This looks like half-polymerized oil. It happens when you overheat a layer of oil in the pan.
It won't come off through scraping. If you insist on removing it mechanically, you will have to try a polishing brush on a Dremel or something similar. I remove these chemically. Make a lye concentrate in the pot and let it sit overnight. Rinse very (!) thoroughly. This works well on stainless steel - but don't ever use it on aluminium pots!
If you don't have lye, you can also try a weaker alcali solution, like baking soda. But I doubt that it will be enough to remove the stuff.
To avoid it from happening again, don't overheat. This happens if the pan is left empty at at least 200°C for a very long time (or higher temperatures for a shorter time). There is no cooking method which requires this. Most things done in a pan are OK at around 150 to 160°C - if you are making steaks, sauteeing, etc., you should start using lower temperatures. Wokking needs these high temperatures - but first, a shallow SS pan is not good for wokking, and second, you should have more oil in there while preheating, and then move vegetables continiously around the pan while wokking. So this layer shouldn't happen at all.