A simple geometrical model was developed for calculation of the
contrast of a polychromatic image-plane speckle pattern from a source
of light with high spatial coherence. It is based on counting the
number of independent speckle patterns that contribute to a given point
in the image plane. This results in a simple equation for the
contrast as a function of imaging geometry; relative orientation of the
projection direction, observation direction, and specimen normal;
bandwidth of the light source; and surface roughness. Its validity
was established by comparison with an exact solution: rms errors in
the calculated contrast were only 0.033 over a wide range of parameter
values likely to be encountered in practice.
© 1999 Optical Society of America
Equations on this page are rendered with MathJax. Learn more.