The Shulchan Aruch (OC 224:8) paskens that when you see a king you make a Bracha, SheNasan Michvodo L’Basar V’Dam”, that Hashem gave from his honor to flesh and blood. Rav Betzalel Stern (Btzel HaChochma 2:18), the Rov in Melbourne, Australia after the Holocaust, was asked if this applies only when you see the king before your eyes or even if you see him on television?He answered that this bracha is only if you see him in real life. He distinguishes this from Hilchos Eidus where the seeing is to ascertain the facts 100%, but for a bracha seeing is not about proving that it exists but rather the seeing itself which must be done eye to eye and not through an intermediary, no matter how accurate.
He paskens this despite the Mogen Avrohom that says, based on the gemara in Brachos (58a), that even a blind man can make the bracha if he knows the king is passing by. The difference is, says the Btzel HaChochma that the blind man feels the presence of the king with his sense of hearing as opposed to sight. Seeing on television is not a direct perception with any sense.