smiledetector.py

#!/usr/bin/env python3

import sys

from sense_hat import SenseHat

# Initialize global instance of Sense HAT API
sense = SenseHat()

k = [0, 0, 0]  # Blank
r = [255, 0, 0]  # Red
y = [255, 127, 0]  # Yellow
g = [0, 255, 0]  # Green

cross = [
    k, r, k, k, k, k, r, k,
    r, r, r, k, k, r, r, r,
    k, r, r, r, r, r, r, k,
    k, k, r, r, r, r, k, k,
    k, k, r, r, r, r, k, k,
    k, r, r, r, r, r, r, k,
    r, r, r, k, k, r, r, r,
    k, r, k, k, k, k, r, k
]

neutral_face = [
    k, k, y, y, y, y, k, k,
    k, y, k, k, k, k, y, k,
    y, k, y, k, k, y, k, y,
    y, k, k, k, k, k, k, y,
    y, k, k, k, k, k, k, y,
    y, k, y, y, y, y, k, y,
    k, y, k, k, k, k, y, k,
    k, k, y, y, y, y, k, k
]

smile_face = [
    k, k, g, g, g, g, k, k,
    k, g, k, k, k, k, g, k,
    g, k, g, k, k, g, k, g,
    g, k, k, k, k, k, k, g,
    g, k, g, k, k, g, k, g,
    g, k, k, g, g, k, k, g,
    k, g, k, k, k, k, g, k,
    k, k, g, g, g, g, k, k
]


def check_sense_stick():

    for event in sense.stick.get_events():
        if event.action == 'pressed':
            print('Stopping Smile Detector...')
            sense.show_message('STOPPING', scroll_speed=0.025)
            sys.exit()


def smile_detector(debug=False):

    import cv2

    print("Initializing Smile Detector...")
    sense.show_message('INITIALIZING', scroll_speed=0.025)

    face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_alt.xml')
    smile_cascade = cv2.CascadeClassifier('haarcascade_smile.xml')

    cam = cv2.VideoCapture(0)
    # Keeps trying to open the camera; press SENSE Hat stick to terminate
    while not cam.isOpened():
        cam.open(0)
        check_sense_stick()

    print("Camera is opened.")

    sense.set_pixels(cross)

    while True:
        ret, img_color = cam.read()
        img_gray = cv2.cvtColor(img_color, cv2.COLOR_BGR2GRAY)

        faces = face_cascade.detectMultiScale(
            img_gray, scaleFactor=1.05, minNeighbors=5, minSize=(45, 45))

        if len(faces) > 0:
            for (x, y, w, h) in faces:
                cv2.rectangle(
                    img_color, (x, y), (x + w, y + h), (0, 0, 255), 2)
                faceimg_color = img_color[y:y + h, x:x + w]
                faceimg_gray = img_gray[y:y + h, x:x + w]

                smiles = smile_cascade.detectMultiScale(
                    faceimg_gray, scaleFactor=1.7, minNeighbors=3, minSize=(15, 15))

                if len(smiles) > 0:
                    sense.set_pixels(smile_face)
                    for (a, b, i, j) in smiles:
                        cv2.rectangle(
                            faceimg_color, (a, b), (a + i, b + j), (0, 255, 0), 1)
                else:
                    sense.set_pixels(neutral_face)
        else:
            sense.set_pixels(cross)

        if debug:
            cv2.imshow('Smile Detector', img_color)
            cv2.waitKey(1)

        check_sense_stick()


if __name__ == '__main__':

    import argparse

    parser = argparse.ArgumentParser()
    parser.add_argument(
        '-d',
        '--debug',
        action='store_true',
        dest='debug',
        default=False,
        help='Enable debug mode with camera window (requires X)')
    debug = parser.parse_args().debug
    assert isinstance(debug, bool)

    try:
        smile_detector(debug)
    except KeyboardInterrupt:
        sense.clear()
        raise