English to Portuguese Tech/Engineering Metrology

"Leading the revolutionary charge was the world’s first photofinish camera, known as the ‘Magic Eye’.
This device could produce a developed image within eight minutes and it distinguished the difference between gold, silver and bronze medal performances with more accuracy than any previous technology.
The camera used in London was a standard 35mm still-frame camera mounted on a box.
Opposite the camera was a fixed drum that projected a rolling time.
Unlike a highspeed camera, which freezes the action, the photofinish camera was designed to record everything that takes place in a range of time in a pre-determined space.

[...]

Next in the photofinish evolution was the XXX – used respectively at the Olympic Games in 1968 and 1972.
Now, instead of a rolling drum placed opposite the camera, time was written directly onto the strip of film.
Within a minute after a race, timekeepers were able to produce that one enlarged image of each runner crossing the line."

Parece que existe um "rolling drum clock", mas não sei se o texto se refere a isso:
https://www.google.co.uk/search?q="rolling drum clock"&noj=1...

Sugestões?