Non Linear Depth Issue

[thechargedneutron]

I used the plugin to obtain a depth map from iPhone X and XR. All works correct, but I guess the returned depth values are non-linear. I captured an image of an object oriented such that the depth changes gradually.
I simply mapped depth in a range to RB from 0-255 and G 255 when out of range / undefined.
The obtained image is as follows:

Now I plotted the R values after taking a suitable window around the region of interest and obtained this:

This is indicative of the fact that the returned depth values are non-linear.

Can you help me out with a solution to this or maybe the error in my formulation?

Thanks

[AtsushiSuzuki]

Very interesting.
Correcting depth map using AVDepthData.cameraCalibrationData may fix this, but I'm not certain.

https://developer.apple.com/documentation/avfoundation/avdepthdata
shu223/iOS-Depth-Sampler#5

[thechargedneutron]

@AtsushiSuzuki Thank you for your reply. I tried following the second link which asks to uncomment certain parts of AVCameraCalibrationData.h but either it is not working, or I am making some mistake. Can you provide a possible working solution to this?

[AtsushiSuzuki]

Unfortunately for now I don't have iOS development environment (and phone), so I cannnot handle this issue right now, sorry.