Now showing items 1-20 of 29

    • An adaptive speckle suppression filter for medical ultrasound imaging 

      Karaman, M.; Kutay, M. A.; Bozdagi, G. (Institute of Electrical and Electronics Engineers, 1995-06)
      An adaptive smoothing technique for speckle suppression in medical B-scan ultrasonic imaging is presented. The technique is based on filtering with appropriately shaped and sized local kernels. For each image pixel, a ...
    • Continuous and discrete fractional fourier domain decomposition 

      Yetik, İ. Şamil; Kutay, M. A.; Özaktaş, H.; Özaktaş, Haldun M. (IEEE, 2000)
      We introduce the fractional Fourier domain decomposition for continuous and discrete signals and systems. A procedure called pruning, analogous to truncation of the singular-value decomposition, underlies a number of ...
    • Digital computation of linear canonical transforms 

      Koç A.; Özaktaş, Haldun M.; Candan, C.; Kutay, M. A. (Institute of Electrical and Electronics Engineers, 2008)
      We deal with the problem of efficient and accurate digital computation of the samples of the linear canonical transform (LCT) of a function, from the samples of the original function. Two approaches are presented and ...
    • Digital computation of the fractional Fourier transform 

      Özaktaş, Haldun M.; Arıkan, Orhan; Kutay, M. A.; Bozdağı, G. (Institute of Electrical and Electronics Engineers, 1996-09)
      An algorithm for efficient and accurate computation of the fractional Fourier transform is given. For signals with time-bandwidth product N, the presented algorithm computes the fractional transform in O(NlogN) time. A ...
    • The discrete fractional Fourier transform 

      Candan, C.; Kutay, M. A.; Özaktaş, Haldun M. (IEEE, 2000-05)
      We propose and consolidate a definition of the discrete fractional Fourier transform that generalizes the discrete Fourier transform (DFT) in the same sense that the continuous fractional Fourier transform generalizes ...
    • The discrete harmonic oscillator, Harper's equation, and the discrete fractional Fourier transform 

      Barker, L.; Candan, C.; Hakioğlu, T.; Kutay, M. A.; Özaktaş, Haldun M. (Institute of Physics Publishing, 2000)
      Certain solutions to Harper's equation are discrete analogues of (and approximations to) the Hermite-Gaussian functions. They are the energy eigenfunctions of a discrete algebraic analogue of the harmonic oscillator, and ...
    • Effect of fractional Fourier transformation on time-frequency distributions belonging to the Cohen class 

      Özaktaş, Haldun M.; Erkaya, N.; Kutay, M. A. (Institute of Electrical and Electronics Engineers, 1996-02)
      We consider the Cohen (1989) class of time-frequency distributions, which can be obtained from the Wigner distribution by convolving it with a kernel characterizing that distribution. We show that the time-frequency ...
    • Efficient computation of quadratic-phase integrals in optics 

      Özaktaş, H. M.; Koç, A.; Sarı, I.; Kutay, M. A. (Optical Society of America, 2006)
      Received June 29, 2005; revised manuscript received August 22, 2005; accepted September 12, 2005 We present a fast N log N time algorithm for computing quadratic-phase integrals. This three-parameter class of integrals ...
    • Fast algorithms for digital computation of linear canonical transforms 

      Koç, A.; Oktem, F. S.; Özaktaş, Haldun M.; Kutay, M. A. (Springer, New York, 2016)
      Fast and accurate algorithms for digital computation of linear canonical transforms (LCTs) are discussed. Direct numerical integration takes O.N2/ time, where N is the number of samples. Designing fast and accurate ...
    • The fractional Fourier domain decomposition 

      Kutay, M. A.; Özaktaş, H.; Özaktaş, Haldun M.; Arıkan, Orhan (Elsevier, 1999)
      We introduce the fractional Fourier domain decomposition. A procedure called pruning, analogous to truncation of the singular-value decomposition, underlies a number of potential applications, among which we discuss fast ...
    • The fractional fourier transform 

      Özaktas, Haldun M.; Kutay, M. A. (IEEE, 2001)
      A brief introduction to the fractional Fourier transform and its properties is given. Its relation to phase-space representations (time- or space-frequency representations) and the concept of fractional Fourier domains are ...
    • Fractional fourier transform 

      Özaktaş, Haldun M.; Kutay, M. A.; Candan, Ç. (CRC Press, 2010)
    • The Fractional Fourier transform and harmonic oscillation 

      Kutay, M. A.; Özaktaş, Haldun M. (Springer, 2002)
      The ath-order fractional Fourier transform is a generalization of the ordinary Fourier transform such that the zeroth-order fractional Fourier transform operation is equal to the identity operation and the first-order ...
    • The fractional fourier transform and its applications to image representation and beamforming 

      Yetik, I. Ş; Kutay, M. A.; Özaktaş, Haldun. M. (ASME, 2003-09)
      The ath order fractional Fourier transform operator is the ath power of the ordinary Fourier transform operator. We provide a brief introduction to the fractional Fourier transform, discuss some of its more important ...
    • Image representation and compression with the fractional Fourier transform 

      Yetik, İ. Ş.; Kutay, M. A.; Özaktaş, Haldun M. (Elsevier, 2001-04-01)
      We discuss the application of fractional Fourier transform-based filtering configurations to image representation and compression. An image can be approximately represented (and stored or transmitted) as the coefficients ...
    • Improved acoustics signals discrimination using fractional Fourier transform based phase-space representations 

      Zalevsky, Z.; Mendlovic, D.; Kutay, M. A.; Özaktaş, Haldun M.; Solomon, J. (Elsevier, 2001-04-01)
      In this communication we propose performing two-dimensional correlation operation between phase-space representations based on the fractional Fourier transform, instead of correlating the signals themselves. A numerical ...
    • Linear algebraic theory of partial coherence: continuous fields and measures of partial coherence 

      Özaktaş, Haldun M.; Gulcu, T. C.; Kutay, M. A. (Optical Society of America, 2016)
      This work presents a linear algebraic theory of partial coherence for optical fields of continuous variables. This approach facilitates use of linear algebraic techniques and makes it possible to precisely define the ...
    • Linear algebraic theory of partial coherence: discrete fields and measures of partial coherence 

      Özaktaş, Haldun M.; Yüksel, S.; Kutay, M. A. (SPIE, 2003-08)
      We present a linear algebraic theory of partial coherence which allows precise mathematical definitions of concepts such as coherence and incoherence. This not only provides new perspectives and insights, but also allows ...
    • Linear algebraic theory of partial coherence: discrete fields and measures of partial coherence 

      Özaktaş, Haldun M.; Yuksel, S.; Kutay, M. A. (OSA Publishing, 2002)
      A linear algebraic theory of partial coherence is presented that allows precise mathematical definitions of concepts such as coherence and incoherence. This not only provides new perspectives and insights but also allows ...
    • Nonseperable two-dimensional fractional Fourier transform 

      Sahin, A.; Kutay, M. A.; Özaktaş, Haldun M. (Optical Society of America, 1998)
      Previous generalizations of the fractional Fourier transform to two dimensions assumed separable kernels. We present a nonseparable definition for the two-dimensional fractional Fourier transform that includes the separable ...