| 摘要 |
PURPOSE:To measure a Modulation Transfer Function (MTF) quickly and at a high speed by a simple constitution, by integrally averaging an output of every 1 line by a two-dimensional solid-state image pickup element, and operating the MTF of a lens. CONSTITUTION:A lens to be measured 2 set to an infinity focus is rotated by a motor 6, and is turned as one body with a mount 4 whose turning angle is monitored by a q monitor 8. On the other hand, a mount 10 incorporating a chart plate 14, etc. of a slit plate formed by an illuminating optical system 16, a slit 14a, 14b, etc. moves in the direction of an optical axis of the lens 2 via a motor (g). Subsequently, a reverse projected image by the lens 2 of the slit of the chart plate 14 is photodetected by a two-dimentional solid-state image pickup element through collimator lenses 20, 26, is integrally averaged at every 1 line through integration circuits 34, 36, etc., and becomes a value which is not influenced by sensitivity between each picture element in the MTF measuring direction, and variations of a dark level. Accordingly, the MTF is measured quickly and at a high speed by a simple constitution for which various corrections are unnecessary. |
