Extracting depth data

Hi I was wondering if there was any way that I could either extract depth data from a 3d photogrammetry model or some kind of scan? I am doing a project on measuring skin wounds/extrusions and I am trying to see if I could use an iPhone to accurately enough measure certain parts of wounds to measure their depths. I have also seen openCV stereo vision being used to measure depth, but I was hoping someone had some idea as to how I could accurately extract this data using an apple sdk.