A New Method to Determine the Size-of-Source Effect

This article introduces a new technique for measuring the size-of-source effect in radiation thermometers. It is based on scanning a thermometer across an aperture and extracting the size-of-source effect data from the residual signal, and is similar to the commonly used indirect method. The method has several advantages including speed, an ability to cover wide angles, and amenability to automation, at the expense of some added mathematical complexity. Results compare favorably with the frequently used indirect method of measuring the size-of-source effect