LENGTH MEASURING APPARATUS

摘要

A length measuring apparatus configured to perform length measurement for an object moving in a measurement region includes a detector (100) for detecting light modulated by the object with a Doppler effect and obtaining a signal based on the detected light, and a processor (101) for obtaining a measurement value of a velocity of the object based on the signal obtained by the detector and obtaining a length for the object based on the measurement value. The processor is configured to specify a point in time corresponding to the object based on an amplitude of the signal, obtain the measurement value based on the signal with respect to a time duration defined by the point in time, and obtain the length based on the measurement value obtained with respect to the time duration.