A common problem when filming short duration events with high speed cine cameras is that of identifying the event in terms of the time elapsed from a given start time. Several systems have been evolved whereby timing marks are printed onto the film at regular intervals. However, their appearance is not related directly to the film frames and identification of a frame and its time of exposure from a given datum requires a great deal of interpretation. The scale of the problem may be seen for example where in say 100 feet of exposed film only a few feet may contain relevant information. A convenient solution would be to uniquely identify each individual frame. This requirement is complicated by the fact that the film speed through the camera gate changes as the camera runs up to operating speed. The device described encodes each individual film frame and also makes allowance for instantaneous film speed.
P. W.W. Fuller, P. W.W. Fuller,
"A Digital Time Encoding Device For A High Speed Cine Camera", Proc. SPIE 0189, 13th Intl Congress on High Speed Photography and Photonics, (27 July 1979); doi: 10.1117/12.957643; https://doi.org/10.1117/12.957643