Watermark pictures inside a folder

watermarking.py

# Coding: utf-8
# Python 3.5
# OpenCV 3.1.0
#
# Developed by Luana Coppio
#

__author__ = "Luana Scoppio"
__version__ = "1.0"
__date__ = "26 july 2016"
__copyright__ = """MIT License, look it up"""

from imutils import paths
import numpy as np
import cv2
import argparse
import os

def resize(frame, 
    scale=None,
    size=None,
    fx=0, 
    fy=0, 
    interpolation=cv2.INTER_CUBIC):
    '''
    Resize image
    size          = Resize image with fixed dimension
    scale         = If set, ignores the value of `size` and resize dividing the image dimensions
    fx            = scale factor along the horizontal axis
    fy            = scale factor along the vertical axis
    interpolation = default is bicubic interpolation over 4x4 pixel neighborhood
    '''
    sz = None if not size else size
    if scale:
        sz = (int(frame.shape[1] // scale), int(frame.shape[0] // scale))
    scaled_image = cv2.resize(frame, sz, fx=fx, fy=fy, interpolation=interpolation)
    return scaled_image

ap = argparse.ArgumentParser()
ap.add_argument("-w", "--watermark", required=True,
    help="input watermark")
ap.add_argument("-i", "--input", required=True,
    help="input directory of images")
ap.add_argument("-o", "--output", required=True,
    help="output directory of watermarked images")
ap.add_argument("-a", "--alpha", type = float, default = 0.25,
    help="output directory of watermarked images")
ap.add_argument("-c", "--correct", type=int, default=1,
    help="flag used to handle if bug is displayed or not")
ap.add_argument("-p", "--preview", action="store_true", 
    help="shows real-time preview of the video")
args = vars(ap.parse_args())

watermark = cv2.imread(args["watermark"], cv2.IMREAD_UNCHANGED)
(wH, wW) = watermark.shape[:2]

if args["correct"] > 0:
    (B, G, R, A) = cv2.split(watermark)
    B = cv2.bitwise_and(B, B, mask=A)
    G = cv2.bitwise_and(G, G, mask=A)
    R = cv2.bitwise_and(R, R, mask=A)
    watermark = cv2.merge([B, G, R, A])

# loop over the input images
imgNumber = 0
for imagePath in paths.list_images(args["input"]):
    imgNumber += 1 
    print("marking image {0} :: {1}".format(imgNumber,imagePath))
    (wH, wW) = watermark.shape[:2]
    # load the input image, then add an extra dimension to the
    # image (i.e., the alpha transparency)
    
    image = cv2.imread(imagePath)
    (h, w) = image.shape[:2]
    factor = h*0.3 / wH
    #print(h*0.3, wH, factor, imagePath)
    watermarkR = resize (watermark, fx=factor, fy=factor)
    (wH, wW) = watermarkR.shape[:2]
    image = np.dstack([image, np.ones((h, w), dtype="uint8") * 255])
 
    # construct an overlay that is the same size as the input
    # image, (using an extra dimension for the alpha transparency),
    # then add the watermark to the overlay in the bottom-right
    # corner
    overlay = np.zeros((h, w, 4), dtype="uint8")
    overlay[h - wH - 20:h - 20, w - wW - 20:w - 20] = watermarkR
 
    # blend the two images together using transparent overlays
    output = image.copy()
    cv2.addWeighted(overlay, args["alpha"], output, 1.0, 0, output)
 
    # write the output image to disk
    filename = imagePath[imagePath.rfind(os.path.sep) + 1:]
    p = os.path.sep.join((args["output"], filename))
    cv2.imwrite(p, output)
    if args["preview"]:
        cv2.imshow('frame',output)
        k = cv2.waitKey(30) & 0xff
        if k == 27:
            break