Browsing by Subject "Scalar optical diffraction"
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Item Open Access Diffraction field computation from arbitrarily distributed data points in space(Elsevier BV, 2007-02) Esmer, G. B.; Uzunov, V.; Onural, L.; Özaktaş, Haldun M.; Gotchev, A.Computation of the diffraction field from a given set of arbitrarily distributed data points in space is an important signal processing problem arising in digital holographic 3D displays. The field arising from such distributed data points has to be solved simultaneously by considering all mutual couplings to get correct results. In our approach, the discrete form of the plane wave decomposition is used to calculate the diffraction field. Two approaches, based on matrix inversion and on projections on to convex sets (POCS), are studied. Both approaches are able to obtain the desired field when the number of given data points is larger than the number of data points on a transverse cross-section of the space. The POCS-based algorithm outperforms the matrix-inversion-based algorithm when the number of known data points is large.Item Open Access Exact diffraction calculation from fields specified over arbitrary curved surfaces(Elsevier, 2011-07-30) Esmer, G. B.; Onural, L.; Özaktaş, Haldun M.Calculation of the scalar diffraction field over the entire space from a given field over a surface is an important problem in computer generated holography. A straightforward approach to compute the diffraction field from field samples given on a surface is to superpose the emanated fields from each such sample. In this approach, possible mutual interactions between the fields at these samples are omitted and the calculated field may be significantly in error. In the proposed diffraction calculation algorithm, mutual interactions are taken into consideration, and thus the exact diffraction field can be calculated. The algorithm is based on posing the problem as the inverse of a problem whose formulation is straightforward. The problem is then solved by a signal decomposition approach. The computational cost of the proposed method is high, but it yields the exact scalar diffraction field over the entire space from the data on a surface.Item Open Access Reconstruction of scalar diffraction field from distributed data points over 3D space(IEEE, 2007) Esmer, G. Bora; Uzunov, V.; Onural, Levent; Gotchev, A.; Özaktaş, Haldun M.Diffraction field computation is an important task in the signal conversion stage of the holographic 3DTV. We consider an abstract setting, where the diffraction field of the desired 3D scene to be displayed is given by discrete samples distributed over 3D space. Based on these samples, a model of the diffraction field should be built to allow the field computation at any desired point. In our previous works, we have proved our concepts for the simplistic 2D case. In this paper, we generalize the earlier proposed techniques, namely the projection onto convex sets and conjugate gradient based techniques and test them for their computational efficiency and memory requirements for a specific 3D case.Item Open Access Simulation of scalar optical diffraction between arbitrarily oriented planes(IEEE, 2004) Esmer, Gökhan Bora; Onural, LeventScalar optical diffraction between arbitrarily oriented planes for monochromatic waves is analyzed and a simulator based on a discrete model is developed. The model is based directly on the Rayleigh-Sommerfeld diffraction integral; there is no need for Fresnel and Fraunhofer approximations. Furthermore, the model permits to use of the FFT algorithm. The simulator results are satisfactory.