| 摘要 |
A depth sensor for sensing contours of an optically rough target surface includes an optic system for radiating first and second discrete areas on the target surface with first and second beams respectively of linearly polarized, coherent light of a predetermined wavelength lambda . The first and second beams have an intersection point an unknown distance from and proximate to the target surface and form an acute included angle phi having a bisector approximately normal to the target surface. The light reradiated from each of the discrete areas creates a speckle pattern on a surface spaced from and facing the target surface. Interference fringes will be formed in the area of overlap between speckles from the two speckle patterns. A detector facing and approximately parallel to the target surface and spaced a predetermined distance from the intersection point provides a first signal indicative of a light intensity pattern reradiated from the first and second discrete areas onto the detector surface during a first time interval. A signal processor provides a frequency signal indicative of the spatial frequency of the light intensity pattern, which will include interference fringes, as a function of the first signal and provides a third signal indicative of the unknown distance during the first time interval as a function of the frequency signal, the predetermined distance, phi and lambda , the third signal being characteristic of the contour of the target surface.
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