MEASURING METHOD OF MODULATION TRANSFER FUNCTION MEASURING MACHINE OF LENS

摘要

PURPOSE:To exactly calculate MTF in a short time, by eliminating a signal which is below a prescribed level, among output signals from a CCD, storing a signal by only linear image formation in an RAM, and executing the operation processing. CONSTITUTION:An output signal from a CCD5 passes through an A/D converter 6 and a zero-comparator 9, is compared with reference level by a comparator 9 through a signal from a clock generator 10, and only a detecting signal of a linear image of a chart is stored in an RAM7. In accordance with its data, MTF is calculated by a computer 8 and is displayed. Accordingly, even if the storage capacity of the RAM7 is small, it is available, also, a noize is small, the operating accuracy is high, and the operating time is reduced.