Computer Vision Security System

This is a cool project that uses computer vision techniques and a webcam to act as a security system. I will demonstrate how to detect if a door is opened then have my computer yell at the opener. For this all you need is a webcam, python, and the modules opencv and pyttsx.

A brief overview:

- Use background subtraction to see if the door gets moved

- Then have the pyttsx module make your computer say whatever you want at the person who opened it

The opencv background subtractors weren't working for me so I made my own.

https://spaces.aperture.science/p/?n=computer-vision-security-system&edit

Door Movement

Opencv has a nice tutorial on their background subtractor, but I'll be using the one I made. Grabbing a frame from the webcam, putting it into the background subtractor, then displaying it looks something like this

import background_subtractor
import cv2
import numpy as np
import video

cap=video.create_capture(0)           #get your webcam

#####wait until a good frame comes in####
ret=False
while not ret:
    ret, frame=cap.read()
#########################################

frame=cv2.cvtColor(cap.read()[1], cv2.COLOR_BGR2GRAY)

bs=background_subtractor.BackgroundSubtractor(frame)

while True:
    #get a grayscale frame from webcam
    frame=cv2.cvtColor(cap.read()[1], cv2.COLOR_BGR2GRAY)   

    foreground_mask=bs.apply(frame)

    cv2.imshow("frame", frame)
    cv2.imshow("mask", foreground_mask)
    
    k=cv2.waitKey(10)  #delay 10 miliseconds and get key press
    if k==1048690:     #the 'r' key; will probably be 114 for you
        bs.update_reference_frame()
    if k==1048603:     #the 'esc' key; will probably be 27 for you
        cv2.destroyAllWindows()
        quit()

Make It Talk!

All we have to do now is use the text to speech module. To do so, add

import pyttsx
engine=pyttsx.init()
talked=False

to the top of the code around the other imports. Then switch out the

print "DOOR IS OPEN"

line with

if not talked:
            engine.proxy._driver.say("Go away!")
            talked=True
    else:
        if talked:
            talked=False

(or whatever else you want it to say inside the quotes). The talked variable makes it so it only talks once each time the door opens and doesn't keep repeating. And if you're wondering where the proxy._driver came from, the original pyttsx API wasn't working properly so I had to do some reverse engineering on it.

Time to test it out

It's not the most convincing voice, it'd be better by playing an audio file of a dog barking or something like that (and python even has a module for reading WAV files), but I'm happy with it right now.

Tyler Haun