在红外辐射计算中，目标区域的选择、标示及面积计算是进行定量处理的前提条件。本文结合红外 定量处理软件的工程实现，介绍了点、线、矩形、圆形、椭圆形、封闭多边形等几种选择目标区域的方式以及用这些方式选择的目标区域的标示 和面积计算方法，并对其中最复杂、应用也最普遍的封闭多边形方式进行了详细描述。

In the computation of infrared radiation, the choosing, marking and calculation of a target area are prerequisite to the quantitative processing. Several methods for choosing a target area, such as dot, line, rectangle, circularity, ellipse and closed polygon, are presented. The calculation and marking of the target areas choosed by using the above methods are given. In particular, the closed polygon method which is most complex and popular is described in detail.