水中直尺像上刻度线的疏密变化研究

Study on the Changes of Scale Mark Density on a Ruler Image under Water

由于存在像散,水中放置直尺所成虚像的清晰度将受到破坏.直尺所成虚像一般呈弧形,像上刻度线的疏密程度随之发生相应变化.数值计算结果表明,像上刻度线的疏密程度随观察位置变化而变化,在同一位置观察时像上各部分刻度线的疏密程度也有所不同.一般地,像上刻度线较原尺变密,而在特定情形下,像上刻度线有可能较原尺变疏.

The clarity of the virtual image of a ruler underwater reduces due to the astigmatism. The virtual image of the ruler bends to some degree, and the scale mark density of the image changes. The calculation shows that the scale mark density of the image changes with the position of the observer. Even when the observer is at the same position, the scale mark density of the different parts of the ruler is somewhat different. The scale mark density of the image may be greater or smaller than the original density.