In the last decade, a technology of thermal imagers based on new infrared detectors has been developed for both civil and military applications. These imagers implement miniaturized infrared detectors arranged in a matrix in the optical focal plane of the imager. FPA's technology links the detector matrix to specific electronics that allow detection and addressing at each pixel. This technology has allowed a rapid improvement in the performance of thermal imagers. Nevertheless, its use in thermographic measurement requires some metrological care. The first problem is the uniformity of the pixel response and the stability of this uniformity over time. The second problem is the compensation of the thermal drift. In this paper we present some practical solutions developed by CEDIP infrared systems to perform non-uniformity and thermal drift corrections. Performance and limitations are discussed.