| 摘要 |
PURPOSE:To secure stable measuring accuracy without being affected by the variation in an S/N ratio, by repeatedly measuring the average number of times set on the basis of the S/N ratio at the time of measurement and dividing the sum total value, obtained by adding measured results, by the average number of times. CONSTITUTION:The luminous flux emitted from a light source 1 is transmitted to a projection lens 2 to irradiate an objective matter 3 to a light spot 4 while a light receiving lens 5 picks up the image of he light spot 4 to form the same on the light receiving surface of a light receiving element 6. The electric signals iA, iB outputted from the light receiving element 6 by the formation of the image are added by an adder 7 and the average number of times are set on the basis of the S/N ratio determined by the added value by an average-number- of-time setting means 11 and measurement is repeated by the set average number of times and the processing is performed by an average processing circuit 15 so that the sum total value of the measured results is divided by the above- mentioned average number of times to obtain the average value of the measured results. |
