Abstract: The invention refers to a method of shortening the closure time of shutters in cinema projectors of the type in which film is intermittently advanced one frame at a time into registry with an image window in the projector, and wherein each time the film is advanced a shutter in the projector closes the image window during the time that the film is being advanced. According to the invention, an optical compensation of the film motion is effected by determining the rate at which each image of the film begins and ends, respectively, its advance into registry with the image window of the projector, generating a control signal proportionate to the rate, and positioning between the image window and the associated projection screen a movable plane-parallel plate which is adjsuted by the control signal to shorten the closure time of the image window during each film advance, thereby to increase the luminous efficiency factor of the projector.

Abstract: The invention refers to a process for scanning a gyroscopic instrument. The invention is characterised by the collection of gyroscopic data being effected by true angle scanning. In order to apply the process of the invention, a gyroscopic instrument including a gyroscopic scanning system is required in which the gyroscopic scanning system is coupled with a rotating, scanned and/or scanning unit. The process may also refer to a gyroscopic instrument including a gyroscopic scanning system in which a scanning module (such as a CCD sensor) is arranged on the side of the gyroscopic instrument as a scanning device, directly scanning horizontal and vertical true angle identifications on a gyroscopic instrument.