Rotoscoping is a technique patented by Max Fleischer in 1917 where animators trace live-action movement, frame by frame.
ɹˈoʊɾəskˌoʊpɪŋ ɪz ɐ tɛknˈiːk pˈæʔn̩ɾᵻd baɪ mˈæks flˈɛʃɚɹ ɪn nˈaɪntiːnhˈʌndɹɪd sˈɛvəntˌiːn wˌɛɹ ˈænɪmˌeɪɾɚz tɹˈeɪs lˈaɪvˈækʃən mˈuːvmənt, fɹˈeɪm baɪ fɹˈeɪm.