import numpy as np
import serial
import cv2

# create video capture, serial port 
cap = cv2.VideoCapture(0)
ser = serial.Serial('/dev/ttyUSB0', 115200)

# main loop
while(1):
    
    # read the current video frame
    _, frame = cap.read()

    # resize captured video frame to smaller size for faster processing
    frame = cv2.resize(frame, (110, 80), interpolation = cv2.INTER_LINEAR)

    # smooth frame
    frame = cv2.blur(frame, (3, 3))

    # convert to hsv and find range of colors
    hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)
    thresh = cv2.inRange(hsv, np.array((5, 60, 60)), np.array((15, 255, 255)))
    thresh2 = thresh.copy()

    # find contours in the threshold image
    contours, hierarchy = cv2.findContours(thresh, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE)
 
    # finding contour with maximum area and store it as best_cnt
    max_area = 0
    for cnt in contours:
        area = cv2.contourArea(cnt)
        if area > max_area:
            max_area = area
            best_cnt = cnt
        
    # find centroid of best_cnt and draw a red box there, send to serial port
    if max_area > 0:
        M = cv2.moments(best_cnt)
        cx, cy = int(M['m10'] / M['m00']), int(M['m01'] / M['m00'])
        cz = int(max_area) 
        cv2.rectangle(frame, (cx - 5, cy - 5), (cx + 5, cy + 5), (0, 0, 255), 2)
        ser.write('!')
        ser.write('&')
        ser.write(chr(cx))
        ser.write(chr(cy))
        ser.write(chr(cz & 0xff))
        ser.write(chr(cz >> 8))

    # Show it, if key pressed is 'Esc', exit the loop
    cv2.imshow('Fr', frame)
    cv2.imshow('Th', thresh2)
    if cv2.waitKey(1) == 27:
        break

# Clean up everything before leaving
ser.close()
cap.release()
cv2.destroyAllWindows()