Patent ID: 7605925

Claim:
A method for mapping a sample surface comprising the following steps: scanning the sample surface in an interferometer at a predetermined scan step to produce a plurality of interference signals registered on a detector; calculating a coarse map of the sample surface by application of a coherence-peak sensing technique on said interference signals; calculating a fine map of the sample surface by application of a quadrature-demodulation technique on said interference signals; subtracting the fine map from the coarse map of the sample surface to produce a noisy fringe map thereof; rounding said noisy fringe map to values corresponding to an integer number of fringes, thereby producing a noise-free fringe map; adding the fine map to the noise-free fringe map to obtain a high-definition map of the sample surface; and processing said high-definition map to produce a visibly perceptible map of the sample surface; wherein said interference signals are used both in the coherence-peak sensing technique and in the quadrature-demodulation technique; and wherein said coherence-peak sensing technique and said quadrature demodulation technique are carried out concurrently in real time during said scanning step.