Measurement of rotation speed of a flying object

摘要

A rotation speed measuring machine for a flying globe B, such as a golf ball, has a device 10 projecting light on a measurement area A which includes the expected flying route of the globe B after the globe has been hit at a hitting position, a device 20 which receives light reflected from the globe in the measurement area A and which outputs a signal according to the reflected light fluctuations, and a means 30 for determining the rotational speed from the output signal of the light receiving device 20. A mark M having a reflectance different from that of the basic surface texture is placed on part of the surface of the globe B, eg by painting opposite quarter segments black. By detecting the period or frequency of fluctuations in the reflected light, the spin of the globe B may be measured around the highest point of the flight locus.