faces_from_pil_images.py

def faces_from_pil_image(pil_image):
    "Return a list of (x,y,h,w) tuples for faces detected in the PIL image"
    storage = cv.CreateMemStorage(0)
    facial_features = cv.Load('haarcascade_frontalface_alt.xml', storage=storage)
    cv_im = cv.CreateImageHeader(pil_image.size, cv.IPL_DEPTH_8U, 3)
    cv.SetData(cv_im, pil_image.tostring())
    faces = cv.HaarDetectObjects(cv_im, facial_features, storage)
    # faces includes a `neighbors` field that we aren't going to use here
    return [f[0] for f in faces]