main.py

from typing import final
import cv2
import numpy as np
import dlib
from math import hypot, pow, sqrt

# CONSTANTS
ESCAPE_KEY_CODE = 27

cap = cv2.VideoCapture(0)
detector = dlib.get_frontal_face_detector()
predictor = dlib.shape_predictor("shape_predictor_68_face_landmarks.dat")
cooler_img = cv2.imread('./assets/cooler.png')

def cooler_filter():
    while True:
        _, frame = cap.read()
        gray_frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

        faces = detector(frame)

        for face in faces:
            landmarks = predictor(gray_frame, face)

            head_center = (landmarks.part(27).x, landmarks.part(27).y)
            head_left = (landmarks.part(0).x, landmarks.part(0).y)
            head_right = (landmarks.part(16).x, landmarks.part(16).y)

            # Calculate distance between left head point and right head point. Factor of 1.1 is applied to make the image scale better.
            cooler_width = int(sqrt(pow(head_left[0] - head_right[0], 2) - pow(head_left[1] - head_right[1], 2)) * 1.1)
            cooler_height = int(cooler_width * 0.33)

            cooler = cv2.resize(cooler_img, (cooler_width, cooler_height))

            # Adding a factor of 10px to y in-order to make the effect look more natural
            top_left = (int(head_center[0] - cooler_width / 2),
                        int(head_center[1] - cooler_height / 2) + 10)
            bottom_right = (int(head_center[0] + cooler_width / 2),
                        int(head_center[1] + cooler_height / 2) + 10)

            # Area where the cooler has to be placed (using a mask)
            cooler_area = frame[top_left[1]: top_left[1] + cooler_height,
                                top_left[0]: top_left[0] + cooler_width]
            cooler_area_gray = cv2.cvtColor(cooler, cv2.COLOR_BGR2GRAY)
            _, cooler_mask = cv2.threshold(cooler_area_gray, 25, 255, cv2.THRESH_BINARY_INV)

            # Taking bitwise AND to remove all empty space in the cooler image mask
            eye_area_cooler = cv2.bitwise_and(cooler_area, cooler_area, mask=cooler_mask)

            final_cooler_area = cv2.add(eye_area_cooler, cooler)

            # Replacing the part of frame where the cooler is supposed to be
            frame[top_left[1]: top_left[1] + cooler_height,
                top_left[0]: top_left[0] + cooler_width] = final_cooler_area

        cv2.imshow("Frame", frame)

        key = cv2.waitKey(1)

        if key == ESCAPE_KEY_CODE:
            break

cooler_filter()

cap.release()
cv2.destroyAllWindows()