The design and operation of a Mueller matrix imaging polarimeter is pr
esented. The instrument is configurable to make a wide variety of pola
rimetric measurements of optical systems and samples. In one configura
tion, it measures the polarization properties of a set of ray paths th
rough a sample. The sample may comprise a single element, such as a le
ns, polarizer, retarder, spatial light modulator, or beamsplitter, or
an entire optical system containing many elements. In a second configu
ration, it measures an optical system's point spread matrix, a Mueller
matrix relating the polarization state of a point object to the distr
ibution of intensity and polarization across the image. The instrument
is described and a number of example measurements are provided that d
emonstrate the Mueller matrix imaging polarimeter's unique measurement
capability.