Browsing by Author "Uhde, Hans-Martin"

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    Three-dimensional analysis by a microlens-array confocal arrangement
    (1994) Tiziani, Hans J.; Uhde, Hans-Martin
    Scanning confocal microscopy is now well developed and applied. As an alternative to a laser spot to be scanned, parallel processing can be obtained when a two-dimensional structure is moved through the focal plane and a series of image sections is recorded. Surface topography is determined by analysis of the normalized intensity of the appropriate image points, i.e., a search of the intensity maximum leads to surface coordinates. With a high numerical aperture of the optical system, the half-width of I (z) is small, and the topography can be calculated with high accuracy. But with a high numerical aperture, only small object fields can be reproduced. As an alternative to the Nipkow disk for parallel processing, high-numerical-aperture microlenses are combined in an array. The reproducible object field is then limited by the size of the array and the number of lens and detector elements.
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    Three-dimensional image sensing by chromatic confocal microscopy
    (1994) Tiziani, Hans J.; Uhde, Hans-Martin
    In the image of a confocal microscope, only those parts of an object appear bright that are located in the focal plane of the objective. Because of an axial chromatic aberration deliberately introduced into the microscope objective, the location of the focal plane depends on the wavelength used. By using a white-light source and examining an object with a depth variation less than the axial range of the chromatic focus, we find that all parts of the object appear sharp and bright in the image, but according to its height they appear in different colors. A camera with black-and-white film sequentially combines; with three selected chromatic filters, intensity and tone of color of each object point. For each tone of color one can assign a height by using a calibration curve. This assignment could be made unequivocal by the selection of filters with adequate chromatic transmission.