Question about diffusion

Hi there, great work! Really appreciate that you open source the code so soon!

I have some questions about the diffusion and denoising process.

The image shown in the README is really impressive:

Does this image show the denoising process? If so, why the depth contents are shown in a 'near-to-far' way?

The random gaussian noise $\epsilon \sim \mathcal N(0, \mathbf I)$, and the GT depth map / depth prediction sould have been normalized to $[-1, 1]$; however, since the above image shows contents appearing from near to far, should I assume that the final depth map / the depth prediction is not of the range $[-1, 1]$, but is of greater range(*e.g.*, $[0, 80]$ for kitti and $[0, 10]$ for NYU)?

If so, the diffusion and denoising steps are probabily problematic, since commonly, if we choose the gaussian noise as $\mathcal N(0, \mathbf I)$, the output range is chosen as $[-1, 1]$. And I have not yet found in the code about the normalization process.

Correct me if I'm wrong, I would be very happy to hear from you!