https://twitter.com/inaniwa3/status/1077563093591371777

smile.py

# coding: utf-8

import glob
import cv2
import os
import shutil

face_classifier = cv2.CascadeClassifier('haarcascade_frontalface_alt2.xml')
smile_classifier = cv2.CascadeClassifier('haarcascade_smile.xml')

def detect_smile(path_in):
    print(path_in)
    img = cv2.imread(path_in)
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    faces = face_classifier.detectMultiScale(gray, scaleFactor=1.1, minNeighbors=2, minSize=(250, 250))
    is_detect = False
    for (x, y, w, h) in faces:
        cv2.rectangle(img, (x, y), (x + w, y + h), (255, 0, 0), 2)
        roi_color = img[y:y+h, x:x+w]
        roi_gray = gray[y:y+h, x:x+w]
        smiles = smile_classifier.detectMultiScale(roi_gray, scaleFactor=1.7, minNeighbors=22)
        for (sx, sy, sw, sh) in smiles:
            cv2.rectangle(roi_color, (sx, sy), (sx + sw, sy + sh), (0, 255, 0), 2)
            is_detect = True
    basebame = os.path.basename(path_in)
    cv2.imwrite('out.all/' + basebame, img)
    if is_detect:
        shutil.copy(path_in, 'out.smile.cp/' + basebame)
        cv2.imwrite('out.smile.rect/' + basebame, img)

paths_in = sorted(glob.glob('in/*.png'))
for path_in in paths_in:
    detect_smile(path_in)