Chipseq - Watson and Crick strand

[New2Bioinfo]

Hi,

I am reading about CHIPseq from this paper and I encountered the following paragraph

We can take advantage of classical methods and measuring standards
in the signal-over-noise problem. At the global scale, we use the
background rate to estimate the ratio of the ChIP signal intensity to the
landscape intensity; in each called peak region, we take the fold change of
the ChIP signal intensity to the control signal intensity as the local estimate
of the signal-to-noise ratio.

Can anybody please explain how background rate is used to estimate the said ratio. And what exactly is landscape intensity?

Regards