A Study of Noise Equivalent Temperature Difference of Thermograph

摘要

The noise equivalent temperature difference (NETD) is one of the most important performance indices of mechanical scanning thermograph, as well as the minimum detectable size as the resolution of the measuring object. This index shows the ability of thermograph that presents the possibility of more precise temperature measurement. It is defined in traditional standard, in which the noise is defined by peak to peak noise voltage. This paper presents a new method to obtain NETD by standard deviation of radiance temperature at individual pixels in thermogram. As this method depends upon statistical treatment, we can treat the NETD quantitatively and objectively. We can also apply this method to another type of thermograph.