[1])

    key5tup = appendDictionary(x,y+2*r)
    patches['Key5'] = (x,y+2*r,key5tup[0],key5tup[1])

    key6tup = appendDictionary(x+r,y+2*r)
    patches['Key6'] = (x+r,y+2*r,key6tup[0],key6tup[1])

    key7tup = appendDictionary(x,y-2*r)
    patches['Key7'] = (x,y-2*r,key7tup[0],key7tup[1])

    key8tup = appendDictionary(x-r,y-2*r)
    patches['Key8'] = (x-r,y-2*r,key8tup[0],key8tup[1])

    #print(patches)
    findlowx = {}
    findlowy = {}
    for key, (x, y, gx, gy) in patches.items():
        findlowx[key] = gx

    for key, (x, y, gx, gy) in patches.items():
        findlowy[key] = gy

    y_key_min = min(findlowy.keys(), key=(lambda k: findlowy[k]))
    x_key_min = min(findlowx.keys(), key=(lambda k: findlowx[k]))

    if x_key_min == y_key_min:
        return patches[x_key_min][0], patches[x_key_min][1]
    else:
        #print("Return x & y conflict, Can take help from FFT")
        return patches[x_key_min][0], patches[x_key_min][1]

# Get the gradients of x and y
def appendDictionary(x,y):
    crop_img = source[y:(y+2*r), x:(x+2*r)]    
    gradient_x, gradient_y = sobelfilter(crop_img)
    return gradient_x, gradient_y

# Apply sobel filter
def sobelfilter(crop_img):
    sobelx64f = cv2.Sobel(crop_img,cv2.CV_64F,1,0,ksize=3)
    abs_xsobel64f = np.absolute(sobelx64f)
    sobel_x8u = np.uint8(abs_xsobel64f)
    gradient_x = np.mean(sobel_x8u)

    sobely64f = cv2.Sobel(crop_img,cv2.CV_64F,0,1,ksize=3)
    abs_ysobel64f = np.absolute(sobely64f)
    sobel_y8u = np.uint8(abs_ysobel64f)
    gradient_y = np.mean(sobel_y8u)

    return gradient_x, gradient_y

# remove the blemish
def blemishRemoval(action, x, y, flags, userdata):
  # Referencing global variables 
  global r, source
  # Action to be taken when left mouse button is pressed
  if action==cv2.EVENT_LBUTTONDOWN:
    # Mark the center
    blemishLocation = (x,y)
    #print(blemishLocation)    
    newX, newY = selectedBlemish(x,y,r)
    newPatch = source[newY:(newY+2*r), newX:(newX+2*r)]
    cv2.imwrite("newpatch.png",newPatch)
    # Create mask for the new Patch  
    mask = 255 * np.ones(newPatch.shape, newPatch.dtype) 
    source = cv2.seamlessClone(newPatch, source, mask, blemishLocation, cv2.NORMAL_CLONE) 
    cv2.imshow("Blemish Removal App",source)

  # Action to be taken when left mouse button is released
  elif action==cv2.EVENT_LBUTTONUP:
    
    cv2.imshow("Blemish Removal App",source)



if __name__ == '__main__':
    import cv2
    import numpy as np

    # Lists to store the points
    r = 15
    i = 0
    source = cv2.imread("blemish-2.jpg",1)
    # Make a dummy image, will be useful to clear the drawing
    dummy = source.copy()
    cv2.namedWindow("Blemish Removal App")
    #cv2.resizeWindow("Blemish Removal App",900,900)
    # highgui function called when mouse events occur
    print(f"Using a patch of radius {r}:")
    cv2.setMouseCallback("Blemish Removal App", blemishRemoval)
    k = 0
    # loop until escape character is pressed
    while k!=27 :
        cv2.imshow("Blemish Removal App", source)
        k = cv2.waitKey(20) & 0xFF
        # Another way of cloning
        if k==99:
            source= dummy.copy()
    cv2.destroyAllWindows()