Tutorial 17: Importing Motion Detection

Moving forward we will be creating our own Python 3 scripts for running our home automation security system. We will therefore need to import our motion detection script and use it in the future scripts we write.

In this tutorial I walk you through how to modify the motion detection script such that we can call on it, and how we can use it in a separate Python 3 script.

This tutorial is a little older (published in 2015!). The main principles are still relevant, so I haven't needed to update this lesson.

What you need...

Raspberry Pi
5VDC Micro USB Power Supply
Pi Camera or NoIR Camera
RJ45 Ethernet cable or Wifi Module (if Raspberry Pi v2 or earlier)
Home Router

DIFFICULTY

MODERATE

LINUX UNDERSTANDING

SOME

PYTHON PROGRAMMING

MODERATE

ABOUT

MINUTES

What you will learn...

The code...

You can copy / paste the code below if you’re having issues with typos or want a shortcut. However I recommend that you follow along in the tutorial to understand what is going on!

P3picam.py


#!/usr/bin/python

# original script by brainflakes, improved by pageauc, peewee2 and Kesthal
# www.raspberrypi.org/phpBB3/viewtopic.php?f=43&t=45235

# You need to install PIL to run this script
# type "sudo apt-get install python-imaging-tk" in an terminal window to do this

# StringIO is not available in Python 3
import io
#import StringIO
import subprocess
import os
import time
from datetime import datetime
from PIL import Image

# Motion detection settings:
# Threshold          - how much a pixel has to change by to be marked as "changed"
# Sensitivity        - how many changed pixels before capturing an image, needs to be higher if noisy view
# ForceCapture       - whether to force an image to be captured every forceCaptureTime seconds, values True or False
# filepath           - location of folder to save photos
# filenamePrefix     - string that prefixes the file name for easier identification of files.
# diskSpaceToReserve - Delete oldest images to avoid filling disk. How much byte to keep free on disk.
# cameraSettings     - "" = no extra settings; "-hf" = Set horizontal flip of image; "-vf" = Set vertical flip; "-hf -vf" = both horizontal and vertical flip
threshold = 10
sensitivity = 20
forceCapture = True
forceCaptureTime = 60 * 60 # Once an hour
filepath = "/home/pi/picam"
filenamePrefix = "capture"
diskSpaceToReserve = 40 * 1024 * 1024 # Keep 40 mb free on disk
cameraSettings = ""

# settings of the photos to save
saveWidth   = 1296
saveHeight  = 972
saveQuality = 15 # Set jpeg quality (0 to 100)

# Test-Image settings
testWidth = 100
testHeight = 75

# this is the default setting, if the whole image should be scanned for changed pixel
testAreaCount = 1
testBorders = [ [[1,testWidth],[1,testHeight]] ]  # [ [[start pixel on left side,end pixel on right side],[start pixel on top side,stop pixel on bottom side]] ]
# testBorders are NOT zero-based, the first pixel is 1 and the last pixel is testWith or testHeight

# with "testBorders", you can define areas, where the script should scan for changed pixel
# for example, if your picture looks like this:
#
#     ....XXXX
#     ........
#     ........
#
# "." is a street or a house, "X" are trees which move arround like crazy when the wind is blowing
# because of the wind in the trees, there will be taken photos all the time. to prevent this, your setting might look like this:

# testAreaCount = 2
# testBorders = [ [[1,50],[1,75]], [[51,100],[26,75]] ] # area y=1 to 25 not scanned in x=51 to 100

# even more complex example
# testAreaCount = 4
# testBorders = [ [[1,39],[1,75]], [[40,67],[43,75]], [[68,85],[48,75]], [[86,100],[41,75]] ]

# in debug mode, a file debug.bmp is written to disk with marked changed pixel an with marked border of scan-area
# debug mode should only be turned on while testing the parameters above
debugMode = False # False or True

# Capture a small test image (for motion detection)
def captureTestImage(settings, width, height):
    command = "raspistill %s -w %s -h %s -t 200 -e bmp -n -o -" % (settings, width, height)
    #imageData = StringIO.StringIO()
    imageData = io.BytesIO()
    imageData.write(subprocess.check_output(command, shell=True))
    imageData.seek(0)
    im = Image.open(imageData)
    buffer = im.load()
    imageData.close()
    return im, buffer

# Save a full size image to disk
def saveImage(settings, width, height, quality, diskSpaceToReserve):
    keepDiskSpaceFree(diskSpaceToReserve)
    time = datetime.now()
    filename = filepath + "/" + filenamePrefix + "-%04d%02d%02d-%02d%02d%02d.jpg" % (time.year, time.month, time.day, time.hour, time.minute, time.second)
    subprocess.call("raspistill %s -w %s -h %s -t 200 -e jpg -q %s -n -o %s" % (settings, width, height, quality, filename), shell=True)
    print("Captured %s" % filename)

# Keep free space above given level
def keepDiskSpaceFree(bytesToReserve):
    if (getFreeSpace() < bytesToReserve):
        for filename in sorted(os.listdir(filepath + "/")):
            if filename.startswith(filenamePrefix) and filename.endswith(".jpg"):
                os.remove(filepath + "/" + filename)
                print("Deleted %s/%s to avoid filling disk" % (filepath,filename))
                if (getFreeSpace() > bytesToReserve):
                    return

# Get available disk space
def getFreeSpace():
    st = os.statvfs(filepath + "/")
    du = st.f_bavail * st.f_frsize
    return du

def motion():

    # Get first image
    image1, buffer1 = captureTestImage(cameraSettings, testWidth, testHeight)

    # Reset last capture time
    lastCapture = time.time()

    while (True):

        # Get comparison image
        image2, buffer2 = captureTestImage(cameraSettings, testWidth, testHeight)

        # Count changed pixels
        changedPixels = 0
        takePicture = False

        if (debugMode): # in debug mode, save a bitmap-file with marked changed pixels and with visible testarea-borders
            debugimage = Image.new("RGB",(testWidth, testHeight))
            debugim = debugimage.load()

        for z in range(0, testAreaCount): # = xrange(0,1) with default-values = z will only have the value of 0 = only one scan-area = whole picture
            for x in range(testBorders[z][0][0]-1, testBorders[z][0][1]): # = xrange(0,100) with default-values
                for y in range(testBorders[z][1][0]-1, testBorders[z][1][1]):   # = xrange(0,75) with default-values; testBorders are NOT zero-based, buffer1[x,y] are zero-based (0,0 is top left of image, testWidth-1,testHeight-1 is botton right)
                    if (debugMode):
                        debugim[x,y] = buffer2[x,y]
                        if ((x == testBorders[z][0][0]-1) or (x == testBorders[z][0][1]-1) or (y == testBorders[z][1][0]-1) or (y == testBorders[z][1][1]-1)):
                            # print "Border %s %s" % (x,y)
                            debugim[x,y] = (0, 0, 255) # in debug mode, mark all border pixel to blue
                    # Just check green channel as it's the highest quality channel
                    pixdiff = abs(buffer1[x,y][1] - buffer2[x,y][1])
                    if pixdiff > threshold:
                        changedPixels += 1
                        if (debugMode):
                            debugim[x,y] = (0, 255, 0) # in debug mode, mark all changed pixel to green
                    # Save an image if pixels changed
                    if (changedPixels > sensitivity):
                        takePicture = True # will shoot the photo later
                    if ((debugMode == False) and (changedPixels > sensitivity)):
                        break  # break the y loop
                if ((debugMode == False) and (changedPixels > sensitivity)):
                    break  # break the x loop
            if ((debugMode == False) and (changedPixels > sensitivity)):
                break  # break the z loop

        if (debugMode):
            debugimage.save(filepath + "/debug.bmp") # save debug image as bmp
            print("debug.bmp saved, %s changed pixel" % changedPixels)
        # else:
        #     print "%s changed pixel" % changedPixels

        # Check force capture
        if forceCapture:
            if time.time() - lastCapture > forceCaptureTime:
                takePicture = True

        if takePicture:
            lastCapture = time.time()
            return True
            #saveImage(cameraSettings, saveWidth, saveHeight, saveQuality, diskSpaceToReserve)
        else:
            return False

        # Swap comparison buffers
        image1 = image2
        buffer1 = buffer2

I also write a second script called cookieMain.py


import P3picam
import picamera
from datetime import datetime
from subprocess import call

motionState = False
picPath = "/home/pi/Desktop/cookie/images/"

def captureImage(currentTime, picPath):
    # Generate the picture's name
    picName = currentTime.strftime("%Y.%m.%d-%H%M%S") + '.jpg'
    with picamera.PiCamera() as camera:
        camera.resolution = (1280, 720)
        camera.capture(picPath + picName)
    print("We have taken a picture.")
    return picName

def getTime():
    # Fetch the current time
    currentTime = datetime.now()
    return currentTime

def timeStamp(currentTime, picPath, picName):
    # Variable for file path
    filepath = picPath + picName
    # Create message to stamp on picture
    message = currentTime.strftime("%Y.%m.%d - %H:%M:%S")
    # Create command to execute
    timestampCommand = "/usr/bin/convert " + filepath + " -pointsize 36 \
    -fill red -annotate +700+650 '" + message + "' " + filepath
    # Execute the command
    call([timestampCommand], shell=True)
    print("We have timestamped our picture.")

while True:
    motionState = P3picam.motion()
    print(motionState)
    if motionState:
        currentTime = getTime()
        picName = captureImage(currentTime, picPath)
        timeStamp(currentTime, picPath, picName)

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