Does not get the distance from colorized_depth image in d435i

I want to get the distance from colorized_depth image. But the output from my colorized image is show value [r g b] instead of distance,Z. So I would like to ask what can I do to solve the problem? I get the distance by Distance = depth_frame[point 1, point[0]] It is same if i use: Distance = depth_frame.getDistance[point 1, point[0]] Thank you for your help.enter image description here