Stelmor system is usually used to control cooling uniformity and rate of hot-rolled wire loops to obtain the desired mechanical properties. First of all, it is necessary to accurately measure the temperature distribution of wire loops. However, there are some shortcomings in the current methods due to the grid structure of overlapping wire loops. This article proposes a new measurement method. The target region is captured dynamically based on the temperature distribution characteristics of the thermal image. The effective radiation between the wire loops is analyzed by building an effective emissivity model. The probability distribution test confirms the validity of the model. The temperature measurement experiment shows that the temperature data measured by our approach are more stable and accurate than those of current pyrometers. Anticipated results indicate the potential application in improving process technology. For example, the transverse temperature distribution curve obtained based on this approach can be used to guide the configuration of air volume during the cooling process of the wire loops to improve product quality.