From Wikipedia

Introverted sensation is the sensing function that perceives phenomena in such a way as extraverted sensation does above, but in a subjective manner. Jung wrote that "the subject perceives the same things as everybody else, only, he never stops at the purely objective effect, but concerns himself with the subjective perception released by the objective stimulus. Subjective perception differs remarkably from the objective. It is either not found at all in the object, or, at most, merely suggested by it[...] Subjective sensation apprehends the background of the physical world rather than its surface. The decisive thing is not the reality of the object, but the reality of the subjective factor, i.e. the primordial images, which in their totality represent a psychic mirror-world. It is a mirror, however, with the peculiar capacity of representing the present contents of consciousness not in their known and customary form but in a certain sense sub specie aeternitatis, somewhat as a million-year old consciousness might see them. Such a consciousness would see the becoming and the passing of things beside their present and momentary existence, and not only that, but at the same time it would also see that Other, which was before their becoming and will be after their passing hence."

Introverted sensation also perceives things in a very detailed manner, as per Emma Jung.