Patent ID: 7701561

Claim:
A polarization imaging apparatus for measuring Stokes images of a sample comprising: an optic lens set, a first variable phase retarder optically coupled to the optic lens set and oriented 22.5-degree angle with respect to the linear polarizer, the first variable phase retarder having a first controllable phase retardation; a second variable phase retarder optically coupled to the first variable phase retarder, the second variable phase retarder oriented at a 45-degree angle with respect to the linear polarizer, the second variable phase retarder having a second controllable phase retardation; a linear polarizer optically coupled to the second variable phase retarder; an imaging sensor optically coupled to the polarizer for sensing the intensity images of the sample through the linear polarizer; an controller for varying the first controllable phase retardation of the first variable phase retarder and for varying the second controllable phase retardation of the second variable phase retarders; and a computer for controlling the controller, recording a sequential of four intensity images by varying the first and second variable phase retarders and converting the four sequential intensity images to four components of a Stokes image.