Some basic image segmentation based on hue.

hue.py

import cv2
import time
import numpy as np
import json
import os

#uncomment this for testing from an image file
#img = cv2.imread(filename)
capture = cv2.VideoCapture(1)

while True:
    if os.path.isfile('range.json'):
        with open('range.json') as f:
            vals = json.load(f)
            for i, j in vals.iteritems():
                vals[i] = float(j)
            _min = np.array([vals['min_h'], vals['min_s'], vals['min_v']])
            _max = np.array([vals['max_h'], vals['max_s'], vals['max_v']])

        time.sleep(0.1)
        ret, img = capture.read()

        img_blur = cv2.GaussianBlur(img, (15, 15), 0)
        img_hsv = cv2.cvtColor(img_blur, cv2.COLOR_BGR2HSV)
        img_green_bw = cv2.inRange(img_hsv, _min, _max)

        element = cv2.getStructuringElement(cv2.MORPH_CROSS,(5,5))
        eroded = cv2.erode(img_green_bw,element)

        cv2.imshow('bgr', img)
        cv2.imshow('hsv', img_hsv)
        cv2.imshow('threshed', img_green_bw)
        cv2.imshow('eroded', eroded)
        cv2.waitKey(1)
cv2.destroyAllWindows()

range.json

{
    "min_h": 0,
    "min_s": 60,
    "min_v": 40,

    "max_h": 10,
    "max_s": 256,
    "max_v": 256
}