Raspberry Pi - Python2 - OpenCV3 Line following rover basics

# OpenCV Line following rover basics Py2Cv3
# Will be used and demonstrated with this Vehikel soon: https://www.youtube.com/watch?v=7wFg_FFjx6Y

import numpy as np
import cv2
import time

video_capture = cv2.VideoCapture(0)
video_capture.set(3, 640)
video_capture.set(4, 480)

# ---- Function definition for converting scales ------
def remap(unscaled, to_min, to_max, from_min, from_max):
    return (to_max-to_min)*(unscaled-from_min)/(from_max-from_min)+to_min

# ---- Main loop ----
while(True):

    # Capture from camera
    ret, frame = video_capture.read()

    # Crop, select part of image to work with
    crop_img = frame[380:480, 0:640]

    # Make the image greyscale
    gray = cv2.cvtColor(crop_img, cv2.COLOR_BGR2GRAY)

    # uncomment next line to view greyscale image
    #cv2.imshow('Gray',gray)

    # Apply a Gaussian blur
    blur = cv2.GaussianBlur(gray,(5,5),0)

    # uncomment next line to view Blurred image
    #cv2.imshow('Blur',blur)

    # Apply Color thresholding
    ret,thresh = cv2.threshold(blur,100,255,cv2.THRESH_BINARY_INV)

    # uncomment next line to view Threshholded image
    #cv2.imshow('Thresh',thresh)

    # Find the contours in the cropped image part
    img, contours, hierarchy = cv2.findContours(thresh.copy(), 1, cv2.CHAIN_APPROX_NONE)

    # ---------------- Find the biggest contour = line -----------------

    if len(contours) > 0:
        c = max(contours, key=cv2.contourArea)
        M = cv2.moments(c)

        cx = int(M['m10']/M['m00'])
        cy = int(M['m01']/M['m00'])

        cv2.line(crop_img,(cx,0),(cx,720),(255,255,0),2)
        cv2.line(crop_img,(0,cy),(1280,cy),(0,255,0),2)
        cv2.drawContours(crop_img, contours, -1, (0,255,255), 2)

        # ---- Draw centre boundry lines (Steer straight)
        cv2.line(crop_img,(270,0),(270,480),(0,0,255),2)
        cv2.line(crop_img,(370,0),(370,480),(0,0,255),2)


 # --------- Steer Right Routine ----------
        if cx >= 370:
            RSteer = cx - 370
            SteerRight = remap(RSteer, 0, 45, 1, 270)
            print ("Turn Right: ", SteerRight)

 # --------- On Track Routine ----------
        if cx < 370 and cx > 270:
            print "On Track"

 # --------- Steer Left Routine ----------
        if cx <= 270:
            LSteer = 270 - cx
            SteerLeft = remap(LSteer, 0, 45, 1, 270)
            print ("Turn Left: ", SteerLeft)

    # ------ Show the resulting cropped image
    cv2.imshow('frame',crop_img)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break


#https://www.facebook.com/mrlunk