Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
The helmet (literally 'egg') in a dream is security from fear, authority, and prestige. Wearing it indicates gaining authority or marrying a noble woman.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
The helmet indicates a strong man who protects his family. For a woman, it is a husband.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
The helmet is interpreted as the king or a noble man. Whoever sees himself wearing it will gain security and high status.