Access to active brightness buffer (clean IR reading)?

[dogadogan]

The Research Mode API documentation for HoloLens 2 talks about an active brightness (Ab) buffer that returns a so-called "IR reading."

The value of pixels in the clean IR reading is proportional to the amount of light returned from the scene. The image looks similar to a regular IR image.

I am using a HoloLens 1 and would like to access this buffer. How could I do this for HoloLens 1?
Thanks a lot for your help and time!