A first taste of OpenCV on a Raspberry Pi 3

#!/bin/sh
# DrJ
sleep 2
# set a hard-wired IP - this will have to change!!!
sudo ifconfig eth0 192.168.1.160
# launch small virtual vncserver on DISPLAY 1
vncserver -Authentication=VncAuth :1
# launch UDP server
$HOME/server.py > /tmp/server.log 2>&1 &
# run virtual env
cd $HOME
# don't need virtualenv if we use this version of python...
#. /home/pi/.profile
#workon cv
#
# now launch our python video capture program
#
export DISPLAY=:1
/home/pi/.virtualenvs/cv/bin/python green.py > /tmp/green.log 2>&1 &

cmake -D CMAKE_BUILD_TYPE=RELEASE \
        -D CMAKE_INSTALL_PREFIX=/usr/local \
        -D INSTALL_C_EXAMPLES=OFF \
        -D ENABLE_PRECOMPILED_HEADERS=OFF \
        -D INSTALL_PYTHON_EXAMPLES=ON \
        -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib-3.1.0/modules \
        -D BUILD_EXAMPLES=ON ..

if not "%minimized%"=="" goto :minimized
set minimized=true
start /min cmd /C "%~dpnx0"
goto :EOF
:minimized
c:\apps\ultravnc\vncviewer -password raspberry 192.168.1.160:1

import Tkinter as tk
from threading import Thread,Event
from multiprocessing import Array
from ctypes import c_int32
import cv2
import numpy as np
import sys
#from Tkinter import *
#cap = cv2.VideoCapture(0)
global x
global f
x = 1
y = 1
f = "green.txt"
 
class CaptureController(tk.Frame):
    NSLIDERS = 7
    def __init__(self,parent):
        tk.Frame.__init__(self)
        self.parent = parent
 
        # create a synchronised array that other threads will read from
        self.ar = Array(c_int32,self.NSLIDERS)
 
        # create NSLIDERS Scale widgets
        self.sliders = []
        for ii in range(self.NSLIDERS):
            # through the command parameter we ensure that the widget updates the sync'd array
            s = tk.Scale(self, from_=0, to=255, length=650, orient=tk.HORIZONTAL,
                         command=lambda pos,ii=ii:self.update_slider(ii,pos))
            if ii == 0:
                s.set(0)  #green min
            elif ii == 1:
                s.set(0)
            elif ii == 2:
                s.set(250)
            elif ii == 3:
                s.set(3)  #green max
            elif ii == 4:
                s.set(255)
            elif ii == 5:
                s.set(255)
            elif ii == 6:
                s.set(249)  #way down below
            s.pack()
            self.sliders.append(s)
 
        # Define a quit button and quit event to help gracefully shut down threads
        tk.Button(self,text="Quit",command=self.quit).pack()
        self._quit = Event()
        self.capture_thread = None
 
    # This function is called when each Scale widget is moved
    def update_slider(self,idx,pos):
        self.ar[idx] = c_int32(int(pos))
 
    # This function launches a thread to do video capture
    def start_capture(self):
        self._quit.clear()
        # Create and launch a thread that will run the video_capture function
#        self.capture_thread = Thread(cap = cv2.VideoCapture(0), args=(self.ar,self._quit))
        self.capture_thread = Thread(target=video_capture, args=(self.ar,self._quit))
        self.capture_thread.daemon = True
        self.capture_thread.start()
 
    def quit(self):
        self._quit.set()
        try:
            self.capture_thread.join()
        except TypeError:
            pass
        self.parent.destroy()
 
# This function simply loops over and over, printing the contents of the array to screen
def video_capture(ar,quit):
    print ar[:]
    cap = cv2.VideoCapture(0)
    Xerror = 0
    Yerror = 0
    XerrorStr = '0'
    YerrorStr = '0'
    while not quit.is_set():
        # the slider values are all readily available through the indexes of ar
        # i.e. w1 = ar[0]
        # w2 = ar[1]
        # etc.
        # Take each frame
        _, frame = cap.read()
        # Convert BGR to HSV
        hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)
        # define range of blue color in HSV
        lower_green = np.array([ar[0],ar[1],ar[2]])
        upper_green = np.array([ar[3],ar[4],ar[5]])
        # Threshold the HSV image to get only green colors
        mask = cv2.inRange(hsv, lower_green, upper_green)
        # Bitwise-AND mask and original image
        res = cv2.bitwise_and(frame,frame, mask= mask)
        cv2.imshow('frame', frame)
#        cv2.imshow('mask',mask)
#        cv2.imshow('res',res)
        #------------------------------------------------------------------
        img = cv2.blur(mask,(5,5))   #filter (blur) image to reduce errors
        cv2.imshow('img',img)
        ret,thresh = cv2.threshold(img,127,255,0)
        im2,contours,hierarchy = cv2.findContours(thresh, cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)
        print 'number of contours==640x480====================  ', len(contours)
        target=0
        if len(contours) > 0:
            numbercontours = len(contours)
            while numbercontours > 0:
                numbercontours = numbercontours -1  # contours start at 0
                cnt = contours[numbercontours]   #this is  getting the first contour found, could look at 1,2,3 etc
                x,y,w,h = cv2.boundingRect(cnt)
#
#---line below has the limits of the area of the target-----------------------
#
                #if w * h > 4200 and w * h < 100000:  #area of capture must exceed  to exit loop
                if h > 30 and w < h/3:  #area of capture must exceed  to exit loop
                    print ' X   Y  W  H  AREA      Xc  Yc      xEr yEr'
                    Xerror = (-1) * (320 - (x+(w/2)))
                    XerrorStr = str(Xerror)
                    Yerror = 240 - (y+(h/2))
                    YerrorStr = str(Yerror)
                    print  x,y,w,h,(w*h),'___',(x+(w/2)),(y+(h/2)),'____',Xerror,Yerror
                    break
 
#-------        draw horizontal and vertical center lines below
                cv2.line(img,(320,0),(320,480),(135,0,0),5)
                cv2.line(img,(0,240),(640,240),(135,0,0),5)
                displaySTR = XerrorStr + '  ' + YerrorStr
                font = cv2.FONT_HERSHEY_SIMPLEX
                cv2.putText(img,displaySTR,(10,30), font, .75,(255,255,255),2,cv2.LINE_AA)
                cv2.imshow('img',img)
# wrtie to file for our server'
                sys.stdout = open(f,"w")
                print 'H,V:',Xerror,Yerror
                sys.stdout = sys.__stdout__
                target=1
                #
                #--------------------------------------------------------------------
        if target==0:
                # no target found. print non-physical values out to a file
                sys.stdout = open(f,"w")
                print 'H,V:',1000,1000
                sys.stdout = sys.__stdout__
        k = cv2.waitKey(1) & 0xFF    #parameter is wait in millseconds
        if k == 27:   # esc key on keboard
            cap.release()
            cv2.destroyAllWindows()
            break
 
if __name__ == "__main__":
    root = tk.Tk()
    selectors = CaptureController(root)
    selectors.pack()
#    q = tk.Label(root, text=str(x))
#    q.pack()
    selectors.start_capture()
    root.mainloop()

#!/usr/bin/env python
# inspired by https://gist.github.com/Manouchehri/67b53ecdc767919dddf3ec4ea8098b20
# first we get client connection, then we read data frmo file. This order is important so we get the latest, freshest data!
 
 
import socket
import re
 
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
 
server_address = '0.0.0.0'
server_port = 5005
 
server = (server_address, server_port)
sock.bind(server)
print("Listening on " + server_address + ":" + str(server_port))
 
while True:
# read up to 32 bytes from client
        payload, client_address = sock.recvfrom(32)
        print("Request from client: " + payload)
# get correction from file
        while True:
                with open('green.txt','r') as myfile:
                        data=myfile.read()
#H,V:  9 -14
                data = data.split(":")
                if len(data) == 2:
                        break
        sent = sock.sendto(data[1], client_address)

#!/usr/bin/env python
import socket
UDP_IP = "127.0.0.1"
UDP_PORT = 5005
 
print "UDP target IP:", UDP_IP
print "UDP target port:", UDP_PORT
 
sock = socket.socket(socket.AF_INET, # Internet
                 socket.SOCK_DGRAM) # UDP
# need to send one newline minimum to receive server's message...
MESSAGE = "correction";
sock.sendto(MESSAGE, (UDP_IP, UDP_PORT))
# get data
data, addr = sock.recvfrom(1024) # buffer size is 1024 bytes
print "received message:", data