| 摘要 |
Light from a broadband source ( 4 ) is directed along a sample path (SP) towards a region of a sample surface ( 7 ) and along a reference path (RP) towards a reference surface ( 6 ) such that light reflected by the region of the sample surface and light reflected by the reference surface interfere. A mover ( 11 ) effects relative movement along a scan path between the sample surface ( 7 ) and the reference surface ( 6 ). A detector ( 10 ) senses light intensity at intervals to provide a series of intensity values representing interference fringes produced by a region of a sample surface. A data processor has a concurrent processing section ( 34 a ;340 ) for carrying out processing on intensity values as the intensity values are received by the receiving means during a measurement operation to produce data indicating the position of a coherence peak, and a post-processing section ( 34 b ;350 ) for, after completion of a measurement operation, using the data produced by the concurrent section to obtain data indicative of a height of the surface region. One of the processing sections has a correlator ( 44;440 ) for correlating intensity values with correlation function data representing a correlation function to provide correlation data to enable a position of a coherence peak to be identified. The post-processing section has a surface topography determiner ( 35;350 ) for determining a height of a sample surface region from coherence peak position data.
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