import cv2
import numpy as np


cap = cv2.VideoCapture(0)

while(True):
    # Take each frame
    _, frame = cap.read()

    # Convert BGR to HSV
    hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)

    # define color range  in HSV
    lower_range = np.array([78,75,150])
    upper_range = np.array([138,255,255])
    
    # Threshold the HSV image to get only blue colors
    mask = cv2.inRange(hsv, lower_range, upper_range)

    kernel =cv2.getStructuringElement(cv2.MORPH_ELLIPSE,(5,5))
    mask = cv2.erode(mask, kernel, iterations=2)
    mask = cv2.dilate(mask, kernel, iterations=4)
    

    # Bitwise-AND mask and original image
    res = cv2.bitwise_and(frame,frame, mask= mask)

    #Detectamos contornos, nos quedamos con el mayor y calculamos su centro
    _, contours, _ = cv2.findContours(mask, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
    if contours != []: 
        mayor_contorno = max(contours, key = cv2.contourArea)    
        momentos = cv2.moments(mayor_contorno)
        cx = float(momentos['m10']/momentos['m00'])
        cy = float(momentos['m01']/momentos['m00'])
	cv2.circle(res, (int(cx), int(cy)), 5, (0,255,0), -1)
       

    cv2.imshow('frame',frame)
    cv2.imshow('mask',mask)
    cv2.imshow('res',res)
   
    k = cv2.waitKey(5) & 0xFF
    if k == 27:
        break

cv2.destroyAllWindows()