A method of extracting a tomographic image of a layer within a body by optic al coherence tomography, involves capturing three images, namely a non- interference background image, a first interference-fringe image of said layer, and a second interference-fringe image phase-shifted relative to the first interference-fringe image. The tomographic image is obtained by mathematically combining the three captured images. In a preferred embodimen t random noise is removed by averaging and inter-layer effects are removed by applying a compensation function. This system is then used to extract the 2D cross-sectional images encoded in a multiple-layer information carrier.</SDO AB>
FULL-FIELD OPTICAL COHERENCE TOMOGRAPHY AND ITS APPLICATION TO MULTIPLE-LAYER INFORMATION DECODING