opens a webcam, and zooms-in on a detectable face

faceviewer.py

import numpy as np
import matplotlib.pyplot as plt
import cv2

def getFaceCrop(image):
    # get image classifier 
    image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
    image_copy = np.copy(image)
    gray_image = cv2.cvtColor(image, cv2.COLOR_RGB2GRAY)
    face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')

    # Detect faces in the image using pre-trained face dectector
    faces = face_cascade.detectMultiScale(gray_image, 1.25, 6)

    # we only care about the first face
    for f in faces:
        # Get the bounding box for the face
        x, y, w, h = [v for v in f]
        cv2.rectangle(image_copy, (x,y), (x+w, y+h), (255,0,0), 3)
        # Define the region of interest in the image  
        face_crop = gray_image[y:y+h, x:x+w]
        return face_crop

    print("Error: no face detected")
    return None

cap = cv2.VideoCapture(0)

while(True):
    # load video capture image
    ret, image = cap.read()
    if ret != True:
        print("there was an error fetching video capture data")
    else:
        face_crop = getFaceCrop(image)
        if not face_crop is None:
            resized_face = cv2.resize(face_crop, (256, 256))
            cv2.imshow('frame', resized_face)
            if cv2.waitKey(1) & 0xFF == ord('q'):
                break