sudo apt-get update
sudo apt-get upgrade
sudo rpi-update
sudo reboot
sudo apt-get install build-essential git cmake pkg-config
sudo apt-get install libjpeg-dev libtiff5-dev libjasper-dev libpng12-dev
sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev
sudo apt-get install libxvidcore-dev libx264-dev
sudo apt-get install libgtk2.0-dev
sudo apt-get install libatlas-base-dev gfortran
cd ~
git clone https://github.com/opencv/opencv.git
cd opencv
git checkout 3.1.0
cd ~
git clone https://github.com/opencv/opencv_contrib.git
cd opencv_contrib
git checkout 3.1.0

sudo apt-get install python2.7-dev
wget https://bootstrap.pypa.io/get-pip.py
sudo python get-pip.py
pip install numpy
cd ~/opencv
mkdir build
cd build
cmake -D CMAKE_BUILD_TYPE=RELEASE \
    -D INSTALL_C_EXAMPLES=OFF \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules \
    -D BUILD_EXAMPLES=ON ..
make -j4
sudo make install
sudo ldconfig

sudo apt-get install python3-dev
wget https://bootstrap.pypa.io/get-pip.py
sudo python3 get-pip.py
pip install numpy
cd ~/opencv
mkdir build
cd build
cmake -D CMAKE_BUILD_TYPE=RELEASE \
    -D CMAKE_INSTALL_PREFIX=/usr/local \
    -D INSTALL_C_EXAMPLES=OFF \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules \
    -D BUILD_EXAMPLES=ON ..
make -j4
sudo make install
sudo ldconfig

from picamera.array import PiRGBArray
import RPi.GPIO as GPIO
from picamera import PiCamera
import time
import cv2
import numpy as np
import math

GPIO.setmode(GPIO.BOARD)
GPIO.setup(7, GPIO.OUT)
GPIO.setup(8, GPIO.OUT)
theta=0
minLineLength = 5
maxLineGap = 10
camera = PiCamera()
camera.resolution = (640, 480)
camera.framerate = 30
rawCapture = PiRGBArray(camera, size=(640, 480))
time.sleep(0.1)

for frame in camera.capture_continuous(rawCapture, format="bgr", use_video_port=True):
   image = frame.array
   gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
   blurred = cv2.GaussianBlur(gray, (5, 5), 0)
   edged = cv2.Canny(blurred, 85, 85)
   lines = cv2.HoughLinesP(edged,1,np.pi/180,10,minLineLength,maxLineGap)
   
   if(lines !=None):
       for x in range(0, len(lines)):
           for x1,y1,x2,y2 in lines[x]:
               cv2.line(image,(x1,y1),(x2,y2),(0,255,0),2)
               theta=theta+math.atan2((y2-y1),(x2-x1))
   
   #print(theta)
   # GPIO pins were connected to arduino for servo steering control
   threshold=6
   if(theta>threshold):
       GPIO.output(7,True)
       GPIO.output(8,False)
       print("left")
   if(theta<-threshold):
       GPIO.output(8,True)
       GPIO.output(7,False)
       print("right")
   if(abs(theta)<threshold):
      GPIO.output(8,False)
      GPIO.output(7,False)
      print("straight")
      
   theta=0
   cv2.imshow("Frame",image)
   key = cv2.waitKey(1) & 0xFF
   rawCapture.truncate(0)
   if key == ord("q"):
       break

#include <Servo.h>

Servo myservo;

void setup() {
  myservo.attach(10); // attach servo motor PWM (orange) wire to pin 10 
  pinMode(0, INPUT);  // attach GPIO 7 & 8 pins from Pi to arduino pin 0 & 1
  pinMode(1, INPUT);
}

void loop() {
  if(digitalRead(0)==HIGH && digitalRead(1)==LOW)
  {
        myservo.write(118);
  }
  if(digitalRead(1)==HIGH && digitalRead(0)==LOW)
  {
        myservo.write(62);
  }
  if(digitalRead(1)==LOW && digitalRead(0)==LOW)
  {
         myservo.write(90);
  } 
}