| 摘要 |
A device for measuring moving filaments includes a laser whose beam is split and the split beams not blocked directed upon distinct filament portions; the light diffracting past the filaments falls upon respective optical sensors. The filament portions may be either longitudinally spaced along the same filament, angularly spaced about the same longitudinal filament position or include the moving filament and a standard. The outputs of the optical sensing means are compared and a signal is produced representative of such a comparison. An arrangement is also disclosed which employs selected energy levels within the diffraction pattern of an unsplit beam to precisely measure a moving filament.
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