Simple script to detect face from camera using OpenCV

face_detection_using_opencv.py

import numpy as np
import os, sys, math
import matplotlib.pyplot as plt
import cv2
import copy


def convert_image_to_BW(image):
    bw_img = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    return cv2.cvtColor(bw_img, cv2.COLOR_GRAY2BGR)


class FaceDetection(object):
    
    def __init__(self, haar_cascade_file_path):
        self.hcfp = haar_cascade_file_path
        self._load_classifier()
    
    def _load_classifier(self):
        self.classifier = cv2.CascadeClassifier(self.hcfp)
        
    def detect_faces(self, image):
        copied_image = copy.deepcopy(image)
        gray = convert_image_to_BW(image)
        
        faces = self.classifier.detectMultiScale(gray, 1.3, 5)
        
        for (x, y, w, h) in faces:
            tagged_image = cv2.rectangle(copied_image, (x, y), (x + w, y + h), (255, 0, 0), 2)
        
        return copied_image


def read_video(video_path: os.path = 0, process_frame = lambda x: x, save_processed_video=False):
    video_stream = cv2.VideoCapture(video_path)
    
    if save_processed_video:
        fourcc = cv2.VideoWriter_fourcc(*'MJPG')
        video_writer = cv2.VideoWriter(os.path.join(data_dir_path, 'processed_video.avi'), fourcc, video_stream.get(5), (int(video_stream.get(3)), int(video_stream.get(4))))
    
    print(video_stream.isOpened())
    
    try:
        while True:

            ret, frame = video_stream.read()

            processed_frame = process_frame(frame)
            
            if save_processed_video:
                video_writer.write(processed_frame)

            horizontal_show = np.concatenate((frame, processed_frame), axis=1)

            cv2.imshow('processed_frame', horizontal_show)

            if cv2.waitKey(1) & 0xFF == ord('q'):
                break
    finally:
        video_stream.release()
        cv2.destroyAllWindows()


if __name__ == '__main__':
    data_dir_path = os.path.join(os.path.dirname(os.getcwd()), 'data')
    fd_obj = FaceDetection(os.path.join(data_dir_path, 'haarcascade_frontalface_default.xml'))
    read_video(process_frame=fd_obj.detect_faces, save_processed_video=False)