Optical biasing on quasi-interferometry with coded correlation filtering.
A new method for optical biasing is developed to improve the performance of quasi-interferometry with coded correlation filtering. First, by defocusing a mask, a quadratic phase factor is added to the object under test; this yields background fringes. Second, a linear phase factor is introduced by off-axis shifting of masks. The formulas describing these two effects are derived for various possible configurations. The condition of invariance is discussed. Simplified systems are also studied to obtain continuous changing of sensitivity independent of quadratic phase biasing. Some experiments and applications are illustrated.
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Universitat Oldenburg, Postfach 2503, D-2900 Oldenburg, Federal Republic of Germany.