When you take photos of people/animals with iPhone 15/16 (or use Portrait Mode on older iPhones), various mattes - secondary images storing information like depth, person segmentation, etc - get stored in the photo I made a little tool to view/export them, free on the App Store

The stock camera app uses them to generate depth of field in the photo + process color differently for skin etc Similarly you can load those maps in photoshop/touch designer/a shader/etc and use them as a source of info for custom processing