That depends on what you mean by "noise".
There is a diagram showing how Skyline calculates "background" here:
https://skyline.ms/wiki/home/software/Skyline/page.view?name=tip_peak_calc

The "Transition Results" report has a columns called "Area" and "Background". You could export that report and then calculate the ratio of those values in another tool such as Microsoft Excel.
The "Area" column contains the background-subtracted area.

You can learn more about the Document Grid and custom reports here:
https://skyline.ms/wiki/home/software/Skyline/page.view?name=tutorial_custom_reports

Someone else recently had a question about signal to noise and you can read the answer here:
https://skyline.ms/announcements/home/support/thread.view?rowId=63007
-- Nick

Thank you for the reply, Nick.
I’m interested in the background area. I noticed that the Skyline report includes both the area and the background for each peak. However, for some peaks, the background is recorded as zero. Additionally, if the area is background-subtracted, calculating the ratio may underestimate the actual value.