Provide demonstration script for producing images cropped to the face

[gwern]

I experimented with using facedetect's cropping script on anime images to try to crop faces into separate files (the goal here being to experiment with modeling faces using WGAN to see if it improves on IllustrationGAN), but it didn't work at all. I tried using this, and it works much better but doesn't provide a simple interface/program for cropping images down to the face. I modified the example file to do this, and it seems to work OK:

import cv2
import sys
import os.path

def detect(cascade_file, filename, outputname):
    if not os.path.isfile(cascade_file):
        raise RuntimeError("%s: not found" % cascade_file)

    cascade = cv2.CascadeClassifier(cascade_file)
    image = cv2.imread(filename)
    gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    gray = cv2.equalizeHist(gray)

    faces = cascade.detectMultiScale(gray,
                                     # detector options
                                     scaleFactor = 1.1,
                                     minNeighbors = 5,
                                     minSize = (50, 50))
    i=0
    for (x, y, w, h) in faces:
        cropped = image[y: y + h, x: x + w]
        cv2.imwrite(outputname+str(i)+".png", cropped)
        i=i+1

if len(sys.argv) != 4:
    sys.stderr.write("usage: detect.py <animeface.xml file>  <input> <output prefix>\n")
    sys.exit(-1)

detect(sys.argv[1], sys.argv[2], sys.argv[3])

Saved as cropy.py, this can then be run on a single file like

python ~/src/lbpcascade_animeface/examples/crop.py ~/src/lbpcascade_animeface/lbpcascade_animeface.xml foo.jpg cropped

or run in parallel on many files using parallel like this:

cropFaces() {
    name=$(basename "$@")
    python ~/src/lbpcascade_animeface/examples/crop.py ~/src/lbpcascade_animeface/lbpcascade_animeface.xml "$@" faces/danbooru/"$name"
    }
export -f cropFaces
find ./danbooru/ -type f -name "*.jpg" | parallel cropFaces

It would be great if you could provide something like this Python crop program in the repo.

[nagadomi]

I added this feature to another project.
See https://github.com/nagadomi/animeface-2009#create-new-dataset-with-animeface-ruby

[gwern]

I see, thanks. Perhaps you could update the README.md for this project with a note that it's obsoleted by animeface-2009 and that animeface-2009 also provides a script for extracting faces?

[nagadomi]

I've updated README.
If someone sends a pull request to add a cropping script like face_collector.rb I will merge it.