The Doctor with a holo-imager.
A holo-imager is a device that records the form and appearance of a subject in three dimensions, so that it can be reproduced in holographic form. It requires that the subject be captured from multiple angles.
In 2371, Quark attempted to secretly capture Major Kira Nerys on holo-imager, to fulfill his client Tiron's request for a holosuite program of her. Kira caught him and promised that if she found his imager pointed in her direction again, he would end up eating it. (DS9: "Meridian")
In 2375, the Doctor modified the resonance spectrum of his holo-imager to scan his subjects down to the subatomic level. This allowed him to render USS Voyager crew members as holograms in full anatomical detail, which he employed as part of his annual check-up. (VOY: "Latent Image")