Magnification:Transverse &Angular
放大率：横向与角向
The linear magnification or transverse magnification is the ratio of the image size to the object size. If the image and object are in the same medium it is just the image distance divided by the object distance.
线性放大率或横向放大率是像的尺寸与物体的尺寸之比。如果像和物体处于同一介质中，它 simply 是像距与物距之比。
Using the Gaussian form of the lens equation, a negative sign is used on the linear magnification equation as a reminder that all real images are inverted. If the image is virtual, the image distance will be negative, and the magnification will therefore be positive for the erect image.
使用高斯形式的透镜方程，线性放大率方程中使用负号作为提醒，所有实像都是倒立的。如果像为虚像，像距将为负，因此放大率将为正，对应直立的像。
If the media are different on the two sides of the surface or lens, the magnification is not quite so straigtforward. It can be variously expressed as
如果介质在表面或透镜的两侧不同，放大率就不太容易直接确定。它可以以各种方式表达为
In this equation V is the vergence, n is the index of refraction, and u is used for the angle. Note that in this expression for the magnification, the minus sign doesn't appear. In this type of setting, the Cartesian sign convention is typically used and the object distance has a negative value. That takes care of the minus sign that is put in above in the Gaussian form.
在这个方程中，V 是 vergence，n 是折射率，u 用于表示角度。请注意，在这个放大率的表达式中，负号并不出现。在这种设置中，通常使用笛卡尔符号约定，物体距离为负值。这解决了在高斯形式中出现的负号问题。
The angular magnification of an instrument is the ratio of the angle subtended at the eye when using the instrument divided by the angular size without the instrument. An important example is the simple magnifier. The angular
magnification of any optical system can be obtained from the system
matrix for the system.
仪器的角放大率是使用仪器时眼睛所看到的角与不使用仪器时的角的比值。一个重要的例子是简单放大镜。任何光学系统的角放大率都可以通过系统的矩阵来获得。
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