How to use the depth map of equirectangular images?

[ZhongmiaoYan]

Hello, thank you for your outstanding work and for providing such an excellent dataset!
But as a beginner in this field, I encountered some problems when using depth maps for panoramic images. I want to know how to obtain the true scale of ERP image depth maps after reading them. And in what format are invalid values stored in the depth map.
Any form of guidance will be appreciated.