Webcam Motion detect and save v1.7

"""
Webcam Motion detect and save v1.7
By Steve Shambles
stevepython.wordpress.com
"""
import os
import time

import cv2
import numpy as np

motion_detect = 0
md_switch = 'OFF'

# Check for folder.
MYDIR = ('detected-images')
CHECK_FOLDER = os.path.isdir(MYDIR)
# If folder doesn't exist, then create it.
if not CHECK_FOLDER:
    os.makedirs(MYDIR)

os.chdir(MYDIR)
CURR_TIME = time.asctime()

# Change sdthresh to suit camera and conditions,
# 15-25 is usually within the threshold range.
sdThresh = 20

# Used to count individualy named frames as jpgs.
img_index = 0

# use this cv2 font
font = cv2.FONT_HERSHEY_SIMPLEX

def distMap(frame1, frame2):
    """outputs pythagorean distance between two frames"""
    frame1_32 = np.float32(frame1)
    frame2_32 = np.float32(frame2)
    diff32 = frame1_32 - frame2_32
    norm32 = np.sqrt(diff32[:,:,0]**2 + diff32[:,:,1]**2 +
                     diff32[:,:,2]**2)/np.sqrt(255**2 + 255**2 + 255**2)
    dist = np.uint8(norm32*255)
    return dist

def print_date_time():
    """Updates current date and time on to video"""
    CURR_TIME = time.asctime()
    cv2.putText(frame2,str(CURR_TIME),(280,24),
                font, 0.8, (0,255,0),2, cv2.LINE_AA)
    cv2.putText(frame2,'Enter to pause. q to quit. Sensitivity = '+str
                (sdThresh)+'. Press + and - to change.' ,
                (10,450), font, 0.5,(255,255,255),1)
    cv2.putText(frame2,'Save detected images is: '+str(md_switch)
                +'. press m to start auto saving. s to stop again.',
                (10,470), font, 0.5,(255,255,255),1)

# Capture video stream.
cap = cv2.VideoCapture(0)
_, frame1 = cap.read()
_, frame2 = cap.read()

# Main loop.
while(True):

    try:
        _, frame3 = cap.read()
        rows, cols, _ = np.shape(frame3)
        dist = distMap(frame1, frame3)
    except:
        print('Camera not found.')
        exit(0)

    frame1 = frame2
    frame2 = frame3
    keyPress = cv2.waitKey(20)

    # Apply Gaussian smoothing.
    mod = cv2.GaussianBlur(dist, (9,9), 0)
    # Apply thresholding.
    _, thresh = cv2.threshold(mod, 100, 255, 0)
    # Calculate st dev test.
    _, stDev = cv2.meanStdDev(mod)

    # If motion is dectected.
    if stDev > sdThresh :
            cv2.putText(frame2,'MD '+str(img_index),
                        (0,20),font, 0.8, (0,255,0),2, cv2.LINE_AA)
            print_date_time()

            # Save jpg.
            if motion_detect == 1:
                frame_name =(str(img_index)+str('.jpg'))
                cv2.imwrite(frame_name, frame2)
                img_index +=1

    print_date_time()
    cv2.imshow('Live video', frame2)

    # Enter key pauses video stream.
    if keyPress & 0xFF == 13:
        cv2.putText(frame2,'PAUSED', (210,260),font, 2,
                    (0,255,0),8, cv2.LINE_AA)
        cv2.imshow('Live video', frame2)
        cv2.waitKey(0)

    # Hold down Escape key to quit.
    if keyPress & 0xFF == ord('q'):
        break

    # Motion detection off.
    if keyPress & 0xFF == ord('s'):
        motion_detect = 0
        md_switch = 'OFF'

    # Motion detection on.
    if keyPress & 0xFF == ord('m'):
        motion_detect = 1
        md_switch = 'ON'

    # Sensitivity inc.
    if keyPress & 0xFF == ord('+'):
        sdThresh +=1

    # Sensitivity dec.
    if keyPress & 0xFF == ord('-'):
        sdThresh -= 1

cap.release()
cv2.destroyAllWindows()