ScriptExtractingFaces.py

import cv2
import glob
import sys

faceDet = cv2.CascadeClassifier("haarcascade_frontalface_default.xml")
faceDet_two = cv2.CascadeClassifier("haarcascade_frontalface_alt2.xml")
faceDet_three = cv2.CascadeClassifier("haarcascade_frontalface_alt.xml")
faceDet_four = cv2.CascadeClassifier("haarcascade_frontalface_alt_tree.xml")

def detect_faces():
    files = glob.glob("%s/*" %str(sys.argv[1])) #Get list of all images
    print(files)
    filenumber = 0
    for f in files:
        frame = cv2.imread(f) #Open image
        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) #Convert image to grayscale
        #Detect face using 4 different classifiers
        face = faceDet.detectMultiScale(gray, scaleFactor=1.1, minNeighbors=10, minSize=(5, 5), flags=cv2.CASCADE_SCALE_IMAGE)
        face_two = faceDet_two.detectMultiScale(gray, scaleFactor=1.1, minNeighbors=10, minSize=(5, 5), flags=cv2.CASCADE_SCALE_IMAGE)
        face_three = faceDet_three.detectMultiScale(gray, scaleFactor=1.1, minNeighbors=10, minSize=(5, 5), flags=cv2.CASCADE_SCALE_IMAGE)
        face_four = faceDet_four.detectMultiScale(gray, scaleFactor=1.1, minNeighbors=10, minSize=(5, 5), flags=cv2.CASCADE_SCALE_IMAGE)
        #Go over detected faces, stop at first detected face, return empty if no face.
        if len(face) == 1:
            facefeatures = face
        elif len(face_two) == 1:
            facefeatures = face_two
        elif len(face_three) == 1:
            facefeatures = face_three
        elif len(face_four) == 1:
            facefeatures = face_four
        else:
            facefeatures = ""
        #Cut and save face
        for (x, y, w, h) in facefeatures: #get coordinates and size of rectangle containing face
            print("face found in file: %s" %f)
            filename = f.replace("%s\\" %str(sys.argv[1]), "")
            filename = filename.replace(".jpg", ".png")
            print("filename %s" %filename) 
            gray = gray[y-30:y+h+50, x-30:x+w+50] #Cut the frame to size
            try:
                out = cv2.resize(gray, (350, 350)) #Resize face so all images have same size
                cv2.imwrite("%s/%s" %(str(sys.argv[2]),filename), out) #Write image
            except:
               pass #If error, pass file
        filenumber += 1 #Increment image number

detect_faces() #Call function