Now showing items 21-40 of 52

    • Extensions to common laplace and fourier transforms 

      Onural, L.; Erden, M. F.; Özaktaş, Haldun M. (Institute of Electrical and Electronics Engineers, 1997-11)
      The extended versions of common Laplace and Fourier transforms are given. This is achieved by defining a new function fe(p), p 2 C related to the function to be transformed f(t), t 2 R. Then fe(p) is transformed by an ...
    • Family of scaling chirp functions, diffraction, and holography 

      Onural, L.; Kocatepe, M. (Institute of Electrical and Electronics Engineers, 1995)
      It is observed that diffraction is a convolution operation with a chirp kernel whose argument is scaled. Family of functions obtained from a prototype by shifting and argument scaling form the essential ground for wavelet ...
    • Full-complex amplitude modulation with binary spatial light modulators 

      Ulusoy, E.; Onural, L.; Özaktaş, Haldun M. (Optical Society of America, 2011-10-19)
      Imperfections and nonrobust behavior of practical multilevel spatial light modulators (SLMs) degrade the performance of many proposed full-complex amplitude modulation schemes. We consider the use of more robust binary ...
    • Generating connected textured fractal patterns using Markov random fields 

      Onural, L. (Institute of Electrical and Electronics Engineers, 1991)
      An algorithm that yields textured and connected binary fractals is presented. The texture is imposed by modeling the fractal as a Markov random field (MRF) at every resolution level. The model size and the parameters specify ...
    • Gibbs random field model based weight selection for the 2-D adaptive weighted median filter 

      Onural, L.; Alp, M. B.; Gürelli, M. I. (IEEE, 1994)
      A generalized filtering method based on the minimization of the energy of the Gibbs model is described. The well-known linear and median filters are all special cases of this method. It is shown that, with the selection ...
    • Graphics processing unit accelerated computation of digital holograms 

      Kang, H.; Yaraş, F.; Onural, L. (Optical Society of America, 2009)
      An approximation for fast digital hologram generation is implemented on a central processing unit (CPU), a graphics processing unit (GPU), and a multi-GPU computational platform. The computational performance of the method ...
    • Hologram synthesis for photorealistic reconstruction 

      Janda, M.; Hanák, I.; Onural, L. (Optical Society of America, 2008)
      Computation of diffraction patterns, and thus holograms, of scenes with photorealistic properties is a highly complicated and demanding process. An algorithm, based primarily on computer graphics methods, for computing ...
    • Image sequence analysis for emerging interactive multimedia services-the European COST 211 framework 

      Alatan, A. A.; Onural, L.; Wollborn, M.; Mech, R.; Tuncel, E.; Sikora, T. (Institute of Electrical and Electronics Engineers, 1998-11)
      Flexibility and efficiency of coding, content extraction, and content-based search are key research topics in the field of interactive multimedia. Ongoing ISO MPEG-4 and MPEG-7 activities are targeting standardization to ...
    • An improvement to MBASIC algorithm for 3-D motion and depth estimation 

      Bozdağı, G.; Tekalp, A. M.; Onural, L. (IEEE, 1994)
      In model-based coding of facial images, the accuracy of motion and depth parameter estimates strongly affects the coding efficiency. MBASIC is a simple and effective iterative algorithm (recently proposed by Aizawa et al.) ...
    • Impulse functions over curves and surfaces and their applications to diffraction 

      Onural, L. (Elsevier Science & Technology, 2006-10-01)
      An explicit preferred definition of impulse functions (Dirac delta functions) over lowerdimensional manifolds in RN is given in such a way to assure uniform concentration per geometric unit of the manifold. Some related ...
    • Integral imaging based 3D display of holographic data 

      Yontem, A. O.; Onural, L. (Optical Society of America, 2012)
      We propose a method and present applications of this method that converts a diffraction pattern into an elemental image set in order to display them on an integral imaging based display setup. We generate elemental images ...
    • Integral imaging using phase-only LCoS spatial light modulators as Fresnel lenslet arrays 

      Ÿontem, A. O.; Onural, L. (Optical Society of Amercia, 2011-10-27)
      We present a digital integral imaging system. A Fresnel lenslet array pattern is written on a phase-only LCoS spatial light modulator device (SLM) to replace the regular analog lenslet array in a conventional integral ...
    • Introduction to the issue on emerging techniques in 3-D 

      Alatan, A. A.; Ostermann, J.; Onural, L.; AlRegib, G.; Mattoccia, S.; Yuan, C. (IEEE, 2012)
      The fifteen papers in this special section that focus on three dimensional content (3D), with particular emphasis on the fusion of conventional camera outputs with those captured by other modalities, such as active sensors, ...
    • Introduction to the special section on 3DTV 

      Onural, L.; Sikora, T. (Institute of Electrical and Electronics Engineers, 2007)
      The set of six papers that we invited to this part of the Special Section present extensive reviews of the state-of-the-art in functional building blocks of 3DTV systems.
    • Message from the chairs 

      Güdükbay, Uğur; Onural, L. (2011)
    • New high-resolution display device for holographic three-dimensional video: principles and simulations 

      Onural, L.; Bozdağı, G.; Atalar, Abdullah (SPIE, 1994)
      A new acousto-optical holographic display device, which is expected to solve the display resolution and refresh problems that are common to available holographic displays, is proposed. The device is based on the ...
    • New radix-2-based algorithm for fast median filtering 

      Karaman, M.; Onural, L. (IEEE, 1989)
      A fast radi-2-based median filtering algorithm is proposed. The median is determined bit-by-bit successively by eliminating the samples whose previous bits are different to that of the median. The intermediate computations ...
    • On a parameter estimation method for Gibbs-Markov random fields 

      Gürelli, M. I.; Onural, L. (IEEE, 1994)
      This correspondence is about a Gibbs-Markov random field (GMRF) parameter estimation technique proposed by Derin and Elliott. We will refer to this technique as the histogramming (H) method. First, the relation of the H ...
    • Perspective projections in the space-frequency plane and fractional Fourier transforms 

      Yetik, I. S.; Özaktaş, Haldun M.; Barshan, B.; Onural, L. (OSA Publishing, 2000-07-06)
      Perspective projections in the space-frequency plane are analyzed, and it is shown that under certain conditions they can he approximately modeled in terms of the fractional Fourier transform, The region of validity of the ...
    • Projection-slice theorem as a tool for mathematical representation of diffraction 

      Onural, L. (Institute of Electrical and Electronics Engineers, 2007)
      Although the impulse (Dirac delta) function has been widely used as a tool in signal processing, its more complicated counterpart, the impulse function over higher dimensional manifolds in ℝN, did not get such a widespread ...