The use of polarization-sensitive sensors is being explored in a variety of applications. Polarization diversity has been shown to improve in a significant way the performance of the automatic target detection and recognition. However, it also brings out the problems associated with processing and storing more data and the problem of calibration of the polarimetric sensors themselves and the problem of dealing with polarimetric signatures that subject to transmission path turbulence and distortionsions. In this paper, we present techniques for extracting attributes that are invariant under polarization transformations. The polarimetric signatures are represented in terms of the components of the Stokes vector. The cases associated with passive infrared polarimetry are considered. In theses cases, invariant algebra are used to extract the target-related attributes that are invariant to the affine transformation of the polarization coordinate systems. Experimental resuls are provided.