It can be visually related to the, but provides a higher armor ranking and can only be discovered in three locations.Places. Go to the 'war room' where all of the most important persons in the Imperial Legion are gathered. In soloutide after i killed the jarl, in the barrck or the armoy i forget, was the last quest kinda for liberation of skyrim with the stormcloaks Steel helmet looks nice too enchant it with something good. The Imperial Helmet is part of the Imperial Armor Set.

Specifically the one imperial palace guards wear. 'centurion's') crest: replaces Imperial Officer's Helmet - Black 'attic' helmet: replaces Penitus Oculatus helmet - Oval shield: replaces Imperial Light Shield, field officers only. I saw a helmet at a loading screen, and I know for a fact that is is a unique or rare item. Here is a screenshot of the Imperial Legion Helmets.