How to extract a depth map from a .heif image created with iphone X with imagemagick

I created an image with my own iPhone application. The image is in .heif format and contains the depth map. (I know it because the Photos app recognizes it)
I have now downloaded and installed imagemagick.
and launched the following command:

magick identify -verbose orginal.HEIC

This only shows me three channels (Channel 0, Channel 1, Channel 2). I guess these are the RGB colors of the image.

How can I access the depth data of this image?