Resize images with a width or height larger than certain number of pixels

resize_images.py

"""
Resize images with a width or height larger than MAX_SIZE pixels.
BEWARE, it will OVERWRITE images.

Is meant to be used with Python 3.

Call it with:
python resize_images.py --dataset dataset
"""

from imutils import paths
import argparse
import cv2
import os
import re

MAX_SIZE = 900 # pixels

def read_im(path_to_file):
    """ Read a color image from a file. """
    return cv2.imread(path_to_file, cv2.IMREAD_COLOR)

def resize(im, ratio=0.5):
    """ Resize an image to attain a target ratio """
    (h, w) = im.shape[:2]
    newDim = (int(w * ratio), int(h * ratio))
    return cv2.resize(im, newDim, interpolation = cv2.INTER_AREA)

def save_im(im, path_to_file):
    """ Save an image to disk """
    cv2.imwrite(path_to_file, im)


ap = argparse.ArgumentParser()
ap.add_argument("-i", "--dataset", required=True, help="path to input directory of faces + images")
args = vars(ap.parse_args())
imagePaths = list(paths.list_images(args["dataset"]))

# loop over the image paths
for (i, imagePath) in enumerate(imagePaths):

    im = read_im(imagePath)
    (h, w) = im.shape[:2]

    print("Image '{}' has a size of {}(w) x {}(h)".format(imagePath, w, h))

    if ((w > MAX_SIZE) or (h > MAX_SIZE)):
        im_resized = resize(im, ratio=0.5)
        (new_h, new_w) = im_resized.shape[:2]

        # capture the folder path, image name and extension with a regular exp
        m = re.search('(.*)(\d{8})\.(\w+)', imagePath)
        if m:
            folder = m.group(1)
            imageName = m.group(2)
            extension = m.group(3)

            #newImageName = "resized-{}.{}".format(imageName, extension)
            newImageName = "{}.{}".format(imageName, extension) #will overwrite the file!
            newFullPath = os.path.join(folder, newImageName)

            save_im(im_resized, newFullPath)
            print("New image has a size of {}(w) x {}(h)".format(new_w, new_h))
        else:
            print("Couldn't find the pattern in this image path:\n'{}'".format(imagePath))