# Dissection of a depth map

I am curious about how depth maps work. While searching I came across this website which contains some images and their depth maps. I took this depth map and tried to study it using a python pillow.

from PIL import Image
import numpy as np

image = Image.open('elephant_depth_s.png')
img = np.asarray(image)

print(img.shape)


The depth map shape is (400, 400, 3) with 3 channels. Contrary to my assumption this depth map has three channels instead of one. Even though most of the values are zeros some are not. This len(np.where(img>0)) shows that all the channels have some values greater than zero. My question is;

• In color images, RGB channel values are used for creating corresponding color pixels. Example RGB (255,255,0) creates yellow.

In this depth map how these three channel corresponds to the depth?