WebCam Motion Detector program in Python ?


In this we are going to write python program which is going to analyse the images taken from the webcam and try to detect the movement and store the time-interval of the webcam video in a csv file.

Required Library

We are going to use the OpenCV & pandas library for that. If it’s not already installed, you can install it using pip, with something like:

$pip install opencv2, pandas

Example Code

#Import required libraries
import cv2
import pandas as pd
import time
from datetime import datetime

#Initialise variables
stillImage = None
motionImage = [ None, None ]
time = []

# Initializing the DataFrame with start and end time
df = pd.DataFrame(columns = ["start", "end"])

# Capturing video
video = cv2.VideoCapture(0)

while True:
   # Start reading image from video
   check, frame = video.read()
   motion = 0

   # Convert color image to gray_scale image
   gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
   gray = cv2.GaussianBlur(gray, (21, 21), 0)
   if stillImage is None:
      stillImage = gray
      continue
   # Still Image and current image.
   diff_frame = cv2.absdiff(stillImage, gray)

   # change the image to white if static background and current frame is greater than 25.
   thresh_frame = cv2.threshold(diff_frame, 25, 255, cv2.THRESH_BINARY)[1]
   thresh_frame = cv2.dilate(thresh_frame, None, iterations = 2)
   # Finding contour and hierarchy from a moving object.
   contours,hierachy = cv2.findContours(thresh_frame.copy(),
      cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
   for contour in contours:
      if cv2.contourArea(contour) < 10000:
         continue
      motion = 1
      (x, y, w, h) = cv2.boundingRect(contour)
      cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 255, 0), 3)
   # Append current status of motion
   motionImage.append(motion)
   motionImage = motionImage[-2:]
   # Append Start time of motion
   if motionImage[-1] == 1 and motionImage[-2] == 0:
      time.append(datetime.now())

   # Append End time of motion
   if motionImage[-1] == 0 and motionImage[-2] == 1:
      time.append(datetime.now())
   # Displaying image in gray_scale
   cv2.imshow("Gray_Frame", gray)

   # Display black and white frame & if the intensity difference is > 25, it turns white
   cv2.imshow("Threshold Frame", thresh_frame)
   # Display colored frame
   cv2.imshow("Colored_Frame", frame)

   key = cv2.waitKey(1)
   # Press q to stop the process
   if key == ord('q'):
      if motion == 1:
         time.append(datetime.now())
      break

# Append time of motion
for i in range(0, len(time), 2):
   df = df.append({"Start":time[i], "End":time[i + 1]}, ignore_index = True)

# Creating a csv file in which time of movements will be saved
df.to_csv("FrameInMotion_time.csv")

video.release()

# close window
cv2.destroyAllWindows()

Output

We can see we’ll get 3 different Windows which are going to display our current movement from webcam in three different modes (grayscale, colored & black&White).

It will also store the datetime of our webcam Motion in a csv and our output from csv will be something like:

FrameMotion_time.csv (output)

start     end      End                            Start
0                  2019-02-21 18:10:59.718005     2019-02-21 18:08:35.791487

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