Speckle roughness measurement on anisotropic surfaces

"Speckles" are points of light that are created when rough surfaces such as paper, wallpaper or metals are illuminated with a laser. By statistically evaluating the speckle pattern (e.g. on the basis of its contrast), the roughness and other surface parameters can be determined over a large area. Figure 1 shows a ground surface topography. Speckle patterns of anisotropically machined surfaces contain information not only about the fine structure, but also about the machining grooves visible to the naked eye. The aim of the current research work is the bidirectional determination (i.e. both in the machining direction and perpendicular to it) of anisotropic surface parameters from a single speckle pattern.

Possible tasks are diverse. An individual emphasis can thus be placed either on theory, measuring or
programming, depending on the student's own experience and interests.

Possible Tasks:

  • Expansion of the measurement setup through
    a modulation of the laser illumination
  • Planning and execution of test series
  • MATLAB analysis of speckle images


  • Enthusiasm for optical measurements
  • Independent style of work
  • Interest in diverse tasks

Contact Details

León Schweickhardt
E-Mail: Enable JavaScript to view protected content.
Phone:+49 (0)421 218 646 57

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