OpenCV Example 2

import cv2

import datetime

import time

import numpy

from multiprocessing import shared_memory

def detect(frame):

    #Convert source image to hsv image

    hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)

    #Define the range of color blue

    lower_boarder = numpy.array([110, 50, 50])

    upper_boarder = numpy.array([130, 255, 255])

    #Show the blue values in white, all others black

    mask = cv2.inRange(hsv, lower_boarder, upper_boarder)

    #Get the treshold and contours of the blue elements

    ret, threshed_img = cv2.threshold(mask, 0, 255, cv2.THRESH_BINARY)

    contours, hier = cv2.findContours(threshed_img, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)

    #Bounding rect around every blue element and get coordinates

    s=''

    for c in contours:

        (x,y,w,h) = cv2.boundingRect(c)

        pt = (x, y+h)

        cv2.rectangle(frame, (x, y), (x+w, y+h), (0, 0, 255), 1)

        s += str(pt) + ' '

        #Prevent to many contours in share memory sting

        if len(s) > 50:

            break

    return s

#Get the image of camera

def getVideoFrame():

    cam = cv2.VideoCapture(0)

    ret_val, frame = cam.read()

    cv2.imshow("frame", frame)

    return frame

def shareMemory(memName, memString, memSize, memTime):

    #Create new shared memory object

    shm = shared_memory.SharedMemory(name=memName, create=True, size=memSize)

    #Encode string in utf-8

    encoded=memString.encode('utf-8')

    #Convert string to bytearray

    bArr = bytearray(encoded)

    #Write every single element in shared memory buffer

    if len(bArr) < memSize:

        for i in range(len(bArr)):

            shm.buf[i] = bArr[i]

    #Delay to read the memory in other application, before close

    time.sleep(memTime)

    shm.close()

if __name__ == '__main__':

    #Get the image of an file

    frame = cv2.imread("Bubbles_640x480.jpg")

    #To get video call getVideoFrame() in a loop

    #Add a time stamp to the string

    s = detect(frame) + str(datetime.datetime.now())

    shareMemory(memName='MySharedMemory', memString=s, memSize=100, memTime=60)