Opencv : How to remove rectangle black box without removing any other characters

I would like to remove a rectangle black box from the below image. [![enter image description here][1]][1] I do some preprocessing operation to keep the upper top of the image only. My problem with the rectangle in the middle of the image This is the preprocessing operation I do on this image gray = cv2.cvtColor(cropped_top, cv2.COLOR_BGR2GRAY) binary = cv2.adaptiveThreshold(gray, 255, cv2.ADAPTIVE_THRESH_MEAN_C, cv2.THRESH_BINARY, 15, 2) binary = cv2.fastNlMeansDenoising(binary, None, 65, 5, 21) ret, thresh1 = cv2.threshold(binary, 0, 255, cv2.THRESH_BINARY | cv2.THRESH_OTSU) k = np.ones((4,4)) binary = cv2.morphologyEx(thresh1, cv2.MORPH_CLOSE, k) This is the output till now
[![enter image description here][2]][2] Here it appears 3 lines connected together. I have used `cv2.findContours`. But till now I failed to remove this rectangle. I know I am doing something wrong regarding contours. Here is the code I used for detecting contours _,binary = cv2.threshold(image, 150, 255, cv2.THRESH_BINARY) # find external contours of all shapes _,contours,_ = cv2.findContours(binary, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE) # create a mask for floodfill function, see documentation h,w= image.shape mask = np.zeros((h+2,w+2), np.uint8) # determine which contour belongs to a square or rectangle for cnt in contours: poly = cv2.approxPolyDP(cnt, 0.05*cv2.arcLength(cnt,True),True) if len(poly) == 4: # if the contour has 4 vertices then floodfill that contour with black color cnt = np.vstack(cnt).squeeze() _,binary,_,_ = cv2.floodFill(binary, mask, tuple(cnt[0]), 0) how I can successfully remove this black rectangle without distorting letter **Q** [1]: https://i.stack.imgur.com/BrRd6.png [2]: https://i.stack.imgur.com/faNJD.png