camera.py

import cv2
import imutils
import time
import numpy as np

class VideoCamera(object):
    def __init__(self, flip = False):
        self.vs = cv2.VideoCapture(0)
        self.flip = flip
        time.sleep(2.0)

    def __del__(self):
        self.vs.stop()

    def flip_if_needed(self, frame):
        if self.flip:
            return np.flip(frame, 0)
        return frame

    def get_frame(self):
        ret, frame = self.vs.read()
        frame = cv2.flip(frame, 1) # use it if you want to flip the image or not
        ret, jpeg = cv2.imencode('.jpg', frame)
        return jpeg.tobytes()

    def get_object(self, classifier):
        found_objects = False
        ret, frame = self.vs.read()
        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

        objects = classifier.detectMultiScale(
            gray,
            scaleFactor=1.1,
            minNeighbors=5,
            minSize=(30, 30),
            flags=cv2.CASCADE_SCALE_IMAGE
        )

        if len(objects) > 0:
            found_objects = True

        # Draw a rectangle around the objects
        for (x, y, w, h) in objects:
            cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 255, 0), 2)

        ret, jpeg = cv2.imencode('.jpg', frame)
        return (jpeg.tobytes(), found_objects)

I am using USB CAM
I try your code but not work
when I run main.py I get the message :

Error sending email: <class 'cv2.error'>

unfortunately this codec doesn't work with USB cam. You will need to use a pi cam