MODULATION MEASURING INSTRUMENT FOR OPTICAL IMAGE

摘要

PURPOSE:To measure the modulation of the optical image on the spot by calculating a quantity corresponding to the result of the division of the difference between the maximum and minimum values of an output signal by the sum of the maximum and minimum values according to parameter quantities featuring the maximum and minimum voltages of the output signal. CONSTITUTION:A line image of an index member 10 is formed on a line image sensor 13 through an optical system 9 and then converted into an electric signal by the sensor 13. Parameter detecting means 15...17, 20 detect the quantities featuring the maximum and minimum voltages of the output signal of the line image sensor 13. An arithmetic means 21 divides the difference between the maximum and minimum voltages by the sum of the maximum and minimum voltages according to the quantities featuring the maximum and minimum voltages to calculate the quantity corresponding to the division result. Consequently, the modulation of the optical image is measured with high accuracy in a short time.