I just hauled this out to take a picture(s) for you. It may still work-haven't had power on it for a couple of years.
This is the complete trigger proto. It has a an encoder as well as the laser trigger, a tachometer output, as well as parameter screen from teh PSOC, which is programmable through the Cypress software. You can see the Keyence amplifier LV-11SB at the top of the screen and the Laser at about 2 oclock
This is the Keyence laser assembly LV-S62. You can see the laser in the mount and directly across from it is the retroreflector. The film can pass between the two. With the height adjustable between the platform and the film, any gauge can work. The hardware is Actobotics from Servocity https://www.servocity.com/structural-components
This is the Sparkfun PSOC Freesoc board. https://www.sparkfun.com/products/13229 The PSOC was the only proto that I could find that was fast enough to trigger in the 1-2 microsecond range. Cypress has a range of devkits pretty cheap. I know the Muller http://www.filmfabriek.nl/ is now using the system from Frank Vine http://www.cine2digits.co.uk/ which is driven by a PIC micro. He bit-bashed the thing to get nanosecond trigger times, which allows him to control the light with extreme accuracy. A very good system.
ABOUT KINETTA. I am pretty sure Jeff senses frame lines and not sprockets, so he is probably doing as you say, an array of lasers that can identify the frame lines. He says he does not rely on sprockets at all, and can even transfer film with no sprockets, like the Library of Congress paper rolls.