Create trackbar in Opencv and Python import cv2 import numpy as np def func ( x ): pass img = cv2.imread( "flower.jpg" ) cv2.namedWindow( 'image' ) cv2.createTrackbar( 'R' , 'image' , 0 , 255 , func) cv2.createTrackbar( 'G' , 'image' , 0 , 255 , func) cv2.createTrackbar( 'B' , 'image' , 0 , 255 , func) switch = '0 : OFF \n 1 : ON' cv2.createTrackbar(switch , 'image' , 0 , 1 , func) while ( 1 ): cv2.imshow( 'image' , img) k = cv2.waitKey( 1 ) & 0xFF if k == 27 : break r = cv2.getTrackbarPos( 'R' , 'image' ) g = cv2.getTrackbarPos( 'G' , 'image' ) b = cv2.getTrackbarPos( 'B' , 'image' ) s = cv2.getTrackbarPos(switch , 'image' ) if s == 0 : img[:] = 0 else : img[:] = [b , g , r] cv2.destroyAllWindows() Trackbar