Recent Works:

  1. Ç. Işıl and F. S. Oktem, “Deep Plug-and-Play HIO Approach for Phase Retrieval,” under review (arXiv).
  2. M. O. Kaya and F. S. Oktem, “DDRM-PR: Fourier Phase Retrieval using Denoising Diffusion Restoration Models,” under review.

  3. O. Oral and F. S. Oktem, “Plug-and-Play Regularization on Magnitude with Deep Priors for 3D Near-Field MIMO Imaging,” IEEE Transactions on Computational Imaging, vol. 10, pp. 762-773, 2024, doi: 10.1109/TCI.2024.3396388.

Journal Papers, Book Chapters, and Editorials:

  1. O. Oral and F. S. Oktem, “Plug-and-Play Regularization on Magnitude with Deep Priors for 3D Near-Field MIMO Imaging,” IEEE Transactions on Computational Imaging, vol. 10, pp. 762-773, 2024, doi: 10.1109/TCI.2024.3396388.
  2. A. Dalkilic, F. S. Oktem and L. Alatan, “Enhanced Near-Field Microwave Imaging System with Polarization Diversity,” IEEE Antennas and Wireless Propagation Letters, vol. 23, no. 3, pp. 1085-1089, 2024, doi: 10.1109/LAWP.2023.3344609.
  3. I. Manisalı, O. Oral, and F. S. Oktem, “Efficient physics-based learned reconstruction methods for real-time 3D near-field MIMO radar imaging.” Digital Signal Processing, vol. 144, pp. 104274, 2024, doi: 10.1016/j.dsp.2023.104274.
  4. J. Ke, T. Alieva, F. S. Oktem, P. E. Silveira, G. Wetzstein, and F. Willomitzer, “Computational Optical Sensing and Imaging 2021: feature issue introduction“, Optics Express, vol. 30, no. 7, pp. 11394-11399, 2022.
  5. J. Ke, T. Alieva, F. S. Oktem, P. E. Silveira, G. Wetzstein, and F. Willomitzer, “Computational Optical Sensing and Imaging 2021: introduction to the feature issue“, Applied Optics, vol. 61, no. 9, pp. COSI1-COSI4, 2022.
  6. E. A. Miran, F. S. Oktem, and S. Koc, “Sparse Reconstruction for Near-Field MIMO Radar Imaging using Fast Multipole Method”. IEEE Access, vol. 9, pp. 151578 – 151589, 2021.
  7. F. S. Oktem, O. F. Kar, C. D. Bezek, and F. Kamalabadi, “High-resolution multi-spectral imaging with diffractive lenses and learned reconstruction.” IEEE Transactions on Computational Imaging, vol. 7, pp. 489 – 504, 2021. (arXiv)
  8. S. Ayazgok and F. S. Oktem, “Efficient computation of 2D point-spread functions for diffractive lenses.” Applied Optics, vol. 59, no. 2, pp. 445-451, 2020.
  9. Ç. Işıl, F. S. Oktem, and A. Koç, “Deep iterative reconstruction for phase retrieval“, Applied Optics, vol. 58, no. 20, pp. 5422-5431, 2019. (arXiv)
  10. O. F. Kar and F. S. Oktem, “Compressive spectral imaging with diffractive lenses.” Optics Letters, vol. 44, no. 18, pp. 4582-4585, 2019. (arXiv)
  11. J. M. Davila, F. S. Oktem, and F. Kamalabadi, “Slitless solar imaging spectroscopy.” The Astrophysical Journal, vol. 883, no. 1, pp. 7, 2019.
  12. F. S. Oktem, “Sparsity-based three-dimensional image reconstruction for near-field MIMO radar imaging.” Turk. J. Elec. Eng. & Comp. Sci., vol. 27, no. 5, pp. 3282-3295, 2019.
  13. K.B. Alici, F. S. Oktem, O. Karci, A.S. Yilmaz, and O. Selimoglu, “Image chain simulation for Earth observation satellites.” IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 12, no. 10, pp. 4014-4023, 2019.
  14. F. S. Oktem, L. Gao, and F. Kamalabadi, “Chapter 5: Computational spectral and ultrafast imaging via convex optimization.” V. Monga (ed.), Handbook of Convex Optimization Methods in Imaging Science, Springer, Cham, pp. 105-127, 2018.
  15. F. S. Oktem, F. Kamalabadi, and J. M. Davila, “Analytical Fresnel imaging models for photon sieves,” Optics Express, vol. 26, no. 24, pp. 32259-32279, 2018.
  16. K. B. Alici, H. Buyuk, A. S. Yilmaz, C. Ozdemir, O. Karci, F. S. Oktem, and O. Selimoglu, “Periodic aperture imaging.” Optical Engineering, vol. 56, pp. 050502, 2017.
  17. F. S. Oktem and H. M. Ozaktas, “Effect of spatial distribution of partial information on the accurate recovery of optical wave fields.” Applied Optics, vol. 56, pp. A133-A144, 2017.
  18. F. S. Oktem, and H. M. Ozaktas, “Chapter 7: Linear canonical domains and degrees of freedom of signals and systems.” J.J. Healy et al. (eds.), Linear canonical transforms, Springer, New York, pp. 293-327, 2016.
  19. A. Koc, F. S. Oktem, H. M. Ozaktas, and M. A. Kutay, “Chapter 9: Fast algorithms for digital computation of linear canonical transforms.” J.J. Healy et al. (eds.), Linear canonical transforms, Springer, New York, pp. 197-239, 2016.
  20. F. S. Oktem, F. Kamalabadi, and J. M. Davila, “A parametric estimation approach to instantaneous spectral imaging,” IEEE Trans. Image Process., vol. 23, pp. 5707-5721, 2014.
  21. H. M. Ozaktas and F. S. Oktem, “Phase-space window and degrees of freedom of optical systems with multiple apertures.” J. Opt. Soc. Am. A., vol. 30, pp.682-690, 2013.
  22. F. S. Oktem and H. M. Ozaktas, “Equivalence of linear canonical transform domains to fractional Fourier domains and the bicanonical width product: a generalization of the space- bandwidth product,” J. Opt. Soc. Am. A, vol. 27, pp. 1885-1895, 2010.
  23. F. S. Oktem and H. M. Ozaktas, “Exact relation between continuous and discrete linear canonical transforms,” IEEE Signal Process. Lett., vol. 16, pp. 727-730, 2009.

Conference Proceedings: 

  1. O. Oral and F. S. Oktem, “Plug-and-Play Reconstruction with 3D Deep Prior for Complex-Valued Near-Field MIMO Imaging.” 31st European Signal Processing Conference (EUSIPCO 2023), Helsinki, Finland, 4–8 Sept. 2023.
  2. I. Manisali and F. S. Oktem, “Deep Learning-Based Reconstruction for Near-Field MIMO Radar Imaging.” 31st European Signal Processing Conference (EUSIPCO 2023), Helsinki, Finland, 4–8 Sept. 2023.
  3. U. Gundogan and F. S. Oktem, “Deep Learning-Based Joint Reconstruction and System Optimization for Single-Shot Compressive Spectral Imaging.” Computational Optical Sensing and Imaging, CW4B. 4, Vancouver, British Columbia, Canada, 11–15 July 2022.
  4. U. Gundogan and F. S. Oktem, “Computational Spectral Imaging with Diffractive Lenses and Spectral Filter Arrays.” IEEE Int. Conf. on Image Processing (ICIP), Virtual Meeting, 19-22 Sept. 2021.
  5. C. D. Bezek and F. S. Oktem, “Unrolling-Based Deep Reconstruction for Compressive Spectral Imaging”. Computational Optical Sensing and Imaging, Virtual Meeting, 19-23 July 2021.
  6. Ç. Işıl and F. S. Oktem, “Model-based Phase Retrieval with Deep Denoiser Prior.” Computational Optical Sensing and Imaging, Virtual Meeting, 22-26 June 2020.
  7. D. Doğan and F. S. Oktem, “Model-based Inversion Methods for Compressive Spectral Imaging with Diffractive Lenses.” Computational Optical Sensing and Imaging, Virtual Meeting, 22-26 June 2020 (Student Paper Award Finalist).
  8. I. Manisali, R. M. Cam, C. D. Bezek, and F. S. Oktem, “Deep CNN Prior Based Image Reconstruction for Multispectral Imaging.” 28th Signal Processing and Communications Applications Conference, Gaziantep, 5-7 Oct., 2020 (in Turkish).
  9. U. Gundogan and F. S. Oktem, “Analysis of Alternative Performance Metrics for Compressive Spectral Imaging.” 28th Signal Processing and Communications Applications Conference, Gaziantep, 5-7 Oct., 2020 (in Turkish).
  10. H. Baskaya and F. S. Oktem, “Evaluation of Sparsity-based Methods for Parameterized Source Separation.” 28th Signal Processing and Communications Applications Conference, Gaziantep, 5-7 Oct., 2020 (in Turkish).
  11. D. Dogan and F. S. Oktem, “Comparison of Dictionary-Based Image Reconstruction Algorithms for Inverse Problems.” 28th Signal Processing and Communications Applications Conference, Gaziantep, 5-7 Oct., 2020 (in Turkish).
  12. Ç. Işıl and F. S. Oktem, “Deep Learning-Based Hybrid Approach for Phase Retrieval.” Computational Optical Sensing and Imaging, Munich, Germany, 24-27 June 2019.
  13. D. Doğan and F. S. Oktem, “Convolutional Inverse Problems in Imaging with Convolutional Sparse Models.” Computational Optical Sensing and Imaging, Munich, Germany, 24-27 June 2019.
  14. O. F. Kar and F. S. Oktem, “Fast Computational Spectral Imaging with a Programmable Diffractive Lens.” Computational Optical Sensing and Imaging, Munich, Germany, 24-27 June 2019.
  15. S. Ayazgok and F. S. Oktem, “Snapshot Spectral Imaging with Generalized Photon Sieves.” Computational Optical Sensing and Imaging, Munich, Germany, 24-27 June 2019.
  16. S. Ayazgok and F. S. Oktem, “Design Optimization For Snapshot Spectral Imaging.” 27th Signal Processing and Communications Applications Conference, 2019 (in Turkish).
  17. O.F. Kar, U. Kamaci, F.C. Akyon, and F. S. Oktem, “Compressive Photon-Sieve Spectral Imaging.” Computational Optical Sensing and Imaging, Orlando, Florida, 25-28 June 2018.
  18. Ç. Işıl and F. S. Oktem, “A Phase-Space Approach to Diffraction-Limited Resolution.” Imaging Systems and Applications, Orlando, Florida, 25-28 June 2018.
  19. M. Sadighi, F. S. Oktem, and B. M. Eyuboglu, “Diffusion Tensor Magnetic Resonance Electrical Impedance Tomography versus Magnetic Resonance Conductivity Tensor Imaging.” 2018 ISMRM Meeting, Paris, France, 16-21 June 2018.
  20. E. Anadol, I. Seker, S. Camlica, T. O. Topbas, S. Koc, L. Alatan, F. S. Oktem, and O. A. Civi, “UWB 3D near-field imaging with a sparse MIMO antenna array for concealed weapon detection”. Proc. SPIE 10633, Radar Sensor Technology XXII, 106331D, 15-19 April 2018.
  21. O. F. Kar, U. Kamaci, F.C. Akyon, and F. S. Oktem, “Effect of Different Priors on Compressive Photon-Sieve Spectral Imaging.” 26th Signal Processing and Communications Applications Conference, 2018 (in Turkish).
  22. F. C. Akyon, U. Kamaci, and F. S. Oktem, “Image Deconvolution via Efficient Sparsifying Transform Learning.” 26th Signal Processing and Communications Applications Conference, 2018 (in Turkish).
  23. B. Iskender and F. S. Oktem, “Image Restoration for Sparse Aperture Optical Systems.” 26th Signal Processing and Communications Applications Conference, 2018 (in Turkish).
  24. U. Kamaci, F.C. Akyon, T. Alkanat, and F. S. Oktem, “Efficient sparsity-based inversion for photon-sieve spectral imagers with transform learning.” IEEE Global Conference on Signal and Information Processing (GlobalSIP), pp. 1225-1229, 2017.
  25. B. Kocamis and F. S. Oktem, “Optimal Design of Sparse MIMO Arrays for Near-Field Ultrawideband Imaging.” 25th European Signal Processing Conference (EUSIPCO), pp. 1952-1956, 2017.
  26. K.B. Alici, O. Karci, A.S. Yilmaz, C. Ozdemir, F. S. Oktem, and O. Selimoglu, “OTF Analysis of a Spaceborne CMOS Imaging Sensor.” 8th International Conference on Recent Advances in Space Technologies (RAST), 2017.
  27. B. Kocamis and F. S. Oktem, “Optimal MIMO Array Configuration for Ultrawideband Microwave Imaging.” 25th Signal Processing and Communications Applications Conference, 1-4, 2017 (in Turkish).
  28. F. S. Oktem, and T. Alkanat, “Fast Computation of Two-Dimensional Point-Spread Functions for Photon Sieves.” Imaging Systems and Applications, JT3A. 34, 2016.
  29. F. S. Oktem, F. Kamalabadi, and J. M. Davila, “Computational spectral imaging with photon sieves.” 24th Signal Processing and Communications Applications Conference, 425-428, 2016 (in Turkish).
  30. F. S. Oktem, F. Kamalabadi, and J. M. Davila, “High-resolution computational spectral imaging with photon sieves.” IEEE Int. Conf. on Image Processing (ICIP), 5122–5126, 2014 (“Top 10%” Paper Award).
  31. F. S. Oktem, F. Kamalabadi, and J. M. Davila, “Parameter estimation for instantaneous spectral imaging.” IEEE Int. Conf. on Acoustic Speech and Signal Processing (ICASSP), 8148–8152, 2014.
  32. H. M. Ozaktas, and F. S. Oktem, “Linear Canonical Transforms, Degrees of Freedom, and Sampling in Optical Signals and Systems.” 22nd Signal Processing and Communications Applications Conference, 429–432, 2014 (in Turkish).
  33. F. S. Oktem, J. M. Davila, and F. Kamalabadi, “Image formation model for photon sieves.” IEEE Int. Conf. on Image Processing (ICIP), 2373–2377, 2013.
  34. F. S. Oktem, and H. M. Ozaktas, “Degrees of freedom of optical systems and signals with applications to sampling and system simulation.” Imaging Systems and Applications (IS), ITu1E–1, 2013 (Invited).
  35. F. S. Oktem, and H. M. Ozaktas, “Condition number in recovery of signals from partial fractional Fourier domain information.” Computational Optical Sensing and Imaging (COSI), JTu4A–18, 2013.
  36. F. S. Oktem, F. Kamalabadi, and J. M. Davila, “Cramer-Rao bounds and instrument optimization for slitless spectroscopy.” IEEE Int. Conf. on Acoustic Speech and Signal Processing (ICASSP), 2169–2173, 2013.
  37. F. S. Oktem and F. Kamalabadi, “Analytical Precision Limits in Slitless Spectroscopy.” IEEE Statistical Signal Processing Workshop (SSP), 468–471, 2012.
  38. F. S. Oktem and R. E. Blahut, “Schulz-Snyder Phase Retrieval Algorithm as an Alternating Minimization Algorithm,” Computational Optical Sensing and Imaging (COSI), CMC3, 2011.
  39. F. S. Oktem and H. M. Ozaktas, “Linear Algebraic Analysis of Fractional Fourier Domain Interpolation Problem.” 17th Signal Processing and Communications Applications Conference, 873–875, 2009 (in Turkish).

Conference Abstracts:

  1. F. S. Oktem, “Computational Imaging and Inverse Problems: Making the Invisible Visible.” 21. Ulusal Optik, Elektro-Optik ve Fotonik Çalıştayı, Istanbul, Turkey, 6 Sept. 2019 (Invited talk).
  2. J. M. Davila, F. S. Oktem, F. Kamalabadi, J. O’Neill, A. Novo-Gradac, A. Daw, and D. M. Rabin, “Milli-Arcsecond (MAS) Imaging of the Solar Corona.” AAS/Solar Physics Division Meeting, Boulder, Colorado, 2016.
  3. F. S. Oktem, F. Kamalabadi, and J.M. Davila, “High-Resolution Solar Imaging With Photon Sieves.” Next Generation Instrumentation in Solar and Space Physics: Critical Measurements From Low Cost Missions/Platforms, AGU Fall Meeting, San Francisco, California, 2014.
  4. F. Kamalabadi, F. S. Oktem, and J.M. Davila, “Slitless Solar Spectroscopy.” Next Generation Instrumentation in Solar and Space Physics: Critical Measurements From Low Cost Missions/Platforms, AGU Fall Meeting, San Francisco, California, 2014.
  5. J. F. O’Neill, J. M. Davila, F. S. Oktem, and A. N. Daw, “Exploring the Photon Sieve: Mathematical Framework and Experimental Categorization”. Next Generation Instrumentation in Solar and Space Physics: Critical Measurements From Low Cost Missions/Platforms, AGU Fall Meeting, San Francisco, California, 2014.
  6. F. S. Oktem, F. Kamalabadi, and J. M. Davila,“Imaging Techniques for High-Resolution and Instantaneous Observations of the Solar Corona.” Seventh Solar Image Processing Workshop, La Roche-en-Ardenne, Belgium, 2014 (Invited talk).
  7. J. F. O’Neill, J.M. Davila, and F. S. Oktem, “Slitless solar spectroscopy”. 2014 Solar Physics Division Meeting, Boston, MA, 2014.
  8. F. S. Oktem, F. Kamalabadi, and J. M. Davila, “Multi-order slitless solar spectroscopy: a Parametric Inversion Approach.” Sixth Solar Image Processing Workshop, Bozeman, MT, 2012.

Invited Talks and Seminars:

  1. F. S. Oktem, “Physics-Informed Deep Learning for Solving Inverse Problems in Radar Imaging.” Invited talk given at IEEE SPS Synthetic Aperture Technical Working Group Meeting, Online, Jun. 6, 2024.
  2. F. S. Oktem, “Computational Imaging and Physics-Informed Deep Learning: Making the Invisible Visible.” Talk given at METU, EE690 Graduate Seminar Series, Ankara, Turkey, Nov. 14, 2023.
  3. F. S. Oktem, “Computational Imaging and Deep Learning: Making the Invisible Visible.” Keynote Speaker at the 7th International Symposium on Multidisciplinary Studies and Innovative Technologies, Ankara, Turkey, Oct. 26, 2023.
  4. F. S. Oktem, “Yeni Nesil Görüntüleme Teknolojileri.” Talk given at METU Dept. of Electrical & Electronics Eng., Departmental Advertising Seminars for High School Students, Ankara, Turkey, Aug. 10, 2020.
  5. F. S. Oktem, “Computational Imaging and Inverse Problems: Making the Invisible Visible.” Talk given at İzmir Biomedicine and Genome Center, IBG External Seminars, İzmir, Turkey, Nov. 22, 2019.
  6. F. S. Oktem, “Computational Imaging and Inverse Problems: Making the Invisible Visible.” Invited talk given at the 21th National Optics, Electro-Optics, and Photonics Workshop, Istanbul, Turkey, Sept. 6, 2019.
  7. F. S. Oktem, “Computational Imaging and Inverse Problems: Making the Invisible Visible.” Talk given at Bilkent University, EEE 591/592 Seminar Series, Ankara, Turkey, Apr. 4, 2018.
  8. F. S. Oktem, “Computational Spectral Imaging Techniques for High-Resolution and Instantaneous Observations of the Solar Corona.” Talk given at the NASA Goddard Space Flight Center, Heliophysics Science Seminars, Greenbelt, USA, Dec. 9, 2014.
  9. F. S. Oktem, “Inverse Problems in Computational Imaging with Applications to Spectral Imaging.” Talk given at Koc University, Engineering Seminar Series, Istanbul, Turkey, Jun. 10, 2014.
  10. F. S. Oktem, “Inverse Problems in Computational Imaging with Applications to Spectral Imaging.” Talk given at the Middle East Technical University, Ankara, Turkey, Jun. 2, 2014.
  11. F. S. Oktem, “Multi-order slitless solar spectroscopy.” Talk given at the University of Illinois at Urbana-Champaign, Remote Sensing \& Space Science Seminars, Urbana, IL, USA, Oct. 29, 2012.
  12. F. S. Oktem, “Schulz-Snyder Phase Retrieval Algorithm as an Alternating Minimization Algorithm and an Approach towards Global Solutions.” Talk given at the University of Illinois at Urbana-Champaign, DSP Seminars, Urbana, IL, USA, Apr. 13, 2011.
  13. F. S. Oktem, “A Unified View of Schulz-Snyder Phase Retrieval Algorithm.” Talk given at the University of Wisconsin at Madison, DSP Seminars, Madison, WI, USA, Dec. 15, 2010.
  14. F. S. Oktem, “The Fractional Fourier Transform and its Applications in Signal Processing and Optics.” Talk given at the Univ. of Illinois at Urbana-Champaign, DSP Seminars, Urbana, IL, USA, Feb. 17, 2010.