process.py

import cv2
import numpy as np

cap=cv2.VideoCapture(0)

def nothing(x):
    pass

#Create trackbar to adjust HSV range
cv2.namedWindow("trackbar")
cv2.createTrackbar("L-H","trackbar",0,179,nothing)
cv2.createTrackbar("L-S","trackbar",0,255,nothing)
cv2.createTrackbar("L-V","trackbar",0,255,nothing)
cv2.createTrackbar("U-H","trackbar",179,179,nothing)
cv2.createTrackbar("U-S","trackbar",255,255,nothing)
cv2.createTrackbar("U-V","trackbar",255,255,nothing)

while True:
    ret,frame =cap.read()
    hsv=cv2.cvtColor(frame,cv2.COLOR_BGR2HSV)    
    
    l_h=cv2.getTrackbarPos("L-H","trackbar")
    l_s=cv2.getTrackbarPos("L-S","trackbar")
    l_v=cv2.getTrackbarPos("L-V","trackbar")
    h_h=cv2.getTrackbarPos("U-H","trackbar")
    h_s=cv2.getTrackbarPos("U-S","trackbar")
    h_v=cv2.getTrackbarPos("U-V","trackbar")
   
    low=np.array([l_h,l_s,l_v])
    high=np.array([h_h,h_s,h_v])

    mask=cv2.inRange(hsv,low,high) 
    result=cv2.bitwise_and(frame,frame,mask=mask)    
    cv2.imshow("result",result)# On pressing ESC it should exit the program
    
    key = cv2.waitKey(1)
    # On pressing `s` then print and save this array.
    if key == ord('s'):
        thearray = [[l_h,l_s,l_v],[h_h, h_s, h_v]]
        # Save this array as penrange.npy
        np.save('penrange',thearray)
        break
    #if esc pressed exit
    if key == 27:
        break

cap.release()
cv2.destroyAllWindows()